Context Poor muscle strength, functional limitations, and
disability often coexist, but whether muscle strength during midlife
predicts old age functional ability is not known.
Objective To determine whether hand grip strength measured during
midlife predicts old age functional limitations and disability in
initially healthy men.
Design and Setting A 25-year prospective cohort study, the
Honolulu Heart Program, which began in 1965 among Japanese-American men
living on Oahu, Hawaii.
Participants A total of 6089 45- to 68-year-old men who
were healthy at baseline and whose maximal hand grip strength was
measured from 1965 through 1970. 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 walking speed (≤0.4 m/s) and inability to rise from a seated
position without using the arms, and multiple self-reported upper
extremity, mobility, and self-care disability outcomes.
Results After adjustment for multiple potential confounders, risk
of functional limitations and disability 25 years later increased as
baseline hand grip strength, divided into tertiles, declined. The odds
ratio (OR) of walking 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 middle third of grip strength vs those
in the highest third. The risk of self-care disability was more than 2
times greater in the lowest vs the highest grip strength tertile.
Adding chronic conditions identified at follow-up to the models
predicting disability reduced the ORs related to grip strength only
Conclusions Among healthy 45- to 68-year-old men, hand grip
strength was highly predictive of functional limitations and disability
25 years later. Good muscle strength in midlife may protect people from
old age disability by providing a greater safety margin above the
threshold of disability.