ABSTRACT: BACKGROUND:The association between change in alcohol intake and metabolic syndrome is unclear. METHODS:This retrospective cohort consisted of 41,368 males and females from the Health Examinees-GEM study. Participants were divided into non-drinkers (0.0 g/day), light drinkers (male: 0.1 to 19.9 g/day; female: 0.1 to 9.9 g/day), moderate drinkers (male: 20.0 to 39.9 g/day; female: 10.0 to 19.9 g/day), and heavy drinkers (male: ?40.0 g/day; female: ?20.0 g/day) for each of the initial and follow-up health examinations. Logistic regression analysis was used to determine the adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for developing metabolic syndrome according to the change in alcohol consumption between the initial and follow-up health examinations. Adjusted mean values for the change in waist circumference, fasting serum glucose (FSG), blood pressure, triglycerides, and high density lipoprotein cholesterol (HDL-C) levels were determined according to the change in alcohol consumption by linear regression analysis. RESULTS:Compared to persistent light drinkers, those who increased alcohol intake to heavy levels had elevated risk of metabolic syndrome (aOR, 1.45; 95% CI, 1.09 to 1.92). In contrast, heavy drinkers who became light drinkers had reduced risk of metabolic syndrome (aOR, 0.61; 95% CI, 0.44 to 0.84) compared to persistent heavy drinkers. Increased alcohol consumption was associated with elevated adjusted mean values for waist circumference, FSG, blood pressure, triglycerides, and HDL-C levels (all P<0.05). Reduction in alcohol intake was associated with decreased waist circumference, FSG, blood pressure, triglycerides, and HDL-C levels among initial heavy drinkers (all P<0.05). CONCLUSION:Heavy drinkers who reduce alcohol consumption could benefit from reduced risk of metabolic syndrome.