Deck 13: Epidemiologic Aspects of Work and the Environment

Question 1

Define the following terms:
a. environmental epidemiology
b. latency
c. synergism
d. threshold
e. dose-response curve
f. ionizing radiation
g. hazard surveillance

Answer 1

(a)Environmental epidemiology is the learning of conditions and maladies that are correlated to environmental indicators. It aims to understand how chemical, physical, biologic, economic, and social factors affect the population.
(b)Latency is the time interval amid the start of contact and the response. The range of latency period is from seconds to a decade. The long latency period makes it difficult for the research to detect hazards.
(c)Synergism is the interaction from the combination of several exposures to factors that produces a greater outcome than separate effects.
(d)Threshold refers to the point at which a stimulus primarily fabricates a sensation. Effects of low-level exposure are difficult to assess. Some researchers believed that low-level exposure might give protective effects to high-level exposures.
(e)Dose-response curve is a curve that illustrates the correlation amid the exposure and its effect. It is illustrated through a graph. The dose is indicated along the x-axis and the response is shown on the y-axis.
(f)Ionizing radiation is a form of energy that is more intensive than nonionizing radiation. It consists of particle energy or electromagnetic energy.
(g)Hazard surveillance is the evaluation of biologic, chemical, and physical agents in the work area. It is utilized to identify if the agents are hazardous and formulate necessary action to avoid the susceptibility of workers.

Question 2

A hypothetical community located near a large military base is suspected of having a toxic chemical present in the groundwater. Propose the design of a case-control and a cohort study to examine the impacts on humans of exposures to the toxic chemicals.

Answer 2

Case-control study design:
Case-control study gathers information on the history of exposures to environmental hazards and toxins on people who do not have or have a health condition. It provides complete data, particularly information from family members and friends of the person. Cohort study selects an assortment of non-exposed and exposed entities and monitored them over the time to assess exposure effect. This study is commonly utilized to evaluate the end-result of the inherent risk factors that is not managed during experiment.
Cohort Study design

Question 3

An ecologic study reports an increase in mortality in census tracts that have high levels of air pollution in comparison with less polluted census tracts. What are some possible alternative explanations for the findings of the study?

Answer 3

Air pollution is the contamination of the atmosphere by chemical, physical, or biological agent. This leads to maladies and death to the exposed populace. The components of air pollution are particles, oxidants, sulfur oxide, lead, and some heavy metals. Formaldehyde, gas stove, and cigarette smoke are form of indoor air pollution. Rapidly industrializing countries have increased severe air pollution.
Air pollutions affect the people by posing peril to respiratory structures. Thin airborne particulates are inhaled into the lungs. They then enter the cardiovascular system. These particles can bypass the body's defense and distributed through the whole system. Individuals who have pre-existing condition such as heart and lung disease are at risk of the fatal effects of air pollution. The synergistic effect of air effluence and cigarette smoking leads to serious lung condition.
Mortality rate are linked to fine and inhalable particles and aerosol acidity. Exposure to carbon monoxide augments the jeopardy of developing cardiovascular and respiratory maladies and aggravating the existing condition.

Question 4

What is meant by end points in occupational health studies? Discuss the advantages and disadvantages of using each of the following end points: self-reported symptoms, results of clinical examinations, and mortality.

Question 5

How does the "healthy worker effect" influence the interpretation of findings from occupational health research? An epidemiologic researcher finds that mortality for assembly line workers in an automobile factory is slightly higher than the mortality of the general population. Assume that the healthy worker effect is operative. Would it tend to decrease or increase mortality differences between the workers and the general population?

Question 6

Name the four major classes of pesticides. What are some of the possible hazards associated with the organochloride pesticide DDT?

Question 7

Discuss the possible long-term and short-term effects that farm workers may experience when they are exposed to organophosphate pesticides.

Question 8

List examples of metallic compounds that pose environmental hazards. What are some examples of health effects thought to be associated with arsenic, mercury, and lead?

Question 9

Discuss the possible health effects that have been associated with exposure to electric and magnetic fields and ionizing radiation. What methodologic difficulties exist with respect to investigations of the health effects of these forms of radiation?

Question 10

Examples of environmental hazards found in the work setting include biologic agents, mineral and organic dusts, vapors, and occupational stress. What are possible roles for epidemiologists in designing research studies to investigate and control exposures to these hazards?

Question 11

Identify challenges and opportunities for epidemiology from the following environmental health problems: hazardous waste sites, air pollution, and nuclear electricity-generating plants.

Question 12

Name three historically important lethal air pollution episodes. What countries or regions of the world are currently faced with extremely poor air quality?

Question 13

Describe two major adverse health outcomes associated with air pollution. Give your own opinions about what can be done to control air pollution.

Question 14

Define the term passive smoking. State why public health officials are concerned about exposure to secondhand tobacco smoke. What is being done to control secondhand tobacco smoke?

Question 15

Describe the 1986 incident in Chernobyl. What health effects have been studied in relation to this event? Have similar events occurred in the United States?

Question 16

Why is the availability of a reliable and safe water source a concern to officials in the United States and the rest of the world? What types of challenges impact the availability of a safe water supply? What is meant by the term TTHM, and why is it relevant to water quality?

Question 17

Regarding the various environmental epidemiologic topics covered in this chapter, name three common challenges that relate to exposure assessment.