Association of change in alcohol consumption with cardiovascular disease and mortality among initial nondrinkers

There is a paucity of studies on the influence of alcohol intake among non-drinkers. We evaluated the association between an increase in alcohol consumption and primary prevention of major adverse cardiovascular events (MACE) among non-drinkers. Data collected by the National Health Insurance Service in the Korea between 2007 and 2013 were analysed. A total of 112,403 subjects were included and followed up from 1 January 2011 to 31 December 2013. Increases in alcohol consumption, measured as glasses per day, at the second medical check-up, were categorized into maintenance of nondrinking (0), > 0– ≤ 1, > 1– ≤ 2, > 2– ≤ 4, and > 4. Hazard ratios (HRs) for MACE and all-cause mortality on increase in alcohol consumption were calculated. Compared to that in non-drinkers at the second check-up, the risk of MACE significantly decreased among the subjects with an increase in alcohol consumption to ≤ 1 glass per day (HR 0.79, 95% CI 0.68–0.92). However, a light increase in alcohol consumption did not reduce the risk of stroke or all-cause mortality (stroke, HR 0.83, 95% CI 0.68–1.02; all-cause mortality, HR 0.89, 95% CI 0.73–1.09). Compared to continual non-drinkers, those who drank > 2 glass per day had higher risk for death due to external causes (aHR 2.06, 95% CI 1.09–3.90). The beneficial effect of light increments in alcohol consumption on the occurrence of MACE may have resulted from the inappropriate inclusion of sick quitters, who maintained a nondrinking status, in the reference group.