Midlife hand grip strength as a predictor of old age disability

Context Poor muscle strength, functional limitations, and disability often coexist, but whether muscle strength during midlife predicts old age functi onal ability is not known. Objective To determine whether hand grip strength measured during midlife p redicts old age functional limitations and disability in initially healthy men, Design and Setting A 25-year prospective cohort study, the Honolulu Heart P rogram, which began in 1965 among Japanese-American men living on Oahu, Haw aii. Participants A total of 6089 45- to 68-year-old men who were healthy at bas eline and whose maximal hand grip strength was measured from 1965 through 1 970, Altogether, 2259 men died over the follow-up period and 3218 survivors participated in the disability assessment in 1991 through 1993, Main Outcome Measures Functional limitations including slow customary walki ng speed (less than or equal to 0.4 m/s) and inability to rise from a seate d position without using the arms, and multiple self-reported upper extremi ty, mobility, and self-care disability outcomes, Results After adjustment for multiple potential confounders, risk of functi onal limitations and disability 25 years later increased as baseline hand g rip strength. divided into tertiles, declined. The odds ratio (OR) of walki ng speed of 0.4 m/s or slower was 2.87 (95% confidence interval [CI], 1.76- 4.67) in those in the lowest third and 1.79 (95% CI, 1.14-2.81) in the midd le third of grip strength vs those in the highest third, The risk of self-c are disability was more than 2 times greater in the lowest vs the highest g rip strength tertile. Adding chronic conditions identified at follow-up to the models predicting disability reduced the ORs related to grip strength o nly minimally, Conclusions Among healthy 45- to 68-year-old men, hand grip strength was hi ghly predictive of functional limitations and disability 25 years later. Go od muscle strength in midlife may protect people from old age disability by providing a greater safety margin above the threshold of disability.