Lecture 2 (Measurement)

Question 1

Uses: descriptive studies

Answer 1

• Common or rare?
• Who does it affect more?
• Increase or decrease over yrs?
• Cyclical aspect?
• Generate hyps

Question 2

Measures can be:

Answer 2

1) Rates (time dimension, measure of risk)

2) Proportions (no time dimension, not measure of risk)

Question 3

Incidence

Answer 3

• Rate of new cases over specified period
• Measure of risk: prob that smn w/o disease will get it
• UNITS: multiplier and time period

Question 4

Cumulative incidence

Answer 4

• Larger, dynamic pop
• Everyone observed for same amount of time
• % of deaths/loss to follow up = low

Question 5

Incidence density

Answer 5

• Person-time denominator

- Diff members observed for diff amounts of time (cohort study)

Question 6

Prevalence

Answer 6

• Proportion of cases (NOT rate, NOT measure of risk)
• Useful measure of burden of disease
• Distorted by factors influencing survival (^ could mean ppl living longer)

= (~) incidence x mean duration of illness

Question 7

Point prevalence

Answer 7

• Proportion of ppl in defined pop w/disease at a specified point in time (not just new cases)
• Not rate, no time unit

Question 8

Period prevalence

Answer 8

• Proportion of ppl in defined pop that had disease at some point during specified period
• Not rate, no time unit

Question 9

Morality rate

Answer 9

• Measure of risk

- Good approximation of incidence rate when case fatality is high and duration is short

Question 10

Specific rates

Answer 10

• Restriction placed on numerator and denominator (age, sex, etc.)
• Calculated for incidence, prevalence, or mortality

Question 11

Case fatality rate

Answer 11

-Proportion of cases of specified disease that are fatal w/in a specific time period

died/# w/in disease in same period

Question 12

Proportionate mortality

Answer 12

-Relative proportion of cause of death compared to others (nothing about risk)

# of deaths cause A/total deaths (same time/pop)
All x100 (expressed as %)

Question 13

Age standardized rates

Answer 13

-To account for age paradox (mortality rises steeply w/age)

Question 14

Direct age-adjustment

Answer 14

= sum (incidence rate x standardized weight)

Question 15

World Vital Statistics

Answer 15

-Specialized studies such as Global Burden of Disease Study (WHO and World Bank): standardized estimates of mortality and disability in 1990

Question 16

Causes of death in developed world

Answer 16

• Mostly chronic diseases (heart disease, lung cancer, lower resp infections)
• More communicable diseases (lower resp infections, heart disease, diarrheal disease)

Question 17

Leading causes of death in Can

Answer 17

1. Cancer
2. Heart disease
3. Stroke
4. Accidents