Background Although guidelines suggest that older adults engage in regular physical activity to reduce heart disease, surprisingly few studies have evaluated this relationship, especially in those >75 years. The researchers wanted to find out whether heart disease was lower among those who had high levels of physical activity compared to those who had low levels of physical activity.

Methods and Results Analysis among 4207 men and women of a mean age of 73 years (standard deviation=6) who were free of cardiovascular disease at the start of the study. Physical activity (assessed as low, moderate, and high) was measured in all participants at the beginning of the study. New heart disease events (yes/no) were assessed from medical records. A total of 1182 heart disease events were noted. The researchers found that greater physical activity was negatively associated with heart disease, even in those 75 years. For example, in comparison with a low physical activity, those in the high category had a lower risk of heart disease (IPR* = 0.50; 95% confidence interval, (0.38-0.67)).

*IPR = incidence proportion ratio (same as risk ratio, RR)

Conclusions - These data provide evidence supporting physical activity recommendations to reduce the incidence of heart disease among older adults.

What is the dependent variable in the study?

• - Older adults
• - Heart disease
• - Gender
• - Physical activity

What is the primary independent (explanatory) variable in the study?

• -Older adults
• -Heart disease
• -Gender
• -Physical activity

What type of measurement is physical activity as described above?

• -Continuous
• -Ordinal
• -Nominal
• -Binary (dichotomous)

What type of measurement is heart disease as described above?

• -Continuous
• -Ordinal
• -Nominal
• -Binary (dichotomous)

What type of measurement is age as described above?

• Continuous
• Ordinal
• Nominal
• Binary (dichotomous)

Based on the excerpt above, what is one way of stating an alternative hypothesis that was tested regarding physical activity and heart disease?

• Heart disease is more common among those with high physical activity compared to those with low physical activity
• Heart disease is less common among those with high physical activity compared to those with low physical activity
• Heart disease is the same among those with high physical activity compared to those with low physical activity
• None of the above

Based on the results of the study, is the relationship between physical activity and heart disease statistically significant?

• Yes
• No

Based on the results of the study, what is the direction of the association between physical activity and heart disease?

• Positive
• Negative
• Null
• None of the above

In this study, what measure of heart disease did the investigators use?

• Incidence
• Prevalence
• None of the above

What type of hypothesis test best describes the one the researchers conducted:

• One-sample test of means
• Independent test of means
• One sample test of proportions
• Comparing two proportions