Frequency and quantity information were used to calculate separate “grams of ethanol consumed per month” alcohol use variables for the baseline and follow-up assessments. At the baseline assessment for the first cohort, participants reported on their alcohol use on continuous measures. The continuous alcohol frequency question was, “During the past 30 days, on how many days did you drink one or more drinks of an alcoholic beverage?” with response options 0 through 30 at one day intervals, I choose not to answer and Don't know. The continuous alcohol quantity question was, “On the days that you drank during the past 30 days, how many drinks did you usually have each day?” with response options 1 through 20 at one drink intervals, more than 20, I choose not to answer and Don't know.
