Are psychosocial stressors associated with the relationship of alcohol consumption and all-cause mortality?

BACKGROUND Several studies have shown a protective association of moderate alcohol intake with mortality. However, it remains unclear whether this relationship could be due to misclassification confounding. As psychosocial stressors are among those factors that have not been sufficiently controlled for, we assessed whether they may confound the relationship between alcohol consumption and all-cause mortality. METHODS Three cross-sectional MONICA surveys (conducted 1984-1995) including 11,282 subjects aged 25-74 years were followed up within the framework of KORA (Cooperative Health Research in the Region of Augsburg), a population-based cohort, until 2002. The prevalences of diseases as well as of lifestyle, clinical and psychosocial variables were compared in different alcohol consumption categories. To assess all-cause mortality risks, hazard ratios (HRs) were estimated by Cox proportional hazards models which included lifestyle, clinical and psychosocial variables. RESULTS Diseases were more prevalent among non-drinkers than among drinkers: Moreover, non-drinkers showed a higher percentage of an unfavourable lifestyle and were more affected with psychosocial stressors at baseline. Multivariable-adjusted HRs for moderate alcohol consumption versus no consumption were 0.74 (95% confidence interval (CI): 0.58-0.94) in men and 0.87 (95% CI: 0.66-1.16) in women. In men, moderate drinkers had a significantly lower all-cause mortality risk than non-drinkers or heavy drinkers (p=0.002) even after multivariable adjustment. In women, moderate alcohol consumption was not associated with lowered risk of death from all causes. CONCLUSIONS The present study confirmed the impact of sick quitters on mortality risk, but failed to show that the association between alcohol consumption and mortality is confounded by psychosocial stressors.