The relationship between mild alcohol consumption and mortality in Koreans: a systematic review and meta-analysis

BACKGROUND A recent systematic review reported that mild drinking showed beneficial effects on mortality. However, this relationship between alcohol consumption and mortality differs by race, and there are few studies on Koreans. In this study, we reviewed previous studies conducted on Koreans to investigate the association between mild drinking and mortality. METHODS Four databases (Medline, Web of Science, KoreaMed, and DBpia) were searched. Studies investigating the risk of alcohol consumption on three types of mortality (all-cause mortality, cancer-related mortality, and cardiovascular mortality) for Koreans were included. RESULTS A total of 16 studies assessed alcohol consumption as a risk factor for mortality. Nine studies reported on the risk of alcohol consumption in relation to all-cause mortality, eight to cancer-related mortality, and three to cardiovascular mortality. Among these, only studies assessing alcohol amount not drink status or drink frequency were included in meta-analysis. The results of the meta-analysis did not show a significant effect of mild alcohol consumption on all-cause mortality (5 studies, OR: 0.85, 95 % CI: 0.72, 1.01). While meta-analysis of studies using all-cancer mortality showed significant effect of alcohol consumption (4 studies, OR: 0.89, 95 % CI: 0.85, 0.94), results of studies including all-cancer and specific type of cancer was not significant (7 studies, OR: 1.02, 95 % CI: 0.9, 1.15). Although a meta-analysis of cardiovascular mortality could not be conducted owing to a lack of studies, all studies reported a non-significant effect of occasional or mild alcohol consumption. DISCUSSION In this study, mild alcohol consumption in Korean did not show beneficial effect on mortality and it might be caused by three factors: criterion of mild drinking, the subjects, and sample size. The criterion of mild alcohol consumption was diverse in included studies. The effect of alcohol consumption could differ based on subjects' sex, age as well as race. In addition, the effect of alcohol consumption might be different from previous one due to the small number of studies. CONCLUSIONS Mild alcohol consumption did not show any beneficial effects in relation to all-cause, cancer-related, and cardiovascular mortality. Additional studies are necessary to verify any association between mild drinking and mortality in Koreans.