1. A cohort study of physical activity (PA) and incidence of diabetes was conducted over a six-year period among Japanese-American men in Honolulu. Data from that study are summarized here, stratified by body mass index (BMI):

Describe three reasons why we might want to control for BMI in this study in the order in which they should be considered. Using results from OpenEpi do you think that BMI should be controlled for in this study and if so, why?