eNOS genotype modifies the effect of leisure-time physical activity on serum triglyceride levels in a Japanese population

Background: Nitric oxide is a key molecule not only in the cardiovascular system, but also in the metabolic-endocrine system. The purpose of this study was to examine possible associations of the NOS3 T-786C polymorphism (rs2070744) with serum lipid levels on the basis of lifestyle factors for tailoring prevention of dyslipidemia. Methods: For this cross-sectional study, a total of 2226 subjects aged 35 to 69 years (1084 men and 1142 women) were selected from Japanese participants in the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study. They were recruited in eight areas throughout Japan between February 2004 and November 2008. Results: In a stratified analysis by leisure-time physical activity, the likelihood of hypertriglyceridemia (serum triglyceride levels >= 150 mg/dL) among subjects with the C allele was significantly lower than those without it in the active group (OR = 0.43, 95% CI = 0.22-0.84 in the fasting group), but not in the sedentary group. A gene-environment interaction between the T-786C polymorphism and leisure-time physical activity for hypertriglyceridemia was significant (P = 0.007 in the fasting group). Additionally, serum triglyceride levels (mean +/- SD) across leisure-time physical activity classes decreased significantly only in the TC + CC genotype group (111 +/- 60 mg/dL for sedentary, 95 +/- 48 mg/dL for moderately active, 88 +/- 44 mg/dL for very active, P for trend = 0.008 in the fasting group), but not in the TT genotype group. Total cholesterol, high-density lipoprotein (HDL) cholesterol, and non-HDL cholesterol levels had no significant association with the polymorphism. Conclusions: This study suggests that the NOS3 T-786C polymorphism modifies the effect of leisure-time physical activity on serum triglyceride levels.