BMI classification was chosen as the primary outcome variable; BMI was calculated from self-reported data as weight (in kg) divided by height (in meters) squared. BMI scores were used to classify participants as obese, defined as BMI >=30 kg /m2, and non-obese, defined as BMI <30 kg/m2..1 This dichotomous classification was used instead of BMI as a continuous variable because of the aforementioned change in the shape of the BMI distribution over time. Moreover, relationships between BMI and morbidity or mortality may be nonlinear,26–28 suggesting that changes in obesity are more relevant for public health considerations than the overall change in mean BMI. The primary predictor variable, family history of alcoholism, was defined as having either a biological parent or full biological sibling with a history of problem drinking or alcoholism based on the AUDADIS family history assessment.
