Each alcohol measure was log-transformed (left anchored at 1) to adjust for positive skew. Relationship status was measured by asking: ‘How long (in years) have you been together with your present partner?’. Respondents that indicated they were not in a relationship were coded as 0. Those who indicated they were in a romantic relationship for any length were coded as 1. We ran sensitivity analyses with a stricter definition of relationship status (those in a relationship ≥ 2 years). Our results did not fundamentally differ from the more inclusive definition and we retained the original measurement of relationship status. Finally, we included age, sex, educational attainment (based on the Finnish education system: basic education; vocational training; secondary education; tertiary education) and whether or not respondents were still in school [50] as covariates.
