Causal associations of hand grip strength with bone mineral density and fracture risk: A mendelian randomization study

Back-leg-chest test as an alternative to the handgrip testing for measuring body strength in adults

The handgrip strength test is commonly used to measure muscle strength throughout the lifespan, other tests may offer equivalent information and potentially serve as better indicators of overall muscle strength. The primary objective of this study was to examine the relationship between handgrip strength and back-leg-chest strength tests. The secondary objective was to determine whether levels of physical activity affect the outcomes of handgrip and back-leg-chest strength tests differently. A convenience sample of participants aged 18-65 years was selected (n = 303), regardless of their engagement in physical activity and with no physical limitations that could prevent completion of the tests. In one laboratory session, they completed the International Physical Activity Questionnaire to determine their level of physical activity and performed the handgrip strength and back-leg-chest strength tests. A high correlation was found between handgrip strength and the back-leg-chest strength test (r = 0.739,p < 0.001). No significant difference in handgrip strength was observed across different levels of activity (p = 0.135). However, significant differences were noted for the back-leg-chest strength test across varying levels of physical activity, with individuals engaging in moderate levels of physical activity demonstrating greater strength on this test compared to those with lower activity levels (p = 0.012). Evidence was provided of a strong correlation between the handgrip and back-leg-chest strength tests, with the back-leg-chest strength test also showing better sensitivity to levels of activity. Thus, the back-leg-chest strength test may serve as a more comprehensive measure of strength, potentially reflecting overall body strength due to its involvement of multiple joints.

The association between hand grip strength and chronic kidney disease progression: insights from SMP-CKD studies

PURPOSE

This study aims to investigate the relationship between handgrip strength (HGS) and the progression of chronic kidney disease (CKD) in non-dialysis patients in China, as part of the Self-Management Program for Patients with CKD Cohort (SMP-CKD).

METHODS

In the SMP-CKD cohort, we utilized Cox regression and Kaplan-Meier survival analysis to explore the association between HGS and CKD progression. Data were stratified by sex-specific HGS quartiles, sarcopenia status, and HGS thresholds. The HGS thresholds were determined through curve analysis of HGS against composite renal outcomes. Group differences were compared to assess the impact of HGS on CKD outcomes.

RESULTS

A total of 441 participants (mean age 57.0 ± 17 years, 56.0% male) with CKD stages 3-5 from the SMP-CKD cohort who underwent grip strength evaluation between April 2019 and June 2024 were included in the analysis. The findings revealed that participants in the highest bilateral HGS quartile had a significantly lower risk of renal endpoints, with a hazard ratio (HR) of 0.102 (95% CI 0.041-0.255) compared to those in the lowest quartile. Patients without sarcopenia had a significantly lower risk of CKD composite outcomes, including increased serum creatinine or acute CKD exacerbations (HR 0.422, 95% CI 0.211-0.844, p < 0.012), as well as severe renal endpoints (HR 0.265, 95% CI 0.101-0.694, p < 0.003). Gender-specific cutoffs identified through log-rank test were 63.7 kg for men and 34.6 kg for women. Participants with bilateral HGS above these thresholds demonstrated better renal outcomes, underscoring the protective effect of higher HGS against CKD progression.

CONCLUSION

The study provides strong evidence that HGS is a crucial factor in reducing the risk of CKD progression. Higher levels of HGS are significantly associated with a lower occurrence of renal endpoint events.

Correlation Between Handgrip Strength and Bone Density and Fragility Fracture Risk Among Older Adults: A Cross-Sectional Study

BACKGROUND

Population aging has led to a surge in elderly care needs worldwide. Bone aging, skeletal muscle degeneration, and osteoporosis pose critical health challenges for the elderly. The process of bone and skeletal muscle aging not only impacts the functional abilities but also increases fragility fracture risk. Although a negative correlation between handgrip strength and fragility fracture risk has been identified in elderly populations, there is a lack of related research in Taiwan.

PURPOSE

This cross-sectional study was designed to investigate the association between handgrip strength and two outcome variables, bone density and risk of fragility fracture, in Taiwanese individuals aged 65 years and older with low bone mass.

METHODS

A total of 548 older adults, including 84 men and 464 women, were recruited between August 2019 and July 2021. Bone mineral density T -scores acquired using dual-energy X-ray absorptiometry scan, the total score for the Taiwan-specific Fracture Risk Assessment (FRAX) tool, and bilateral handgrip strength acquired using a digital hand dynamometer were recorded along with other factors such as comorbidities, dietary habits, and daily activities.

RESULTS

In this study, the mean age was 70.9 ( SD = 5.6) years, mean bone mass index was 24.1 ( SD = 3.5) kg/m 2 , mean FRAX main fracture risk score was 19.5% ( SD = 8.3), and mean FRAX hip fracture risk score was 7.7% ( SD = 5.7). Lumbar and hip T -scores were both significantly correlated with both dominant and nondominant handgrip strength in older woman. Older age; both lower hip and spine T -scores; both lower dominant and nondominant handgrip strengths; having Type 2 diabetes, coronary artery disease, or chronic hepatic disease; and lacking a steady job were significantly associated with a higher risk of fragility fracture.

CONCLUSIONS/IMPLICATIONS FOR PRACTICE

The results of this study provide important information regarding the correlation between handgrip strength and several variables, including bone mineral density T -score, FRAX score, comorbidities, and job status, among older adults. Notably, these correlations were found to be particularly strong in the female participants. This information may be used to facilitate the early identification of elderly individuals at a high risk of fragility fractures, enabling the timely development of preventive nursing strategies and the provision of targeted interventions.

GWAS-Informed data integration and non-coding CRISPRi screen illuminate genetic etiology of bone mineral density

Over 1,100 independent signals have been identified with genome-wide association studies (GWAS) for bone mineral density (BMD), a key risk factor for mortality-increasing fragility fractures; however, the effector gene(s) for most remain unknown. Informed by a variant-to-gene mapping strategy implicating 89 non-coding elements predicted to regulate osteoblast gene expression at BMD GWAS loci, we executed a single-cell CRISPRi screen in human fetal osteoblasts (hFOBs). The BMD relevance of hFOBs was supported by heritability enrichment from stratified LD-score regression involving 98 cell types grouped into 15 tissues. 23 genes showed perturbation in the screen, with four (ARID5B, CC2D1B, EIF4G2, and NCOA3) exhibiting consistent effects upon siRNA knockdown on three measures of osteoblast maturation and mineralization. Lastly, additional heritability enrichments, genetic correlations, and multi-trait fine-mapping revealed unexpectedly that many BMD GWAS signals are pleiotropic and likely mediate their effects via non-bone tissues. Extending our CRISPRi screening approach to these tissues could play a key role in fully elucidating the etiology of BMD.

Predicting grip strength-related frailty in middle-aged and older Chinese adults using interpretable machine learning models: a prospective cohort study

Introduction

Frailty is an emerging global health burden, and there is no consensus on the precise prediction of frailty. We aimed to explore the association between grip strength and frailty and interpret the optimal machine learning (ML) model using the SHapley Additive exPlanation (SHAP) to predict the risk of frailty.

Methods

Data for the study were extracted from the China Health and Retirement Longitudinal Study (CHARLS) database. Socio-demographic, medical history, anthropometric, psychological, and sleep parameters were analyzed in this study. We used the least absolute shrinkage and selection operator (LASSO) regression to filter the model for the best predictor variables and constructed six ML models for predicting frailty. The feature performance of six ML models was compared based on the area under the receiver operating characteristic curve (AUROC) and the light gradient boosting machine (LightGBM) model was selected as the best predictive frailty model. We used SHAP to interpret the LightGBM model and to reveal the decision-making process by which the model predicts frailty.

Results

A total of 10,834 eligible participants were included in the study. Using the lowest quartile of grip strength as a reference, grip strength was negatively associated with the risk of frailty when grip strength was >29.00 kg for males or >19.00 kg for females (p < 0.001). The LightGBM model predicted frailty with optimal performance with an AUROC of 0.768 (95% CI 0.741 ~ 0.795). The SHAP summary plot showed that all features predicted frailty in order of importance, with cognitive function being considered the most important predictive feature. The poorer the cognitive function, nighttime sleep duration, body mass index (BMI), and grip strength, the higher the risk of frailty in middle-aged and older adults. The SHAP individual force plot clearly shows that the LightGBM model predicts frailty in the individual decision-making process.

Conclusion

The grip strength-related LightGBM prediction model based on SHAP has high accuracy and robustness in predicting the risk of frailty. Increasing grip strength, cognitive function, nighttime sleep duration, and BMI reduce the risk of frailty and may provide strategies for individualized management of frailty.

Hand grip strength and all-cause mortality risk in individuals with decreased bone mass: a study from NHANES database

Objective

Previous studies have demonstrated that grip strength is associated with various health outcomes, including osteoporosis. However, the impact of grip strength on long-term mortality risk among individuals with low bone mass remains unclear. This study aims to investigate the association between grip strength and the risk of all-cause mortality in the population with low bone mass.

Methods

We included 1,343 cases of decreased bone mass from the NHANES database spanning 2013 to 2014. All-cause mortality data were ascertained through linkage with national death index records up to December 31, 2015. Analysis was conducted using the Cox proportional hazards regression model, and we assessed result reliability through various model adjustments and hierarchical analyses, Schoenfeld's global and individual tests are utilized to estimate the time-varying covariance in the Cox proportional hazards regression model's hypothesis.

Results

Throughout an average follow-up period of 69.5 months, 148 deaths were documented. After adjusting for covariates, a significant association between grip strength and the risk of all-cause mortality was observed in individuals with decreased bone mass (HR = 0.9, 95% CI: 0.87-0.93, p < 0.001). Individuals with normal grip strength, compared to those with low grip strength, exhibited a 56% lower risk of all-cause mortality (HR = 0.44, 95% CI: 0.29-0.67, p < 0.001). Various models consistently demonstrated similar significant trends post-adjustment. Subgroup analysis revealed an interaction between grip strength and coronary heart disease (p < 0.05). Schoenfeld's global and individual tests confirmed the reliability of the model (p > 0.05).

Conclusion

Our findings indicate that low grip strength is associated with increased all-cause mortality risk in individuals with decreased bone mass. The inclusion of routine monitoring of grip strength in patients with osteopenia and the encouragement of maintaining or improving grip strength in this population may offer a novel approach to health management for these individuals.

The impact of creatine levels on musculoskeletal health in the elderly: a mendelian randomization analysis

BACKGROUND

Musculoskeletal health among the elderly emerges as a pivotal public health concern against the backdrop of a globally aging population. Creatine, popular within fitness circles, has emerged as a subject of scientific inquiry for its potential benefits on elderly' musculoskeletal well-being. Despite extensive documentation of its effects on athletic performance, investigations into creatine's long-term contributions to the musculoskeletal health of the elderly are comparatively limited. Utilizing publicly accessible genetic datasets, this study aimed to explore the potential causal link between creatine levels and a variety of musculoskeletal health markers in the elderly population, such as osteoarthritis (OA), rheumatoid arthritis (RA), osteoporosis (OP), bone-specific alkaline phosphatase, bone mineral density(BMD), serum calcium levels, and reduced hand grip strength in individuals aged 60 and above.

METHODS

Our methodological approach was grounded in Mendelian Randomization (MR) analysis, with a primary emphasis on the Inverse Variance Weighted (IVW) technique, to explore potential causal links under specific assumptions and limitations inherent to MR analysis.

RESULTS

A significant inverse relationship was observed between creatine levels and reduced hand grip strength in individuals aged 60 and above (OR = 0.64, b=-0.44, p = 0.01), suggesting higher creatine levels might be beneficial in maintaining hand grip strength. Conversely, analysis of other bone health parameters, including bone-specific alkaline phosphatase, bone mineral density, serum calcium levels, and conditions such as osteoarthritis, rheumatoid arthritis, and osteoporosis, yielded p-values exceeding 0.05, denoting no statistically significant associations.

CONCLUSIONS

This study provides preliminary evidence indicating a link between creatine levels and decreased hand grip strength among the elderly, notably in individuals aged 60 and older. This finding is significant for understanding the potential impact of creatine supplementation on elderly Musculoskeletal health and underscores the need for evidence-based decision-making in nutritional supplementation. To robustly validate these observations, it is essential to conduct future randomized controlled trials with large sample sizes.

The genetic causal effect of hand grip strength on osteoporosis and falling risk: a Mendelian randomization study

Background

Patients with osteoporosis (OP) are often associated with decreased hand grip strength and increased risk of falling. It remains unclear whether there is a genetic causal between hand grip strength and OP, falling risk.

Methods

The Mendelian randomization study was used to investigate the genetic causal effect of low hand grip strength on total body bone mineral density (BMD) at different ages, OP, and falling risk. Genes for low hand grip strength, total body BMD at different ages, OP, and falling risk were obtained from published genome-wide association studies. Inverse variance weighted, MR-Egger, and weighted median were applied to perform the MR analysis. The Cochran's Q test, MR-Egger intercept test, MR-PRESSO global test, and leave-one-out analysis were used to detect the pleiotropy or heterogeneity.

Results

The results showed strong evidence that low hand grip strength was positively associated with OP (OR: 1.006, 95% CI: 1.003-1.010; P= 0.0001) and falling risk (OR: 1.069, 95% CI: 1.013-1.129; P= 0.0160), and could not directly affect the different ages of total body BMD (P> 0.05). There was no heterogeneity or horizontal pleiotropy in the sensitivity analysis (all P> 0.05).

Conclusion

The study found a positive causal relationship between low hand grip strength and higher risk of OP and falling, which should be taken into account in the development of future prevention and screening strategies for OP and falling.

Association between handgrip strength and physical activity: A nationwide population-based study in Korea

BACKGROUND

This study investigated the association between handgrip strength (HGS) and physical activity (PA) at different levels in Korean adults for the purpose of providing direction for increasing HGS, which represents muscular strength, and increasing understanding of PA and HGS.

METHODS

This study targeted adults aged ≥30 years from the Korean National Health and Nutrition Examination Survey (2014-2019), including 31,888 participants for analysis. HGS was defined as the maximum value of the three measurements of the dominant hand. PA was defined as an activity that causes shortness of breath or a fast heartbeat. Data were weighted according to survey district and household data; p < .05 was considered statistically significant.

RESULTS

In men, HGS in those aged 30-64 years was significantly associated with high-intensity PA and in those aged ≥65 years was associated with moderate-intensity PA. In women, HGS in those aged 30-64 years was also significantly associated with high-intensity PA, and in those aged ≥65 years, it was significantly associated with both moderate- and high-intensity PA. Moreover, compared to participants who did not participate in weight training, those who participated showed higher HGS in both sexes.

CONCLUSIONS

This study demonstrated age- and sex-specific characteristics of the association between HGS and PA in Koreans. The findings suggest the importance of managing health by considering differences in age- and sex-related PA. In particular, this study suggests that adequate PA is necessary despite its importance of PA for elderly individuals.

Effects of Frailty Syndrome on Osteoporosis, Focusing on the Mediating Effect of Muscle Strength and Balance in Community-Dwelling Older Adults (≥60 years) in Iran: Results From the Amirkola Health and Aging Project Cohort Study

Introduction

For older adults, maintaining muscle strength and balance is crucial to preserve an upright posture and independently manage their basic activities of daily living (ADL). This study aimed to examine whether muscle strength and balance mediate the relationship between frailty syndrome (FS) and osteoporosis in a large sample of community-dwelling older adults.

Material and Methods

This cross-sectional study is part of the second phase (2016-2017) of the Amirkola Health and Ageing Project (AHAP), a cohort study conducted on all elderly aged 60 and over in Amirkola, Northern Iran, since 2011. Data from 2018 older adults were collected by a trained person using bone mineral density (BMD), frailty index, activities of daily living (ADL), instrumental activities of daily living (IADL), handgrip strength (HGS), quadriceps muscle strength (QMS), Berg Balance Scale (BBS), and Timed Up and Go test (TUG test) and analyzed using analysis of variance, chi-square, and path analysis tests.

Results

The mean indices of femoral neck BMD and lumbar spine BMD, HGS, QMS, BBS, ADL, and IADL were lower in the frail older adults than in the pre-frail and non-frail older adults. In addition, the mean TUG test level was higher in the frail older adults than in the non-frail and pre-frail older adults. The results of the present study have indicated that frailty is significantly related to osteoporosis, and that balance and muscle strength can predict osteoporosis; these variables play a mediating role in the relationship between frailty and osteoporosis.

Conclusion

From the results of the present study, it can be concluded that frailty may increase the odds of osteoporosis. The results of the current study have indicated that balance (BBS and TUG test) and muscle strength (HGS and QMS) are associated with osteoporosis and these variables play a mediating role in the relationship between frailty and osteoporosis.

Is inflammation a missing link between relative handgrip strength with hyperlipidemia? Evidence from a large population-based study

BACKGROUND

Relative handgrip strength (RHGS) was positively correlated with healthy levels of cardiovascular markers and negatively correlated with metabolic disease risk. However, its association with hyperlipidemia remains unknown. The present study investigated the link between RHGS and hyperlipidemia, utilizing data from the National Health and Nutrition Examination Survey (NHANES) and further examined the hypothesis that inflammation may serve a mediating role within this relationship.

METHODS

Data were extracted from 4610 participants in the NHANES database spanning 2011-2014 to explore the correlation between RHGS and hyperlipidemia using multivariate logistic regression models. Subgroup analyses were conducted to discern the correlation between RHGS and hyperlipidemia across diverse populations. Additionally, smooth curve fitting and threshold effect analysis were conducted to validate the association between RHGS and hyperlipidemia. Furthermore, the potential mediating effect of inflammation on this association was also explored.

RESULTS

According to the fully adjusted model, RHGS was negatively correlated with hyperlipidemia [odds ratio (OR) = 0.575, 95% confidence interval (CI) = 0.515 to 0.643], which was consistently significant across all populations, notably among women. Smooth curve fitting and threshold effect analysis substantiated the negative association between RHGS and hyperlipidemia. Moreover, the mediating effects analysis indicated the white blood cell (WBC) count, neutrophil (Neu) count, and lymphocyte (Lym) count played roles as the mediators, with mediation ratios of 7.0%, 4.3%, and 5.0%, respectively.

CONCLUSIONS

This study identified a prominent negative correlation between RHGS and hyperlipidemia. Elevated RHGS may serve as a protective factor against hyperlipidemia, potentially through mechanisms underlying the modulation of inflammatory processes.

Eight Weeks of Intermittent Exercise in Hypoxia, with or without a Low-Carbohydrate Diet, Improves Bone Mass and Functional and Physiological Capacity in Older Adults with Type 2 Diabetes

In an increasingly aging and overweight population, osteoporosis and type 2 diabetes (T2DM) are major public health concerns. T2DM patients experience prejudicial effects on their bone health, affecting their physical capacity. Exercise in hypoxia (EH) and a low-carbohydrate diet (LCD) have been suggested for therapeutic benefits in T2DM, improving bone mineral content (BMC) and glycemic control. This study investigated the effects of EH combined with an LCD on body composition and functional and physiologic capacity in T2DM patients. Older T2DM patients (n = 42) were randomly assigned to the following groups: (1) control group: control diet + exercise in normoxia; (2) EH group: control diet + EH; (3) intervention group: LCD + EH. Cardiopulmonary tests (BRUCE protocol), body composition (DEXA), and functional capacity (6MWT, handgrip strength) were evaluated. Body mass index (kg/m2) and body fat (%) decreased in all groups (p < 0.001). BMC (kg) increased in all groups (p < 0.001) and was significantly higher in the EH and EH + LCD groups (p < 0.001). VO2peak improved in all groups (p < 0.001), but more so in the hypoxia groups (p = 0.019). Functional capacity was increased in all groups (p < 0.001), but more so in the EH group in 6MWT (p = 0.030). EH with and without an LCD is a therapeutic strategy for improving bone mass in T2DM, which is associated with cardiorespiratory and functional improvements.

Dynamic Foot Pressure During Walking: A Potential Indicator of Bone Mineral Density

BACKGROUND

Physical skeletal loading can affect the bone mineral density (BMD). This study investigated the association between BMD and dynamic foot pressure during gait.

METHODS

A total of 104 patients (mean age, 62.6 ± 12.4 years; 23 male and 81 female) who underwent dual x-ray absorptiometry and pedobarography were included. BMD values of the lumbar spine, femoral neck, and total femur were assessed. The mean and maximum pressures were measured at the hallux, lesser toes, 1st metatarsal head, 2nd and 3rd metatarsal heads, 4th and 5th metatarsal heads, midfoot, medial heel, and lateral heel. Multivariable regression analysis was performed to identify factors significantly associated with BMD.

RESULTS

The lumbar spine BMD was significantly associated with the mean pressure at the 4th and 5th metatarsal heads (p = 0.041, adjusted R 2 of model = 0.081). The femoral neck BMD was significantly associated with the maximum pressure at the 2nd and 3rd metatarsal heads (p = 0.002, adjusted R 2 = 0.213). The total femoral BMD also showed a significant association with the maximum pressure at the 2nd and 3rd metatarsal heads (p = 0.003, adjusted R 2 = 0.360).

CONCLUSIONS

Foot plantar pressure during gait was significantly associated with BMD, and could potentially be used to predict the presence of osteoporosis.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Predictors of Hand Grip Strength in Adults Without Sarcopenia: Data From the NHANES, 2013-2014

Background

Grip strength measurement is used to estimate muscle strength and predict health status; yet, an accurate examination of grip strength predictors from body composition variable is lacking.

Objectives

This study aimed to examine the association of grip strength with lumbar bone mineral density (BMD) and total lean mass in adults without sarcopenia.

Methods

Adults without sarcopenia (N = 3100) were included from the NHANES, 2013-2014, in this cross-sectional study. Body mass (kg), body height (cm), body mass index (kg/m2), grip strength (kg), total percent fat (%), lumbar BMD (g/cm2), and total lean mass excluding bone mineral content (BMC, kg) were obtained and tested as predictors of grip strength.

Results

The regression analysis yielded a significant model [F(2,343732) = 71,284.2; R2 = 0.713; P < 0.001], with all predictors explaining ∼71.3% of the variance in grip strength. Age [β: -0.043; 95% confidence interval (CI): -0.040, -0.036], sex (β: -0.296; 95% CI: -6.431, -6.270), total percent fat (β: -0.245; 95% CI: -0.315, -0.308), lumbar BMD (β: 0.037; 95% CI: 2.529, 2.806), and total lean mass (β: 0.482; 95% CI: 0.001, 0.001) were all significant predictors of grip strength.

Conclusions

The predictive value of the BMD and total lean mass can serve as a useful measure in predicting grip strength and overall health status in adults without sarcopenia.

Association Between Advanced Glycation End Products and Sarcopenia: The Mediating Role of Osteoporosis

CONTEXT

Advanced glycation end products (AGEs) are a group of molecules formed through nonenzymatic reactions. These compounds are associated with several age-related diseases, including sarcopenia and osteoporosis.

OBJECTIVE

This work aimed to investigate the relationships between AGEs, osteoporosis, and sarcopenia in community-dwelling older adults.

METHODS

This cross-sectional study included 1991 older adults aged 72.37 ± 5.90 years from China. AGE levels were measured by the AGE Reader device. Bone mineral density was assessed using dual-energy X-ray absorptiometry, and osteoporosis was diagnosed based on a T score of less than -2.5. Sarcopenia was defined as loss of muscle mass plus loss of muscle strength and/or reduced physical performance. Presarcopenia was defined as low muscle mass with normal muscle strength and normal physical performance.

RESULTS

The prevalence of sarcopenia was 18.5%, and that of osteoporosis was 40.5%. Compared to the lowest AGE quartile, the highest AGE quartile showed a significant association with sarcopenia (odds ratio [OR] 2.42; 95% CI, 1.60-3.66) (P for trend <.001), but not with presarcopenia. Per-SD increase in AGE was associated with higher odds of sarcopenia (OR 1.44; 95% CI, 1.26-1.66). Additionally, in the mediation analysis, when AGEs were treated as a continuous variable (the mediation effect is denoted by Za*Zb = 18.81; 95% CI, 8.07-32.32]-the 95% CI does not contain zero, representing a significant mediating effect) or a categorical variable (the mediating effect is expressed as Zmediation = 3.01 > 1.96, which represents a significant mediating effect), osteoporosis played a partial mediating role in the association between AGEs and sarcopenia.

CONCLUSION

Elevated AGEs are associated with sarcopenia but not with presarcopenia. This association was partially mediated by osteoporosis.