In the HBCS, alcohol use has been measured with a single item on the frequency of alcohol use (‘Have you recently used any alcoholic beverages; e.g. beer or spirit?’) with response options ranging from quitted completely (0), never used (1), less than once a month (2), 1–2 times a month (3), 1–2 times a week (4), three to seven times a week (5). Due to not knowing the reason for quitting alcohol consumption, the participants stating ‘Quitted completely’ were discarded from the analyses (n = 63). A total of 1393 participants had both genotypic and alcohol consumption data available. Of these, participants with X-chromosomal genotypes discrepant with the reported sex were removed from the analyses on alcohol consumption (n = 9). Altogether 1384 participants were thus included in the analyses on alcohol consumption.
