CARDIORESPIRATORY FITNESS AND MORTALITY IN MEN WITH METABOLIC SYNDROME

Abstract

Identification and treatment of persons at high risk for coronary heart disease now includes a specific definition of the metabolic syndrome. The specific definition of metabolic syndrome for men is to have 3 or more of the following: HDL-cholesterol <40 mg/dL, triglycerides ≥150 mg/dL, systolic blood pressure ≥130 mmHg, fasting plasma glucose ≥110 mg/dL, or waist circumference >102 cm. PURPOSE To determine the association between cardiorespiratory fitness (CRF) and mortality in men with the metabolic syndrome. METHODS We applied the above criteria to the male cohort of the ACLS and identified 3241 men aged 20 to 80 years with metabolic syndrome. All men completed a baseline medical evaluation and were followed for up to 26 years (mean=9.2 years) for mortality. The baseline examination consisted of clinical assessments including a maximal exercise test on a treadmill to measure CRF. Mortality surveillance was primarily by the National Death Index, and 123 men died during 29,896 man-years of observation. We grouped the men into low, moderate, and high CRF categories, and evaluated death risk using proportional hazards regression analyses. With age, examination year, smoking habit, and history of cardiovascular disease in the model, there was a steep inverse gradient for all-cause mortality across CRF groups. We selected low fit men as the reference category, and calculated odds ratios (OR) for the moderate and high CRF groups. RESULTS OR (95% CIs) were 0.52 (0.35–0.77) and 0.40 (0.22–0.72) for moderate and high fit groups respectively. The addition of BMI to the model had virtually no effect on the results, and BMI was not associated with mortality [OR per BMI unit=0.99 (0.95–1.04)]. These results changed little after adding individual components of the metabolic syndrome to the model. CONCLUSION Our results support the hypothesis that moderate and high CRF protect against mortality in men with metabolic syndrome. Supported in part by NIH grants AG06945, HL66262, and HL71900.