Vigorous physical activity, cardiorespiratory fitness and a diet low in saturated relative to polyunsaturated fat may protect against development of the metabolic syndrome in middle-aged men.
Few studies have prospectively addressed the role of physical activity, fitness and dietary fat type in the development of the metabolic syndrome (MS), a condition that markedly increases the risk for diabetes and cardiovascular disease. We examined the development of MS in 453 normoglycemic men participating in the Kuopio Ischemic Heart Disease Risk Factor Study who had no more than 2 features of MS at baseline. Leisure-time physical activity for the preceding 12 mo was measured at baseline with a validated questionnaire. Maximum oxygen uptake was measured directly during an exercise stress test. Long-term dietary fat composition was estimated from lipid-standardized proportions of saturated and polyunsaturated fatty acids measured from fasting whole serum. After 4 y 145 men had developed 3 or more features of MS as defined by the presence of impaired fasting glucose or diabetes (fasting blood glucose ≥5.6 mM), overweight or obesity (BMI ≥27 kg/m 2 ), waist-hip ratio ≥0.90, hypertension (blood pressure ≥140/90) or dyslipidemia (serum triglycerides ≥1.7 mM or HDL <0.9 mM). In logistic regression analyses adjusting for confounding factors, the serum palmitate proportion (OR 2.7, 95%CI 1.4-5.1 for upper vs lower third) and palmitate/linoleate ratio (OR 2.3, 95%CI 1.2-4.4 for upper vs lower third) was positively and the α-linolenate proportion (OR 0.44, 95%CI 0.23-0.84) negatively associated with development of MS. The serum linoleate proportion tended to protect against development of MS (OR 0.55, 95%CI 0.28-1.04). Cardiorespiratory fitness (OR 0.37, 95%CI 0.28-0.97 for highest vs lowest fourth) and at least 20 min vigorous exercise/wk (OR 0.53, 95%CI 0.28-1.00) protected against development of MS independently of confounding factors. Although genetic and other factors may also play a role, these findings underscore the importance of dietary fat modification and physical exercise for primary prevention of the metabolic syndrome and its consequences even in apparently low-risk middle-aged men.