Musculoskeletal fitness and risk of mortality

KATZMARZYK, P. T., and C. L. CRAIG. Musculoskeletal fitness and risk of mortality. Med. Sci. Sports Exere., Vol. 34, No. 5, pp. 740-744, 2002. Purpose: To quantify the relationship between musculoskeletal fitness and all-cause mortality in the Canadian population. Methods: The sample consisted of 8116 people (3933 men and 4183 women), aged 20-69 yr, who participated in the 1981 Canada Fitness Survey. Measures of musculoskeletal fitness included sit-ups, push-ups, grip strength, and sit-and-reach trunk flexibility. In the 13 yr after the Canada Fitness Survey, there were 239 deaths and a total of 101,685 person-years. Proportional hazards regression was used to estimate the risk of mortality across baseline age- and sex-specific quartiles of the musculoskeletal fitness measures. All models included the effects of age, smoking status, body mass, and estimated VO2max as covariates, and the upper quartile was set as the reference group. Results: There was no pattern of increased risk of mortality across quartiles of trunk flexibility or push-ups; however, there was a significantly higher risk in the lower quartile of sit-ups in both men (relative risk (RR) = 2.72, 95% CI 1.56-4.64) and women (RR = 2.26, 95% CI 1.15-4.43). Grip strength was not predictive of mortality in women, although there was a 49% increased risk of death in the lower quartile of grip strength in males (RR = 1.49, 95% CI 0.86-2.59). Conclusion: The results suggest that some components of musculoskeletal fitness, particularly sit-ups (abdominal muscular endurance), are predictive of mortality in the Canadian population.