Rantanen T, Guralnik JM, Foley D, Masaki K, Leveille S, Curb JD, White L. Midlife Hand Grip Strength as a Predictor of Old Age Disability. JAMA. 1999;281(6):558-560. doi:10.1001/jama.281.6.558
Author Affiliations: Epidemiology, Demography and Biometry Program, National Institute on Aging, National Institutes of Health, Bethesda, Md (Drs Rantanen, Guralnik, Leveille, and Mr Foley); Honolulu Heart Program, Honolulu-Asia Aging Study, Kuakini Medical Center, Honolulu, Hawaii (Drs Masaki, Curb, and White); and the University of Hawaii School of Medicine, Honolulu (Dr Curb). Dr Rantanen is now with the Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland.
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.
In old age, decreased muscle strength predisposes people to functional
limitations and disability.1- 3 Cross-sectionally, muscle
strength is significantly, but not linearly, associated with functional
limitations such as walking speed.4- 7 A minimum level of
strength is needed to perform tasks. Conversely, when strength is well
above the minimum required level, a reserve capacity
exists.4,5,7 Reserve capacity serves as a safety margin
that helps prevent functional limitations from developing, eg,
following inactivity and deconditioning associated with surgery or an
The purpose of this research was to study midlife muscle strength as a
predictor of late life functional limitations and disability among
initially healthy men with an average age of 54.0 years (range, 45-68
years) at baseline. The average follow-up time was 25.3 years.
Subjects in these analyses are from the Honolulu Heart Program
and the Honolulu-Asia Aging Study.8 From 1965 through 1968,
8006 men aged 45 to 68 years participated in exam 1. Exam 2 took place
3 years later (1968 through 1970), with 7498 men participating. Exam 4
data were collected from 1991 through 1993 when participants were 71 to
93 years old.
The current analyses were limited to those participants who were
healthy at baseline. Persons who had missing data on disease status
(n = 37); who had diabetes, gout, arthritis, stroke, heart attack,
angina pectoris, or other heart disease at exam 1 or exam 2
(n = 1454); who dropped out or died between exams 1 and 2
(n = 406); or who reported at exam 4 that difficulty in upper
extremity, mobility, or self-care tasks had been present for 25 years
or more (n = 20) were excluded. All together, 6089 men qualified for
the study cohort.
Hand grip strength was measured using a dynamometer (Smedley Hand
Dynamometer, Stoelting Co, Wood Dale, Ill) at exams 1 and 2 with
midlife strength determined as the average of the best results in these
Measures of functional limitations at exam 4 included
customary walking speed of 0.4 m/s or slower10 and
inability to rise from a chair. Participants were asked to walk a
distance of 3.05 m (10 ft) at their usual pace and time was measured
using a stopwatch. Ability to rise from a chair was
measured by asking the subject to stand up without using his arms and
observing the performance. Disability was ascertained by asking the
participants the following question: "Because of health or physical
problems, do you have any difficulty . . . ?" Upper extremity
disability items were doing heavy household work (washing the car,
raking leaves, mowing the lawn, or cleaning up the garage) and lifting
something as heavy as 4.5 kg (10 lb). Mobility disability items were
walking 0.8 km (12 mile) and walking up 1 flight of stairs.
Self-care disability items were dressing, eating, bathing, and
At exam 4, the presence of chronic conditions was ascertained
with ongoing surveillance using hospital records (stroke, coronary
heart disease)11 or laboratory test results (coronary heart disease, diabetes, hypertension),12 or on the basis of participants' self-reports (chronic obstructive pulmonary disease,
Death ascertainment was based on perusal of newspaper obituaries and
listings of death certificates filed with the Hawaii State Department
of Health and through a computer linkage to the National Death Index.
Participants were divided into 3 groups based on the
baseline hand grip strength tertiles. The relative risks of mortality
prior to follow-up tests and functional limitations and disability at
follow-up for the hand grip strength groups were estimated using
multiple logistic regression models. The models were adjusted for
baseline age, socioeconomic status, body weight and height, physical
activity and smoking, and chronic conditions ascertained at exam 4.
At baseline, the average age was 54.0 years (SD, 5.5). The
average hand grip strength was 39.2 kg (SD, 6.0), and the cutoff points
for grip strength tertiles were 37.0 and 42.0 kg. The mean height was
160.3 cm (SD, 5.7), the mean weight was 63.2 kg (SD, 8.7), and mean
body mass index was 23.7 kg/m2 (SD, 3.1).
Among the 6089 men who qualified for the study, 2259 (37%) died
before exam 4. Of the 3830 survivors, 3218 (84.0%) participated in the
follow-up tests. Baseline grip strength did not predict participation
among the survivors.
Of these 3218 initially healthy men, 72 (2.2%) became
unable to rise from a chair without using their arms, and 201 (6.2%)
had a walking speed of 0.4 m/s or slower at follow-up. The numbers with
self-reported disability were difficulty walking 0.8 kg (12
mile) (n = 598 [18.6%]); walking up a flight of stairs (n = 451
[14.1%]);lifting 4.5 kg (10 lb) (n = 247 [7.7%]); doing heavy
household work (n = 586 [18.2%]); dressing (n = 169 [5.3%]);
bathing (n = 165 [5.2%]); eating (n = 72 [2.2%]); and
toileting (n = 110 [3.4%]). There was a clear gradient of
increasing risk for all functional limitations and disability outcomes
according to weaker baseline hand grip strength tertiles (Figure 1). This gradient persisted
after adjustment for multiple baseline confounders (Table 1). Finally, after adjusting for
chronic conditions ascertained at exam 4, the risks of functional
limitations and disability in the lowest and middle baseline grip
strength tertiles decreased moderately after these adjustments, but
remained statistically significant in most cases (Table 1).
Our study provides strong evidence that hand grip strength
predicts functional limitations and disability 25 years later in an
initially healthy cohort of 45- to 68-year-old men. Those in the lowest
grip strength tertile had the greatest risk and those in the middle
tertile had intermediate risk compared with those in the highest
tertile. Muscle strength is found to track over the life span: those
who had higher grip strength during midlife remained stronger than
others in old age.9 People with greater muscle strength during midlife are at a lower risk of becoming disabled because of
their greater reserve of strength regardless of chronic conditions that
Hand grip strength has been found to correlate with strength of other
muscle groups and is thus a good indicator of overall
strength.13 Consequently, grip strength measurements could
be used for early screening of populations to identify those at higher
risk of physical disability related to low muscle strength. In these
persons, exercise interventions aimed at improving strength in all
muscle groups could potentially lower the risk of subsequent physical
disability. Muscle strength can be increased substantially by physical
exercise at all ages.14- 16
There are also other potential explanations for our
results. Grip strength may be a marker of physical activity, which
itself preserves function and prevents disability.17 Low grip strength may indicate subclinical disease, which later develops
into clinical disease and disability. Finally, good grip strength may
mark some general intrinsic midlife vitality or motivation that tracks
into good functional ability in old age.
The Japanese-American men studied here are not
representative of all older people. However, it is unlikely that major
racial or sex differences in the strength-disability relationship would
be found, as the biomechanical principles of human movement are
universal. Also, data were not available at baseline to allow for the
exclusion of all participants with functional limitations and
disability. However, activities of daily living disability is rare
among middle-aged men: the prevalence is 0.9% among 45- to 54-year-old
men and 1.8% among 55- to 64-year-old men18 and disability is usually related to a disease.19 After people with documented chronic conditions at baseline were excluded, it is likely
that the baseline cohort contained very few disabled individuals.
Overall, there are very few long-term prospective studies
on risk factors for disability and mortality in old age. Cigarette
smoking, deviations from normal weight, and a low level of physical
activity have been shown to be long-term predictors of self-reported
disability and mortality in studies with 17 to 27 years of
follow-up.20- 22 This is the first study to show that muscle
strength is a powerful predictor of physical disability as long as 25
years later. This study suggests that hand grip strength could be used
for early screening of people at increased risk of physical disability
in old age.