Two types of unsafe drinker judged to have metabolic syndrome: Typical metabolic syndrome or alcohol-related syndrome?

Background: Hypertension, hyperlipidemia, and hyperglycemia often occur in drinkers regardless of obesity. Thus, the diagnostic criteria of metabolic syndrome (MS) may judge some drinkers as having MS even when typical MS is absent. Material/Methods: To verify this, 1,346 Japanese men aged 40 to 65 were divided into four groups based on their statuses of MS and drinking habits, and various parameters were compared among them. According to the suggestion of the Japanese Ministry of Health, Labour and Welfare, daily ethanol consumption up to 20 grams was defined as safe drinking. Results: The serum adiponectin level was significantly higher in unsafe drinkers with MS than in those without it, whereas drinking habits were shown not to affect it. Among subjects judged to have MS, the ALT/AST ratio (ALT/AST) was the most effective parameter to distinguish between safe and unsafe drinkers. When unsafe drinkers with MS were classified into two subgroups by ALT/AST, i.e. that of ≥0.9 or <0.9, levels of ALT and adiponectin significantly differed between them and levels in the former and the latter subgroups were comparable to those in safe drinkers with MS and in unsafe drinkers without MS, respectively. Although the prevalence of MS was higher in unsafe drinkers than in safe drinkers, it became equivalent to each other when the latter subgroup was eliminated. Conclusions: In drinkers who satisfy the diagnostic criteria of MS, subjects whose characteristics are different from those of typical MS, but comparable to those of alcohol-related syndrome, co-exist. This overdiagnosis is most likely due to ethanol consumption.