Choice reaction time and grip strength as predictors of cardiovascular mortality in middle‐aged and elderly Japanese: from the Radiation Effects Research Foundation Adult Health study

Associations of grip strength and walking pace with mortality in stroke survivors: A prospective study from UK Biobank

INTRODUCTION

Although stroke is an emerging cause of disability and mortality globally, associations between physical capability markers and mortality in stroke survivors are elusive. This study investigated the individual and combined associations of walking pace and grip strength with all-cause and stroke mortality in stroke survivors.

METHODS

Individual and combined associations of walking pace and grip strength with stroke deaths and all-cause mortality were investigated using Cox proportional-hazard models adjusted for sociodemographic, lifestyle, and health-related variables.

RESULTS

Seven thousand four hundred eighty-six stroke survivors from the UK Biobank study (aged 40-70 years; 42.4% women) were included in this prospective study. Over a median follow-up of 12.6 (IQR: 11.9-13.3) years, 1490 (19.9%) participants died, of whom 222 (3.0%) died from stroke. After adjusting for confounding factors, and compared to individuals in the average/brisk walking pace category, those who reported a slow walking pace had 2.00 (95% CI: 1.50-2.68) and 1.99 (95% CI: 1.78-2.23) times higher risk of stroke mortality and all-cause mortality, respectively. Similar associations were identified for participants with low grip strength compared with those with normal levels. For combined associations, those with both slow walking pace and low grip strength showed the highest risk of stroke mortality (hazard ratio: 2.86 [95% CI: 1.93-4.22]). Similar results were found for all-cause mortality.

CONCLUSIONS

Low grip strength and slow walking pace were associated with a higher risk of stroke and all-cause mortality in stroke survivors. If these associations are causal, improving physical capability among stroke survivors might potentially prolong survival.

COVID-19 Quarantine Impact on Wellbeing and Cognitive Functioning During a 10-Week High-Intensity Functional Training Program in Young University Students

Physical exercise can improve cognitive functioning and wellbeing; however, the degree of change in either of these two variables seems to be related to the exercise intensity or type. Therefore, new physical training (PT) programs have been developed to increase exercise efficiency. One such example is high-intensity functional training (HIFT), which has proven to be a time-efficient and highly effective strategy to improve physical fitness. This study analyzed whether HIFT can affect reaction time (RT) and vitality, as well as positive and negative affect. Forty-two college students participated in the study, 21 in the experimental group and 21 in the control group. The experimental group completed 10 weeks of training, five of which were supervised, and the remainder consisted of online training during the COVID-19 quarantine. Participants were evaluated at the beginning, at the end of the 5 weeks of supervised training, and after the 5 weeks of online training. HIFT improved RT without changes in psychological wellbeing during the entire period of training supervised and online. Therefore, during the HIFT program, the quarantine situation did not adversely affect this population’s wellbeing, but it did negatively affect adherence to the training program.

Is simple reaction time or choice reaction time an indicator of all-cause mortality or CVD mortality?

OBJECTIVES

Simple reaction time (SRT) and choice reaction time (CRT) have been shown to be good indicators for quantitatively assessing the level of human cognitive impairment, but these parameters have also been linked to the risk of human death. This study aimed to quantitatively assess the independent predictive value of SRT or CRT for all-cause mortality or cardiovascular disease (CVD) mortality by conducting a meta-analysis of prospective studies.

STUDY DESIGN

The study design of this study is a prospective cohort study.

METHODS

We conducted a meta-analysis by combining hazard ratios (HRs) and 95% confidence intervals (95% CIs) of SRT or CRT with all-cause mortality or CVD mortality in healthy community residents aged 18 and over. Heterogeneity was evaluated by using Q statistics and Cochrane's I² statistics.

RESULTS

A total of seven prospective studies that examined all-cause mortality and CVD mortality were included. The pooled HR of all-cause mortality in SRT was 1.099 (1.065-1.134, I² = 11.9%), and an increased risk of CVD mortality was associated with lower SRT (HR = 1.186, 95% CI = 1.137-1.236; I² = 52.4%). Similarly, the pooled HR of all-cause mortality in CRT was 1.140 (95% CI = 1.085-1.197, I² = 33.7%). However, lower CRT was not statistically associated with an increased risk of CVD mortality.

CONCLUSION

SRT may be a predictor of all-cause-mortality and CVD mortality, and CRT is significantly associated with an increased risk of all-cause mortality.

Exposure to phthalates is associated with grip strength in US adults

The potential association of exposure to phthalates with muscle strength was reported in previous animal experiments. However, their association was rarely directly investigated in general populations. Thus, we aimed to ascertain the association of exposure to phthalates with grip strength using cross-sectional analysis which included 2436 individuals aged ≥ 20 years from the National Health and Nutrition Examination Survey (NHANES) during 2011-2014. The multivariable linear regression models were performed with the adjustment of related covariates. The results suggested that a one-unit increase in log-transformed phthalate metabolites (μg/g creatinine) was inversely associated with grip strength, including Mono-(2-ethyl)-hexyl phthalate (β: -2.727 kg, 95% CI: -3.452, -2.002), Mono-(2-ethyl-5-hydroxyhexyl) phthalate (β: -3.721 kg, 95% CI: -4.836, -2.607), Mono-(2-ethyl-5-oxohexl) phthalate (β: -4.669 kg, 95% CI: -5.761, -3.577), Mono-2-ethyl-5-carboxypentyl phthalate (β: -4.756 kg, 95% CI: -5.957, -3.554), Mono-carboxyoctyl phthalate (β: -1.324 kg, 95% CI: -2.412, -0.235), Mono-carboxynonyl phthalate (β: -2.036 kg, 95% CI: -3.185, -0.886), Mono-benzyl phthalate (β: -2.940 kg, 95% CI: -3.853, -2.026), Mono-n-butyl phthalate (β: -2.100 kg, 95% CI: -3.474, -0.726), Mono-isobutyl phthalate (β: -2.982 kg, 95% CI: -4.331, -1.633), and Mono-ethyl phthalate (β: -1.709 kg, 95% CI: -2.368, -1.050). In subgroup analyses, the associations remained largely unchanged when the samples were stratified by gender and age; However they became ambiguous among underweight subjects when the samples were stratified by BMI status. Overall, exposure to phthalates was inversely associated with grip strength among US adults, regardless of their genders and ages. The suggestive potential BMI status-specific effects of phthalates on grip strength were observed.

Cadmium exposure is associated with reduced grip strength in US adults

BACKGROUND

Muscle strength is a strong predictor of all-cause mortality in the general population. Recent studies have shown an association between environmental pollution and declined grip strength. No previous research has evaluated the specific association between cadmium exposure, a well-known risk factor of several chronic diseases, and muscle strength.

METHODS

Cross-sectional study among 4,197 individuals aged ≥40 years, who participated in the National Health and Nutrition Examination Survey (NHANES) 2011-2014, provided data on grip strength, and had either blood or urine cadmium determinations. Grip strength was measured using a Takei digital handgrip dynamometer, and combined grip strength was calculated as the sum of the largest reading from each hand.

RESULTS

Median (interquartile range) concentrations of blood (BCd) and creatinine-corrected urine cadmium (Cr-UCd) were 0.32 μg/L (0.20-4.56) and 0.27 μg/g (0.15-0.46), respectively. After adjusting for sociodemographic, anthropometric, health-related behavioral, and clinical risk factors, and serum creatine phosphokinase concentrations, the highest (vs lowest) quartile of BCd was associated with a reduction in combined grip strength of 1.93 kg (95% confidence interval [CI]: -3.51, -0.34), p-trend <0.001. The corresponding values comparing Cr-UCd quartiles 4 vs 1 were -3.24 kg (95% CI: -5.68, -0.79), p-trend <0.001. These results were consistent across socio-demographic and clinical subgroups.

CONCLUSIONS

In the US adult population, higher cadmium exposure was associated with decreased grip strength. These results may have important public health implications given the widespread cadmium exposure.

Skeletal muscle function and need for long-term care of urban elderly people in Japan (the Bunkyo Health Study): a prospective cohort study

PURPOSE

The proportion of elderly individuals (age ≥65 years) in Japan reached 27.7% in 2017, the highest in the world. A serious social problem in a super-aged society is the rise in the number of elderly people who need long-term care (LTC), which is mainly due to cerebrovascular disease, dementia, age-related frailty, falls and fractures, and joint disease. We hypothesised that decreased muscle mass, muscle strength and insulin sensitivity are the common risk factors for these diseases related to needing LTC. We developed a prospective cohort study of elderly subjects in an urban community to test this hypothesis. The primary objective is to prospectively investigate associations between muscle mass, muscle strength, and insulin sensitivity and incidence of main disease and risk factors of needing LTC. The primary outcomes are the incidence of cerebrovascular disease and cognitive decline.

PARTICIPANTS

Participants were 1629 people aged 65-84 years living in 13 communities in an urban area (Bunkyo-ku, Tokyo, Japan). Average age was 73.1±5.4 years.

FINDINGS TO DATE

We obtained baseline data on cognitive function, cerebral small vessel disease (SVD) determined by brain MRI, body composition, bone mineral density, arteriosclerosis, physical function, muscle mass, muscle strength and insulin sensitivity. Mild cognitive impairment and dementia were observed in 18.1% and 3.3% of participants, respectively. The prevalence of cerebral SVD was 24.8%. These characteristics are similar to those previously reported in elderly Japanese subjects.

FUTURE PLANS

We will ask participants about their health status, including incidence of cerebrovascular disease, falls, fractures and other diseases every year by mail. We plan to re-evaluate cognitive function, brain MRI parameters and other parameters at 5 and 10 years after the baseline evaluation. We will evaluate whether low muscle function (muscle mass, muscle strength or insulin sensitivity) is a risk factor for cognitive decline or cerebrovascular disease.