Epidemiology

Question 1

Person-Place-Time Model

Answer 1

• Person: “who” factors; demographic characteristics, hlth, & disease status
• Place: “where” factors; geographic location, climate & envirn’t conditions, & political & social envirn’t
• Time: “where” factors; time of day, week, or month & secular trends over mnths & year

Question 2

Epidemiological Triangle

Answer 2

• Agent: etiologic factors
• Host: intrinsic factros
• Environment: extrinsic factors

Question 3

Agent: Etiologic Factors

epidemiological triangle

Answer 3

1. Nutritive elements:
   > excesses, deficiencies
2. Chemical agents:
   > poisons & allergens
3. Physical agents:
   > ionizing radiation, mechanical
4. Infectious agents:
   > metazoa
   > protozoa
   > bacteria
   > fungi
   > rickettsia
   > viruses

Question 4

Host: Intrinsic Factors

epidemiological triangle

Answer 4

1. Genetic makeup
2. Age
3. Sex
4. Ethnic group
5. Physiological state
6. Prior immunological experience
   > active/passive
7. Intercurrent or preexisting disease
8. Human behavior

Question 5

Environment: Extrinsic Factors

epidemiological triangle

Answer 5

• Influence existence of the agent, exposure, or susceptibility to agent
• Phsyical envirn’t
• Biological envirn’t
  > human pops, flora, fauna
• Socioeconomic envirn’t
  > occupation, urbanization, & economic development, disruption

Question 6

Calculation of Rates

Answer 6

• Rate = # of hlth events in a specified period OVER pop in same area in same specified period
• Ratio: compare 1 number w/ another (EX: compare female borths w/ male births)
• Proportions: can describe characteristics of a pop; often documented as a %

Question 7

Incidence Rates

Answer 7

• Describe occurence of new cases of a disease or condition in a community over a given period
• May be most sensitive indicator of changing hlth of a community, bc it captures the fluctuations of disease in a pop
• Valuable for monitoring trends in chronic disease & useful in detecting short-term changes in acute disease (flu or measles)

Question 8

Attack Rates

Answer 8

• A specialized form of incidence rate
• # of new cases of diseasein those exposed to disease

Question 9

Prevalence Rate

Answer 9

• # of all cases of a specific disease or condition in a pop at a given point in time relative to pop at same point in time
• Influenced by # of ppl who experience a particular condition & duration