Long-term determinants of muscle strength decline: prospective evidence from the 22-year mini-Finland follow-up survey

Inverse effects of midlife occupational and leisure time physical activity on mobility limitation in old age--a 28-year prospective follow-up study

OBJECTIVES

To evaluate in a sample of initially middle-aged municipal employees whether leisure time (LPA) or occupational physical activity (OPA) was associated with mobility limitation (ML) in old age.

DESIGN

Prospective population-based follow-up.

SETTING

Municipalities in Finland.

PARTICIPANTS

Public sector employees from the Finnish Longitudinal Study on Municipal Employees (FLAME) initially aged 44 to 58 (N = 5,200).

MEASUREMENTS

Baseline data were collected in 1981, including LPA (average exercise within previous year: inactive (no exercise), moderate (some form of exercise ≤ 1 time per week), vigorous (brisk exercise ≥ 1 time per week)) and OPA (usual activities at work within previous year: light (light work sitting, standing, or moving around), moderate (moderate work moving around), vigorous (heavy physical work)). Number of MLs was assessed using a questionnaire (8 items) in 1985, 1992, 1997, and 2009; the latest mobility score available for each subject was used for analyses. Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) for LPA and OPA predicting ML were estimated in a joint Poisson regression model adjusted for survival data; the other type of PA; and sociodemographic, socioeconomic, and health-related factors.

RESULTS

Mean age at baseline was 50.3 ± 3.6; 56.9% of participants were female. Participants with vigorous OPA in midlife had greater risk of a unit increase in ML in old age than those with light OPA (fully adjusted IRR = 1.09, 95% CI = 1.03-1.16). Participants with vigorous LPA had lower risk of ML than inactive participants (fully adjusted IRR = 0.81, 95% CI = 0.76-0.86).

CONCLUSION

Findings suggest that LPA and OPA in midlife have independent, inverse effects on mobility in old age in terms of a harmful effect of vigorous OPA and a protective effect of vigorous LPA.

Midlife and late-life handgrip strength and risk of cause-specific death in a general Japanese population: the Hisayama Study

BACKGROUND

Decreased handgrip strength has been reported to be a risk factor for all-cause death among the elderly. However, it is unclear whether handgrip strength measured in midlife is associated with risk of all-cause and cause-specific death in the general population.

METHODS

We followed, prospectively, a total of 2527 community-dwelling Japanese (1064 men and 1463 women) aged ≥40 years for 19 years. Participants were divided into three groups according to the age-specific and sex-specific tertiles of handgrip strength (T1, lowest; T3, highest).

RESULTS

During the follow-up period, 783 participants died, of whom 235 died of cardiovascular disease, 249 of cancer, 154 of respiratory disease and 145 of other causes. In the middle-aged group (40-64 years), multivariable-adjusted HRs (95% CIs) for all-cause death were 0.75 (0.56 to 0.99) in T2 and 0.49 (0.35 to 0.68) in T3 compared with T1 as a reference. Corresponding HRs (95% CI) in the elderly group (≥65 years) were 0.50 (0.40 to 0.62) and 0.41 (0.32 to 0.51), respectively. As regards the cause of death, higher levels of handgrip strength were significantly associated with decreased risks of cardiovascular death, respiratory death and death from other causes, but not of cancer, in the middle-aged and the elderly.

CONCLUSIONS

Our findings suggest that handgrip strength levels in midlife and late life are inversely associated with the risks of all-cause and non-cancer death in the general Japanese population.

Longitudinal impact of aging on muscle quality in middle-aged men

The present follow-up study aims at assessing the longitudinal changes in muscle quality after an interval of 9.45 years in middle-aged men. In addition, the relative contribution of muscle mass, muscle strength, and muscle power at middle age to these changes was investigated. The results showed a small, though unexpected, increase in total body and leg muscle mass (respectively 0.22 ± 0.04 and 0.29 ± 0.06 % yearly, p < 0.0001), whereas basic strength (-0.71 to -0.87 % yearly, p < 0.0001) and velocity-dependent strength and power (-1.19 to -1.86 % yearly, p < 0.0001) declined. Consequently, muscle quality, defined as the ratio of basic strength or velocity-dependent strength and power to muscle mass decreased (-1.46 to -2.43 % yearly, p < 0.0001) from baseline to follow-up. We found that baseline basic strength is a strong determinant of the decline in muscle quality basic strength with advancing age, whereas only a small part of the age-associated decline in muscle quality based on velocity-dependent strength and power could be explained. To conclude, our results indicate that muscle becomes less efficient at middle age and that baseline muscle strength is a strong predictor of this change. These findings imply that unmeasured neural factors, influencing both contraction speed and the capacity of muscle to produce strength, are possibly other involved determinants. Therefore, timely interventions including strength training and higher-velocity strength training at middle age are recommended.

Handgrip strength and associated factors in hospitalized patients

BACKGROUND

Handgrip strength (HGS) is a marker of nutrition status. Many factors are associated with HGS. Age, height, body mass index, number of diagnoses, and number and type of drugs have been shown to modify the association between undernutrition and HGS. Nevertheless, other patient characteristics that could modify this association and its joint modifier effect have not been studied yet.

OBJECTIVE

To evaluate the association of inpatients' HGS and undernutrition considering the potential modifier effect of cognitive status, functional activity, disease severity, anthropometrics, and other patient characteristics on HGS.

METHODS

A cross-sectional study was conducted in a university hospital. Sex, age, abbreviated mental test score, functional activity score, Charlson index, number of drugs, Patient-Generated Subjective Global Assessment (PG-SGA) score, body weight, mid-arm muscle circumference, adductor pollicis muscle thickness, body height, wrist circumference, hand length, and palm width were included in a linear regression model to identify independent factors associated with HGS (dependent variable).

RESULTS

The study sample was composed of 688 inpatients (18-91 years old). All variables included in the model were associated with HGS (β, -0.16 to 0.38; P ≤ .049) and explained 68.5% of HGS. Age, functional activity decline, Charlson index, number of drugs, PG-SGA score, body weight, and wrist circumference had a negative association with HGS. All other studied variables were positively associated with HGS.

CONCLUSION

Nutrition status evaluated by PG-SGA was still associated with HGS after considering the joint effect of other patient characteristics, which reinforces the value of HGS as an indicator of undernutrition.

Predictors of Handgrip Strength Among Adults of a Rural Community in Malaysia

Handgrip strength is useful for screening the nutritional status of adult population as it is strongly associated with physical disabilities and mortality. Therefore, we aimed to determine the predictors of handgrip strength among adults of a rural community in Malaysia using a cross-sectional study design with multistage sampling. All adults aged 30 years and older from 1250 households were invited to our study. Structured questionnaire on sociodemographic characteristics, medical history, occupation history, lifestyle practices, and measurements, including anthropometry and handgrip strength were taken. There were 2199 respondents with 55.2% females and majority were of Malay ethnicity. Their mean (standard deviation) age was 53.4 (13.2) years. The response rate for handgrip strength was 94.2%. Females had significantly lower handgrip strength than males ( P < .05). In the multiple linear regression models, significant predictors of handgrip strength for males were age, height, job groups, and diabetes, while for females, the significant predictors were age, weight, height, and diabetes.

Physical activity levels across adult life and grip strength in early old age: updating findings from a British birth cohort

INTRODUCTION

observational studies do not always find positive associations between physical activity and muscle strength despite intervention studies consistently showing that exercise improves strength in older adults. In previous analyses of the MRC National Survey of Health and Development (NSHD), the 1946 British birth cohort, there was no evidence of an association between leisure time physical activity (LTPA) across adulthood and grip strength at age 53. This study tested the hypothesis that cumulative benefits of LTPA across mid-life on grip strength will have emerged by age 60-64.

METHODS

data from the MRC NSHD were used to investigate the associations between LTPA at ages 36, 43, 53 and 60-64 and grip strength at 60-64. Linear regression models were constructed to examine the effect of activity at each age separately and as a cumulative score, including adjustment for potential confounders and testing of life course hypotheses.

RESULTS

there were complete longitudinal data available for 1,645 participants. There was evidence of a cumulative effect of LTPA across mid-life on grip strength at 60-64. Compared with the third of participants who reported the least LTPA participation across the four time points, those in the top third had on average 2.11 kg (95% CI: 0.88, 3.35) stronger grip after adjustments.

CONCLUSIONS

increased levels of LTPA across mid-life were associated with stronger grip at age 60-64, in both men and women. As these associations have emerged since age 53, it suggests that LTPA across adulthood may prevent decline in grip strength in early old age.

Muscle size, strength, and physical performance and their associations with bone structure in the Hertfordshire Cohort Study

Sarcopenia is associated with a greater fracture risk. This relationship was originally thought to be explained by an increased risk of falls in sarcopenic individuals. However, in addition, there is growing evidence of a functional muscle-bone unit in which bone health may be directly influenced by muscle function. Because a definition of sarcopenia encompasses muscle size, strength, and physical performance, we investigated relationships for each of these with bone size, bone density, and bone strength to interrogate these hypotheses further in participants from the Hertfordshire Cohort Study. A total of 313 men and 318 women underwent baseline assessment of health and detailed anthropometric measurements. Muscle strength was measured by grip strength, and physical performance was determined by gait speed. Peripheral quantitative computed tomography (pQCT) examination of the calf and forearm was performed to assess muscle cross-sectional area (mCSA) at the 66% level and bone structure (radius 4% and 66% levels; tibia 4% and 38% levels). Muscle size was positively associated with bone size (distal radius total bone area β = 17.5 mm2 /SD [12.0, 22.9]) and strength (strength strain index (β = 23.3 mm3 /SD [18.2, 28.4]) amongst women (p < 0.001). These associations were also seen in men and were maintained after adjustment for age, height, weight-adjusted-for-height, limb-length-adjusted-for-height, social class, smoking status, alcohol consumption, calcium intake, physical activity, diabetes mellitus, and in women, years since menopause and estrogen replacement therapy. Although grip strength showed similar associations with bone size and strength in both sexes, these were substantially attenuated after similar adjustment. Consistent relationships between gait speed and bone structure were not seen. We conclude that although muscle size and grip strength are associated with bone size and strength, relationships between gait speed and bone structure and strength were not apparent in this cohort, supporting a role for the muscle-bone unit.

Clustering of lifestyle risk factors and poor physical function in older adults: the Hertfordshire cohort study

OBJECTIVES

To examine the relationship between number of lifestyle risk factors (out of low physical activity, poor diet, obesity, smoking) and physical function in older community-dwelling men and women.

DESIGN

Cross-sectional study, Hertfordshire, United Kingdom.

PARTICIPANTS

Men (n = 1,682) and women (n = 1,540) aged 59 to 73.

MEASUREMENTS

Physical activity was assessed using an administered questionnaire with a score from 0 to 100; low activity was defined as a score of 50 or less. Diet was assessed using a food frequency questionnaire; diet quality was assessed according to a score for a principal component analysis-defined "healthy" dietary pattern. Poor diet was categorized as a dietary pattern score in the lowest quarter of the distribution. Obesity was defined as a body mass index of 30.0 kg/m(2) or more. Physical function was assessed according to self-report (SF-36); poor function was defined as a score in lowest quarter of the distribution. A subgroup of participants had objective assessments of physical function (Timed Up-and-Go Test, timed 3-m walk, chair rises, one-legged standing balance).

RESULTS

There was a graded increase in prevalence of poor self-reported physical function in men and women with increasing number of risk factors (men, adjusted odds ratio (AOR) for 3 or 4 risk factors vs none = 3.79, 95% confidence interval (CI) = 2.31-6.21; women, AOR = 5.37, 95% CI = 2.66-10.84). With the exception of balance, the objective assessments also showed graded relationships with number of risk factors, such that more risk factors was associated with poorer physical function.

CONCLUSION

These modifiable lifestyle risk factors are linked to marked differences in risk of poorer physical function in older adults. Efforts to encourage healthy lifestyles have the potential to improve physical function and to promote healthier ageing.

New normative values for handgrip strength: results from the UK Biobank

OBJECTIVES

To develop normative values for right and left handgrip strength after stratification for confounders like gender, age, and height.

DESIGN

Cross-sectional, descriptive.

SETTING

General population.

PARTICIPANTS

A total of 502,713 people living in the United Kingdom.

INTERVENTION

None.

MEASUREMENTS

Handgrip strength was measured using a Jamar hydraulic hand dynamometer, which is considered to be an accurate instrument to measure handgrip strength. In addition, self-reported chronic conditions and ethnic background were registered, and lung function was assessed using spirometry.

RESULTS

After exclusion of all individuals with missing data, a nonwhite ethnic background, the presence of 1 or more self-reported conditions, and/or an obstructive lung function (defined as FEV1/FVC <0.7), new normative values for right and left handgrip strength were derived from 224,830 and 224,852 individuals (54.2% women; age: 55.0 [8.0] years; height: 169.0 [9.2] cm; body mass index: 26.9 [4.4] kg/m(2)) with a nonobstructed spirometry (FEV1: 3.0 [0.8] L). Men were stronger than women. Moreover, significant associations were found between handgrip strength and height, and between handgrip strength and age. Finally, percentiles 5, 10, 25, 50, 75, 90, and 95 were calculated for right and left handgrip strength, after stratification for gender, age, and height.

CONCLUSION

The UK Biobank dataset provided the opportunity to determine new normative values for handgrip strength in men and women aged 39 to 73 years. These normative values take into consideration age, height, and measurement side. Therefore, these new normative handgrip strength values are of broad clinical interest.

A cross-sectional assessment of oxidative DNA damage and muscle strength among elderly people living in the community

OBJECTIVES

The mechanism by which muscle weakness leads to an increased risk of death remains a subject of interest. In this context, the aim of this study is to assess the relationship between urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and muscle strength, and other risk factors contributing to poor muscle strength in older persons.

METHODS

This was a cross-sectional study in which a total of 86 participants, both men and women, aged 65 years or above were screened for urinary 8-OHdG, and muscle strength as measured by handgrip strength.

RESULTS

Handgrip strength was lower in participants who had history of acute or chronic disease. Urinary 8-OHdG level was negatively associated with muscle strength, and the association remained after adjusting for confounding factors.

CONCLUSIONS

Urinary 8-OHdG is associated with muscle strength. These findings may be clinically relevant as there is a possibility of controlling oxidative DNA damage by healthy behaviors related to lifestyle.

Impaired bone microarchitecture at the distal radius in older men with low muscle mass and grip strength: the STRAMBO study

The aim was to study the association between bone microarchitecture and muscle mass and strength in older men. Volumetric bone mineral density (vBMD) and bone microarchitecture were assessed in 810 men aged ≥60 years at the distal radius by high-resolution peripheral computed tomography (HR-pQCT). Areal bone mineral density (aBMD) and appendicular muscle mass (ASM) were assessed by dual-energy X-ray absorptiometry (DXA). Relative ASM of the upper limbs (RASM-u.l.) was calculated as ASM of the upper limbs/(height)(2). Grip strength was measured by dynanometry. In multivariable models, men in the lowest RASM-u.l. quartile had lower cross-sectional area (CSA), cortical area (Ct.Ar), cortical thickness (Ct.Th), and trabecular area (Tb.Ar) at distal radius compared with men in the highest quartile. The trends remained significant after adjustment for grip strength. Men in the lowest quartile of the normalized grip strength (grip strength/[height](2)) had lower aBMD, total vBMD, Ct.Ar, Ct.Th, Tb.vBMD, and Tb.N, and higher Tb.Sp and Tb.Sp.SD. The associations for Ct.Ar, total vBMD, Ct.Th, Tb.vBMD, and Tb.Sp remained significant after adjustment for RASM-u.l. In the models including RASM-u.l. and normalized grip strength, CSA and Tb.Ar were associated with RASM-u.l. but not with the strength. Lower Ct.Th, Tb.vBMD, and Tb.N were associated with lower grip strength but not with RASM-u.l. Lower Ct.Ar was associated with lower grip strength and with lower RASM-u.l. In conclusion, in older men, low RASM-u.l. and low grip strength are associated with poor cortical and trabecular microarchitecture partly independently of each other, after adjustment for confounders.

The relationship of testosterone and AR CAG repeat genotype with knee extensor muscle function of young and older men

The inter-relationship between muscle strength and serum testosterone is not fully understood, and may be confounded or influenced by age. The polymorphism of androgen receptor gene CAG number (AR CAGn) could also influence these variables. The study examined the relationship between total testosterone (TT), free testosterone (FT) and AR CAGn with the muscle strength of young (YM, 18-30 yrs, n=82) and older (OM, 60-70 yrs, n=101) Caucasian men. Knee extensor strength was measured isometrically and isokinetically, and thigh and whole-body lean mass of the OM was determined by DXA. TT and serum hormone binding globulin (SHBG) were assayed by ELISA and used to calculate FT. AR CAGn was determined using polymerase chain reaction and microchip electrophoresis. OM were weaker than YM (-20 to -29%, all P<0.001), and serum androgens were lower (TT, -13%; FT, -13%; both P<0.001). TT was unrelated to any strength measurement in YM or OM. In the OM only, FT had a weak positive association with all three strength measures (r(2)=4.1-9.3%, P<0.036) and both whole body and thigh lean mass (r(2)=6.1-8.6%; P<0.013). Muscle strength was unrelated to AR CAGn for either the YM or OM, or when data were collapsed across both age groups (age normalised strength). Lean mass in the older cohort was also independent of AR CAGn. In conclusion, FT, but not TT or AR CAGn, was positively associated with muscle strength, but only as values declined with age.