Health Epidemiology and Exercise

Question 1

Distribution

Answer 1

frequency and patterns of disease occurrence in a population

Question 2

Prevalence

Answer 2

• *how often the disease occurs (commonness)**
  ex) the prevalence of all cardiovascular diseases in the US was estimated to be 58,800,000 people or 25% of the population

Question 3

Incidence/occurrence

Answer 3

• *rate of new** disease or health events
  ex) the mortality rates for cardiovascular disease were 304 per 100,000 in the US in 2001

Question 4

epidemiological research

Answer 4

is observational not experimental
ex) a portion of the population chooses to drink while others do not

Question 5

why is epidemiological research important?

Answer 5

it is virtually the only way in which a quantitative understanding of the exposure-disease relationship can be obtained

ex) it would be unethical to randomize a group of individuals to either a drinking or non-drinking condition, wait 10 years, then see how much death and disease, drinking causes

Question 6

types of epidemiological study designs

Answer 6

analytical

case-control

cohort

Question 7

analytical study designs

Answer 7

the analytical designs are designed to test specific hypotheses regarding causal links between various exposures and mortality and incidence outcones using purely observational methods

• cohort
• case-control

Question 8

person year

Answer 8

represents 1 year of observation for one person during the follow-up period

Question 9

cohort studies

Answer 9

• what happens to smokers?
  ex) compare smokers and non-smokers with the incidence of lung cancer
• whatever the topic, a group of individuals is identified and watched to see what events befall them
• disease rates in cohort studies are often expressed relative to “person years” of follow-up
• terms like prospective studies, and longitudinal studies have all been used to describe the cohort study design

Question 10

cohort study research example

Answer 10

• enrolled 17,000 male Harvard alumni 35-74 years in 1962 and 1966
• baseline - participants completed questions about their daily physical activities
• using simple questions about walking, stair climbing, and exercise activities participants were categorized into six levels of physical activity energy expenditure: <500; 500-999; 1000-1999; 2000-2999; 3000-3999; 4000+ kcal/week
• 6-10 follow up period for heart attacks

Question 11

case-control studies

Answer 11

• case-control studies select patients with a defining characteristic: a diagosed disease
  ex) women with breast cancer
• the characteristics of these are compared with a control group (often similar in age, sex, and background) who do not have the disease
• because the method looks backwards in time its sometimes called a retrospective study
• these types of studies usually look for treatments which reduce event rates

Question 12

case-control study example (Bernstein)

Answer 12

Question 13

what is MET?

Answer 13

MET refers to “metabolic equivalent”, a unit used to estimate the metabolic cost of physical activity

the value of 1 MET is approximately equal to a person’s resting energy expenditure

all activities can be categorized as multiples of resting energy expenditure

ex) walking is considered to be 4 METS because it requires an energy expenditure 4 times greater than that required at rest

Question 14

physical activity and risk of breast cancer, colon cancer, diabetes, ischemic heart disease and ischemic stroke events

Answer 14

by Kyu

relative risks - anything less than 1 is reducing the risk

MET - level of physical activity

more level of physical activity -> significantly reduces risk of ischaemic heart disease, ischaemic stroke and diabetes (levels off after 3000 - 4000 MET min/week)

colon cancer is reduced but not as much as the diseases like diabetes

breast cancer is reduced slightly

each profile (disease) has their own drop offs and relationships between physical activity