Long-term body weight fluctuation is associated with metabolic syndrome independent of current body mass index among Japanese men

Background: The relation between weight fluctuation and the risk of cardiovascular disease (CVD) is fairly consistent, although the physiologic basis for the relationship is uncertain. In the present study the association between long-term weight fluctuation and the development of metabolic syndrome (MS), a potent CVD risk factor, was investigated. Methods and Results: A cross-sectional study of 664 Japanese men aged 40-49 years was conducted. The root mean square error around the slope of weight on age (weight-RMSE) was calculated by a simple linear regression model, in which the subject's actual weights at ages 20, 25, 30 years and 5 years prior to the study, as well as current weight, were dependent variables against the subject's age as the independent variable. Weight-RMSE was significantly and positively associated with the prevalence of each MS components (high blood pressure, hypertriglyceridemia, low-high density lipoprotein-cholesterol, high fasting glucose, and obesity). Such associations, as well as clustering of the MS component together with RMSE increase, were apparent among subjects with body mass index (BMI) <25 kg/m², although the prevalence of MS or its components was much higher among overweight subjects (BMI ≥25 kg/m ²). Conclusions: Development of MS possibly explains the risk of CVD not only in overweight or obese persons, but also in normal-weight persons with large weight fluctuation.