Understanding the differential effect of alcohol consumption on the relation between socio-economic position and alcohol-related health problems: results from the Stockholm Public Health Cohort.

AIM: To test (i) whether the harmful effects of average volume of alcohol consumption (AC) and heavy episodic drinking (HED) differ by socio-economic position (SEP), and (ii) if so, to what extent such differential effects can be attributed to an unequal distribution of harmful levels and patterns of drinking, health, life-style and social factors.

DESIGN

A longitudinal cohort study with baseline in 2002 or 2006, with record-linkage to national registers.

SETTING

Stockholm County, Sweden.

PARTICIPANTS

A total of 37 484 individuals, aged 25-70 years, responding to the survey in 2002 or 2006.

MEASUREMENTS: The outcome of alcohol-related health problems was obtained from the National Patient Register and Cause of Death Register using the Swedish index diagnoses related to alcohol use. Self-reported information on occupational class (measure of SEP), AC, HED as well as other health-related factors were extracted from the surveys. Average follow-up time was 13.3 years.

FINDINGS: During follow-up, a total of 1237 first-time events of alcohol-related health problems occurred. After initial adjustments, heavy drinking appeared to be more harmful to individuals with low SEP compared with high SEP (P = 0.001). Differences in HED frequency explained the largest part of the differential effect of AC. Engaging in weekly HED was more harmful to individuals with low SEP (P = 0.031) than high SEP. Differences in AC, together with other factors, explained a large part of the differential effect of HED. Conclusions The greater adverse impact of alcohol consumption on health in Sweden on people with lower socio-economic position may be largely attributable to higher prevalence of heavy episodic drinking, as well as other behavioral and social risk factors.