Public Health Chapter 8
What is the Burden of Disease due to the physical environment?
Measuring the impact of the physical environment on health is difficult because of the many types of impacts and the often subtle effects that occur. The impacts we experience today may pale in comparison to what we can expect in the future. Nonetheless, it is useful to appreciate the current estimates of the magnitude of the direct and indirect burden.
Four Step Risk Assessment (table 8.2)-pg 169
*Hazard identification* :What health effects are caused by the pollutant? *Dose-response relationship* : What are the health problems at different exposures? *Exposure assessment* : How much of the pollutant are people exposed to during a specific time period? How many people are exposed? *Risk characterization* : What is the extra risk of health problems in the exposed population?
What Is an Interaction Analysis Approach to Environmental Diseases? box 8.6-pg.173
*interaction analysis* : implies that to understand and control the impacts of environmental exposures, it is necessary to take into account the effect of two or more exposures. Risk assessment approaches make the assumption that each exposure stands on its own. Thus, if there is more than one type of exposure, we need to make the assumption that the total impact is the sum of the two impacts For example: if one exposure has a relative risk of 4 and a second has a relative risk of 6, we assume that exposure to both results in a relative risk of 10.
What is an ecological risk assessment?
-Examines the impacts of contamination on: ~ecological systems ranging from chemicals, to radiation, to genetically altered crops plants and animals and the ecosystems in which they exist. Human health consequences remain an important, but not necessarily direct, consequence of the impacts of environmental contamination or pollution health risk of mercury(box8.5)
What is a public health assessment? (box 8.4) -pg.170 health risk due to lead
A public health assessment goes beyond a risk assessment by including data on actual exposure in a community. Public health assessments address not just the risks in a specific location, such as in an occupational setting, but also the risks to large numbers of individuals and often to the population as a whole. *Risk assessments* and *public health assessments* both focus exclusively on the health impacts on human beings.
Occupational injuries have been declining in recent years, but they remain an important cause of death and disability
Cancer caused by occupational exposures has been of particular concern. As much as 5% of cancer deaths in males have been estimated to be due to occupational exposures. Cancers of the lung, bladder, and white blood cells (leukemia) are particularly likely to result from chronic exposures to chemicals, such as formaldehyde, benzene, and organic dyes. Reductions in occupational exposures in the last 30 years have resulted in a declining burden of disease from these exposures in the United States. The opposite is being seen in many newly industrializing countries, where current exposures are increasing and may result in more cases of cancer and other diseases in the not-too-distant future.
toxic exposures can occur in occupational settings
Certain occupations are particularly vulnerable to injuries, including mining, construction, and agriculture Occupational exposures that result in morbidity and mortality include lung diseases caused by exposures to hazardous dusts, hearing loss from loud noises, and back pain from excessive lifting, as well as a wide range of other mechanical problems, including carpal tunnel syndrome, which is often caused by repetitive motion of the hand and wrist.
Not all risks for environmental disease require high-level or long-term exposure.
In addition to causing lung cancer, asbestos has also been shown to cause a form of cancer called mesothelioma, which originates in the lining of the lung or pleura. Even small and short-term exposures to asbestos may cause mesothelioma, as evidenced by well-documented cases among household members who washed the clothing of those exposed. New technologies, such as nanotechnology, are raising concerns that the risks of low-level exposure need to be investigated as much as those of high-level exposure. Low-dose environmental exposures to estrogen- like substances may pose threats to the reproductive health of animal species and could even affect the human rate of breast cancer. Addressing these types of issues requires us to focus on the interactions between multiple factors.
What Do We Mean by "Intentional and Unintentional Injuries"?
In public health, we try to avoid the use of the term "accident" because "accident" implies that the reasons for the injury are beyond our control. Injuries can be categorized as *intentional* and *unintentional*. *Intentional injuries* are brought about on purpose, that is, by intention, whether the injury is self-inflicted or meant for others. -Intentional injuries can impact entire populations, such as bioterrorist actions that lead to fear and fatalities among a population, or can directly impact individuals, such as with suicide. *Unintentional injuries* encompass injuries sustained in motor vehicle collisions, drownings, falls, fires, unintentional poisonings, and many other incidents.
built environment may also affect our mood, social interactions, and social attitudes for better or worse
Indoor air pollution from cooking is the most prominent source of air pollution in much of the developing world. Motor vehicle injuries are the most deadly consequences of the built environment in most developed countries. The built environment has subtle impacts as well: -The way we build our cities affects the amount of exercise we get and the quantity of noise pollution we experience. -Construction methods affect air systems in buildings and an increase our exposure to "sick buildings."
Built environment
Is relatively new and includes all the impacts of the physical environment as a result of human construction. (Summary): The man-made surroundings that provide the setting for human activity, ranging in scale from personal shelter to neighborhoods to the large-scale civic surroundings. The impacts of human construction include injuries and exposures in the home, the transportation system, and where we work and play. They also include factors ranging from the way we build and heat our buildings and cook our food, to the way we travel from place to place. The built environment influences our safety through its impact on injuries and hazardous exposures. It also influences our activity levels and our social interactions, which impact our health.
What is meant by Environment?
It is sometimes used to imply all influences other than genetic influences, including social, economic, and cultural influences. -The physical environment can be thought of in three categories: *unaltered("natural")* *altered* *built environment* Floods, earthquakes, and volcanoes have always been a part of the physical environment. In addition to these intermittent and often isolated impacts, daily exposures to communicable diseases in water and food have always been a part of the unaltered environment.
History of risk assessment impacting physical environment: occupational
One of the earliest occupational investigations occurred among chimney sweeps in England during the *1700s* -Their high-dose exposure to carbon residues in smokestacks led to early and frequent testicular cancer. In the *1800s* , industrializing countries also provided ample opportunities to study the impacts of work-related exposures. -For instance, the dangers of radiation came to light after high levels of cancer were detected in workers who painted watches with radiation-containing paint for the purposes of nighttime illumination. The dangers of asbestos became evident after high-dose exposures among ship workers during World War II resulted in cases of cancer many years later. The dangers of exposure to polyvinyl chloride, a common industrial compound, were recognized after five workers from the same manufacturing plant came down with a rare liver tumor in the *1970s*.
Unaltered environment
Radon, a common naturally occurring breakdown product of uranium, increases the risk of lung cancer. Exposure to naturally occurring sunlight increases the chances of skin cancer, including melanoma—a potentially lethal skin cancer—especially among light-skinned individuals. ~Human activity has altered nearly every aspect of our physical environment. Some alterations to our environment may improve human health—from water treatment, to waste management, to mosquito and flood control. Nonetheless, we need to consider the overall impacts that these changes have on the physical environment.
What risk assessment attempts to do
Risk assessment attempts to evaluate the impact of environmental exposures one at a time and to measure the types and magnitudes of the impacts. If a substantial risk is found to exist, the process then reviews options to protect, detect, and react to the risk to minimize the burden of disease on humans
How does risk assessment address the impacts of the physical environment?
Risk assessment is a formal process that aims to measure the potential impact of known hazards A *hazard* indicates the inherent danger of an exposure while a *risk assessment* aims to take into account not only the inherent danger, but also the quantity, route, and timing of the exposure. The risk assessment approach to environmental hazards represents the mainstay of our current approach. The underlying principles have a long history in public health, often resulting from the investigation of specific occupational exposure
What is being done to keep the population safe?
Safety is approached like many other public health issues: the problem is described; risk and protective factors are identified; and interventions and strategies are developed, implemented, evaluated, and disseminated. *All-hazards approach* : * Using surveillance systems, communication systems, evacuations, and an organized health care response -The DHS has developed what is called an all- hazards approach. *Outbreak investigations* : -One of the most visible public health tools used to keep populations safe. -These investigations conjure images of public health professionals serving as "disease detectives," tracking and responding to outbreaks of acute disease, and these investigations are often viewed as quintessential public health. *National incident management system* (NIMS): -which is part of the Department of Homeland Security (DHS). -A central feature of the NIMS is an incident command system (ICS) *Incident command system* (ICS): - widely used by police, fire, and emergency management agencies. The ICS attempts to establish uniform procedures and terminology, and an integrated communications system with established and practiced roles for each agency. The goal is to integrate these approaches into ongoing operations and not reserve them solely for emergency situations - CDC injury center
we cannot evaluate the impact of toxic exposures solely by tracing them to human deaths and disabilities
The altered environment has impacts on entire ecosystems of plants and animals. The ecological impact of environmental factors can have long-term and largely irreversible consequences. Once chemicals, radiation, and biological products are released into the environment, the process cannot generally be easily reversed. Thus, we need to take a broad and long-term perspective when we address environmental health
What Are the Health Impacts of the Built Environment?
The impacts of the built environment are most evident in urban areas. to tuberculosis, lack of clean water was a recognized cause of diarrheal diseases, uncollected garbage was thought to lead to an increase in rat borne disease, and noise was thought to contribute to mental illness. All of these conditions and other urban hazards were addressed as part of public health efforts in the late *1800s* and early *1900s* In recent years attention has been focused on the subtler impacts of the way cities are constructed. The dependence on the automobile for transportation has resulted in increased air pollution and reduced exercise
Healthy Communities or Healthy Cities.
The impacts of the urban environment go even deeper than air pollution and lack of exercise. They also involve important social implications that are being recognized in a new movement The Robert Wood Johnson Foundation (RWJ) has taken a lead role in defining an approach to Healthy Communities which they call "creating a culture of health." Creating a culture of health addresses a wide range of social issues from housing to employment, crime, social interactions, and recreational opportunities.
The risk assessment process builds in a margin of error designed to provide extra protection for especially vulnerable individuals or populations.
Thus, those exposed to levels above the recommended maximum levels of exposure will not necessarily experience adverse effects.
How do we interact with our physical environment (box 8.2)-pg. 167
To understand how the physical environment—be it the unaltered, altered, or built environment—affects health, we need to explore the myriad ways that we interact with it. Because of the complexity of the interactions between human beings and the physical environment, a range of approaches has been developed for addressing these issues. We will categorize and examine these approaches as follows: * Risk assessment* *Public health assessment* *Ecological assessment* *Interaction analysis* ~We can think of these strategies as a progression of approaches of increasing complexity. We will organize our approach to environmental diseases and injuries starting with risk assessment and proceeding in order to examine each of these strategies.
The impact of toxic substances on population health
extends beyond acute symptoms such as skin and respiratory irritation to chronic conditions. The impact on death and disability is difficult to measure due to the length of time the substances may take to affect the body. It may be years after an exposure before an individual experiences negative health effects on their kidneys, liver, nerves, and other organs.
Risk assessment today (box 8.3) (figure 8.2)-pg. 168-169
has become a complex technical effort requiring quantitative measures of the magnitude of the risk. The history of risk assessment in the United States is closely tied to the investigations and regulations surrounding benzene (box 8.3) The formal process of risk assessment represents the current framework for assessing environmental hazards in the United States( figure 8.2) Risk assessment attempts to evaluate the impact of environmental exposures one at a time and to measure the types and magnitudes of the impacts. If a substantial risk is found to exist, the process then
multiplicative interaction (8.7)-pg.173
provide an approximation of the risk of two or more exposures. However, in an increasing number of situations, we are recognizing that there are interactions between exposures themselves so that the presence of both exposures results in an overall impact much greater than expected. For instance: we may find that having both exposures results in a relative risk of a bad outcome of 4 times 6, or 24, instead of 10.
Motor vehicle injuries and exposure to toxic substances are two important actual causes of death
represent the largest known impact of the physical environment Motor vehicle injuries and other unintentional injuries have especially heavy impacts on the young; in fact, they are the number one cause of death in the United States among those 1−24 years of age. As a cause of disability, injuries also rank high especially considering their disproportionate impact on the young.
In an effort to alert individuals to the air quality in their region: (table and box 8.1)
the Environmental Protection Agency (EPA) created an Air Quality Index (AQI) The (AQI) is an index for reporting daily air quality. It focuses on health effects that may be experienced within a few hours or days after breathing unhealthy air. The AQI is calculated for four major air pollutants regulated by: *The Clean Air Act* : (1) ground level ozone (2) particle pollution, (3) carbon monoxide (4) sulfur dioxide.
altered environment
the impact of chemicals, radiation, and biological products that humans introduce into the environment
health equity
which RWJ defines as follows: "... we cannot leave anyone behind. Everyone should have the opportunity to pursue the healthiest life possible, no matter where they live or work, the color of their skin, or the amount of money they have
The impact on the physical environment of so many humans takes two major forms:
■■ Consumption of resources such as land, food, water, air, fossil fuels, and minerals ■■ Waste products as a result of consumption such as air and water pollutants, toxic materials, and greenhouse gases
