Seasonal variation in metabolic syndrome prevalence

Kamezaki, Fumihiko; Sonoda, Shinjo*; Tomotsune, Yusuke; Yunaka, Hiromi; Otsuji, Yutaka*

Accumulating evidences have demonstrated that seasonal variations exist in metabolic syndrome parameters. The aim of this study was to examine the hypothesis that there is seasonal variation in metabolic syndrome prevalence in Japanese subjects. We investigated a total of 1,202 male workers in our institution (44 10 years), who underwent health checkups in both June (summer) and December (winter), 2008. In this study, metabolic syndrome was defined according to the criteria proposed by National Cholesterol Education Program (NCEP), International Diabetes Federation (IDF), and Japanese Society of Internal Medicine (JSIM). Serum levels of high-density lipoprotein-cholesterol and fasting glucose, and blood pressure (BP) were significantly higher in winter than in summer, whereas waist circumference and serum levels of triglyceride were little changed. Prevalence of NCEP-, IDF-, and JSIM- metabolic syndrome in this study was 3.8, 15.1 and 12.4% in winter, 3.2, 10.7 and 8.4% in summer, respectively. Out of the metabolic syndrome components, elevated BP component was mainly connected with the seasonal variation of metabolic syndrome prevalence. The present study demonstrated the seasonal variation in metabolic syndrome prevalence in Japanese male workers. This result indicates that season of health checkups may affect a clinical diagnosis and management of metabolic syndrome.