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 Trondelag (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. (C) 2017 Mayo Foundation for Medical Education and Research