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Published by Oxford University Press on behalf of the International Epidemiological Association International Journal of Epidemiology
Ó The Author 2006; all rights reserved. doi:10.1093/ije/dyl224
Grip strength, body composition,
and mortality
Catharine R Gale,* Christopher N Martyn, Cyrus Cooper and
Avan Aihie Sayer
Accepted 18 September 2006
Background Several studies in older people have shown that grip strength predicts all-cause
mortality. The mechanisms are unclear. Muscle strength declines with age,
accompanied by a loss of muscle mass and an increase in fat, but the role that
body composition plays in the association between grip strength and mortality
has been little explored. We investigated the relation between grip strength,
body composition, and cause-specific and total mortality in 800 men and women
aged 65 and over.
Methods During 1973–74 the UK Department of Health and Social Security surveyed
random samples of men and women aged 65 and over living in eight areas of
Britain to assess the nutritional state of the elderly population. The survey
included a clinical examination by a geriatrician who assessed grip strength and
anthropometry. We used Cox proportional hazards models to examine mortality
over 24 years of follow-up.
Results Poorer grip strength was associated with increased mortality from all-causes,
from cardiovascular disease, and from cancer in men, though not in women.
After adjustment for potential confounding factors, including arm muscle area
and BMI, the relative risk of death in men was 0.81 (95% CI 0.70–0.95) from
all-causes, 0.73 (95% CI 0.60–0.89) from cardiovascular disease, and 0.81 (95%
CI 0.66–0.98) from cancer per SD increase in grip strength. These associations
remained statistically significant after further adjustment for fat-free mass or %
body fat.
Conclusion Grip strength is a long-term predictor of mortality from all-causes, cardiovascular
disease, and cancer in men. Muscle size and other indicators of body
composition did not explain these associations.
Keywords grip strength, mortality, body composition
Several studies have shown that poor grip strength predicts
increased all-cause mortality in older people.
1–6
The underlying
mechanisms are poorly understood. The association persists
after adjustment for body size and does not appear to
be explained by nutritional status, the presence of chronic
disease, or degree of physical activity. Little is known about the
influence of grip strength on mortality from specific causes. In
the only previous study into this relation—in a cohort of
disabled women—poorer grip strength was linked with
increased mortality from cardiovascular and respiratory disease,
though not from cancer.
6
Muscle strength is known to decline with age, accompanied
by a loss of muscle mass and an increase in fat.
7–9
There is
evidence that body composition may influence mortality in
older people,
10,11
but whether it plays a part in the association
between grip strength and mortality in older people has been
little explored.
During 1973–74 the Department of Health and Social
Security surveyed random samples of men and women aged
65 and over living in eight areas of Britain to assess the
nutritional state of the elderly population. The areas were
chosen so that the socioeconomic characteristics of the study
sample were representative of older people in Britain who were
living at home. In addition to the assessment of their diet
MRC Epidemiology Resource Centre, (University of Southampton),
Southampton General Hospital, Southampton SO16 6YD, UK.
* Corresponding author. Dr Catharine R Gale, MRC Epidemiology Resource
Centre, Southampton General Hospital, Southampton SO16 6YD, UK.
E-mail: crg@mrc.soton.ac.uk
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and physical activity, the participants underwent a clinical
examination by a geriatrician, which included anthropometry
and measurement of grip strength. We explored how muscle
strength and body composition influenced cause-specific and
total mortality in a 24 year follow-up study of this national
sample.
Materials and methods
Participants
During 1973 and 1974, 1775 people in eight areas of Britain
(5 in England, 2 in Scotland, and 1 in Wales) were randomly
sampled from family practitioner committees’ lists of all patients
aged 65 years and over. The areas were Islington, Harrow,
Hastings, Bristol, Salford, Rutherglen, Angus, and Merthyr
Tydfil. Stratified sampling was used to obtain equal numbers of
men and women aged 65–74, and 75 and over.
Of the participants selected, 1688 were living at home and
were invited to take part in the study; 1419 (84%) agreed. In
all, 983 (69%) of those who participated in the nutritional
survey agreed to be examined by a geriatrician.
Nutritional survey
Participants kept a diary of every item of food or drink
consumed over a week. They were provided with a set of scales
to weigh each item. An interviewer visited them at least four
times during the week. If the participants were unable to cope
with the weighing procedure, the interviewer used the
food diary to quantify their consumption; food purchases
were used as a cross check. Nutrient intake was calculated by
using a food composition table compiled by the Department of
Health and Social Security. As part of the survey, participants
were asked whether they had lost or gained weight in the
previous few months. They were also asked whether they
engaged in any hobbies or activities away from home and, if so,
how much physical activity was involved.
Clinical examination
The geriatricians measured height, weight, mid-arm circum-
ference, and skinfold thickness at four sites (biceps, triceps,
subscapular, and suprailiac), three times at each site. They
questioned participants about their smoking habits and
medications taken in the previous 6 months and took a sample
of blood for biochemical and haematological analysis.
Grip strength of the right and left hands was measured three
times using isometric dynometry. After the examination,
the geriatricians recorded diagnoses of disease according to
the International Classification of Diseases categories.
Mortality follow-up
Of the 983 participants examined by a geriatrician, 921 (95%)
were traced through the NHS central register. We obtained
death certificates for those who had died and all causes of death
entered in parts I and II were coded according to the
International Classification of Diseases (ninth revision). All cases
where cardiovascular disease (codes 390–459), cancer
(140–208), or respiratory disease (codes 462–519) were
mentioned on the death certificate were counted as deaths
from these causes.
Statistical analysis
Body mass index (BMI) was calculated as weight (in kg)/
height
2
(in metres). The averages of the triplicate skinfold thick-
ness measurements at each site were taken and the % body fat
was derived using the four average skinfold thickness
measurements in the formulae devised by Durnin and
Wormesley.
12
Fat mass was derived by multiplying body
weight by % body fat. Fat-free mass was derived by subtracting
fat mass from body weight. Corrected arm muscle area,
corrected for bone, was calculated from triceps skinfold
thickness and mid-arm circumference using formulae devised
by Heymsfield et al.
13
Based on criteria outlined by the World
Health Organization (WHO),
14
BMI was classified into the
following groups: underweight (,18.5), normal (18.5–24.99),
overweight (25–29.99), and obese (>30). The best of the six
grip strength measurements was selected for use in analysis.
Nutrient intake variables were skewed and were transformed to
normality using logarithms. The characteristics of the men and
women in the study were compared using t-test or x
2
-test as
appropriate. A Cox proportional hazards model was used to
examine the associations between grip strength, body
composition measures and mortality over the 24 year follow-up
period based on deaths that occurred before January 1, 1999.
We analysed men and women separately as the relation
between BMI and % body fat and mortality differed between
the sexes (P for interaction terms ,0.01). The results are
presented as relative risks (hazard ratios) per SD increase in
grip strength and body composition measures. Risk estimates
were adjusted for age in 5 year strata. Models including BMI or
% body fat were also fitted with BMI squared or % body fat
squared in order to assess whether there were any significant
J-shaped or U-shaped associations.
The analyses that follow are based on the 800 men and
women who were examined by a geriatrician and had complete
data on all anthropometric and body composition variables.
Comparison of these 800 men and women with the 436 study
participants who declined to be examined by a geriatrician
showed that there was no difference between them in age but
that those who agreed to a clinical examination were more
likely than those who declined to be male (56.5% vs 41.1%,
P , 0.001) and from non-manual social classes (36.3% vs
28.1%, P 5 0.02).
Results
Selected baseline characteristics of the 800 people in the study
(452 men and 348 women) are shown in Table 1. As expected,
there were significant differences between the sexes in all body
composition variables and in grip strength. Men had a higher
daily calorie intake than women. They were more likely than
women to be current smokers and to report that they engaged
in hobbies that involved high levels of physical activity. They
had a slightly lower prevalence of disease, diagnosed at the
clinical examination, but there was no difference between
them in their assessment of whether their weight had changed
in the previous 6 months. There was also no difference between
the sexes in social class distribution.
There was a strong inverse association between grip strength
and age (r 5 0.43, P , 0.001). Partial correlation coefficients,
adjusted for age and sex, showed that grip strength was more
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strongly correlated with height (r 5 0.31, P , 0.001),
fat-free mass (r 5 0.28, P , 0.001), and corrected arm muscle
area (r 5 0.28, P , 0.001) than with BMI (r 5 0.11, P , 0.001)
or % body fat (r 5 0.09, P 5 0.008). Grip strength tended
to be poorer in people with a lower calorie intake (r 5 0.17,
P , 0.001). Mean grip strength, adjusted for age and sex, was
also poorer in people who reported that they had lost weight
compared with those whose weight had remained stable,
54.8 vs 58.6 kg (P 5 0.03), in smokers compared with
non-smokers, 56.7 vs 58.7 kg (P 5 0.04), in people with
diagnosed disease compared with those who were healthy,
57.4 vs 62.7 kg (P , 0.001), in those who reported having no
hobbies outside the home compared with those who had
hobbies involving high levels of physical activity, 56.9 vs 60 kg
(P 5 0.04), and in those from manual compared with
non-manual social classes, 58.2 vs 60.4 (P 5 0.004). All
these associations were similar in men and women.
Over the 24 year follow-up period, there were 756 deaths,
441 in men and 315 in women. The crude all-cause mortality
rate was 102.7 per 1000 person-years (124.8 per 1000 person-
years in men and 82.3 per 1000 person-years in women).
Table 2 shows the relative risks of death from all causes per SD
increase in grip strength and measures of body composition.
Risk estimates are shown for men and women separately,
adjusted for age, and then further adjusted for the potential
confounding factors, height, smoking, social class, physical
activity, diagnosed disease at baseline, calorie intake, reported
weight loss, and the measures of body composition. Correlation
coefficients between BMI and % body fat were 0.74 in both
sexes, while those between BMI and fat-free mass were 0.73 in
men and 0.79 in women. To avoid potential problems with
collinearity, fat-free mass, % body fat, and BMI were added to
multivariate models separately.
In both men and women, better grip strength was associated
with a significantly reduced risk of mortality from all causes in
age-adjusted analyses. In women, this relation was weakened
by further adjustment for the potential confounding factors
and, separately, for fat-free mass, % body fat, or BMI. In men,
adjustment for height, smoking, social class, physical activity,
diagnosed disease at baseline, calorie intake, reported weight
loss, and the measures of body composition had little effect on
the association and it remained statistically significant. There
was no evidence of a statistical interaction between grip
strength and sex as regards mortality (P 5 0.71). Figure 1 shows
survival curves for the 24 year follow-up period for all-cause
mortality according to thirds of the distribution of grip strength
in men and women.
The relation between % body fat and BMI and mortality
differed between the sexes (p for interaction terms ,0.01).
In men, there was a linear relation between these variables and
mortality, with a higher % body fat or higher BMI associated
with a lower risk of death. BMI ceased to be a significant
predictor of all-cause mortality in men, after adjustment for
grip strength and the potential confounding variables, but
the relation between higher % body fat and mortality persisted
after multivariate adjustment. In women, there was a weak
quadratic relation between % body fat and mortality that
was weakened by multivariate adjustment. There was a
statistically significant quadratic relation in women between
BMI, analysed as a continuous variable, and mortality that
persisted in multivariate analysis, though when relative
risks were calculated according to WHO classifications, the
increased risk of death in the underweight and obese
groups did not reach statistical significance. Compared with
those with a normal BMI, the multivariate-adjusted risk of
death was 1.41 (95% CI 0.9–2.38) in those with a BMI of
,18.5 kg/m
2
, 1.00 (95% CI 0.74–1.34) in those with a BMI
of 25–29.9 kg/m
2
, and 1.14 (95% 0.76–1.71) in those with a
BMI >30 kg/m
2
.
Over the follow-up period, there were 488 deaths where
cardiovascular disease was the underlying or a contributory
cause. The crude mortality rate was 66.4 per 1000 person-years
(76.4 in men and 57.2 in women). As with all-cause mortality,
risk of death from cardiovascular disease was reduced in men
and women with better grip strength (Table 3). In women, this
relation was weakened by multivariate adjustment, but in men
the association remained statistically significant after adjust-
ment for potential confounders and for measures of body
composition. There were no significant associations between
risk of death from cardiovascular disease and arm muscle area
or fat-free mass in either sex in multivariate analyses. There
was a statistically significant quadratic association between
BMI, analysed as a continuous variable, and risk of cardiovas-
cular mortality in women that persisted after multivariate
Table 1 Characteristics of the study participants
Men
(n 5 452)
Women
(n 5 348)
Age, y 74.7 (5.8) 74.4 (6.1)
Height, m 1.67 (0.72) 1.55 (0.67)
Weight, kg 67.6 (11.9) 60.1 (11.3)
BMI, kg/m
2
24.1 (3.70) 25.1 (4.48)
% body fat 21.2 (5.4) 32.0 (4.4)
Fat-free mass, kg 52.8 (7.5) 40.6 (6.2)
Corrected arm
muscle area, cm
2
44.9 (10.8) 37.3 (10.8)
Grip strength, kg 68.7 (15.7) 46.1 (10.6)
Daily calorie intake, kcal
a
2106 (1.29) 1549 (1.28)
Current smoker, n (%) 237 (52.4) 65 (18.7)
Recent weight change, n (%)
No 370 (81.9) 277 (80.8)
Lost weight 43 (9.5) 30 (8.7)
Gained weight 39 (8.6) 36 (8.7)
Disease diagnosed at
clinical exam, n (%)
390 (86.3) 322 (92.5)
Activities away from home, n (%)
No activities 185 (41.1) 155 (44.8)
High physical activity 49 (10.9) 16 (4.6)
Low physical activity 138 (30.7) 139 (40.2)
Both high and low
physical activity
65 (8.2) 277 (34.8)
Social class, n (%)
Non-manual 157 (34.4) 133 (38.4)
Manual 299 (65.6) 213 (61.6)
Values are means (SD) unless otherwise indicated.
a
Geometric mean (SD).
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adjustment, though, as with all-cause mortality, this did not
reach statistical significance when risks were expressed
according to WHO categories: compared with those with a
normal BMI, risk of cardiovascular mortality was 1.55 (95% CI
0.85–2.8) in those with a BMI of ,18.5 kg/m
2
, 1.04 (95% CI
0.7–1.5) in those with a BMI of 25–29.9 kg/m
2
, and 1.20 (95%
CI 0.76–1.9) in those with a BMI >30 kg/m
2
. In men, having a
higher BMI or a higher % body fat tended to be associated
with a reduced risk of death from cardiovascular disease,
though after multivariate adjustments these relations were not
statistically significant.
Over the follow-up period, there were 425 deaths where
cancer was an underlying or contributory cause. The crude
mortality rate was 58 per 1000 person-years (77.0 in
men and 40.4 in women). Risk of dying from cancer was
reduced in men with better grip strength, and this association
remained statistically significant after multivariate adjustment
for potential confounding factors and for measures of body
composition (Table 4). In women, the relation between grip
strength and risk of death from cancer ceased to be statistically
significant in multivariate analyses. In men, a higher BMI or a
higher % body fat was associated with a reduced risk of dying
from cancer that persisted after multivariate adjustment. In
women, there was a quadratic association between BMI and
risk of dying from cancer in age-adjusted analysis, but this
ceased to be statistically significant after multivariate adjust-
ment. There were no significant associations between risk of
death from cancer and arm muscle area or fat-free mass in
either sex in multivariate analyses.
Respiratory disease was the third most frequent cause of
death mentioned on death certificates (n 5 314). The crude
mortality rate was 43.1 per 1000 person-years (55.7 in men and
31.5 in women). Better grip strength was associated with
reduced mortality from respiratory disease in both sexes in
age-adjusted analyses, but these relations were not statistically
significant once adjusted for potential confounding variables
and for measures of body composition (Table 5). None
of the measures of body composition were significant
predictors of death from respiratory disease after multivariate
adjustment.
We explored whether the associations described above
might be explained by serious illness at the time of the survey
by restricting the multivariate analyses to participants who
survived for at least 5 years after the clinical examination. The
apparent protective effect on all-cause or cancer mortality in
men of a higher % body fat or a higher BMI disappeared once
early deaths were excluded. The ‘reversed J-shaped’ association
in women between BMI and risk of all-cause and cardiovas-
cular mortality remained statistically significant and became
stronger once deaths in the first 5 years were excluded:
compared with women with a normal BMI, women with a BMI
,18.5 kg/m
2
had a risk of all-cause mortality of 2.03 (95% CI
1.15–3.59) and a risk of cardiovascular mortality of 2.44 (95%
CI 1.25–4.77), after multivariate-adjustment, while those
with a BMI >30 kg/m
2
had a multivariate-adjusted risk of
all-cause mortality of 1.41 (95% CI 1.50–2.07) and of
cardiovascular mortality of 1.62 (95% CI 1.03–2.55). Having
a BMI of 25–29 kg/m
2
was not associated with increased risk of
either all-cause (1.05, 95% CI 0.76–1.45) or cardiovascular
mortality (1.10, 95% CI 0.73–1.63). The relations between
grip strength and all-cause, cardiovascular, and cancer
mortality in men all remained statistically significant and
became slightly stronger when deaths in the first 5 years of
follow-up were excluded. For 1 SD increase in grip strength,
the multivariate-adjusted risks of all-cause, cardiovascular, and
cancer mortality were 0.78 (95% CI 0.63–0.95), 0.73 (95%
0.56–0.94), and 0.73 (95% CI 0.56–0.95), respectively.
Discussion
In this 24 year follow-up study of elderly men and women,
poorer grip strength was associated with increased mortality
from all causes, cardiovascular disease, and cancer in
men, though not in women, after adjustment for age, height,
smoking, reported weight change, physical activity, calorie
intake, and diagnosed disease at baseline. Grip strength at
baseline was strongly positively correlated with corrected arm
muscle area and fat-free mass, and, more weakly, with % body
Men
0 5 10 15 20 25
Time (years)
0.0
0.2
0.4
0.6
0.8
1.0
Survival probability
<62 kg
62-74 kg >74 kg
Women
0 5 10 15 20 25
Time (years)
0.0
0.2
0.4
0.6
0.8
1.0
Survival probability
<41 kg
42-49 kg
>49 kg
Figure 1 Kaplan–Meier survival curves for all-cause mortality
according to thirds of the distribution of grip strength in men and
women
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fat and BMI. These indicators of body composition did not
explain the association in men between grip strength and
mortality.
Few previous studies of the relation between grip strength
and mortality have examined the role that muscle size plays in
the association. In a follow-up study of men in the Baltimore
Longitudinal Study of Aging, grip strength at baseline was a
significant predictor of all-cause mortality in men aged 60 and
over, whereas rate of change in grip strength was predictive in
men aged under 60.
4
Men with a lower 24 h creatinine
excretion, used as an estimate of muscle mass, had an increased
risk of death but adjustment for this factor strengthened the
association between grip strength, or rate of change in strength,
and mortality suggesting that the relation was not due to the
amount of muscle in these men. More recently, results from
the Health, Aging and Body Composition Study, showed that
although poorer grip strength was associated with increased
all-cause mortality, low muscle mass, measured by CT scan and
DXA, was not strongly related to mortality.
15
In our study, we
had data on corrected arm muscle area and fat-free mass, but
neither of these explained the increased mortality associated
with poorer grip strength in men. As regards mortality from
Table 2 Relative risks (95% CI) of all-cause mortality per SD increase in grip strength and body composition measures
Age-adjusted
Multivariate-adjusted,
a
model 1 includes
fat-free mass
Multivariate-adjusted,
a
model 2 includes
% body fat
Multivariate-adjusted,
a
model 3 includes
BMI
Men
Grip strength 0.77 (0.68–0.87) 0.81 (0.69–0.94) 0.81 (0.70–0.94) 0.81 (0.70–0.95)
Arm muscle area 0.81 (0.73–0.89) 0.84 (0.72–0.98) 0.86 (0.76–0.98) 0.89 (0.76–1.03)
Fat-free mass 0.85 (0.75–0.97) 1.05 (0.85–1.29) – –
% body fat 0.79 (0.69–0.90) – 0.80 (0.70–0.92) –
BMI 0.84 (0.74–0.94) – – 0.94 (0.81–1.09)
Women
Grip strength 0.81 (0.67–0.97) 1.11 (0.86–1.43) 1.10 (0.86–1.40) 1.04 (0.81–1.32)
Arm muscle area 0.90 (0.80–1.02) 0.88 (0.73–1.06) 0.94 (0.81–1.08) 0.91 (0.77–1.08)
Fat-free mass 0.96 (0.79–1.15) 1.09 (0.82–1.45) – –
% body fat 0.27 (0.06–1.26) – 0.41 (0.05–3.13) –
% body fat squared 2.82 (0.79–10.0) – 2.03 (0.38–10.9)
BMI 0.25 (0.11–0.59) – – 0.26 (0.10–0.68)
BMI squared 4.00 (1.73–9.24) – – 3.83 (1.49–9.84)
a
Multivariate models include age, height, social class, smoking, reported change in weight, daily calorie intake, physical activity, diagnosed disease at baseline,
and other variables in the table, though to avoid potential problems with collinearity, fat-free mass, % body fat, and BMI have been analysed in separate
models.
Table 3 Relative risks (95% CI) of cardiovascular mortality per SD increase in grip strength and body composition measures
Age-adjusted
Multivariate-adjusted,
a
model 1 includes
fat-free mass
Multivariate-adjusted,
a
model 2 includes
% body fat
Multivariate-adjusted,
a
model 3 includes
BMI
Men
Grip strength 0.70 (0.60–0.82) 0.71 (0.59–0.86) 0.72 (0.60–0.87) 0.73 (0.60–0.89)
Arm muscle area 0.83 (0.73–0.95) 0.86 (0.70–1.04) 0.91 (0.78–1.06) 0.91 (0.75–1.10)
Fat-free mass 0.86 (0.73–1.01) 1.08 (0.82–1.41) – –
% body fat 0.84 (0.71–0.99) – 0.88 (0.73–1.05) –
BMI 0.87 (0.75–1.00) ––0.97 (0.81–1.17)
Women
Grip strength 0.79 (0.63–0.99) 1.03 (0.76–1.38) 1.09 (0.82–1.45) 1.02 (0.77–1.36)
Arm muscle area 0.98 (0.84–1.13) 0.95 (0.76–1.18) 0.99 (0.83–1.17) 0.94 (0.78–1.14)
Fat-free mass 0.97 (0.78–1.21) 1.05 (0.75–1.48) – –
% body fat 0.44 (0.06–3.41) – 1.10 (0.7–13.9) –
% body fat squared 2.00 (0.38–10.6) – 1.04 (0.12–9.94) –
BMI 0.21 (0.09–0.58) ––0.17 (0.6–0.54)
BMI squared 4.87 (1.85–12.83) --5.74 (1.93–17.1)
a
Multivariate models include age, height, social class, smoking, reported change in weight, daily calorie intake, physical activity, diagnosed disease at baseline,
and other variables in the table, though to avoid potential problems with collinearity, fat-free mass, % body fat, and BMI have been analysed in separate
models.
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specific causes, grip strength was not significantly related to risk
of death from respiratory disease after adjustment for other risk
factors, but it was strongly predictive of mortality in men from
cardiovascular disease and cancer, and these associations
remained after control for corrected arm muscle area and
other measures of body composition. These findings suggest
that the influence of grip strength on survival may have more
to do with the effectiveness with which muscle functions than
its size. As poorer grip strength has been associated with higher
fasting insulin levels, both cross-sectionally and longitudinally,
it seems likely that muscle weakness may precede the
development of insulin resistance.
16,17
This may help to
account for the link between poorer grip strength and increased
risk of death from cardiovascular disease found in men in the
current study and in a cohort of elderly disabled women.
6
In
the latter study, grip strength was significantly associated with
risk of death from respiratory disease as well as from
cardiovascular disease, though not from cancer. The lack of
association between grip strength and respiratory mortality in
our smaller study may be due to reduced statistical power.
The fact that we found no statistically significant associations
between grip strength and mortality in women may be a
reflection of the relatively small number of women who took
part in the clinical examination. There was no indication of a
Table 5 Relative risks of respiratory mortality per SD increase in grip strength and body composition measures
Age-adjusted
Multivariate-adjusted,
a
model 1 includes
fat-free mass
Multivariate-adjusted,
a
model 2 includes
% body fat
Multivariate-adjusted,
a
model 3 includes
BMI
Men
Grip strength 0.72 (0.60–0.89) 0.80 (0.63–1.02) 0.79 (0.63–0.98) 0.80 (0.63–1.01)
Arm muscle area 0.76 (0.65–0.89) 0.83 (0.65–1.06) 0.86 (0.71–1.03) 0.90 (0.72–1.13)
Fat-free mass 0.78 (0.64–0.95) 1.06 (0.76–1.46) – –
% body fat 0.74 (0.61–0.90) – 0.79 (0.63–0.99) –
BMI 0.84 (0.71–0.99) ––0.91 (0.73–1.15)
Women
Grip strength 0.72 (0.53–0.99) 1.16 (0.74–1.81) 1.04 (0.67–1.59) 1.01 (0.67–1.54)
Arm muscle area 0.80 (0.65–0.98) 0.77 (0.56–1.07) 0.91 (0.69–1.18) 0.80 (0.61–1.06)
Fat-free mass 0.96 (0.70–1.31) 1.33 (0.83–2.14) – –
% body fat 0.87 (0.65–1.17) – 1.07 (0.74–1.53) –
BMI 0.14 (0.04–0.51) ––0.22 (0.05–1.01)
BMI squared 6.77 (1.93–23.7) ––4.88 (1.09–21.9)
a
Multivariate models include age, height, social class, smoking, reported change in weight, daily calorie intake, physical activity, diagnosed disease at baseline,
and other variables in the table, though to avoid potential problems with collinearity, fat-free mass, % body fat, and BMI have been analysed in separate
models.
Table 4 Relative risks of cancer mortality per SD increase in grip strength and body composition measures
Age-adjusted
Multivariate-adjusted,
a
model 1 includes
fat-free mass
Multivariate-adjusted,
a
model 2 includes
% body fat
Multivariate-adjusted,
a
model 3 includes
BMI
Men
Grip strength 0.73 (0.63–0.85) 0.81 (0.66–0.99) 0.79 (0.65–0.97) 0.81 (0.66–0.98)
Arm muscle area 0.77 (0.68–0.88) 0.82 (0.67–0.99) 0.82 (0.70–0.97) 0.80 (0.72–1.07)
Fat-free mass 0.79 (0.67–0.93) 1.04 (0.79–1.37) – –
% body fat 0.76 (0.64–0.90) – 0.77 (0.65–0.92) –
BMI 0.83 (0.71–0.95) ––0.83 (0.71–0.97)
Women
Grip strength 0.79 (0.63–0.99) 1.03 (0.76–1.38) 1.28 (0.89–1.83) 1.18 (0.83–1.68)
Arm muscle area 0.98 (0.84–1.13) 0.95 (0.76–1.18) 0.93 (0.14–1.17) 0.80 (0.63–1.01)
Fat-free mass 0.97 (0.78–1.21) 1.05 (0.75–1.48) – –
% body fat 0.36 (0.04–3.34) – 1.09 (0.80–1.51) –
% body fat squared 2.23 (0.36–13.8) – 1.66 (0.14–20.3) –
BMI 0.29 (0.09–0.96) ––0.38 (0.10–1.52)
BMI squared 3.53 (1.10–11.3) ––2.58 (0.65–10.2)
a
Multivariate models include age, height, social class, smoking, reported change in weight, daily calorie intake, physical activity, diagnosed disease at baseline,
and other variables in the table, though to avoid potential problems with collinearity, fat-free mass, % body fat, and BMI have been analysed in separate
models.
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statistical interaction between grip strength and sex. Grip
strength has been shown to predict mortality in previous
studies of women, but these studies were based on considerably
larger numbers.
1,6
Most of the studies into the relation between grip strength
and mortality have been carried out in elderly people.
But findings in a population of healthy men that grip strength
measured in middle age predicts long-term risk of death
suggest that influences affecting muscle size and function
earlier in life may be important.
18
Greater strength tends to
be associated with tallness so it may in part be an indicator
of better nutrition in the first years of life, though observations
in cohorts of middle-aged and elderly people that those who
had weighed more at birth had significantly better grip
strength, independently of current height and weight, implies
that fetal development is a major determinant of muscle
strength.
19,20
The prognostic importance of increased BMI in older people
has been controversial.
21
A recent systematic review concluded
that mild to moderate overweight, defined as a BMI of
25–27 kg/m
2
, was not linked with higher mortality in elderly
people, though there was evidence that those with a BMI of
over 27 had an increased risk of death from all causes and from
cardiovascular disease.
22
In the current study, we too found no
evidence in either sex that mild to moderate overweight was
associated with increased mortality. There was a reverse-
J-shaped association between BMI and mortality from all causes
and cardiovascular disease, with the highest mortality occurring
among those with a BMI of less than 18 kg/m
2
, and slightly
increased mortality in those with a BMI >30 kg/m
2
but this
association was only present in women.
We found some evidence to link a higher % body fat or BMI
in men with a lower mortality from all causes and cancer.
These associations persisted after adjustment for potential
confounding factors, including weight loss, though numbers
reporting weight loss were low and longer-term weight loss
might not have been identified. Weight loss over a period of
several years, whether assessed by decrease in BMI,
23
loss of fat
mass, or loss of lean tissue,
11,24
has been linked to increased
mortality in previous studies of elderly people. In the present
study, these associations appeared to be concentrated among
people who died in the early years of follow-up, as they ceased
to be statistically significant when the analysis was restricted to
those who survived for at least 5 years after the clinical
examination.
Our study has some limitations. At the time the nutritional
survey was conducted, in 1973–74, anthropometry was the
usual method of assessing body composition. The data collected
may be less accurate than that obtainable with more modern
methods such as dual energy X-ray absorptiometry.
25
The
results of the study are based on 800 participants. This is 47%
of those originally invited to participate in the Department of
Health and Social Security’s nutritional survey. No data were
available on the characteristics of those who declined to
participate in the survey, so it is not possible to gauge how
representative these 800 people were of those originally
invited, though there were indications that of those who
agreed to take part in the nutritional survey, women and those
from manual social classes were less likely to agree to a clinical
examination. All comparisons, however, have been made
internally, so unless the relation between grip strength, body
composition, and mortality is different in non-responders or in
those we were unable to trace, no bias will have been
introduced.
Our findings in this 24 year follow-up of a national cohort of
people aged 65 and over that poorer grip strength predicted
increased mortality in men from all causes, from cardiovascular
disease, and from cancer, after adjustment for potential
confounding factors including indicators of body composition,
provide further evidence that the effectiveness with which
muscle functions may be a more important long-term
determinant of survival than its size. The explanation for the
grip strength/mortality association remains unclear.
Acknowledgements
We thank the Department of Health for allowing us to use data
from the 1973–74 Department of Health and Social Security’s
nutritional survey. The survey was coordinated by the late
Professor A N Exton-Smith.
Conflict of interest: none of the authors has any conflict of
interest.
Author contribution: C Gale analysed the data and wrote the
first draft of the report. C Martyn, C Cooper, and A Aihie Sayer
were involved in planning the analysis and contributed to the
final version of the report.
KEY MESSAGESKEY MESSAGESKEY MESSAGESKEY MESSAGESKEY MESSAGESKEY MESSAGES
Grip strength has been shown to predict all-cause mortality in older people, but less is known about its influence
on risk of death from specific causes and on the role of body composition in the grip strength/mortality
association.
In a 24 year follow-up of a national cohort aged 65 and over, grip strength was a strong, long-term predictor of
mortality from all-causes, cardiovascular disease and cancer in men, though not in women.
Indicators of body composition did not explain these associations.
The effectiveness with which muscle functions may be a more important determinant of survival than
muscle size.
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