You Are Investigating the Role of Physical Activity in Heart

Multiple Choice

You are investigating the role of physical activity in heart disease and suggest that physical activity protects against having a heart attack. While presenting these data to your colleagues, someone asks if you have thought about confounders such as factor X. This factor X could have confounded your interpretation of the data if it:

A) is a factor for some other disease, but not heart disease.
B) is a factor associated with physical activity and heart disease.
C) is a part of the pathway by which physical activity affects heart disease.
D) has caused a lack of follow-up of test subjects.