CH10 DISEASES AND DISORDERS

The Healthy Heart

(a) The heart muscle is nourished by blood from the coronary arteries, which arise from the aorta. (b) The cross section shows the four chambers and the myocardium, the muscle that does the heart's work. The pericardium is the outer covering of the heart.

Metabolic syndrome

, once called Syndrome X, or insulin-resistance syndrome, is not a disease but a cluster of disorders of the body's metabolism—including high blood pressure, high insulin levels, abdominal obesity, and abnormal cholesterol levels—that make a person more likely to develop diabetes, heart disease, or stroke. Each of these conditions is by itself a risk factor for other diseases. In combination, they dramatically boost the chances of potentially life-threatening illnesses.

Several factors—some of which you can control—increase your risk for prediabetes and diabetes.

- Being overweight or obese is the strongest predictor of undiagnosed type 2 diabetes. - Age 60 or older. - Physically inactive. - Parent or sibling with diabetes. - Family background that is African American, Alaska - Native, American Indian, Asian American, Hispanic/Latino, or Pacific Islander. Asian Americans start developing diabetes at lower weights. The reason may be that Asian Americans tend to deposit "visceral" fat around their internal organs, which increases the risk of insulin resistance, a precursor to type 2 diabetes. The American Diabetes Association recommends that Asian Americans with a body mass index (BMI) of 23 or higher, rather than the 25 used for other races, undergo screening for type 2 diabetes. - Sitting—the more time that individuals spend on a chair or sofa, the greater their odds of developing high blood sugar. - Exercising fewer than three times a week. - Giving birth to a baby weighing more than 9 pounds or being diagnosed with diabetes during pregnancy. - High blood pressure—140/90 mmHg or above—or being treated for high blood pressure. - HDL, or "good," cholesterol level below 35 mg/dL or a triglyceride level above 250 mg/dL. - Impaired fasting glucose (IFG) or impaired glucose tolerance (IGT) on previous testing. - Other conditions associated with insulin resistance, such as severe obesity. - History of cardiovascular disease. - Sugary drinks—even a single can of sugary soda a day can increase the risk of prediabetes and diabetes. - Certain common medications, including antibiotics such as penicillin and cholesterol-lowering statin drugs, may increase the risk of type 2 diabetes.

RISK FACTORS YOU CAN NOT CONTROL!!

- Family History - Race and Ethnicity - Socioeconomic Status - Age - Height

The choices you make and the habits you follow can have a significant impact on whether you remain healthy. For the sake of your cardiometabolic health, avoid the following potential risks. RISK FACTORS YOU CAN CONTROL!!

- Overweight/Obesity - Body Fat - Waist Circumference - Physical Inactivity - Too Much Sitting, Not Enough Sleep - Healthy Diet - Tobacco Use - High Blood Glucose - High Blood Pressure (Hypertension) - Lipoprotein Levels

How the Heart Works The heart is a hollow, muscular organ with four chambers that serve as two pumps (Figure 10.4). Its key characteristics include:

A human heart is about the size of a clenched fist. Each pump consists of a pair of chambers formed of muscles. The upper two—each called an atrium—receive blood, which then flows through valves into the lower two chambers, the ventricles, which contract to pump blood out into the arteries through a second set of valves. A thick wall divides the right side of the heart from the left side; even though the two sides are separated, they contract at almost the same time. Contraction of the ventricles is called systole; the period of relaxation between contractions is called diastole. The heart valves, located at the entrance and exit of the ventricular chambers, have flaps that open and close to allow blood to flow through the chambers of the heart. The myocardium (heart muscle) consists of branching fibers that enable the heart to contract, or beat, between 60 and 80 times per minute, or about 100,000 times a day. With each beat, the heart pumps about 2 ounces of blood. This may not sound like much, but it adds up to nearly 5 quarts of blood pumped by the heart in 1 minute, or about 75 gallons per hour. The heart is surrounded by the pericardium, which consists of two layers of a tough membrane. The space between the two contains a lubricating fluid that allows the heart muscle to move freely. The endocardium is a smooth membrane lining the inside of the heart and its valves. Blood circulates through the body by means of the pumping action of the heart, as shown in Figure 10.5. The right ventricle (on your own right side) pumps blood, via the pulmonary arteries, to the lungs, where it picks up oxygen (a gas essential to the body's cells) and gives off carbon dioxide (a waste product of metabolism). The blood returns from the lungs via the pulmonary veins to the left side of the heart, which pumps it, via the aorta, to the arteries in the rest of the body. The arteries divide into smaller and smaller branches and finally into capillaries, the smallest blood vessels of all (only slightly larger in diameter than a single red blood cell). The blood within the capillaries supplies oxygen and nutrients to the cells of the tissues and takes up various waste products. Blood returns to the heart via the veins: The blood from the upper body (except the lungs) drains into the heart through the superior vena cava, while blood from the lower body returns via the inferior vena cava.

Unlike many other medical conditions, patients must take charge of their diabetes and monitor their blood glucose regularly to prevent or delay the serious complications of the disease. Diabetes educators teach patients a new set of ABCs:

A is for the A1c test. This test measures the amount of glucose attached to hemoglobin molecules, the iron-rich molecules in red blood cells that deliver oxygen to the body. The higher your blood glucose levels, the more hemoglobin molecules you will have with glucose attached—and the greater the risk of damage to eyes, kidneys, and feet. In general, the life cycle of a red blood cell is 75 to 90 days, which is why the A1c test shows average blood glucose levels for the past 2 to 3 months. The American Diabetes Association recommends a goal for A1c of less than 7 percent. The American College of Endocrinology recommends a goal of 6.5 percent. (Normal A1c levels are below 6.) Individuals with diabetes should have their A1c levels checked at least twice a year. B is for blood pressure. High blood pressure can cause heart attack, stroke, and kidney disease. C is for cholesterol. The LDL goal for most people is less than 160 mg/dL (see Table 10.2). Bad cholesterol, or LDL, can build up and clog your blood vessels. [Regular exercise and healthy eating are critical to diabetes management. In its most recent recommendations, the American Diabetes Associations advises individuals with diabetes to engage in mild to moderate physical activity—such as walking, standing in place, torso twists, and lunges—for 3 minutes at 30-minute intervals.]

Three or more of the following characteristics indicate metabolic syndrome:

A larger-than-normal waist measurement: 40 inches or more in men and 35 inches or more in women (for Asians and individuals with a genetic predisposition to diabetes, 37 to 39 inches in men and 31 to 35 inches in women). A higher-than-normal triglyceride level: 150 mg/dL or more. A lower-than-normal high-density lipoprotein (HDL) level: Less than 40 mg/dL in men or 50 mg/dL in women. A higher-than-normal blood pressure: 130 mmHg systole over 85 mmHg diastole (130/85) or higher. A higher-than-normal fasting blood sugar: 110 mg/dL or higher.

Waist Circumference

A measurement of more than 40 inches in men and more than 35 inches in women indicates increased health risks. A "pot belly" raises risk even when a person's weight is normal. Rather than waist circumference alone, the ratio of waist to height may be a more precise indicator of risk (see Chapter 5). Among college students, the ratio of muscle mass to visceral fat is a significant predictor of metabolic syndrome. The lower an individual's muscle mass and physical fitness, the greater the risk.

Is It a Heart Attack? If they experience the following symptoms, individuals should seek immediate medical care and take an aspirin (325 mg) to keep the blood clot in a coronary artery from getting any bigger:

A tight ache; heavy, squeezing pain; or discomfort in the center of the chest, which may last for 30 minutes or more and is not relieved by rest. Chest pain that radiates to the shoulder, arm, neck, back, or jaw. Anxiety. Sweating or cold, clammy skin. Nausea and vomiting. Shortness of breath. Dizziness, fainting, or loss of consciousness. Women often experience heart attacks differently than men. In the month before an attack, many report unusual fatigue and disturbed sleep. Far fewer women than men experience chest pain. More common symptoms are shortness of breath, weakness and fatigue, a clammy sweat, dizziness, and nausea.

Lowering Cholesterol

According to federal guidelines, about one in five Americans may require treatment to lower his or her cholesterol level. However, nearly half of people who need cholesterol treatment, which can reduce the risk of heart disease by 30 percent over 5 years, don't get it. Depending on your lipoprotein profile and an assessment of other risk factors, your physician may recommend that you take steps to lower your LDL cholesterol.

Cancer Heredity

An estimated 13 million to 14 million Americans may be at risk of a hereditary cancer. In hereditary cancers, such as retinoblastoma (an eye cancer that strikes young children) or certain colon cancers, a specific cancer-causing gene is passed down from generation to generation. The odds of any child with one affected parent inheriting this gene and developing the cancer are 50-50. Other people are born with genes that make them susceptible to having certain cells grow and divide uncontrollably, which may contribute to cancer development. The most well known are mutations of the BRCA gene, linked with increased risk of breast, colon, and ovarian cancer. Genetic tests can identify some individuals who are born with an increased susceptibility to cancer. Spotting a mutated gene in an individual may alert doctors to increase screening and possibly detect cancer years earlier than they otherwise would have. The most likely sites for inherited cancers to develop are the breast, brain, blood, muscles, bones, and adrenal glands. A growing number of women who develop breast cancer before age 40 are being tested for the BRCA gene mutations that substantially raise the risks of breast and ovarian tumors.

HEART DISEASE-Anger and Hostility

Anger and hostility have both short- and long-term consequences for the heart, particularly for men. In general, the angriest men are three times more likely to develop heart disease than the most placid ones. Hostility more than doubles the risk of recurrent heart attacks in men (but not women). Research has linked hostility to increased cardiac risk factors, to decreased survival in men with coronary artery disease below the age of 61, to an increased risk of heart attack in men with metabolic syndrome, and to an increased risk of abnormal heart rhythms. The risk of a heart attack or other cardiovascular "event" is highest in the 2 hours following an angry outburst. The more frequent the outbursts, the greater the danger to heart health. Angry young men may be putting their future heart health in jeopardy. In longitudinal studies the angriest young men were more likely to suffer heart attacks by age 55 and, more significantly, to develop any form of cardiovascular disease. Hostility in men of any age can increase their risk of heart attacks and heart disease. How does hostility harm the heart? Anger triggers a surge in stress hormones that can provoke abnormal and potentially lethal heart rhythms and activates platelets, the tiny blood cells that trigger blood clotting. High levels of anger can also trigger a spasm in a coronary artery, which results in the additional narrowing of a partially blocked blood vessel. In women, anger and hostility do not always lead to heart troubles. However, women who outwardly express anger may be at increased risk if they also have other risk factors for heart disease, such as diabetes or unhealthy levels of lipoproteins.

Body Fat

Apple-shaped people who carry most of their excess weight around their waists are at greater risk of cardiometabolic conditions than are pear-shaped individuals who carry most of their excess weight below their waist. The more visceral (abdominal) fat that you have, the more resistant your body's cells become to the effects of your own insulin. However, as newer research suggests, fat alone, regardless of where it is stored, boosts the likelihood of heart attack or stroke. Subcutaneous fat (located under the skin) as well as visceral fat can pose dangers to cardiometabolic health.

Physical Inactivity

As discussed in Chapter 6, about one-quarter of U.S. adults are sedentary and another third are not active enough to reach a healthy level of fitness. Among young people, physical activity—or inactivity—is the most influential factor in cardiometabolic health. One significant culprit: smartphones. In a study of adults between the ages of 18 and 89, cell phone use (an average of 239 minutes a day) contributed to sedentary behavior and physical inactivity. Simply replacing sedentary time with physical activity, whether light, moderate, or vigorous, has been shown to improve cardiometabolic health 10 years later. The greater the exercise "dose," the more benefits it yields. In studies that compare individuals of different fitness levels, the least fit are at much greater risk of dying than the fittest. In men, more rigorous exercise, such as jogging, produces greater protection against heart disease and boosts longevity. High-intensity interval training improves metabolic control and provides significant cardiovascular benefits.

Healthy Diet

As research has consistently confirmed, closely following the Mediterranean diet—high in fresh fruits and vegetables, whole grains, beans, nuts, fish, and olive oil—can reduce the risk of heart disease by almost half. Additional benefits include weight loss, lower blood pressure and cholesterol levels, and a lower risk of diabetes. Even a single meal can trigger metabolic changes that lower the risk of cardiometabolic diseases . "Problematic" eating behaviors and attitudes, such as binge-eating, among young adults (ages 27-41) increase the risk of metabolic syndrome and diabetes. According to the most recent research, vitamin D supplements do not prevent or lower the risk of cardiovascular disease or cancer. Fish oil supplements also do not protect against these diseases.

Diabetes Management

Before the development of insulin injections, diabetes was a fatal illness. Today, diabetics can have normal lifespans. However, uncontrolled glucose levels slowly damage blood vessels throughout the body. Diabetes is the number one cause of blindness, nontraumatic amputations, and kidney failure, and diabetes increases by two or three times the risk of heart attack or stroke.

Racial and Ethnic Groups Although cancer death rates have fallen in the United States, they vary in different racial and ethnic groups:

Biological, racial, and ethnic differences can affect whether a cancer is aggressive and will spread beyond its initial site. In breast cancer, for instance, black women had a higher risk of dying compared with white women, even when both were diagnosed with small tumors. African Americans have the highest rates of fatal cancers. Black women have the highest incidence of colorectal and lung cancers of any ethnic group, while black men have the highest rates of prostate, colorectal, and lung cancers. African Americans also have higher rates of incidence and deaths from other cancers, including those of the mouth, throat, esophagus, stomach, pancreas, and larynx. Cancer death rates have been declining annually since the 1990s for black men and women. Hispanics have a six times lower risk of developing melanoma than Caucasians yet tend to have a worse prognosis than Caucasians when they do develop this skin cancer. The incidence of female breast cancer is highest among white women and lowest among Native American women. Cervical cancer is most common in Hispanic women. Vietnamese men have much higher rates of liver cancer than whites, while Korean men and women are much more likely to develop stomach cancer. Compared with other Asian Americans, Chinese and Vietnamese women have higher rates of lung cancer. Asian Americans who have lived in the United States the longest are likely to develop the cancers that are most common here, such as breast and colon cancer, although at lower rates than whites

Race and Ethnicity Cardiometabolic risk factors occur at increased rates and increase mortality rates among ethnic minority populations such as African Americans, Hispanic Americans, and Native Americans. Here are some examples:

Blacks and Hispanics have double the rates of diabetes as whites. The incidence of diabetes is even higher among American Indians. Among the Pima Indians of Arizona, half of all adults have type 2 diabetes, one of the highest rates of diabetes in the world. Mexican Americans are likely to have heart-damaging risk factors such as high blood pressure and high blood sugar levels, even if they are not obese. Nearly 4 in every 10 black adults have cardiovascular disease. Among Hispanic Americans, nearly 3 in 10 have cardiovascular disease. African Americans are twice as likely to develop high blood pressure as whites and suffer strokes at an earlier age and of greater severity. Black women are twice as likely as white women to suffer heart attacks and to die from heart disease. They are also less likely to receive common medications, such as cholesterol-lowering drugs, to lower their risk.

The Path of Blood Flow

Blood is pumped from the right ventricle into the pulmonary arteries, which lead to the lungs, where gas exchange (oxygen for carbon dioxide) occurs. Oxygenated blood returning from the lungs drains into the left atrium and is then pumped into the left ventricle, which sends the blood into the aorta and its branches. The oxygenated blood flows through the arteries, which extend to all parts of the body. Again gas exchange occurs in the body tissues; this time oxygen is "dropped off" and carbon dioxide "picked up" [The workings of this remarkable pump affect your entire body. If the flow of blood to or through the heart or to the rest of the body is reduced, or if a disturbance occurs in the small bundle of highly specialized cells in the heart that generate electrical impulses to control heartbeats, the result may at first be too subtle to notice. However, without diagnosis and treatment, these changes could develop into a life-threatening problem.]

Who Is at Risk? According to the CDC, about 3 in 10 adults ages 18 or older in the United States—some 65 million men and women—have high blood pressure.

Blood pressure has increased among children and adolescents as well as adults, with the highest rates among African American and Mexican American children. The primary culprit is the increase in obesity in the young. Binge drinking, discussed in Chapter 16, can raise systolic blood pressure (the top number in a blood pressure reading) among young adults and increase their risk of hypertension later in life. An African American with the same elevated blood pressure reading as a Caucasian faces a greater likelihood of hospitalization and risk of stroke, heart disease, and kidney problems. Even small increases in blood pressure can be dangerous for black people. A rise of as little as 10 mmHg in systolic blood pressure in blacks raises the risk of dying and is even greater for black people under age 60. Family history increases the risk. If one or both of your parents have high blood pressure, have yours checked regularly. Men and women are equally likely to develop hypertension. Women who develop high blood pressure during pregnancy may face an increased risk of heart and kidney disease. Blood pressure also tends to rise around the time of menopause. People with chronic insomnia who take longer than 14 minutes to fall asleep may have a 300 percent higher risk of high blood pressure. The longer before sleep onset, the greater their risk. Lowering blood pressure is a key to preventing stroke,

Hypertension

Blood pressure refers to the force of blood against the walls of arteries. When blood pressure remains elevated over time—a condition called hypertension—the heart must pump harder than is healthy. Because the heart must force blood into arteries that are offering increased resistance to blood flow, the left side of the heart becomes enlarged. If untreated, high blood pressure can cause a variety of cardiovascular complications, including heart attack and stroke—as well as blindness and kidney disease (Figure 10.3). If left untreated, elevated blood pressure can damage blood vessels in several areas of the body and lead to serious health problems. The "silent killer" continues to live up to its nickname. Since 2000, the overall death rate from hypertension has increased 23 percent for both men and women, with the greatest spike in those ages 45 to 64. People living in low-income states are more likely to have high blood pressure than the residents of more affluent states. Globally blood pressure in less developed countries has increased significantly over the past four decades. Regulating blood pressure for all Americans could prevent 56,000 heart attacks and strokes and 13,000 deaths each year. However, 44 percent of adults with elevated blood pressure do not have it under control. Globally, treating half of people with uncontrolled high blood pressure could prevent 10 million heart attacks and strokes over 10 years.

Cancer of Obesity Long recognized as threats to cardiovascular health, overweight and obesity may play a role in an estimated 90,000 cancer deaths each year. The higher an individual's BMI, the greater the likelihood of dying of cancer. An unhealthy body weight increases the risk of many types of cancer, including non-Hodgkin's lymphoma, multiple myeloma, and cancers of the following:

Breast (in postmenopausal women). Colon and rectum. Kidney. Cervix. Ovary. Uterus. Esophagus. Gallbladder. Stomach (in men). liver Pancreas. Prostate. The degree to which extra pounds affect cancer risk varies by the site of the cancer. Obesity elevates the risk of esophageal cancer fivefold; increases the risk of breast or uterine cancer by two to four times; and boosts the risk for colon cancer by 35 to 50 percent.

Metastasis, or Spread of Cancer

Cancer cells can travel through the blood vessels to spread to other organs or through the lymphatic system to form secondary tumors.

Cancer

Cancer refers to a group of diseases characterized by the uncontrolled growth and spread of abnormal cells. Cancer is the second leading cause of death worldwide; 8.7 million die from the disease. The lifetime risk of developing cancer is one in three for men and one in four for women. In the United States, about 1.7 million new cancers are diagnosed every year and about 607,000 Americans die of cancer every year. The gap in cancer deaths among blacks and whites has narrowed for most cancers, but disparities remain.

Common Types of Cancer

Cancer refers to a group of more than a hundred diseases characterized by abnormal cell growth. Although all cancers have similar characteristics, each is distinct. Some cancers are relatively simple to cure, whereas others are more threatening and mysterious (see Table 10.3). The earlier any cancer is found, the easier it is to treat and the better the patient's chances of survival.

Who is at risk of cancer?

Cancer strikes individuals at all social, economic, and educational levels

Cancers are classified according to the type of cell and the organ in which they originate, such as the following:

Carcinoma, the most common kind, which starts in the epithelium, the layers of cells that cover the body's surface or line internal organs and glands. Sarcoma, which forms in the supporting, or connective, tissues of the body: bones, muscles, and blood vessels. Leukemia, which begins in the blood-forming tissues: bone marrow, lymph nodes, and the spleen. Lymphoma, which arises in the cells of the lymph system, the network that filters out impurities. Skin Cancer

Cardiac Arrest

Cardiac arrest occurs when the heart stops beating. If circulation is not restored within 4 or 5 minutes, the brain shuts down completely, and the person dies. Cardiopulmonary resuscitation (CPR) is an emergency procedure for a person whose heart has stopped or who is no longer breathing. CPR can maintain circulation and breathing until emergency medical help arrives. The combination of mouth-to-mouth "rescue" breathing and chest compressions performed by individuals trained in CPR is the most effective method. However, according to the most recent research, chest compressions or "hands-only" CPR, which does not require extensive training, can also keep blood circulating until emergency help arrives. Automated external defibrillators (AEDs), portable computerized devices, can actually restart a heart with a lethal rhythm (ventricular fibrillation) or that is not beating at all. The machines, widely available on airplanes and in public places like stadiums and terminals, can also be purchased by individuals. Written and voice instructions allow laypeople as well as trained professionals to use them in case of emergency. A combination of CPR and defibrillation boosts the survival rate much higher than from CPR alone.

Age

Cardiometabolic risk factors increase as people get older, especially past age 45. This may be because many individuals tend to exercise less, lose muscle mass, and gain weight as they age.

Family History

Certain cardiometabolic risk factors, such as abnormally high blood levels of lipids, can be passed down from generation to generation. Individuals with an inherited vulnerability can lower the danger by changing the risk factors within their control, such as body weight and fat. A child's risk of developing heart disease later in life depends on many factors, including family history, diet, and physical activity.

Tobacco Use

Chapter 13 provides compressive coverage of smoking's harmful effects, but here are some key facts to keep in mind: Each year smoking causes more than 250,000 deaths from cardiovascular disease—far more than it causes from cancer and lung disease. Smokers who have heart attacks are more likely to die from them than are nonsmokers. Smoking is the major risk factor for peripheral arterial disease, in which the vessels that carry blood to the leg and arm muscles become hardened and clogged. Both active and passive smoking accelerate the process by which arteries become clogged and increase the risk of heart attack and stroke.

Lipoprotein Levels

Cholesterol is a fatty substance found in certain foods and is also manufactured by the body. Figure 10.1 shows food sources of cholesterol. The measurement of cholesterol in the blood is one of the most reliable indicators of the formation of plaque, the sludgelike substance that builds up on the inner walls of arteries. You can lower blood cholesterol levels by cutting back on high-fat foods and exercising more, thereby reducing the risk of a heart attack.

Psychosocial Risk Factors Researchers classify psychological risk factors for heart disease into three categories:

Chronic factors, such as job strain or lack of social support, play an important role in the buildup of artery-clogging plaque and may increase blood pressure. Even feeling that life has treated you unfairly boosts your chance of having a heart attack. Episodic factors, such as depression, can last from several weeks to 2 years and may lead to the creation of "unstable" plaque, which is more likely to break off and block a blood vessel within the heart. Short-term, or acute, factors, such as an angry outburst, can directly trigger a heart attack in people with underlying heart disease. [These factors may act alone or combine and exert different effects at different ages and stages of life. They may influence behaviors such as smoking, diet, alcohol consumption, and physical activity, as well as directly cause changes in physiology.]

Too Much Sitting, Not Enough Sleep

Defined as being seated from 8 to 12 hours a day, prolonged sitting significantly increases the odds of heart disease, diabetes, cancer, and death, according to an analysis of about four dozen studies of the impact of inactivity. To prevent these problems, take a 3-minute break every 30 minutes to stand, lift, or extend your legs, stretch your arms overhead, twist your torso side to side, lunge to the back or side, or walk in place. The quantity and quality of your time in bed also matters. In a study of healthy young adults, ages 21 to 35, sleep disturbances—including getting less than 6 hours of total sleep time and waking for more than 60 minutes after sleep onset—increased the risk factors for metabolic syndrome.

HEART DISEASE-Depression

Depression and heart disease often occur together. People with heart disease are more likely than others to be depressed, and some seemingly healthy people with depression are at greater risk of heart problems. Depressed women younger than age 60 are more likely to suffer a heart attack than those who do not suffer from depression. The combination of stress, depression, and heart disease can be so deadly that researchers have dubbed the combination a "psychosocial perfect storm" that increases the risk of heart attack or death among men and women with heart disease.

Types of Diabetes

Diabetes includes several conditions in which the body has difficulty controlling levels of glucose in the bloodstream. After an overnight fast, most people have blood glucose levels between 70 and 100 mg/dL. This is considered normal. If your fasting blood glucose level is between 101 and 125 mg/dL, you have prediabetes. If your fasting blood glucose is consistently 126 mg/dL or higher, you have diabetes. There are three types of diabetes: type 1 diabetes, type 2 diabetes, and gestational diabetes.

Some individuals with elevated cholesterol can improve their lipoprotein profile with lifestyle changes:

Dietary changes. In the past, dietary changes produced relatively modest improvements compared to the effects of medications, which can cut cholesterol by as much as 35 percent. However, a diet consisting of cholesterol-lowering foods, including nuts, soy, oats, and plant sterols (in margarine and green leafy vegetables), reduced LDL cholesterol by about 30 percent. Researchers are recommending this diet as an effective first treatment for individuals with high cholesterol levels, particularly coupled with exercise and weight loss. Weight management. For individuals who are overweight, losing weight can help lower LDL. This is especially true for those with high triglyceride levels and/or low HDL levels and those who have a large waist measurement (more than 40 inches for a man and more than 35 inches for a woman). Physical activity. Regular activity can help lower LDL, lower blood pressure, reduce triglycerides, and, particularly important, raise HDL. Again, these benefits are especially important for those with high triglyceride levels or large waist measurements. [Lifestyle changes can lower harmful LDL levels by 5 to 10 percent. Alternative therapies, such as garlic, may have some limited benefit but remain unproven. A greater reduction of 30 to 40 percent requires either intensive lifestyle changes, including an extremely low-fat diet or the addition of cholesterol-lowering medication.]

Medications

Drugs called statins—best known by brand names such as Lipitor, Mevacor, Pravachol, and Zocor—can cut the risk of dying of a heart attack by as much as 40 percent. Initially tested in men, statins have proved equally beneficial for women, including those whose cholesterol levels rise after menopause. Statins work in the liver to block production of cholesterol. When the liver can't make cholesterol, it draws LDL cholesterol from the blood to use as raw material. This means that less LDL is available to trigger or promote the artery-clogging process known as atherosclerosis. Statins also appear to stabilize cholesterol-filled deposits in artery walls and to cool down inflammation. The combination of statins with moderate exercise, such as 30 minutes a day of brisk walking, has the most dramatic effect on cholesterol levels and reduced risk of dying. Statins also protect patients who have not had a heart attack but are at high risk for developing cardiovascular disease because of high cholesterol or other risk factors. Large-scale studies indicate that statins protect against heart attacks and strokes even in older adults without known cardiovascular disease or diabetes and with low cholesterol—if these patients also have high levels of CRP or C-reactive protein.

The Heart of a Woman Many people still think of heart disease as a "guy problem." Men do have a higher incidence of cardiovascular problems than women before age 45, but young women who have heart attacks are more likely to die as a result.

Every year 35,000 women under age 65 experience a heart attack. More than 15,000 women younger than age 55 die from heart disease in the United States each year. High blood pressure is a stronger risk factor for women than for men. Diabetes raises a young woman's heart disease risk up to five times higher compared to young men. Black women of any age have a higher incidence of heart attack than white women; and black and Hispanic women have more risk factors such as obesity, diabetes, and high blood pressure at the time of heart attack compared to white women.

Diabetes

Glucose is the primary form of sugar that body cells use for energy. When a person without diabetes eats a meal, the level of glucose in the blood rises, triggering the production and release of insulin by special cell clusters in the pancreas. Insulin enhances the movement of glucose into various body cells, bringing down the level of glucose in the blood. In those who have diabetes, however, insulin secretion is either nonexistent or deficient. Without sufficient insulin, the glucose in the blood is unable to enter most body cells, so the energy needs of the cells aren't met. The levels of glucose in the blood rise higher and higher after each meal. This unused glucose eventually passes through the kidneys, which are unable to process the excessive glucose, and out of the body in urine. Deprived of the fuel it needs, the body begins to break down stored fat as a source of energy. This process produces weak acids, called ketones. A buildup of ketones leads to ketoacidosis, an upheaval in the body's chemical balance that brings on nausea, vomiting, abdominal pain, lethargy, and drowsiness. Severe ketoacidosis can lead to coma and, eventually, death (see Figure 10.2).

Here are some crucial facts:

Heart disease is the third leading cause of death among adults ages 25 to 44. Diabetes, family history, and other risk factors increase the likelihood of heart disease. It's never too soon to start protecting your heart. High aerobic fitness in the college-age years has been linked with a lower risk of heart attack later in life. Among the behaviors that put students' hearts at risk is binge drinking, which may hinder the function of the blood vessels and increase the likelihood of stroke, sudden cardiac death, and heart attack. Young athletes face special risks. Each year, seemingly healthy teens or young adults die suddenly on playing fields and courts. The culprit in one of every three cases of sudden cardiac death in young athletes is a silent condition called hypertrophic cardiomyopathy (HCM), an excessive thickness of the heart muscle. Because of HCM, the heart is more prone to dangerous heart irregularities. Some medical groups have recommended routine electrocardiograms to reduce risk of sudden cardiac death in competitive collegiate sports; others believe that a simpler physical exam-based screening is sufficient.

Cardiovascular (Heart) Disease

Heart disease, stroke, and other cardiovascular diseases cause about one of every three deaths in the United States, killing about 787,000 Americans annually. Globally, cardiovascular disease is the leading cause of death, claiming more lives than all cancers combined. An American dies of a heart-related disease every 40 seconds. Fewer than 20 percent of adults meet at least five of the following American Heart Association criteria for ideal heart health: Never smoked or quit more than a year ago Body mass index (BMI) less than 25 Physical exercise—at least 150 minutes of moderate intensity or 75 minutes of vigorous intensity a week At least four components of a healthful diet, such as fewer calories and more fruits and vegetables (see Chapter 4) Total cholesterol lower than 200 mg/dL Blood pressure below 120/80 mmHg Fasting blood sugar below 100 mg/dL

HEART DISEASE- STRESS

How you respond to stress (discussed in Chapter 3) can affect your heart as well as your overall health. Even stressed teenagers may be at risk. In a longitudinal analysis that followed teens into middle age, those who scored high in stress early in life were more likely to develop atherosclerosis by their mid-40s. Although you may not be able to control the sources of stress, you can change how you habitually respond to it.

Infectious Agents. An estimated 12 percent of cancers in the United States can be attributed to infection, including the following:

Human papillomavirus (HPV) with cancer of the cervix, mouth and throat, vulva, and anus. Helicobacter pylori with stomach cancer. Epstein-Barr virus (EBV), a herpesvirus, transmitted primarily through saliva infecting more than 90 percent of adults worldwide. Although most people infected with EBV remain healthy, EBV can lead to certain types of lymphomas and stomach cancers as well as nasopharyngeal cancer. Human immunodeficiency virus (HIV) with certain lymphomas and leukemias and a type of cancer called Kaposi's sarcoma. [Generally, the presence of a bacterium or a virus per se is not enough to cause cancer. A predisposing environment and other cofactors—most still unknown—are needed for cancer development and growth.]

Do you know your lifetime risk of developing cancer?

If you're male: slightly less than one in two. If you're female: a little more than one in three.

Insulin Resistance

In a healthy body, the digestive system breaks down food into glucose, which then travels in the bloodstream to cells throughout the body. As blood glucose rises after a meal, the pancreas releases insulin to help cells take in the glucose. As noted earlier, insulin resistance is a condition in which the body produces insulin but does not use it properly. When muscle, fat, and liver cells do not respond properly to insulin, the pancreas tries to keep up with the increased demand for insulin by producing more, but eventually it cannot. Excess glucose builds up in the bloodstream, setting the stage for diabetes. Many people with insulin resistance have high levels of both glucose and insulin circulating in their blood at the same time. Excess weight, particularly in men, and lack of physical activity, along with genetic factors, contribute to insulin resistance.

Hypertension in the Young

In a young person, even mild hypertension can cause organs such as the heart, brain, and kidneys to start to deteriorate. High blood pressure can damage the structure of the brain in people as young as age 40. In individuals at genetic risk, high blood pressure may spur development of the brain plaques characteristic of Alzheimer's disease. Especially when combined with obesity, smoking, high cholesterol levels, or diabetes, hypertension greatly increases the risks of cardiovascular problems. Young adults in their 20s with even mildly elevated blood pressure may face an increased risk of clogged arteries by middle age, according to a 25-year study of nearly 4,700 people. Among college students, binge drinking has been linked with an increased short- and long-term risk of hypertension. For young adults, high systolic blood pressure—the top number in a reading—may herald increased risk for heart disease. A systolic reading of 120 mmHg or higher may signal a significantly greater risk of dying from heart disease over time, particularly for women.

Monitoring Your Blood Pressure

In healthy adults, blood pressure screening should begin at age 21, with repeat evaluations at least every 2 years, or more often, depending on a person's current health, medical history, and risk factors for cardiovascular disease. According to the National College Health Assessment survey, 3.2 percent of undergraduates have been diagnosed or treated for high blood pressure.

Type 1 Diabetes

In this form of diabetes (once called juvenile-onset or insulin-dependent diabetes), the body's immune system attacks the insulin-producing beta cells in the pancreas and destroys them. The pancreas then produces little or no insulin, and therefore blood glucose cannot enter the cells to be used for energy. Type 1 diabetes develops most often in young people but can appear in adults. People with type 1 diabetes lose an average of 11 years for men and 13 years for women to the chronic disease, compared to those without diabetes. The largest single cause of lost years is the impact diabetes has on the heart. However, type 1 diabetics under age 50 also die because of conditions related to management of their disease, such as a diabetic coma triggered by low blood sugar. Women with type 1 diabetes have a nearly 40 percent greater risk of dying from any cause and more than double the risk of dying from heart disease than men with type 1 diabetes. The reason may be that high levels of blood sugar may cause more damage to women's blood vessels than to men's. Individuals with type 1 diabetes require insulin therapy because their own bodies no longer supply this vital hormone. As long-term follow-up studies have shown, people with type 1 diabetes who intensively control their blood glucose early in their disease are likely to live longer than those who do not.

Diabetes Mellitus

In those with diabetes mellitus, the pancreas, which produces insulin (the hormone that regulates carbohydrate and fat metabolism), doesn't function as it should. When the pancreas either stops producing insulin or doesn't produce sufficient insulin to meet the body's needs, almost every body system can be damaged (see Figure 10.2). Diabetes mellitus, the seventh-leading cause of death in the United States, can shorten life expectancy by a decade or more. The risk of premature death among people with diabetes is about twice that of people without the disease. Obesity, diabetes, and heart disease can also work together to speed dementia and other brain disorders, such as cognitive impairment.

Type 2 Diabetes

In type 2 diabetes (once called adult-onset or non-insulin-dependent diabetes), either the pancreas does not make enough insulin or the body is unable to use insulin correctly. Type 2 diabetes, which affects 90 to 95 percent of diabetics, is becoming more common in children and teenagers because of the increase in obesity in the young. Although type 1 and type 2 diabetes have different causes, two factors are important in both: an inherited predisposition to the disease and something in the environment that triggers diabetes. Genes alone are not enough. In most cases of type 1 diabetes, people need to inherit risk factors from both parents and to experience some environmental trigger, which might involve prenatal nutrition, a virus, or an unknown agent. In type 2 diabetes, family history is one of the strongest risk factors for getting the disease, but only in Westernized countries. African Americans, Mexican Americans, and Native Americans have the highest rates, but people who live in less developed nations tend not to get type 2 diabetes, no matter how high their genetic risk. Excess weight, especially around the waistline, is the major and most controllable risk factor for type 2 diabetes. Losing weight greatly reduces this risk and, in individuals with the disease, can help get blood sugar under control.

Diabetes Signs and Symptoms About one-third of individuals with type 2 diabetes do not realize they have the illness. If you have risk factors for the disease, watch for the following warning signs:

Increased thirst and frequent urination. Excess glucose circulating in your body draws water from your tissues, making you feel dehydrated. Drinking water and other beverages to quench thirst leads to more frequent urination. Flulike symptoms. Type 2 diabetes can sometimes feel like a viral illness, with such symptoms as extreme fatigue and weakness. When glucose, your body's main fuel, doesn't reach cells, you may feel tired and weak. Weight loss or weight gain. Because your body is trying to compensate for lost fluids and glucose, you may eat more than usual and gain weight, or the opposite may occur. Although eating more than normal, you may lose weight because your muscle tissues don't get enough glucose to generate growth and energy. Blurred vision. High levels of blood glucose pull fluid from body tissues, including the lenses of the eyes, which affects ability to focus. Vision should improve with treatment of diabetes. Slow-healing sores or frequent infections. Diabetes affects the body's ability to heal and fight infection. Bladder and vaginal infections can be a particular problem for women. Nerve damage (neuropathy). Excess blood glucose can damage the small blood vessels to your nerves, leading to symptoms such as tingling and loss of sensation in hands and feet. Red, swollen, tender gums. Diabetes increases the risk of infection in your gums and in the bones that hold your teeth in place.

There are two types of strokes:

Ischemic stroke results from a blockage that disrupts blood flow to the brain. One of the most common causes is the blockage of a brain artery by a thrombus, or blood clot—a cerebral thrombosis. Clots generally form around deposits sticking out from the arterial wall. Sometimes a wandering blood clot (embolus), carried in the bloodstream, becomes wedged in one of the cerebral arteries. This is called a cerebral embolism, and it can completely plug up a cerebral artery. Hemorrhagic stroke occurs when a diseased artery in the brain floods the surrounding tissue with blood. The cells nourished by the artery are deprived of blood and can't function, and the blood from the artery forms a clot that may interfere with brain function. This is most likely to occur if the patient suffers from a combination of hypertension and atherosclerosis. Hemorrhage (bleeding) may also be caused by a head injury or by the bursting of an aneurysm, a blood-filled pouch that balloons out from a weak spot in the wall of an artery. [For patients who suffer a thrombotic stroke, thrombolytic drugs such as tissue-type plasminogen activator (tPa) can restore brain blood flow and save blood cells. Other medications called heparinoids can reduce the blood's tendency to clot. For thrombolytic drugs to be effective, they must be administered within 3 hours after the stroke; heparinoids must be given within 24 hours. People who get to a hospital within an hour of having the first symptoms of a stroke are twice as likely to receive tPa. However, more than one-third of people having a stroke do not call 911, and an equally large percentage live more than an hour away from a stroke center.]

High Blood Pressure (Hypertension) (pt1) Blood pressure is a result of the contractions of the heart muscle, which pumps blood through your body, and the resistance of the walls of the vessels through which the blood flows. Each time your heart beats, your blood pressure goes up and down within a certain range:

It is highest when the heart contracts; this is called systolic blood pressure. It is lowest between contractions; this is called diastolic blood pressure. A blood pressure reading consists of the systolic measurement "over" the diastolic measurement, recorded in millimeters of mercury (mmHg). High blood pressure, or hypertension, occurs when the artery walls become constricted so that the force exerted as the blood flows through them is greater than it should be. Physicians see blood pressure as a continuum: The higher the reading, the greater the risk of stroke and heart disease. In studies of young adults ages 18 to 40, elevated blood pressure predicted hypertension and other metabolic abnormalities later in life.

How Atherosclerosis Happens

LDL cholesterol penetrates an artery wall, and the accumulation of LDL cholesterol triggers an inflammation. Macrophages engulf the LDL and become foam cells. The artery wall creates a fibrous cap over this plaque, and the artery is narrowed. If the plaque ruptures, blood clots can block flow to the heart or to the brain.

Lowering High Blood Pressure

Lifestyle changes are a first-line weapon in the fight against high blood pressure. Rather than make a single change, a combination of behavioral changes, including losing weight, eating heart-healthy foods, reducing sodium, and exercising more, yields the best results.

Lipoproteins

Lipoproteins are compounds in the blood that are made up of proteins and fat. The different types are classified by their size or density. The heaviest are high-density lipoproteins, or HDLs, which have the highest proportion of protein. These "good guys," as some cardiologists refer to them, pick up excess cholesterol in the blood and carry it back to the liver for removal from the body. An HDL level of 40 mg/dL or lower substantially increases the risk of heart disease. (Cholesterol levels are measured in milligrams of cholesterol per deciliter of blood [mg/dL].) The average HDL for men is about 45 mg/dL; for women, it is about 55 mg/dL. Low-density lipoproteins (LDLs), and very low-density lipoproteins (VLDLs) carry more cholesterol than HDLs and deposit it on the walls of arteries—they're the "bad guys." The higher your LDL cholesterol, the greater your risk for heart disease. If you are at high risk of heart disease, any level of LDL higher than 100 mg/dL may increase your danger.

Medications for high blood pressure (hypertension)

Making healthy lifestyle modifications can help reduce Stage 1 hypertension, but most people also require a medication. Drugs for lowering blood pressure come in a range of regimens (once a day to several times a day) with a range of effects on other conditions, interactions with other drugs, and potential side effects. They have been shown to lower the risk of stroke and add years to life expectancy. Treatment with a combination of medications may lead to a faster reduction in blood pressure and earlier protection for individuals at high cardiovascular risk.

Heart Risks on Campus

Many people, including college students and other young adults, are unaware of habits and conditions that put their hearts at risk. Many undergraduates view heart disease as mainly a problem for white men and underestimate the risks for women and ethnic groups. Students rate their own knowledge of heart disease as lower than that of sexually transmitted infections and psychological disorders.

Reducing Sodium

Medical scientists continue to debate the risks of sodium consumption. Low sodium intake (less than 3 grams a day) has been linked with cardiovascular problems and greater risk of dying regardless of an individual's blood pressure. High sodium intake (of 71 grams daily) increases the risks—but only for those with hypertension. Talk with your health-care providers about how much sodium may be too much for you.

What Your Blood Pressure Reading Means Based on the most recent federal guidelines, nearly half of Americans (46 percent) have high blood pressure. The blood pressure categories in the guidelines are:

Normal: Less than 120/80 mmHg. Elevated: Systolic between 120 and 129 and diastolic less than 80. Stage 1: Systolic between 130 and 139 or diastolic between 80 and 89. Stage 2: Systolic at least 140 or diastolic at least 90 mmHg. Hypertensive crisis: Systolic over 180 and/or diastolic over 120, with patients needing prompt changes in medication if there are no other indications of problems or immediate hospitalization if there are signs of organ damage. [Unlike previous recommendations, the new guidelines do not differentiate on the basis of age. Medications are recommended to lower blood pressure in stage 1 hypertension only if individuals have already had a heart attack or stroke. For others with stage 1 hypertension, lifestyle changes alone are recommended.]

Skin Cancer

One of every five Americans can expect to develop skin cancer in his or her lifetime. Once scientists thought exposure to the B range of ultraviolet light (UVB), the wavelength of light responsible for sunburn, posed the greatest danger. However, longer-wavelength UVA, which penetrates deeper into the skin, also plays a major role in skin cancers. UV light can damage DNA in melanocytes, cells in the skin that make the substance called melanin, which gives skin its color. Damage to melanocytes can continue long after UV exposure, even in the dark. Exposure to tanning salons and sunlamps also increase the risk of skin cancer because they produce UV radiation. A 30-minute dose of radiation from a sunlamp can be equivalent to the amount you'd get from an entire day in the sun. Often skin damage is invisible to the naked eye but shows up under special diagnostic lights. According to a recent analysis of data on more than 400,000 people, more than one-third of all Americans—and nearly 6 of 10 U.S. university students—have used indoor tanning. Even when they perceive the seriousness of skin cancer, college students—particularly women—describe suntanned skin as attractive, healthy, and athletic looking and view the benefits of getting a suntan as outweighing the risks of skin cancer or premature aging. (See Consumer Alert.) However, a CDC report concluded that indoor tanning is "simply not safe" and causes sunburn, infection, eye damage, and increased risk of skin cancer.

HEART DISEASE-The Power of Positive Emotions

Our psychological and social health affects not just our minds but our bodies, including the heart. While problems such as depression and stress may increase cardiovascular risk, happiness may help keep our hearts healthy. In a study that followed men and women for 10 years, those who showed more "positive" emotions—such as enthusiasm, joy, and contentment—were less likely to develop heart disease than less happy individuals. The happier people were, the lower their risk of heart disease became. An optimistic outlook may also boost heart health. When socioeconomic factors such as education and income are taken into account, optimistic people are more likely to be in ideal cardiovascular health, with lower blood sugar, cholesterol, blood pressure, and BMIs, compared with pessimists. A sense of purpose affects your heart as well as your mindset. Individuals who feel motivated by a sense of meaning and direction in life and view life as worth living are at lower risk of cardiovascular disease, stroke, and death from any cause.

Socioeconomic Status

Poverty in childhood and young adulthood can contribute to increased cardiometabolic risk, in part because families with low incomes are less likely to receive medical treatments or undergo corrective surgery.

Detecting Diabetes- To identify individuals with this disease as early as possible, the American Diabetes Association recommends screening every 3 years for all men and women beginning at age 45. The American College of Endocrinology recommends screening at age 30 for individuals at risk, including those who are overweight, are sedentary, have a family history of diabetes, or have high blood pressure or heart disease. Tests that can detect diabetes include:

Random blood sugar test. Because you don't necessarily fast for this test, your blood glucose may be high because you've just eaten. Even so, it shouldn't be higher than 200 mg/dL. Fasting blood glucose test. In general, glucose is lowest after an overnight fast. That's why the preferred way to test your blood sugar is after your blood sugar is after you've fasted overnight or for at least 8 hours. Glucose challenge test. Often used to screen pregnant women for gestational diabetes, this test measures glucose before drinking 8 ounces of an extremely sweet liquid after fasting for 6 hours, then every hour for a 3-hour period. If your blood sugar rises more than expected and doesn't return to normal by the third hour, you likely have diabetes.

Exercise

Regular exercise, both aerobic workouts and resistance training, can lower blood pressure. Walking has proven as beneficial as running in lowering blood pressure and other cardiovascular risk factors. See Your Strategies for Change for ways to lower your blood pressure.

Who Is at Risk? Risk factors for stroke, like those for heart disease, include some that cannot be changed (such as gender, race, and age) and some that can be modified:

Sex. Up to age 85, men have a greater risk of stroke than women. However, women are at increased risk at times of marked hormonal changes, particularly pregnancy and childbirth. Although older oral contraceptives had been linked with stroke, particularly in women over age 35 who smoke, the newer low-dose oral contraceptives have not shown an increased stroke risk among women ages 18 to 44. Early menopause (before age 42) may double a woman's stroke risk. Race. The incidence of strokes is two to three times greater in blacks than in whites in the same communities. Hispanics are also more likely to develop hemorrhagic strokes than whites. Age. A person's risk of stroke more than doubles every decade after age 55. Obesity. The more overweight individuals are, the more likely they are to have a stroke. Obesity may increase stroke risk by contributing to high blood pressure and diabetes. Hypertension. Detection and treatment of high blood pressure are the best means of stroke prevention. High red blood cell count. A moderate to marked increase in the number of a person's red blood cells increases the risk of stroke. Heart disease. Heart problems can interfere with the flow of blood to the brain; clots that form in the heart can travel to the brain, where they may clog an artery. Atrial fibrillation, the most common abnormal heart rhythm, also may increase the risk of stroke. Blood fats. Although the standard advice from cardiologists is to lower harmful LDL levels, what may be more important to lower stroke risk is an increase in the levels of protective HDL. Diabetes mellitus. Diabetics have a higher incidence of stroke than nondiabetics. Estrogen therapy. In the Women's Health Initiative—a series of clinical trials of hormone therapy for postmenopausal women—estrogen-only therapy significantly increased the risk of stroke. A diet high in fat and sodium. Individuals consuming the largest amounts of fatty foods and sodium are at much greater risk than those eating low-fat, low-salt diets. Marijuana. According to current research, smoking marijuana (discussed in Chapter 15) may double the risk of stroke in young adults.

Height

Shorter men are more likely to develop cardiovascular disease, regardless of their smoking status, blood pressure, body mass index, blood fats, alcohol consumption, education level, or occupation. Every extra 2.5 inches of height brings a 13.5 percent reduction in heart disease risk Researchers theorize that the same gene variations that determine height may also affect the likelihood of atherosclerosis.

High Blood Pressure (Hypertension) (pt2) As a result of increased effort in pumping blood, the heart muscle of a person with hypertension can become stiffer. This stiffness increases resistance to filling up with blood between beats, which can cause the following:

Shortness of breath with exertion. Damage to the arteries in the kidneys, which can lead to kidney failure. Accelerated development of plaque buildup in the arteries.

For men and women, chest pain or discomfort is the most common heart attack symptom, but women are more likely to report:

Shortness of breath, back or jaw pain, and nausea and vomiting. Tiredness, even after getting adequate sleep. Trouble breathing. Trouble sleeping Feeling sick to the stomach. Feeling scared or nervous. New or worse headaches. An ache in the chest. "Heaviness" or "tightness" in the chest. A burning feeling in the chest. Pain in the back, between the shoulders. Pain or tightness in the chest that spreads to the jaw, neck, shoulders, ear, or the inside of the arms. Pain in the belly, above the belly button. [Unhealthy lifestyles may be responsible for almost 75 percent of heart disease cases in young and middle-aged women. Healthful habits can reduce the danger. Even a few bouts of moderate exercise each week can cut a middle-aged woman's odds for heart disease, blood clots, and stroke. More frequent exercise, at least in this study of more than 1.1 million middle-aged women with no history of heart disease, did not yield more benefits than walking, gardening, cycling, or engaging in other activities that caused sweating or increased heart rate 2 or 3 days a week.]

Prediabetes

Sometimes called impaired fasting glucose, impaired glucose tolerance, or intermediate hyperglycemia, prediabetes is a condition in which blood glucose levels are higher than normal but not high enough for a diagnosis of diabetes. There is no standard definition of prediabetes, and many individuals told that they are prediabetic do not develop diabetes over time. According to the most recent estimates from the CDC, more than one-third of adults in the United States—an estimated 79 million men and women—could be assessed as prediabetic, although more than 90 percent are not aware of this risk. They face increased odds of cardiovascular events, such as heart attack and stroke, although regular exercise (Chapter 6) and the Mediterranean diet (Chapter 5) can lower the likelihood of developing diabetes. One way to reduce this risk is by walking. Adding 2,000 steps more per day could lower the risk for heart disease in subsequent years by 10 percent.

The DASH Eating Pattern

The National Heart, Lung, and Blood Institute (NHLBI) has developed the DASH (Dietary Approaches to Stop Hypertension) eating pattern, which has proved as effective as drug therapy in lowering blood pressure. An additional benefit: DASH also lowers harmful blood fats, including cholesterol and LDL, and the amino acid homocysteine (one of the new suspects in heart disease risk).

Carcinogens

The federal government has identified 248 specific substances implicated in cancer, including metals, chemicals, physical agents such as X-rays and ultraviolet radiation, and infectious agents. Each represents a cancer hazard, but does not by itself mean that a substance or a virus will cause cancer. Many factors, including an individual's susceptibility to a substance, and the amount and duration of exposure, can affect whether a person will develop cancer. In the case of viruses, a weakened immune system may also be a contributing factor. Of all known carcinogens, tobacco takes the biggest toll. Smoking is linked to almost one-third of fatal cancers in people 35 or older.

Coronary Artery Disease

The general term for any impairment of blood flow through the blood vessels, often referred to as "hardening of the arteries," is arteriosclerosis. The most common form is atherosclerosis, a disease of the lining of the arteries in which plaque—deposits of fat, fibrin (a clotting material), cholesterol, other cell parts, and calcium—narrows the artery channels. Inflammation also plays a crucial role.

Treatment for Diabetes

The goal for diabetics is to keep blood sugar levels as stable as possible to prevent complications, such as kidney damage. Home glucose monitoring, including new continuous glucose monitors, allows diabetics to check their blood sugar levels as many times a day as necessary and to adjust their diet or insulin doses as appropriate. Types of insulin differ in how long they take to start working after injection (onset), when they work hardest (peak), and how long they last in the body (duration). Individuals with diabetes may use different types in various combinations, depending on time of day and timing of meals. New insulin inhalers offer an alternative to injections for those with type 2 diabetes. Those with type 1 diabetes require daily doses of insulin via injections, an insulin infusion pump, or oral medication. Those with type 2 diabetes can often control their disease through a well-balanced diet, exercise, and weight management. However, insulin therapy may be needed to keep blood glucose levels normal or near normal, thereby reducing the risk of damage to the eyes, nerves, and kidneys. New medications help control weight and lower blood pressure and cholesterol. In most cases, diabetes requires lifelong management and treatment. However, a cure for some patients no longer seems impossible. About 400 to 500 pancreas transplants are performed in the United States every year; when successful they normalize glucose levels, thereby curing diabetes. However, only about half of these transplants continue to function for 10 years. Gastric bypass surgery (which limits the amount of food a person can ingest) for extremely obese individuals has led to lasting remission of diabetes, sometimes even before a patient loses weight. (See Chapter 6.) Scientists believe that bypass surgery "cures" diabetes by changing the hormones and amino acids produced during digestion. Some surgeons are advocating this approach for all diabetics with body mass indexes (BMIs) over 50; others, as an option for those with BMIs over 35. Among other promising approaches are, the use of stem cells to "rejuvenate" the pancreas, antibodies to block the autoimmune response of type 1 diabetes, and a more sophisticated artificial pancreas to monitor and manage glucose levels. High-tech alternatives to the dreaded fingerstick may include smartphone apps, a contact lens to monitor blood sugar in tears, a breathalyzer, a saliva test, and a tattoo that would refract infrared light back through the skin to a monitor that could translate the readings into blood sugar levels.

Overweight/Obesity Excess weight, an increasingly common and dangerous cardiometabolic risk factor in both men and women, undermines good health:

The higher your body mass index (BMI) during adolescence, the greater your risk of type 2 diabetes and heart disease in the future. Even teens with a BMI in the high "normal" range face an increased likelihood of health problems. Overweight and obese individuals are more likely to have additional risk factors for cardiovascular disease, including physical inactivity, hypertension, high cholesterol, and diabetes mellitus. Overweight teens who lose weight and keep their BMI within a healthy range as adults can eliminate the danger of diabetes, but being obese at any age endangers cardiovascular health.

Heart Attack (Myocardial Infarction)

The medical name for a heart attack, or coronary, is myocardial infarction (MI). The myocardium is the cardiac muscle layer of the wall of the heart. It receives its blood supply, and thus its oxygen and other nutrients, from the coronary arteries. If an artery is blocked by a clot or plaque, or by a spasm, the myocardial cells do not get sufficient oxygen, and the portion of the myocardium deprived of its blood supply begins to die. Although such an attack may seem sudden, usually it has been building up for years, particularly if the person has ignored risk factors and early warning signs. According to research, 80 to 90 percent of those who develop heart disease and 95 percent of those who suffer a fatal heart attack have at least one major risk factor.

Who Is at Risk?

The national prevalence of metabolic syndrome has fallen, particularly among teenagers who have lower levels of triglycerides (blood fats are discussed on page 312) and higher levels of "good" HDL cholesterol. However, teen obesity has risen. Researchers have targeted sugary beverages as contributors to weight and metabolic problems by leading to unhealthy waist circumference, blood glucose, and dietary patterns.

Understanding Cancer

The uncontrolled growth and spread of abnormal cells cause cancer. Normal cells follow the code of instructions embedded in DNA (the body's genetic material); cancer cells do not. Think of the DNA within the nucleus of a cell as a computer program that controls the cell's functioning, including its ability to grow and reproduce itself. If this program or its operation is altered, the cell goes out of control. The nucleus no longer regulates growth. The abnormal cell divides to create other abnormal cells, which again divide, eventually forming neoplasms (new formations), or tumors. Tumors can be either benign (slightly abnormal, not considered life threatening) or malignant (cancerous). The only way to determine whether a tumor is benign is by microscopic examination of its cells. Cancer cells have larger nuclei than the cells in benign tumors; they vary more in shape and size; and they divide more often. In general, 1 billion cancer cells need to have formed before a cancer can be detected. This is the number of cells in a tumor that measures 1 centimeter (about 0.3 inch). Without treatment, cancer cells continue to grow, crowding out and replacing healthy cells. This process is called infiltration, or invasion. Cancer cells may also metastasize, or spread to other parts of the body via the bloodstream or lymphatic system (Figure 10.8). For many cancers, as many as 60 percent of patients may have metastases (which may be too small to be felt or seen without a microscope) at the time of diagnosis. Early detection and treatment result in the highest rate of cure.

Atherosclerosis

This process begins when LDL cholesterol penetrates the wall of an artery. Ideally, HDL cholesterol carries the cholesterol out of the artery wall to the liver for disposal. However, if LDL accumulates, the artery responds by releasing chemical messengers called cytokines, which trigger active inflammation in the artery wall. Elevated levels of LDL cholesterol and apolipoprotein B (apoB), the main structural protein of LDL, are directly associated with the risk of atherosclerosis. T lymphocytes and macrophages, specialized white blood cells that are part of the body's defensive immune system, move from the bloodstream into the artery and engulf the LDL. As they ingest the LDL, the macrophages enlarge and become foam cells, which rupture, releasing cholesterol into the artery wall, where the cycle of damage begins again. In response, the smooth muscle cells in the artery wall create a fibrous cap over the inflamed area (Figure 10.6). These hard-capped plaques are dangerous: They narrow arteries, reduce the flow of blood, and produce angina (chest pain). However, the usual culprits in heart attacks are smaller, softer plaques that can rupture. As the body responds with clotting factors, platelets, and blood cells, a blood clot, or thrombus, forms on the disrupted plaque's surface. The clot ultimately blocks the artery and kills heart muscle cells. Similar clots can block blood flow to the brain and lead to other complications, including kidney failure and circulation problems in the legs and feet.

An estimated 42 percent of cancers are preventable, including those caused by the following:

Tobacco smoking. Heavy alcohol consumption. Overweight and obesity. Physical inactivity. Poor nutrition. Excessive sun exposure and indoor tanning. Infections that could be avoided by behavioral changes or vaccination. Cancers such as colorectal and cervical cancers in which screening can detect precancerous lesions that can be removed. [Prevention, early detection, and improved treatment have lowered the death rates for cancers of the lungs, colon, breast, and prostate. Since 1991 cancer death rates have declined by 27 percent.]

What Is a Healthy Cholesterol Reading?

Total cholesterol is the sum of all the cholesterol in your blood. Less than 200 mg/dL total cholesterol is ideal, and 200 to 239 mg/dL is borderline high. Total cholesterol above 240 mg/dL is high and doubles your risk of heart disease. However, total cholesterol is not the only crucial number you should know. Because LDL increases your risk for heart disease, you should always find out your LDL level. Even if your total cholesterol is higher than 200, you may not be at high risk for a heart attack. Some people—such as women before menopause and young, active men who have no other risk factors—may have high HDL cholesterol and desirable LDL levels. Ask your doctor to interpret your results so you both know your numbers and understand what they mean (Table 10.2). HDL, good cholesterol, is important in everyone, but particularly in women. Federal guidelines define an HDL reading of less than 40 mg/dL as a major risk factor for developing heart disease. HDL levels of 60 mg/dL or more are protective and lower the risk of heart disease. Triglycerides, the free-floating molecules that transport fats in the bloodstream, should ideally be below 150 mg/dL. Individuals with readings of 150 to 199 mg/dL, considered borderline, as well as those with higher readings, may benefit from weight control, physical activity, and, if necessary, medication.

Your Lipoprotein Profile Medical science has changed the way it views and targets the blood fats that endanger a healthy heart. In the past, the focus was primarily on total cholesterol in the blood. The higher this number was, the greater the risk of heart disease. The NHLBI's National Cholesterol Education Program has recommended more comprehensive testing, called a lipoprotein profile, for all individuals age 20 or older. This blood test, which should be performed after a 9- to 12-hour fast and repeated at least once every 5 years, provides readings of:

Total cholesterol. LDL (bad) cholesterol, the main culprit in the buildup of plaque within the arteries. HDL (good or healthy) cholesterol, which helps prevent cholesterol buildup. Triglycerides, the blood fats released into the bloodstream after a meal. [Long-term exposure to higher cholesterol levels can damage a person's future heart health. Individuals who live for more than a decade with high cholesterol have four times the risk of heart disease than those with shorter exposure. The longer your cholesterol remains high, the more likely you are to develop heart problems.]

As many as 80 percent of strokes are preventable, primarily through lifestyle modification. The most important steps are as follows:

Treating hypertension. Not smoking. Managing diabetes. Lowering cholesterol. Taking aspirin, which reduces stroke risk in women but not in men. [Quick treatment with a clot-busting drug at a hospital can reduce the chance of disability after a stroke, but few people recognize the signs of a stroke and seek medical care within 3 hours of the first symptoms.]

Triglycerides

Triglycerides are fats that flow through the blood after meals and have been linked to increased risk of coronary artery disease, especially in women. Triglyceride levels tend to be highest in those whose diets are high in calories, sugar, alcohol, and refined starches. High levels of these fats may increase the risk of obesity, and cutting back on these foods can reduce high triglyceride levels. In assessing an individual's risks, cardiologists consider not just the levels of various blood fats, but also their ratios and associations.

Stroke

When the blood supply to a portion of the brain is blocked, a cerebrovascular accident, or stroke, occurs. The proportion of strokes among young adults between ages 20 and 45 has been rising, perhaps as a consequence of the higher incidence of obesity, hypertension, and diabetes. Young adults who suffer strokes are at higher risk of diabetes and further "vascular events." Although the number and mortality rate have declined, strokes rank third, after heart disease and cancer, as a cause of death in this country. Worldwide, stroke is second only to heart disease as a cause of death. An estimated 20 percent of stroke victims die within 3 months; 50 to 60 percent are disabled. Among those who survive a stroke before age 50, one-third are unable to live independently or require assistance with daily activities 10 years later. (See Your Strategies for Prevention: How to Recognize a Stroke.)

Gestational Diabetes

Women who get diabetes while they are pregnant are more likely to have a family history of diabetes, especially on their mothers' side; they are at increased risk of developing diabetes later in life. Children of mothers who develop gestational diabetes early in pregnancy may be at increased risk for autism spectrum disorders (discussed in Chapter 3). Early screening and good control of glucose levels during pregnancy may reduce this risk.

High Blood Glucose

Your stomach and digestive system break down the food you eat into glucose, a type of sugar. The hormone insulin acts like a key, letting glucose into cells and providing energy. "Insulin-resistant" cells no longer respond well to insulin, and so glucose, unable to enter the cells, builds up in the bloodstream. Frequent thirst, blurry vision, weakness, unexplained weight loss, and unusual hunger can be signs of high blood glucose. A simple blood test will tell you if your glucose levels are too high. Here is what the readings mean: Healthy blood glucose Under 100 Prediabetes 100-125 Diabetes More than 125

Blood pressure readings may be affected by many different conditions, including cardio-vascular disorders; neurological conditions; kidney and urological disorders; psychological factors such as stress, anger, or fear; various medications; and "white coat hypertension," which may occur if the medical visit itself produces extreme anxiety. Unlike previous recommendations, the new guidelines do not differentiate on the basis of age. Medications are recommended to lower blood pressure in stage 1 hypertension only if individuals have already had a heart attack or stroke. For others with stage 1 hypertension, lifestyle changes alone are recommended. t/f

t

By 1925, diseases of the heart had become the number one cause of death in the United States, followed by pneumonia and influenza. By the 1940s, cancer had edged out pneumonia for the dubious distinction of being the nation's second most lethal disease. Today, heart disease and cancer account for nearly half of all deaths in the United States. t/f

t

Compared with people with no factors of metabolic syndrome, those with three factors are nearly twice as likely to have a heart attack or stroke and more than three times likely to develop heart disease. Men with four or five characteristics of the syndrome have nearly four times the risk of heart attack or stroke and more than 24 times the risk of diabetes. Young adults with metabolic syndrome are more likely than others their age to have thicker neck arteries, an indicator of atherosclerosis, the buildup of fatty plaques in arteries. College-age men and women who maintain their weights as they get older are much less likely to develop metabolic syndrome. Among those who are obese, losing 7 to 10 percent of their body weight may reverse the symptoms of metabolic syndrome. t/f

t

Diabetes affects almost every organ system of the body in complex and often subtle ways. An estimated 29 million Americans—almost 1 in 10—have diabetes. The Centers for Disease Control and Prevention (CDC) projects that up to one-third of Americans could have diabetes by 2050 if they continue to gain weight and avoid exercise. The rate of diabetes is much higher in 15 states, mostly in the South. People living in this so-called diabetes belt are more likely to be obese, sedentary, and less educated than in the country as a whole. Certain racial and ethnic minorities—American Indians/Alaska Natives, African Americans, and Hispanic American—around the country also have higher rates of diabetes. Before the development of insulin injections, diabetes was a fatal illness. Today, diabetics can have normal lifespans. However, diabetes still can lead to devastating complications. Uncontrolled glucose levels slowly damage blood vessels throughout the body; thus, individuals who become diabetic early in life may face major complications even before they reach middle age. Diabetes is the number one cause of blindness, nontraumatic amputations, and kidney failure, and diabetes increases by two or three times the risk of heart attack or stroke. t/f

t

Did you know that only one-third of people with hypertension have it effectively controlled? Reducing blood pressure to healthy levels could prevent 1 death in every 11 people treated for hypertension. t/f

t

In Canada, where more than 10 percent of adults (particularly young women) report using an indoor tanning device, this exposure contributes to 7 percent of melanomas, as well as 5 percent of basal cell carcinomas and 8 percent of squamous cell carcinomas. Using tanning beds at a young age significantly raises a woman's risk of developing melanoma before the age of 50. Among adults ages 25 to 49, the risk for the deadly skin cancer increased two to six times for women who tanned indoors, with the greatest odds seen for those who used tanning beds in their teens and 20s. Younger women with melanoma also reported more tanning sessions than older women—an average of 100 tanning sessions compared with 40 sessions for women diagnosed at 40 to 49. In a recent study, some college women reported that indoor tanning eased negative feelings such as being upset, nervous, irritable, jittery, or afraid and increased positive mood states. Frequent tanners who report relatively high rates of psychiatric and substance abuse symptoms may be especially vulnerable to dependence. One novel approach being tried to alert people to the potential dangers is text messaging. t/f?

t

Many everyday activities—eating, drinking coffee, having sex, even breathing—can spur a heart attack. Air pollution from traffic poses the greatest risk. Other triggers include drinking alcohol, physical exertion, and eating a heavy meal. If you are with someone who's exhibiting the classic signs of a heart attack and if these signs last for 2 minutes or more, act at once. Expect the person to deny the possibility of anything as serious as a heart attack, but insist on taking prompt action. Time is of the essence when a heart attack occurs. Call 911 immediately. The sooner emergency personnel get to a heart attack victim and administer cardiac life support, the greater the odds of survival. Yet according to the American Heart Association, most patients wait 3 hours after the initial symptoms begin before seeking help. By that time, half of the affected heart muscle may already be lost. t/f?

t

Medical science has increasingly focused on the complex connections between various risk factors, symptoms, and diseases. Physical inactivity, for instance, increases the likelihood of obesity, which in turn leads to greater risk of many diseases. This awareness has led to a focus on cardiometabolic health. "Cardio" refers to the heart and blood vessels of the cardiovascular system; "metabolic" refers to the biochemical processes involved in the body's functioning. Every day more than 2,200 Americans die of cardiovascular diseases—an average of one death every 39 seconds. Cardiovascular diseases (all diseases of the heart and blood vessels) account for one of every three deaths, including an increasing number among younger adults ages 35 to 54. Medical scientists fear that the obesity epidemic and the rise in metabolic disorders may be responsible. t/f

t

Only about half of young Americans get passing grades for heart-healthy behaviors. Fewer than 1 percent eat "ideal" diets; about one-third have high body mass indexes (BMIs) (discussed in Chapter 5), and one-third have unfavorable cholesterol readings. Unhealthy habits in youth, such as drinking sugary beverages, not only increase the odds of disease in old age but also lower the likelihood of surviving to age 55. The opposite is also true: For individuals who reach age 55 with low blood pressure and cholesterol levels, do not smoke, and are not diabetic, the risk for heart disease or a heart attack is significantly lower than for those with two or more risk factors. t/f

t

Specific risk factors determine your cardiometabolic health. Once you understand your risk, you can start making changes to lower your odds of developing metabolic syndrome, diabetes, and heart disease. t/f

t

At the turn of the twentieth century, the major killers of Americans were two deadly infections:

tuberculosis and pneumonia.