Long-term weight gain is related to risk of metabolic syndrome even in the non-obese

ObjectiveTo examine the relationship between long-term weight gain and risk of metabolic syndrome (MetS) in non-obese and obese subjects.MethodsCross-sectional data from 3342 participants (1614 men, 1728 women) were obtained from a Specific Medical Checkup and a self-reported questionnaire survey conducted by a health insurance society between April 2009 and March 2010. Subjects were divided into four groups based on body mass index (BMI) and experience of weight gain since the age of 20 years using a self-reported questionnaire: non-obese/non-gain, non-obese/gain, obese/non-gain, and obese/gain. Relationships between weight gain and risk of MetS were investigated using logistic regression analysis, with the four groups as a dependent variable.ResultsThere were 2103 (62.9%) subjects in the non-obese/non-gain, 545 (16.3%) in the non-obese/gain, 125 (3.7%) in the obese/non-gain, and 569 (17.0%) in the obese/gain groups. The obese/gain group showed the highest risk of MetS in men (odds ratio [OR]: 37.45, 95% confidence interval [95% CI]: 25.32–55.40) and women (OR: 163.13, 95% CI: 56.22–473.32). Even the non-obese/gain group had an increased risk of MetS, in men (OR: 4.98, 95% CI: 3.47–7.15) and women (OR: 6.28, 95% CI: 1.53–25.83).ConclusionThe data show that the obese/gain group had the highest risk of MetS, and that those who gained weight were at risk of MetS, even the non-obese.