Alcohol use disorders (AUD) is well known to aggregate in families and is associated with socioeconomic status (SES). The objective was to study the effect of education, income and neighborhood SES in adulthood on AUD, and to explore whether the potential associations were confounded by shared familial factors, by using a co-relative control design.
Data on AUD was drawn from the Swedish inpatient and outpatient care registers; prescription drug register; and crime data. Through national population registers we collected information on income, education and neighborhood SES at age 25, 30, 35 and 40 years in all individuals born in Sweden between 1950 and 1980. Each sex-specific stratum consisted of approximately 750,000-1,200,000 individuals, who were followed for AUD for a mean follow-up time ranging between 10 and 15 years until the end of 2013. Cox proportional hazards models were used to investigate the risk of AUD as a function of income, education and neighborhood SES in the general population and in pairs of first cousins and full siblings within the same sex, who differed in their exposure to the SES measure.
Higher educational level, higher income and higher neighborhood SES were all associated with a reduced risk for AUD for both males and females in all ages. The potentially protective effect remained but was attenuated when comparing pairs of first cousins and full siblings.
High educational level and income in adulthood, as well as high neighborhood socioeconomic status, may represent protective factors against alcohol use disorders, even when shared familial factors, e.g. childhood socioeconomic status and genetic factors, have been taken into account.