Epidemiology and Application to Community health Nursing
what are the factors of a cross-sectional study?
"Snapshot" or cross section of a population or group Historical information can be collected-uses survey research Frequency (number) of existing cases of a disease in a population (prevalence studies) Good to use to relate a variable to a disease or condition but not cause and effect
"rates" are a factor of descriptive studies. What is the definition of rates?
"are statistical measures expressing the proportion of people with a given health problem among a population at risk Rates are calculated by taking the total number of people in a group as the denominator for the equation. The two types of rates that are of utmost importance to community health nurses are the incidence rates and the prevalence rates.
Clinical (therapeutic) trials are a type of experimental study. What is the definition of clincial (therapeutic) trials?
A clinical or therapeutic trial is a clinical trial in which the investigator provides a specific treatment (therapy) to the group under study and follows the group to determine the effects of the treatment •Clinical trials are conducted under a controlled environment so there is greater control over other factors that could influence outcome. Therapeutic trials are based on secondary prevention which focuses on limiting the spread of disease. Double-blind, placebo-control group design Controlled environment Focuses on secondary prevention and limits spread of disease
what is a descriptive study?
A descriptive study "seeks to observe and describe patterns of health-related conditions that occur naturally in a population" The studies are *observational*, so the investigator does not intervene to change or introduce new factors. *Health-related conditions occur naturally* in a population. The book describes some examples as how many STD's have occurred in the city the past month or how many automobile accidents occurred near a high school in the community. *Provides the foundation for the development and testing of hypotheses •The data derived from descriptive studies could suggest the testing of hypotheses for further research.* •Counts, rates and computing rates are used to measure data from descriptive studies.
Agent is one part of the basic epidemiologic concepts of the . Epidemiologic Triangle/Triad. What are Agents? (know the examples)*
Agents are an element or force that under proper conditions can initiate or perpetuate a health problem. It also can be an animate or inanimate factor that must be present or lacking for a disease or condition to develop. Examples include bacteria that causes TB or low serum iron level that causes anemia Biological agents, chemical agents, physical agents, psychosocial agents
An example of a cross sectional study is the Behavioral Risk Factor Surveillance System (BRFSS). What is this?
BRFSS was established by the CDC as an efficient method that takes a cross-section of the population at a single point in time and monitors prevalence of the major behavioral risks in adults associated with premature morbidity and mortality at the state level (p 140-141). The risks assist with planning, initiating, supporting and evaluating health promotion and disease prevention programs. Because of this, many states use the data obtained by the BRFSS to determine progress toward achievement of the HP 2010 objectives and will be using the data to see if they are meeting the newly developed objectives of HP 2020. Scientific research indicated personal health behaviors contributed to premature death and disability Conducted by the CDC Health promotion and disease prevention programs Determines progress toward achievement of HP2010/2020 objectives
what are the basic epidemiological concepts of the Epidemiologic Triangle/Triad?
Basic epidemiologic concepts are the interrelationships between agent, host and environment In their study of infectious diseases, epidemiologists considered disease states in terms of the epidemiologic triad (host, agent and environment model)
definition of causality?
Causality is the second basic concept of epidemiology and refers to the "relationship between a cause and its effect"
definition of cohort studies?
Cohort studies are an example of an analytic study which focused on a cohort or group of people who share a common experience during a period of time. The study selects a group participants who were initially free from a disease but were known to have been exposed a particular factor •Because of the study's ability to observe the development of new cases of disease, the cohort study design allows for calculation of incidence rates and therefore estimates risk for disease. Cohort of people often becomes a focus of study Allow for calculation of incidence rates and estimates the risk of disease Attempts to find cause-and-effect relationships
where is secondary level prevention provided? what are examples of secondary interventions?
Community settings Primary and secondary levels of health care Secondary interventions ◦Mammography ◦Pap tests ◦Colonoscopy Screening guidelines are reviewed and revised regularly Secondary prevention occurs in community settings and in primary and secondary levels of health care. Secondary interventions include mammography to detect breast cancer, Pap tests to detect cervical cancer, colonoscopy for early detection of colon cancer). Screening guidelines are reviewed and revised regularly on the basis of epidemiologic research results and CHN's must stay current in their knowledge of the screening guidelines.
describe the chain of causation and its relation to noninfectious diseases?
Due to the availability of antibiotics and vaccines, most infectious diseases are now prevented or controlled in the United States. Because of this, the chain of causation was found to be insufficient in understanding the causes of emerging health threats of noninfectious diseases, such as diabetes and cancer. If we used smoking as an example, there was interest in the 1950s on the role that smoking played on lung cancer. Later, in 2104, the Surgeon General Report further found that smoking was linked to diabetes mellitus, rheumatoid arthritis, inflammation, impaired immune function, and liver/colon cancers.
Environment is one part of the basic epidemiologic concepts of the Epidemiologic Triangle/Triad. What does environment refer to? (know the examples)**
Environment "refers to all external factors surrounding the host that might influence vulnerability or resistance". Examples of the physical environment includes climate and weather, safety of buildings, geography, food and water supply or presence of animals, plants, insects or microorganisms that may serve as reservoirs for transmitting disease. The psychosocial environment refers to the cultural, economic, social and psychological influences and conditions that affect health and include access to health care, poverty, work stressors, and cultural health practices Climate, plant and animal life, crowding, social support, education, resources, noise, work satisfaction, vectors, heat, political systems, demographics
what is epidemiology and what does it provide to nursing?
Epidemiology is scientific research, but it is specialized. The term is derived from the Greek words "epi" which means "upon"; "demos (the people); and "logos" which means "knowledge". So, it is "the knowledge or study of what happens to people" This type of knowledge provides Community Health Nurses with a body of knowledge on which to base their practice and provides methods for studying new and existing problems. Epidemiology offers community health nurses a specific methodology for assessing the health of aggregates (or groups) It draws on methods from biostatistics and informatics and includes principles from the biologic, social, economic, and behavioral sciences
definition of experimental (intervention) studies?
Experimental epidemiology "follows and builds on information gathered from descriptive and analytic approaches" (Rector, 2018, p. 260). Experimental studies may be therapeutic (clinical trials) or preventive (community trials). In experimental or interventions studies, the investigator initiates a treatment or intervention to influence the risk or course of disease. The studies test whether interventions can prevent disease or improve health. They use comparison or control groups. Persons can be randomly assigned to a particular group; intervention is applied and the effects of the intervention are measured. The two types of intervention studies are clinical and community trials. Initiates a treatment or intervention Test whether interventions can prevent disease or improve health Use comparison or control groups Persons randomly assigned to a particular group ◦Clinical trials (therapeutic) ◦Community trials (preventive)
the "tools of epidemiology" are used by community health nurses so they can use epidemiology effectively in their community setting. What do community health nurses use the basic concepts for? (triad (agent, host and environment), causality, ect.)
First, they use it to provide baseline information for assessing needs. They then identify problems, design strategies to evaluate the problems, develop a plan of care after priorities are set, and evaluate how effective the care was after the care was delivered. "The science of epidemiology draws on certain basic concepts and principles to analyze and understand patterns of occurrence among aggregate health conditions"
what type of primary prevention teaching do community nurses provide?
Health promotion activities ◦Nutrition ◦Sex education ◦Exercise Environmental protection teaching ◦Food safety ◦Sanitation ◦Air quality control Specific protection against disease or injury you can see that community health nurses are actively involved in primary prevention by teaching health promotion activities such as nutrition, sex education, and exercise, to name a few. CHN's also get involved by teaching about environmental protection such as food safety, sanitation, and air quality control. Last, CHN's teach about specific protection against disease or injury and examples of this type of teaching include teaching about immunizations, proper use of seatbelts and infant car seats, water fluoridation, and how to reduce exposure to cancer.
Host is one part of the basic epidemiologic concepts of the Epidemiologic Triangle/Triad. What are Hosts? (know the examples)**
Host is defined as a "susceptible human or animal who harbors and nourishes a disease-causing agent". It is the living species capable of being infected or affected by an agent. There are physical, psychological, and lifestyle factors (diet, exercise) that influence susceptibility and response to an agent. Genetic makeup, age, sex, nutritional choices, lifestyle factors, race, exercise level, health knowledge, motivation to achieve optimal wellness
definition of infant mortality rate:
Infant mortality rate is the number of infant deaths before one year of age in a year per number of live births in the same year. Infant mortality rates are important rates to consider in a population because it is used around the world as an indicator of overall health and availability of health care services. Unfortunately, according to the State of the World's Mother's Index, the United States' infant mortality rate is 6.4 per 1,000 births which puts us near the bottom of industrialized nations. Used around the world as an indicator of overall health and availability of health care services
Who is considered the "father of epidemiology"?
John Snow
what is a retrospective study? what is a disadvantage?
Looks backward in time Quick assessment about association Utilizes existing information Less labor intensive Less expensive Disadvantage: data may not be collected with a research outcome in mind •A retrospective study "looks backward in time to find a causal relationship" and makes a quick assessment of whether or not an association exists (Rector, 2018, p. 249). As you recall, the prefix "retro" means "back" or "backward." Retrospective studies utilize existing information that has been recorded for other reasons besides research, are less labor intensive and expensive. However, "the data may not be collected with a research outcome in mind" (Rector, 2018, p. 249).
what is a prospective study?
Looks forward in time ◦Concerned with current information ◦Provides a direct measure of the variables in question As opposed to the retrospective study which looks backward in time, the prospective study looks forward in time to find a causal relationship to ensure the causal factor precedes the onset of the health problem. The study is concerned with "current information and provides a direct measurement of the variables in question"
how is infant mortality rate calculated?
Number of Deaths Under 1 Year of Age for Given Year / Number of Live Births Reported for Same Year X 1,000
how do we calculate crude mortality rate?
Number of Reported death during 1 year/ estimated population as of July 1 of same year . * 100,000
how is proportional mortality rate calculated?
Number of deaths from a specific illness within a time period / Total number of deaths in the same time period from all other causes
how do nurses utilize basic methods in epidemiology?
Nursing Process Works as a detective Detective searches for information or clues ◦reviews literature ◦designs a study ◦collects data Analyzes and interprets findings (clues) Narrows possible suspects Detectives (nurses) draw further conclusions and make new applications ◦To improve health care service When using the nursing process, epidemiology helps to provide baseline information for assessment, planning, implementation and evaluation. The community health nurse who utilizes epidemiology works as a detective( identifies a problem, a puzzle to unravel or a question to answer). A detective searches for information or clues to help answer the question or problem (reviews literature, designs a study, collects data). A detective analyzes and interprets the findings (clues). A detective narrows possible suspects until the causes of a disease, consequences of a prevention plan, or results of treatment are identified. Based on the results of the investigation, detectives (nurses) can draw further conclusions and make new applications to improve health care service.
what are examples of tertiary care?
Occur in community and primary care settings Examples ◦Physical and occupational therapies ◦Rehabilitation ◦Medical treatment Diagnosing individuals with active TB Using direct observed therapy
definition of secondary prevention?
Secondary prevention is maximizing health and wellness through strategies that are set in place at the early and active chronic stages of pathogenesis of illness and injury (Harkness & DeMarco, 2016, p. 83). CHN's perform interventions that seek to detect disease early in its progression, before clinical signs and symptoms become apparent, in order to make an early diagnosis and begin treatment. *Health screenings epitomize secondary prevention* Screening programs are necessary for diseases with few specific primary prevention strategies.
definition of tertiary prevention?
Tertiary prevention is maximizing health and wellness through strategies that are set in place at the palliation and end-stage of disease and injury trajectories (Harkness & DeMarco, 2016, p. 85). CHN interventions are aimed at disability limitation and rehabilitation from disease, injury, or disability. The interventions tend to occur at secondary and tertiary levels of care (hospitals, rehabilitation centers, specialized clinics). Occur at secondary and tertiary levels of care ◦Hospitals ◦Rehabilitation centers ◦Specialized clinics
what is a crude mortality rate?
The crude mortality rate is defined as an annual rate that represents the proportion of a population who die from any cause during the one year period, using the midyear population as the denominator (Stanhope & Lancaster, 2010, p. 161). Because the population changes during the course of a year, the usual practice is to estimate the population at midyear as the denominator for annual rates. Even though the crude mortality rate represents the actual death rate for the total population, it does not reveal specific causes of death. The rate is also affected by the population's age distribution. Older people are at much greater risk of death than their younger counterparts.
what role did hippocrates play in epidemiology?
The development of epidemiology as a science started with Hippocrates in the Fourth Century B.C. Hippocrates is thought to be the "first epidemiologist" because he looked at how health is influenced by environmental and host factors, such as lifestyle behaviors. He examined health and disease in a community more specifically by epidemiologic observation and how disease spread and affect populations by looking at time and seasons of the year, place, food and water consumed, environmental conditions and disease control ◦Health influenced by environmental and host factors ◦Examined health and disease in a community
what is the conceptual model on the natural history of any disease affecting humans by Levall and Clark
The model integrated pathogenesis of an illness with primary, secondary, and tertiary prevention measures. For example, the three levels of prevention could be applied during the stages of the natural history of a disease to reduce or eradicate risk factors in order to avoid negative health conditions, immediately diagnosis and treat the problem, or could restore them to their fullest possible potential.
definition of "the natural history of disease"
The natural history of disease is the course of the disease process from onset to resolution
definition of a cross sectional study?
cross-sectional study is a study that can show that a health factor and the health problem in a population coexist (Rector, 2018). The health outcomes and exposures or characteristics of interest are examined for an association in a population or sample, providing a picture of existing levels of all factors (Stanhope, 2010, p. 150). This study provides a "snapshot" or cross section of a population or group because the data represent a point in time. Historical information can be collected such as diet or history of any radiation exposures.
definition of primary prevention?
maximizing health and wellness through strategies that are set in place before illness or injury are present (Harkness & DeMarco, 2016, p. 83). This level of prevention is aimed at individuals and groups who are susceptible to disease but have no identified pathology. Nurses utilize primary prevention in homes, community settings, public health clinics, doctor's offices, and rural health clinics.
definition of incidence rate:
measures all new cases of a disease or health condition appearing during a given time ◦Example: the number of new emerging cases of measles in a school over a period of time 200 new cases of measles/1,000 students at risk An incidence rate "refers to all new cases of a disease or health condition appearing during a given time" (Rector, 2018, p. 258). • Incidence rate is the measure of choice to study etiology because incidence is affected only by factors related to the risk of developing disease. For example, in the case of a measles outbreak, the number of children having measles would be removed from the total number of children at risk in the school population (denominator). Three weeks after the start of the measles epidemic, the incidence rate will describe the number of cases of measles that appear during that period in terms of the number of persons at risk (numerator).
can a single study be adequate to establish causality?
no single study is adequate to establish causality. Causal inference is based on consistent results obtained from many studies
definition of proportional mortality ratio:
ratio. Proportional mortality ratio is defined as a ratio that compares deaths from a specific illness with deaths from all other causes PMR reflects the proportion of deaths due to a specific cause PMR is not a rate
Causality is the second basic concept of epidemiology. What was the chain of causation used for?
the chain of causation was used by epidemiologists to think about the cause of disease in relation to the epidemiologic triad of host, agent and environment. It describes the relationshp between a cause and its effect. In this example, the reservoir is the infected human with malaria and this is where the agent can live and multiply. The agent then must have a portal of exit from the reservoir (human) and mode of transmission. In this example, the bite of the mosquito provides the portal of exit for the parasites and the mosquito is the mode of transmission. Next, the agent is the protozoa in the mosquito. The mosquito bite serves as the portal of entry into the uninfected human host. In this case, the environment can have an effect on any part of the chain (pools of water exposed to sun, breeding grounds for mosquitos)
definition of epidemiology?
the definition of epidemiology is the "scientific discipline that studies the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems States of health and illness include health, disease, morbidity, injuries, disability and mortality. The goals of epidemiology is to use the information to provide a frame of reference for investigating and improving clinical practice, such as lowering the incidence of STD's/STI's, improve nutrition of a population, reduce the number of automobile crashes injuries at a specific location, etc. (
morbidity rate defintion:
the incidence of disease in a population, so the ratio is the number of sick people to the total population.(sickness)
definition of case control studies
•(number of cases with the condition) with those who lack this condition (controls)" The studies are retrospective and look for presence or absence of the causal factor in the cases and in the control group. • • It compares differences in exposures, behaviors, and other characteristics to identify and quantify associations, test hypotheses, and identify causes ◦Cases-subjects with the disease/condition ◦Controls-subjects without condition ◦Ex. Do persons with the outcome of interest (suicide attempts) have the exposure characteristic (or history of exposure) more frequently than those without the outcome (control)
what are the disadvantages of performing clinical trials?
•A few disadvantages to performing clinical trials is that clinical trials are expensive in terms of time, facilities and supplies; there are more ethical considerations involved and treatment may not be as effective when applied to more realistic community conditions in a more diverse population.
definition of analytic epidemiology?
•Analytic epidemiology "seeks to identify associations between a particular human disease or health problem and its possible causes" (Rector, 2018, p. 258), as opposed to simple description or observation. •Analytic epidemiology is more specific than descriptive studies in their focus and they test hypotheses or seek to answer specific questions (Rector, 2018, p. 258). •Case-control studies and cohort studies are the two type of analytic studies that will be discussed in the next slides. Discover the determinants of health outcomes Influence the observed patterns of health and disease More specific than descriptive Test hypotheses or seek to answer specific questions
defintion of association as it related to causality?
•Association is a term used to refer to the concept in determining multiple causalities. For instance, events are associated if they appear together more often than would be the case by chance alone and can include risk factors or other characteristics that affect disease or health states. The association of smoking with diseases was already discussed, but other examples could include obesity with heart disease, high fat diets with certain cancers, and premature infants with infant mortality. As stated by Fletcher and Fletcher (2012) and cited by Rector (2018), "the associations among lifestyle, behavior, environment, and stress of all kinds and the ways in which they affect health states are gaining importance in epidemiology" (p. 243).
Counts are part of descriptive studies. What is the definition of counts?
•Counts is the simplest measure used and is obtained from many data sources such as death certificates, hospital records, U. S. Census Bureau, etc. Another name for counts are cases. For example, if a community health nurse discovers there were 25 cases of gonorrhea in the high school, then that is a simple count.
Community (preventative) trials are a type of experimental studies. What is the definition of community trials?
•In community trials( or preventive trials), the investigator determines what the exposure or intervention will be at the community level. The intervention is undertaken on a large scale. The unit of treatment is the community, region, or group rather than individuals. The trials can be expensive, require large staff, have complicated logistics and need extensive communication about the study. These trials deal with health promotion and disease prevention mainly primary prevention to reduce the incidence of disease rather than on treatment of an existing disease like therapeutic or clinical trials Investigator determines exposure or intervention Intervention undertaken on a large scale Community, region, or group rather than individuals Expensive, large staff, complicated logistics and need extensive communication *Health promotion and disease prevention*
what is the web of causation?
•In the 1960s, the web of causation was the causal paradigm that emerged to explain the concept of multiple causation in order "to explain the existence of health and illness states to provide guiding principles for epidemiologic practice" (Rector, 2018, p. 242). For example, a combination of factors, and not only one factor, is the deciding factor in the development of poor health outcomes. Due to this concept, health care interventions have to be provided at a variety of levels.
mortality rate definition
•Mortality rate- is the relative death rate or sum of deaths in a given population at a given time. This rate provides information about diseases that are fatal. However, it does not provide direct information about the level of existing disease or the risk of getting a particular disease. •
definition of prevalence rate:
•Prevalence rate measures "all of the people with a particular health condition existing in a given population at a given point in time" (includes new and old cases)(Rector, 2018, p. 258). In the measles example, there are 50 existing cases of the measles discovered in the total population of students in the school (500), so 50/500 x 100= 10% -Prevalence rate-all of the people with a particular health condition existing in a given population at a given point in time (includes new and old cases) ◦Example: using the same measles scenario, the prevalence rate is if the nurse discovers 50 existing cases of measles out of total school population 50 students with measles/500 population of students(10%)
what is the gold standard for experimental studies?
•The "gold standard" for experimental studies is the double-blind, placebo-control group design. The double-blind study means that neither the subject nor investigator knows who is getting which treatment. Subjects are also randomly assigned to groups.
what is the goal of epidemiology?
•the goal of epidemiology is to identify and understand causal factors and mechanisms of disability, disease and injuries so that effective interventions can be implemented to prevent occurrence of adverse events before they begin or progress.
Nurses' health study is an example of a prospective study. What is this?
◦Association of alcohol, diet, obesity, oral contraceptive use, physical activity, postmenopausal hormones, smoking, and other factors with ◦Cancer, CHD, stroke, macular degeneration, glaucoma, hip fractures, etc. •The Nurse's Health Study is an example of how the study analyzed risk factors that impacted the health of nurses. A few examples of the causal relationships that were found include how alcohol, diet, obesity, oral contraceptive use, physical activity, postmenopausal hormones, smoking, and other factors diet are associated with cancer, CHD, stroke, macular degeneration, glaucoma, hip fractures, etc.
what did John Snow contribute to epidemiology?
◦Best known epidemiologist (Father of Epidemiology) ◦Conducted epidemiologic research on transmission of cholera ◦Used mapping and natural experiment ◦Foul water from a pump was the vehicle for transmission John Snow was the best known epidemiologist of the 19th century. Through epidemiologic research, he developed death rates as an objective measure to compare populations. He used mapping and natural experiment, comparing rates in groups exposed to different water supplies from two different water companies in London's Soho district. He discovered that foul water from a local pump was the vehicle for transmission of the agent that caused cholera by mapping cholera cases, plotting where cholera deaths were occurring, characterized where the epidemic started, peaked, and subsided. He ordered the removal of the Broad Street Pump so people could not get water from the public pump in order to stop the epidemic
What did Florence Nightingale contribute to epidemiology?
◦Development of epidemiology ◦Conditions of environment and recovery of soldiers ◦Used measures of rates of illness per 1,000 soldiers ◦Improving environmental conditions and adding nursing care Not only was Florence Nightingale credited with founding the profession of nursing, she was actively engaged in preventing illness and death. Florence Nightingale contributed toward the development of epidemiology during the Crimean War. She demonstrated that by using morbidity (sickness) statistics and careful description of the health conditions among the soldiers fighting in the Crimean War, and there was descriptive studies of the distribution and patterns of disease in a population (Rector, 2018, p. 234). By using data that she collected while taking care of the soldiers, she found a relationship between the conditions of the environment and the recovery of soldiers. She utilized simple epidemiologic measures of rates of illness per 1,000 soldiers. Florence was eventually able to show that improving environmental conditions, such as improving sanitary methods in hospitals and adding nursing care decreased mortality rates of soldiers (Harkness & DeMarco, 2018, p. 110). Eventually, the British government implemented her sanitary reforms.
what are the epidemiologic investigation goals?
◦Identify the causal mechanisms of health and illness states ◦Develop measures for preventing illness and promoting health
what is epidemiology used to do?
◦provide baseline information ◦ identify problems ◦ design strategies ◦ develop plan of care ◦ evaluate care
