Deck 2: Physical Activity, Mortality and the Nature of the Evidence

Question 1

Which of the following is the most fundamental limitation of studies linking physical inactivity to an increased risk of mortality?

A) Lack of randomised controlled trials
B) Lack of control of pre-existing illness
C) Measurements of mortality are often inaccurate
D) Physical activity has been assessed using questionnaires and these may be inaccurate

Answer 1

A

Question 2

How many additional years could an active/fit individual expect to live by avoiding premature mortality compared with an inactive/unfit individual?

A) 0.5-1.5 years
B) 1.5-4 years
C) 4-5.5 years
D) 5.5-8 years

Answer 2

B

Question 3

Why is the association between television viewing and mortality thought to be stronger than the association between overall sitting time and mortality?

A) Television viewing can be more accurately recalled than overall sitting time
B) Television viewing is linked to the clustering of other risk factors for mortality
C) Television viewing is more commonly measured than overall sitting time
D) Television viewing is associated with a lower energy expenditure than overall sitting time per unit of time

Answer 3

B

Question 4

According to the meta-analysis by Kodama et al. (2009), what is the mortality rate associated with each 1 MET increase in cardiorespiratory fitness?

A) 5% lower
B) 48% lower
C) 13% lower
D) 22% lower

Question 5

Which of the following statements is false?

A) The risk of premature mortality is lower in individuals who become more active over time than those who remain inactive
B) The strength of association with mortality is stronger for cardiorespiratory fitness than physical activity
C) The risk of mortality associated with high levels of sitting can be attenuated by being sufficiently active
D) Higher levels of physical activity abolish the adverse effects of obesity on mortality

Question 6

What type of study is the Aerobics Center Longitudinal Study?

A) Case-control
B) Prospective cohort
C) Randomised controlled trial
D) Cross-sectional survey

Question 7

Which statistic quantifies the proportion of individuals in a population that exhibits the outcome of interest at a specified time?

A) Relative risk
B) Incidence
C) Prevalence
D) Population-attributable risk

Question 8

In epidemiology, what is meant by 'confounding'?

A) Distortion of the effect of an exposure on disease because of systematic error
B) Introduction of a systematic error into results because of selection bias
C) Distortion of the effect of an exposure on disease because a third factor associated with the exposure independently affects the risk of developing the disease
D) A finding due to chance or the 'luck of the draw'

Question 9

What does the unit called the 'MET' measure?

A) Total volume of physical activity
B) Intensity of physical activity relative to the individual
C) Intensity of physical activity relative to V̇O₂max reserve
D) Intensity of physical activity in multiples of the resting metabolic rate

Question 10

Which of the following statements is false?

A) Physical activity has most commonly been measured using questionnaires in epidemiology
B) Questionnaires systematically underestimate MVPA compared with accelerometers
C) Inaccuracy of questionnaire-based measures of physical activity may attenuate relationships between physical activity and health-related outcomes
D) Accelerometers can measure dynamic accelerations and body posture in real time