Seasonal variation in serum lipid levels in Japanese workers

日本人労働者における血清脂質値の季節性変動

亀崎 文彦; 園田 信成*; 友常 祐介; 湯中 弘美; 尾辻 豊*

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

Seasonal variation in serum lipid levels in Japanese population remains unclear. The aim of this study was to determine whether the variation in lipid levels exists in Japanese workers. We investigated a total of 1,331 employees in our institution (1,192 men, 4410 years; 139 women, 3811 years) who underwent health checkups in both June (summer) and December (winter), 2008. Serum levels of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol, and triglyceride were significantly higher in winter than in summer (129.131.2 mg/dL versus 125.230.2 mg/dL, 0.0001; 65.916.8 mg/dL versus 63.516.1 mg/dL, 0.0001; 110.467.5 mg/dL versus 107.570.4 mg/dL, 0.05; respectively), although the ratio of LDL to HDL cholesterol was comparable (2.110.81 in summer versus 2.120.81 in winter). Frequency of study subjects diagnosed hypercholesterolemia defined as LDL cholesterol 140 mg/dL was significantly higher in winter than in summer (34.5% versus 30.9%, 0.0001). In Japanese workers, we demonstrated that there is seasonal variation in serum lipid levels and prevalence of hypercholesterolemia. This result indicates that we have to give careful consideration to the season of blood sampling in clinical diagnosis and management decisions of hypercholesterolemia.