The Combined Association of Skeletal Muscle Strength and Physical Activity on Mortality in Older Women: The HUNT2 Study

Objective To assess the isolated and combined associations of leg and arm strength with adherence to current physical activity guidelines with all-cause and cause-specific mortality in healthy elderly women. Patients and Methods This was a prospective cohort study of 2529 elderly women (72.6±4.8 years) from the Norwegian Healthy survey of Northern Trøndelag (second wave) (HUNT2) between August 15, 1995, and June 18, 1997, with a median of 15.6 years (interquartile range, 10.4-16.3 years) of follow-up. Chair-rise test and handgrip strength performances were assessed, and divided into tertiles. The hazard ratio (HR) of all-cause and cause-specific mortality by tertiles of handgrip strength and chair-rise test performance, and combined associations with physical activity were estimated by using Cox proportional hazard regression models. Results We observed independent associations of physical activity and the chair-rise test performance with all-cause and cardiovascular mortality, and between handgrip strength and all-cause mortality. Despite following physical activity guidelines, women with low muscle strength had increased risk of all-cause mortality (HR chair test, 1.37; 95% CI, 1.07-1.76; HR handgrip strength, 1.39; 95% CI, 1.05-1.85) and cardiovascular disease mortality (HR chair test, 1.57; 95% CI, 1.01-2.42). Slow chair-test performance was associated with all-cause (HR, 1.32; 95% CI, 1.16-1.51) and cardiovascular disease (HR, 1.41; 95% CI, 1.14-1.76) mortality. The association between handgrip strength and all-cause mortality was dose dependent (P value for trend <.01). Conclusion Handgrip strength and chair-rise test performance predicted the risk of all-cause and CVD mortality independent of physical activity. Clinically feasible tests of skeletal muscle strength could increase the precision of prognosis, even in elderly women following current physical activity guidelines.