Muscular Strength And All-cause Mortality Among Men With Impaired Fasting Glucose Or Type 2 Diabetes

Abstract

Muscular strength is inversely associated with mortality in healthy men. This association has not been examined in men with impaired fasting glucose (IFG) or type 2 diabetes mellitus (DM). PURPOSE: To examine the association between muscular strength and all-cause mortality in men with IFG and DM. METHODS: Participants were 4183 men with IFG or DM at baseline, aged 20 to 82 years, enrolled in the Aerobics Center Longitudinal Study from 1980 to 2003. Muscular strength was quantified by combining one repetition maximum (1-RM) measures for leg and bench presses, and cardiorespiratory fitness (CRF) was assessed by a maximal exercise test on a treadmill. Hazard ratios (HR) and 95% confidence intervals (CI) were computed with Cox regression analysis. RESULTS: During an average follow-up of 18.7 years, 297 deaths occurred. Age-adjusted death rates per 10 000 person-years across incremental thirds of muscular strength were 46.6, 36.4, and 31.3 (p<0.05). After additional adjustment for smoking, alcohol intake, physical activity, fasting glucose levels, health status (presence of hypertension, diabetes, hypercholesterolemia, or abnormal electrocardiogram), and family history of cardiovascular disease, a significant quadratic trend existed between muscular strength thirds and risk of mortality (HR=1.00, 0.75 (95% CI=0.56-0.99), and 0.94 (0.71-1.24), for low (referent), middle, and upper strength thirds, respectively, p=0.04). When stratified by age (<60 and ≥60 years), a significant quadratic trend existed for men age < 60 years (HR=1.00; 0.70 (0.51-0.97); and 0.93 (0.68-1.27) for lower (referent), middle, and upper strength thirds, respectively, p=0.03). When stratified by CRF (unfit and fit), a significant quadratic trend existed among fit men (HR= 1.00; 0.69 (0.51-0.95); and 0.90 (0.67-1.21) for lower (referent), middle, and upper strength thirds, respectively, p=0.03). In the muscular strength and CRF combined analysis, men who were fit and among the middle third of muscular strength had a 48% lower mortality risk compared with the reference group, classified as unfit and within the lowest strength third (HR=0.52 (0.32-0.85)). CONCLUSION: Moderate levels of muscular strength appear to be protective against all-cause mortality among men with IFG or DM. Supported by NIH Grant AG06945, HL62508, and DK088195.