ResultsSix prospective studies invo

Results
Six prospective studies involving 28,862 participants with 3305 cases of metabolic syndrome were included in the meta-analysis. On the basis of the Newcastle Ottawa Scale system, 83.3% of the studies were identified as relatively high-quality. In our primary analysis, compared with nondrinker, very light drinker was associated with decreased risk of metabolic syndrome [pooled relative risk (RR) 0.86, 95% CI: 0.75–0.99, fixed-effect model] while heavy drinker was associated with increased risk of metabolic syndrome (pooled RR 1.84, 95% CI: 1.34–2.52, fixed-effect model). No indications of heterogeneity and publication bias were found in these two groups. Estimates of total effects were generally consistent in the sensitivity and stratification analyses.