Association of Sarcopenia with Osteopenia and Osteoporosis in Community-Dwelling Older Korean Adults: A Cross-Sectional Study

Association between handgrip strength, handgrip strength asymmetry, and anxiety in Korean older adults: The Korean National Health and Nutrition Examination Survey 2022

Low handgrip strength (HGS) and HGS asymmetry are associated with age-related physical and mental disorders in older adults. This study aimed to examine the association between HGS-related factors and anxiety to evaluate whether HGS assessments can assist in identifying anxiety risk. In total, 1,750 participants from the Korea National Health and Nutrition Examination Survey of 2022 were included in this study. Individuals whose HGS values were below the 20th percentile of the study population stratified by sex were classified into the low-HGS group. Anxiety was assessed using the generalized anxiety disorder with a 7-item scale. Multiple logistic regression was used to analyze the relationship between HGS level and asymmetry and anxiety, adjusting for covariates. Overall, 70 (8.7%) men and 123 (13.0%) women had anxiety. Elevated odds of anxiety were observed in older women with low HGS (adjusted odds ratio: 2.17, 95% confidence interval: 1.31-3.61). There was a positive correlation between the degree of asymmetrical HGS and anxiety among women. This study found positive associations between low HGS, HGS asymmetry, and anxiety in older Korean women. This population may require specific interventions to help maintain good mental health.

Relationship between physical functional status indicators and bone mineral density in older women

Background

Osteoporosis significantly predisposes patients to fragility fractures and a reduced quality of life. Therefore, osteoporosis prevention plays an important role in extending healthy life expectancy. The purpose of this study was to identify whether physical functional status was associated with low bone mineral density, and to determine cut-off values of physical status indicators for osteoporosis.

Methods

This cross-sectional study evaluated 343 women aged 60 years or older who were able to walk independently. The measured variables were the body mass index, lumbar and total hip bone mineral density, grip strength, 5-m normal walking speed, one-leg standing time, timed up-and-go test, and skeletal muscle mass using bioelectrical impedance analysis. The associations between physical status indicators and low bone mineral density were analyzed and the cut-off values for detecting osteoporosis were calculated using receiver operating characteristic curve analyses.

Results

The prevalence of osteoporosis was 29.2 %. All measured variables significantly differed between the osteoporotic and non-osteoporotic groups (p < 0.05). Multivariate logistic regression analysis showed that the factors associated with osteoporosis were the skeletal muscle mass index, walking speed, and body mass index. In the receiver operating characteristic curve analysis, the cut-off values of the skeletal muscle mass index, walking speed, and body mass index associated with osteoporosis were 6.31 kg/m2, 1.29 m/s, and 22.6 kg/m2, respectively.

Conclusions

Older women with low bone mineral density have lower skeletal muscle mass, slower walking speed, and lower body mass index. Measuring the skeletal muscle mass index, walking speed, and body mass index might be useful for daily exercise guidance or osteoporosis screening.

The role of bile acid metabolism in bone and muscle: from analytics to mechanisms

Osteoporosis and sarcopenia are both common age-related disorders that are associated with increased morbidity and mortality. Bone and muscle are metabolically very active tissues that require large amounts of energy. Bile acids (BAs), a group of liver-derived steroid compounds, are primarily known as emulsifiers that facilitate the resorption of dietary fat and lipids. In addition, they have pleiotropic metabolic functions in lipoprotein and glucose metabolism, inflammation, and intestinal bacterial growth. Through these effects, they are related to metabolic diseases, such as diabetes, hypertriglyceridemia, atherosclerosis, and nonalcoholic steatohepatitis. BAs mediate their metabolic effects through receptor dependent and receptor-independent mechanisms. Emerging evidence suggests that BAs are also involved in bone and muscle metabolism. Under normal circumstances, BAs support bone health by shifting the delicate equilibrium of bone turnover toward bone formation. In contrast, low or excessive amounts of BAs promote bone resorption. In cholestatic liver disease, BAs accumulate in the liver, reach toxic concentrations in the circulation, and thus may contribute to bone loss and muscle wasting. In addition, the measurement of BAs is in rapid evolution with modern mass spectrometry techniques that allow for the detection of a continuously growing number of BAs. This review provides a comprehensive overview of the biochemistry, physiology and measurement of bile acids. Furthermore, it summarizes the existing literature regarding their role in bone and muscle.

The Impact of Demographics and Comorbidities on Fall Incidence and Prevalence in Older Adults

Introduction

Falls among older adults are more than mere accidents; they are a silent epidemic, profoundly impacting the health and well-being of millions of older adults worldwide. This study examines the incidence and prevalence of falls among individuals aged 65 and above, focusing on the influence of demographic factors and comorbid conditions such as hypertension, diabetes mellitus, cancer, and obesity.

Methods

A retrospective cohort study was conducted using data from the TriNetX network at Virginia Commonwealth University Health System (VCUHS) from 2019 to 2023. The study population included 16,400 individuals aged 65 and above who presented with fall-related trauma. Data on demographics, clinical diagnoses, procedures, and comorbid conditions were analyzed using descriptive statistics to evaluate the incidence and prevalence of falls.

Results

The mean age of the study population was 77.3 years, with a higher proportion of females (60.97%) compared to males (39.02%). Despite the larger number of female participants, incidence and prevalence of falls were highest among individuals aged 65-69 years, and fall rates were notably higher among males compared to females. This suggests that while fewer in number, males in our study experienced falls more frequently. Patients with hypertension had the highest incidence proportion (56.67%) and prevalence (75.75%) among comorbid conditions.

Conclusions

Falls among older adults are significantly influenced by demographic factors and comorbid conditions. Hypertension, in particular, is associated with the highest fall risk. These findings highlight the need for targeted interventions to manage comorbidities and reduce fall risks among older adult patients.

Prevalence and Risk Factors for Hand-Grip-Determined Dynapenia in the Korean Population: A Cross-Sectional Study

Dynapenia refers to muscle weakness related to aging and is defined as a loss of muscle strength associated with muscle quality. The purpose of this study is to identify the prevalence of dynapenia and associated risk factors by gender and age in domestic adults and to provide customized basic data for the prevention of dynapenia through its management. Based on the data from 2014 to 2019 of the Korea National Health and Nutrition Survey, 20,950 adults over the age of 20 who participated in grip strength tests and health surveys were selected as participants. Factors related to dynapenia were analyzed using complex sample multilogistic regression analysis. The prevalence of dynapenia in domestic adults was 6.3%, 4.1% in men, and 8.7% in women. Prevalence in the second decade was 5.3%, in the third decade was 3.2%, in the fourth decade was 3.3%, in the fifth decade was 4.8%, in the sixth decade was 8.9%, and was 24.6% for participants in their seventh decade or beyond. Among the factors related to dynapenia, age, BMI, and alcohol status were common in both men and women; education level, HDL-C, and resistance exercise were common in men; and high blood pressure, high blood sugar, and aerobic exercise were common in women. Our findings indicate that several factors are associated with dynapenia, which should be considered as potential targets for interventions focused on both individual and public health measures.

Association of osteoporosis with sarcopenia and its components among community-dwelling older Chinese adults with different obesity levels: A cross-sectional study

We aimed to investigate whether sarcopenia and its components are associated with osteoporosis in community-dwelling older Chinese adults with different obesity levels. This cross-sectional study included 1938 participants (42.1% male) with a mean age of 72.1 ± 5.9 years. The categorization of individuals into various weight categories was based on the Working Group on Obesity in China's criteria, utilizing the body mass index (BMI) as follows: underweight, BMI < 18.5 kg/m2; normal weight, 18.5 ≤ BMI < 24 kg/m2; overweight, 24 ≤ BMI < 28 kg/m2; and obesity, BMI ≥ 28 kg/m2. In this research, the osteoporosis definition put forth by the World Health Organization (bone mineral density T-score less than or equal to -2.5 as assessed by Dual-energy X-ray absorptiometry (DXA)). Sarcopenia was defined according to the diagnostic criteria of the Asian Working Group for Sarcopenia. The prevalence of osteoporosis was highest in the underweight group and gradually decreased with increasing BMI (Underweight: 55.81% vs Normal weight: 45.33% vs Overweight: 33.69% vs Obesity: 22.39). Sarcopenia was associated with elevated odds of osteoporosis in normal-weight subjects independent of potential covariates (OR = 1.70, 95% CI = 1.22-2.35, P = .002). In normal-weight participants, a higher appendicular skeletal muscle mass index (ASMI) was associated with a reduced risk of osteoporosis (OR = 0.56, 95% CI = 0.42-0.74, P < .001). In this study, we found that the prevalence of osteoporosis was highest in the underweight group and gradually decreased with increasing BMI. Sarcopenia, body fat percentage, and ASMI were associated with elevated odds of osteoporosis in normal-weight subjects independent of potential covariates, and higher percent body fat (PBF) was associated with an increased risk of osteoporosis in overweight people, and no such association was found in other weight groups. Different amounts of adipose tissue and muscle mass may alter bone biology. Further longitudinal follow-up studies are required to more accurately assess the risk of osteoporosis and sarcopenia in different weight populations. This cross-sectional study found that the prevalence of osteoporosis was highest in the underweight group and gradually decreased with increasing BMI. Sarcopenia was associated with elevated odds of osteoporosis in normal-weight subjects independent of potential covariates.

Sex-Specific Sarcopenia Prevalence and Risk Factors in the Korean Population: A Cross-Sectional Epidemiological Study

Background and Objective: This study aimed to identify the incidence of sarcopenia and disease risk factors in Korean adults and to provide data for sarcopenia prevention. Materials and Methods: Based on the Korea National Health and Nutrition Survey, 2008-2011, we selected 14,185 adults over the age of 20 who participated in sarcopenia diagnostic tests and health surveys. We analyzed sarcopenia risk factors using complex sample multi-logistic regression analysis. Results: The prevalence of sarcopenia in Korea was 31.3%, with 20.2% in men and 40.4% in women. In men, there was a higher risk of sarcopenia in those of older age, without a spouse, with a low body mass index (BMI), who never engage in resistance exercise, or who do mid-level intensity resistance exercises. In women, sarcopenia risk was higher in those in their 20s compared to those in their 60s, and risk factors included a low BMI, high-density lipoprotein cholesterol and waist circumference measurements, alcohol consumption, aerobic exercise, and resistance exercise. Conclusions: Interventions and lifestyle improvements will help prevent the onset of sarcopenia in elderly men and young women with risk factors such as a low BMI.

Dexamethasone-induced muscle atrophy and bone loss in six genetically diverse collaborative cross founder strains demonstrates phenotypic variability by Rg3 treatment

Background

Osteosarcopenia is a common condition characterized by the loss of both bone and muscle mass, which can lead to an increased risk of fractures and disability in older adults. The study aimed to elucidate the response of various mouse strains to treatment with Rg3, one of the leading ginsenosides, on musculoskeletal traits and immune function, and their correlation.

Methods

Six Collaborative Cross (CC) founder strains induced muscle atrophy and bone loss with dexamethasone (15 mg/kg) treatment for 1 month, and half of the mice for each strain were orally administered Rg3 (20 mg/kg). Different responses were observed depending on genetic background and Rg3 treatment.

Results

Rg3 significantly increased grip strength, running performance, and expression of muscle and bone health-related genes in a two-way analysis of variance considering the genetic backgrounds and Rg3 treatment. Significant improvements in grip strength, running performance, bone area, and muscle mass, and the increased gene expression were observed in specific strains of PWK/PhJ. For traits related to muscle, bone, and immune functions, significant correlations between traits were confirmed following Rg3 administration compared with control mice. The phenotyping analysis was compiled into a public web resource called Rg3-OsteoSarco.

Conclusion

This highlights the complex interplay between genetic determinants, pathogenesis of muscle atrophy and bone loss, and phytochemical bioactivity and the need to move away from single inbred mouse models to improve their translatability to genetically diverse humans. Rg3-OsteoSarco highlights the use of CC founder strains as a valuable tool in the field of personalized nutrition.

Prevalence and Risk Factors of Osteoarthritis in Korea: A Cross-Sectional Study

Background and Objectives: The goal of this study is to determine the prevalence of knee osteoarthritis (OA) and risk factors for the disease in Korean adults over the age of 50, as well as to provide basic data for OA prevention through management. Materials and Methods: Based on 2010-2013 data from the Korean National Health and Nutrition Survey, 7962 adults over the age of 50 who participated in radiological tests and health surveys for the diagnosis of osteoarthritis were chosen as participants. Results: The risk factors for OA occurrence were investigated using complex sample multiple logistic regression analysis. According to the findings, the prevalence of knee OA in Korea was 33.3% in this study, with the risk of OA being higher in women, the elderly, people with a lower education level, and people with obesity. Conclusions: To reduce the incidence of OA, interventions and lifestyle changes are needed to prevent the onset of disease in participants with risk factors for OA, such as older women, low education levels, and obesity.

Sarcopenia and Anemia in Elderly Koreans: A Nationwide Population-Based Study

Sarcopenia and anemia are common diseases in the elderly and are caused by various factors. In this study, the association between sarcopenia and anemia in an elderly Korean population was examined. The Korea Centers for Disease Control and Prevention's cross-sectional, nationally representative Korea National Health and Nutrition Examination Survey (KNHANES, 2008-2011) served as the source of the data for this study. Of the 2769 participants (1167 men and 1602 women) included in this study, a significant association was found between sarcopenia and anemia in the elderly in Korea. In Model 1, unadjusted for covariates, the prevalence of sarcopenia in all participants was 1.805 (95% CI 1.364-2.388) and 2.746 (95% CI 1.740-4.334) in men, and 1.494 (95% CI 1.045-2.138) in women. In Model 4, adjusted for all covariates, the prevalence of sarcopenia in all participants was 1.455 (95% CI 1.064-1.989) and 2.649 (95% CI 1.475-4.755) in men, but it was insignificant in women. While prior studies failed to consider variables such as exercise status and nutritional intake, this research incorporated these factors as covariates. Despite this comprehensive approach, this study still revealed an independent association between sarcopenia and anemia. Moreover, a significant association was uncovered among elderly men, with no corresponding association identified among women.

Sarcopenic obesity is associated with coffee intake in elderly Koreans

This study assessed the association between sarcopenic obesity (S+O+) and coffee intake inelderly Koreans. This study obtained data from the Korea National Health and Nutrition Examination Survey (KNHANES, 2008-2011), a cross-sectional and nationally representative survey conducted by the Korean Centers for Disease Control and Prevention. Of the 2,661 participants included in this study, there was a significant difference between 5.861 (95% CI 2.024-16.971) in less than one cup of coffee, and 6.245 (95% CI 2.136-18.260) in one cup of coffee, and 4.323 (95% CI 1.457-12.824) in two cups of coffee compared to three or more than cups of coffee. In contrast, in the case of sarcopenia or obesity only (S+O- or S-O+), no significant difference was found in any model. The results suggest that the elderly who consume less than one cup of coffee per day had a greater risk of S+O+ than those who consume more than three cups per day. Furthermore, there was an association between coffee intake and sarcopenia but not with obesity. Therefore, coffee intake may have prevented musculoskeletal loss in these patients.

Osteosarcopenic Adiposity and Nutritional Status in Older Nursing Home Residents during the COVID-19 Pandemic

The aim was to evaluate body composition and prevalence of osteosarcopenic adiposity (OSA) in nursing home residents (NHR) and to assess their nutritional status. This research builds on our pilot study (conducted prior COVID-19 pandemic) that revealed high OSA prevalence and poor nutritional status in NHR. The current study included newly recruited n = 365 NHR; 296 women, 69 men, aged 84.3 ± 5.6 and 83.1 ± 7.3 years, respectively. Body composition was measured by bioelectrical impedance BIA-ACC®, yielding total bone mass along with all components of lean and adipose tissues. The Mini Nutritional Assessment-Short Form (MNA-SF) was used to assess nutritional status. Participants reported about their present/past diseases, including COVID-19. Mean duration of stay in nursing homes was 46.3 ± 47.0 months. Approximately 30% of participants had COVID-19 prior (median 6.7 months) to entering the study. OSA was diagnosed in 70.8% women and 47.8% men (p < 0.001). Malnourishment was detected in 5.8% women and 6.2% men while the risk of malnourishment was found in 30.8% women and 30.0% men. No significant differences in age, body composition parameters, prevalence of OSA, malnutrition/risk for malnutrition were found in participants who had COVID-19 compared to those who did not. Regression analysis showed that intramuscular adipose tissue (%) was significantly positively, while bone mass was significantly negatively associated with OSA. In this population, the high prevalence of OSA coincided with the high prevalence of malnutrition/risk of malnutrition. Such unfavorable body composition status is more likely a consequence of potentially poor diet quality in nursing homes, rather than of health hazards caused by COVID-19.

Bibliometrics Analysis and Visualization of Sarcopenia Associated with Osteoporosis from 2000 to 2022

Purpose

Recent years have seen an increased awareness of sarcopenia in the cross field of osteoporosis and sarcopenia. The goal of this study was to evaluate current bibliometric characteristics and the status of cross-sectional studies between osteoporosis and sarcopenia.

Methods

Publications related to osteoporosis and sarcopenia published between January 2000 and November 2022 were extracted from the Web of Science Core Collection; bibliometric and visualization were performed by Microsoft Office Excel, VOSviewer, Citespace, and R.

Results

A total of 1128 documents written by 5791 authors from 1758 organizations in 62 countries and published in 405 journals were identified. USA was the leading country with the highest publication and total citation. University of Melbourne contributed the most publications, while Tufts University had the largest citations. Osteoporosis International was the most influential journals in this field with the highest publications, citations and H index. Cooper C was the most influential author, who published the 20 studies, had the highest local citations and the highest H index. The keywords were classified into 6 clusters: Cluster 1 (aging), Cluster 2 (frailty) and Cluster 3 (osteosarcopenia).

Conclusion

Our bibliometric results revealed that the global osteoporosis and sarcopenia-related research increased rapidly from 2000 to 2022, suggesting it was a promising area of research for the future. The future trends in the cross field of sarcopenia and osteoporosis would be the molecular mechanisms of crosstalk between muscles and bones, safety and efficacy interventions with a dual effect on muscle and bone and osteosarcopenia.

A pooled analysis of the association between sarcopenia and osteoporosis

BACKGROUND

Sarcopenia is a progressive generalized skeletal muscle disorder that causes the accelerated loss of muscle mass and function. Osteoporosis is a systemic condition of the skeleton that results in low bone mass and quality. Several studies have suggested that osteoporosis and sarcopenia are interrelated; however, a few studies indicate the lack of a significant association between sarcopenia and osteoporosis. We aimed to evaluate the association between sarcopenia and osteoporosis via a systematic review and pooled analysis.

METHODS

From the inception of the PubMed and Embase databases until September 2022, we conducted a systematic search for studies evaluating the relationship between sarcopenia and osteoporosis. Study appraisal and synthesis methods: We included observational studies that provided 95% confidence intervals (CIs) and risk estimates. Two reviewers independently extracted data and assessed the quality of the research. The random-effects model was applied to the pool analysis, and the odds ratios (ORs) and 95% CIs were finally calculated.

RESULTS

The primary statistic was the mutual risk between sarcopenia and osteoporosis. According to the inclusion criteria, 56 studies (796,914 participants) were finally included. Sarcopenia was significantly correlative to the risk of osteoporosis (OR, 3.06; 95% CI, 2.30-4.08), and each standard deviation increase in relative appendicular skeletal muscle mass was significantly related to a decreased risk of osteoporosis (OR, 0.65; 95% CI, 0.56-0.75). Osteoporosis observably referred to a higher risk of sarcopenia (OR, 2.63; 95% CI, 1.98-3.49).

CONCLUSION

Our research indicated that sarcopenia and osteoporosis are highly positively correlated. Osteoporosis is closely associated with the risk of sarcopenia. Our finding highlights the importance of sarcopenia screening for those at risk of osteoporosis, and vice versa. However, heterogeneity was noted among the studies, and this might have influenced the accuracy of the results. Therefore, the results of our study should be interpreted with caution.

The Roles of Androgens in Humans: Biology, Metabolic Regulation and Health

Androgens are an important and diverse group of steroid hormone molecular species. They play varied functional roles, such as the control of metabolic energy fate and partition, the maintenance of skeletal and body protein and integrity and the development of brain capabilities and behavioral setup (including those factors defining maleness). In addition, androgens are the precursors of estrogens, with which they share an extensive control of the reproductive mechanisms (in both sexes). In this review, the types of androgens, their functions and signaling are tabulated and described, including some less-known functions. The close interrelationship between corticosteroids and androgens is also analyzed, centered in the adrenal cortex, together with the main feedback control systems of the hypothalamic-hypophysis-gonads axis, and its modulation by the metabolic environment, sex, age and health. Testosterone (T) is singled out because of its high synthesis rate and turnover, but also because age-related hypogonadism is a key signal for the biologically planned early obsolescence of men, and the delayed onset of a faster rate of functional losses in women after menopause. The close collaboration of T with estradiol (E2) active in the maintenance of body metabolic systems is also presented Their parallel insufficiency has been directly related to the ravages of senescence and the metabolic syndrome constellation of disorders. The clinical use of T to correct hypoandrogenism helps maintain the functionality of core metabolism, limiting excess fat deposition, sarcopenia and cognoscitive frailty (part of these effects are due to the E2 generated from T). The effectiveness of using lipophilic T esters for T replacement treatments is analyzed in depth, and the main problems derived from their application are discussed.

Evaluation of Geriatric Sarcopenia and Nutrition in the Case of Cachexia before Exitus: An Observational Study for Health Professionals

It is important to assess the physical and nutritional status of the body using a bioelectrical impedance analyzer (BIA) in patients with cachexia; however, the correlation between cachexia and nutritional evaluations remains unclear. The objective of this study is to follow the effects of diet therapy in patients with cachexia/sarcopenia, using parameters measured by BIA, clinical parameters, and other nutrition-related assessments in patients with osteoporosis. This study aims to clarify the correlation between BIA-measured parameters, clinical parameters, and other nutrition-related assessments. Methods: Measurements of body composition, a clinical assessment of the sarcopenia/cachexia, and nutritional goal setting/a nutrition care process were performed. Results: The number of subjects was 200, of which 15 people (7.5%) were diagnosed with sarcopenia/cachexia. Univariate analyses showed that participants with a high body-fat mass tend to develop sarcopenic obesity (p = 0.029), those who lost a significant and progressive amount of muscle mass tend to develop sarcopenia (p = 0.001), as well as those with malnutrition (p < 0.001). The regression study shows not only the correlation but also the cause of the correlation, as is the case with obesity. As obesity increases, so does the sarcopenic index (this can explain sarcopenic obesity), and as fat mass decreases it leads to muscle mass loss, increasing the risk of cachexia with age. Conclusions: There was an improvement, but statistically insignificant, in cachexia and the nutritional objectives (p > 0.05); at the same time, correlations were established between the independent parameters (sex, age) and malnutrition parameters (hemoglobin and amylase) with the parameters of the research.

The Effects of the 'Catabolic Crisis' on Patients' Prolonged Immobility after COVID-19 Infection

Background and Objectives: Quarantine, isolation and bed rest associated with COVID-19 infection favored the loss of muscle and bone mass, especially in elderly patients. The current study aims to compare the presence of sarcopenia and osteoporosis in patients with a recent (one month) history of SARS-CoV-2 infection versus the general population. Materials and Methods: A cross-sectional study was conducted in which 157 patients were enrolled, divided into two groups, comparable in structure. The COVID-19 group (group C) consisted of 86 patients who were diagnosed with SARS-CoV-2 respiratory infection within the last 30 days. The non-COVID-19 group (group NC) consists of 71 patients who had no clinical signs of respiratory infection and were not quarantined/hospitalized in the last 3 months. Muscle strength, incidence of sarcopenia (using SARC-F score) and osteoporosis (DEXA determination) and physical performance (SPPB score) in the two groups were assessed and compared. Results: No statistically significant differences were found between the SPPB scores of the C group versus the NC group. Statistically significant differences were found in the evaluation of three parameters included in the SARC-F score. Patients in the C group had difficulties in standing up from a chair (p = 0.009) and climbing stairs (p = 0.030) due to lower muscle strength (p = 0.002) compared with patients in the NC group. No correlation of the SARC F and SPPB scores with the T score values obtained by osteo-densitometry was found. Conclusions: The sudden and significant reduction in physical activity, through various measures taken in the general population during the pandemic, led to an increased incidence of sarcopenia, both in patients who did not have COVID-19 infection and among those quarantined/hospitalized for this condition.

Osteoporosis and sarcopenia-related traits: A bi-directional Mendelian randomization study

BACKGROUND

With the advancement of world population aging, age-related osteoporosis (OP) and sarcopenia (SP) impose enormous clinical and economic burden on society. Evidence from accumulating studies indicates that they mutually influence one another. However, an observational study may be affected by potential confounders. Meanwhile, a Mendelian randomization (MR) study can overcome these confounders to assess causality.

OBJECTIVES

The aim of this study was to evaluate the causality between OP and SP, informing new strategies for prevention, diagnosis, and treatment of osteosarcopenia.

METHODS

Instrumental variables (IVs) at the genome-wide significance level were obtained from published summary statistics, and the inverse variance weighted method and several other MR methods were conducted to evaluate the bi-directional causality between SP and OP. Myopia was analyzed as a negative control outcome to test the validity of IVs.

RESULTS

Femoral neck bone mineral density (FN BMD), lumbar spine BMD (LS BMD), and forearm BMD (FA BMD) had a direct causal effect on appendicular lean mass (ALM) [FA BMD-related analysis: odds ratio (OR) = 1.028, 95% confidence interval (CI) = (1.008,1.049), p = 0.006; FN BMD-related analysis: OR (95% CI) = 1.131 (1.092,1.170), p = 3.18E-12; LS BMD-related analysis: OR (95% CI) = 1.080 (1.062,1.098), p = 2.86E-19]. ALM had a significant causal effect on LS BMD [OR (95% CI) = (1.033,1.147), p = 0.001]. There was no evidence for causal association between BMD and low grip strength.

CONCLUSIONS

OP and SP might mutually have a significant causal effect on each other. Our results supported the idea that the patient with severe OP was more susceptible to lose ALM and severe ALM loss might reduce LS BMD.