Association between muscular strength and mortality in men: prospective cohort study

Abstract

Objective: To examine prospectively the association between muscular strength and mortality from all causes, cardiovascular disease, and cancer in men.

Design: Prospective cohort study.

Setting: Aerobics centre longitudinal study.

Participants: 8762 men aged 20-80.

Main outcome measures: All cause mortality up to 31 December 2003; muscular strength, quantified by combining one repetition maximal measures for leg and bench presses and further categorised as age specific thirds of the combined strength variable; and cardiorespiratory fitness assessed by a maximal exercise test on a treadmill.

Results: During an average follow-up of 18.9 years, 503 deaths occurred (145 cardiovascular disease, 199 cancer). Age adjusted death rates per 10,000 person years across incremental thirds of muscular strength were 38.9, 25.9, and 26.6 for all causes; 12.1, 7.6, and 6.6 for cardiovascular disease; and 6.1, 4.9, and 4.2 for cancer (all P<0.01 for linear trend). After adjusting for age, physical activity, smoking, alcohol intake, body mass index, baseline medical conditions, and family history of cardiovascular disease, hazard ratios across incremental thirds of muscular strength for all cause mortality were 1.0 (referent), 0.72 (95% confidence interval 0.58 to 0.90), and 0.77 (0.62 to 0.96); for death from cardiovascular disease were 1.0 (referent), 0.74 (0.50 to 1.10), and 0.71 (0.47 to 1.07); and for death from cancer were 1.0 (referent), 0.72 (0.51 to 1.00), and 0.68 (0.48 to 0.97). The pattern of the association between muscular strength and death from all causes and cancer persisted after further adjustment for cardiorespiratory fitness; however, the association between muscular strength and death from cardiovascular disease was attenuated after further adjustment for cardiorespiratory fitness.

Conclusion: Muscular strength is inversely and independently associated with death from all causes and cancer in men, even after adjusting for cardiorespiratory fitness and other potential confounders.

Fig 1 Age adjusted death rates per 10 000 person years from all causes and cancer by thirds of muscular strength and age groups

Fig 2 Age adjusted death rates per 10 000 person years by thirds of muscular strength and body mass index groups

Fig 3 Number of men and age adjusted all cause death rates per 10 000 person years according to thirds of muscular strength and cardiorespiratory fitness categories. Adjusted death rate was inversely related to muscular strength within fit cardiorespiratory category (P=0.008 for trend) but not within unfit category (P=0.44 for trend), and inversely related to cardiorespiratory fitness within lowest third (P=0.003) and middle third (P=0.03) for muscular strength but not within highest third (P=0.27)