Study variables were assessed by interview, using versions of the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) [26]. BMI was calculated from self-reported height and weight. Participants were removed from data analysis if they had missing data on either height or weight, height was < 1.4 or > 2 meters, weighed < 38 or > 166 kg, or if calculated BMI was < 14.5 or > 60 kg/m2, as values not in these ranges were likely due to data entry errors or suggestive of eating or syndromic disorders (n = 12). Clinical bodyweight categories were defined as overweight (BMI ≥ 25 kg/m2), obese class I (BMI ≥ 30 kg/m2), II (BMI ≥ 35 kg/m2) and III (BMI ≥ 40 kg/m2). Age was included as age at interview in years. Alcohol dependence (AD) was defined by the SSAGA according to DSM-IV criteria [27] and nicotine dependence (ND) was defined as having a Fagerström Test for Nicotine Dependence score of 4 or greater as assessed from the SSAGA.
