environmental health

Question 1

What is environmental health?

Answer 1

• The branch of public health that focuses on all aspects of the natural and built environment that may affect human health.
• Field of EH tends to focus on man-made (anthropogenic) environmental hazards that lie outside of an individual’s immediate control (involuntary)

Question 2

why is environmental health important?

Answer 2

Globally, nearly 25 percent of all deaths and the total disease burden can be attributed to environmental factors

Question 3

Environmental Factors affecting health

Answer 3

Exposure to hazardous substances in the air, water, soil & food
Natural and technological disasters
Physical hazards
Nutritional deficiencies
The built environment

Question 4

environmental quality and health impact

Answer 4

Poor environmental quality has its greatest impact on people whose health status is already at risk. Therefore, environmental health must address the societal and environmental factors that increase the likelihood of exposure and disease.

Question 5

Environmental health on a global scale

Answer 5

Note that environmental exposures and their effects on human health vary across the globe.
With economic development and population change, there introduces the potential for Environmental Risk Transmission

Question 6

Three demographic transition stages

Answer 6

Stage 1 → most of the population is young; fertility and mortality rates are high; the population remains small
Stage 2 → drop in mortality rate; fertility remains high; rapid increase in population
Stage 3 → drops in fertility rates causing a more even distribution of the population according to age and sex

Question 7

Environmental Risk Transition

Answer 7

Changes in environmental risks that happen as a consequence of economic development in the less developed regions of the world

Question 8

Environmental Risk Transition in less and more developed countries

Answer 8

Less developed countries
—Risks due to poor housing, unsafe food and water (i.e. diarrhea, malaria)
More developed countries
—-New set of environmental problems— Risks due to long-term exposure to pollution, chemical exposures (i.e. cancer, developmental disabilities)

Question 9

Epidemiologic Transition

Answer 9

Shift in pattern of morbidity and mortality

TOP TEN LEADING CAUSES OF DEATH

Question 10

What is epidemiology

Answer 10

The study of the distribution and determinants of disease frequency in human populations……and the application of this study to control health problems; “population medicine”

Question 11

What is environmental epidemiology

Answer 11

• Focuses on diseases linked to environmental exposures/hazards
• Usually focuses on factors that are beyond a persons control

Question 12

Descriptive epidemiology

Answer 12

• includes surveillance
• Track and compare disease rates in populations across place or time
• Provides info for understanding risk factors for disease

Question 13

Analytical epidemiology

Answer 13

• epidemiological research/studies

- Document link between exposure and disease

Question 14

Descriptive epidemiology: Measures of disease frequency

Answer 14

Prevalence

incidence

Question 15

prevalence

Answer 15

• Number of existing cases of a disease in a population at a certain point in time
• # of existing cases of disease / total # of people in population
• Provides a snapshot of disease occurrence in the population
• used to:
• —Assess variation in disease occurrence
• —Estimating needs of medical facilities and for allocating resources for treating people who already have a disease
• —Aid in the development of hypotheses

Question 16

incidence

Answer 16

• Different from prevalence because it focuses on the number of NEW cases of a disease that develop in a population at risk during a certain period of time
• # of NEW cases of disease / total # of people at risk (during a given period of time)
• used to:
• —Estimate the probability of someone developing a disease during a certain period of time
• —evaluate effectiveness of programs that try to prevent disease from occurring
• —demonstrate causality between an exposure and a health outcome

Question 17

types of study design

Answer 17

experimental and observational studies

Question 18

types of experimental studies

Answer 18

clinical trial/Randomized control trials

Question 19

types of observational studies

Answer 19

cohort
cross-sectional
case-control
ecological
case series

Question 20

cohort studies

Answer 20

Classify participants based on exposure status, then observe them over time to determine incidence of disease
Prospective - Outcome has not yet occurred
enroll now and follow in the future
Retrospective — outcome has already occurred
use historical records to assess health outcome
Good for identifying multiple outcomes
Not good for identifying multiple exposures

Question 21

case-control studies

Answer 21

Classify participants based on presence or absence of disease
Cases — have the disease
Controls — sample of pop. that produced the cases and do not have the disease
Determine exposure retrospectively
Good for studying rare outcomes (can only examine one or a few outcomes)
Good for identifying multiple exposures

Question 22

cross-sectional studies

Answer 22

Assess exposure and disease status at the same point in time
Unable to tell which came first — exposure or disease
Not good for testing hypotheses
Good for generating hypotheses

Question 23

ecological studies

Answer 23

Evaluates an association between disease and exposure on the population level
Individual data are not used
Ecological Fallacy — Unknown if people with disease are the same people that have been exposed
Good for looking at association and generating hypotheses

Question 24

case series

Answer 24

Collect information about people who all have the same disease
Not good for finding causal associations
Good for developing hypotheses

Question 25

identification of vulnerable populations

Answer 25

children
elderly
pregnant women
people with disabilities / chronic diseases
occupation (increased vulnerability/exposure w specific jobs

Question 26

limitations of environmental epidemiology

Answer 26

Long latency periods
low incidence and prevalence
recall bias

Question 27

recall bias

Answer 27

People with disease may be more likely to recall an exposure than people without a disease
Reduced reliability of exposure information from control group

Question 28

difficulties in exposure assessment

Answer 28

• Need accurate exposure assessment
• Exposure often misclassified
• Challenging to measure exposure to a chemical mixture
• Challenging to monitor low-level environmental exposures
• Lack of individual exposure measurements - ambient measurements do not provide direct information about an individual’s exposure

Question 29

Hills criteria of causality

Answer 29

strength, consistency, specificity, temporality, biological gradient, plausibility, coherence