Appendicular Lean Mass Index Research Articles

Changes in Muscle Mass and Bone Density and Their Relationship After Total Knee Arthroplasty

Purpose: To investigate the effects of total knee arthroplasty (TKA) on muscle mass and bone density in end-stage knee osteoarthritis (OA). Methods: This prospective study was conducted on 111 patients with Kellgren–Lawrence grade 4 knee OA who underwent TKA after failing to respond to conservative treatment for more than 3 months at a single institution from June 2022 to May 2023. Appendicular lean mass index (ALMI) and bone mineral density (BMD) were measured using dual-energy X-ray absorptiometry before and every 6 months after surgery. The average follow-up period was 15.5 ± 2.31 months (range, 11.6–24 months). Results: During the follow-up period after TKA, the ALMI increased relatively continuously and consistently. The BMD of the L-spine and proximal femur did not change significantly until 12 months after TKA surgery but began to increase steeply after 12 months and slowed down after 18 months. The increase in muscle mass showed a significant positive correlation with the increase in BMD. Conclusions: Muscle mass gradually increased after TKA for end-stage knee OA, whereas bone density also increased but not until 12 months after surgery. The significant positive correlation between the increase in muscle mass and bone density suggests that the increase in muscle mass after TKA may be one of the causes of the increase in bone density.

Associations of sarcopenia, obesity, and metabolic health with the risk of urinary incontinence in U.S. adult women: a population-based cross-sectional study.

Urinary incontinence (UI) significantly impairs women's quality of life. Identifying its risk factors is essential for developing effective interventions. Sarcopenia, characterized by the accelerated loss of muscle mass and function, is an emerging concern often linked to obesity and abnormal metabolic status, exacerbating various adverse health outcomes. This population-based study aimed to explore the independent and joint associations of sarcopenia, obesity, and metabolic health with UI risk, as well as to evaluate the mediating role of metabolic indicators in these associations. A total of 3,557 women aged ≥20 years from the National Health and Nutrition Examination Survey were included. Sarcopenia was assessed using the appendicular lean mass index (ALMI), and obesity was defined by body mass index and waist circumference. Metabolic health was evaluated using revised criteria from the National Cholesterol Education Program-Adult Treatment Panel III. UI was identified through responses to the "Kidney Conditions-Urology" questionnaire and classified into stress UI (SUI), urgency UI (UUI), and mixed UI (MUI). Multivariable logistic regression and restricted cubic spline models were used to evaluate the associations and visualize the relationship between ALMI and UI. Mediation models were constructed to assess the mediating role of metabolic indicators. We found that sarcopenia was significantly associated with an increased risk of MUI in the general population. Age-specific analysis revealed that sarcopenia is an independent risk factor for SUI in women aged ≥60, and for MUI in women aged 40-59 years. Sarcopenic obesity, particularly under central obesity criteria, further elevated the risk of UI. Notably, women with the metabolically unhealthy obese phenotype with sarcopenia were at the highest risk for both SUI and MUI. Metabolically unhealthy status, glycohemoglobin, vitamin D, and serum albumin levels were partial mediators of these associations. Our findings elucidated the complex interactions between sarcopenia, obesity, and metabolic health, underscoring the critical need for integrated therapeutic strategies that address both metabolic health and targeted nutritional interventions, aiming to enhance muscular health and effectively manage and prevent UI.

324P A longitudinal study of creatine kinase, creatinine levels, and appendicular lean mass index in pediatric Becker muscular dystrophy

324P A longitudinal study of creatine kinase, creatinine levels, and appendicular lean mass index in pediatric Becker muscular dystrophy

The phase angle before transplantation can predict the status of low muscle mass after kidney transplantation.

This study aimed to evaluate the association between phase angle, muscle strength, and muscle mass in patients undergoing kidney transplantation. Patients whose pre- and follow-up phase angles were measured after kidney transplantation were enrolled. Phase angle and body composition were measured using a multi-frequency bioimpedance analysis device before and at 7 and 14days and 3, 6, and 12months after transplantation. Muscle strength was evaluated using handgrip strength (HGS). Low HGS was defined as < 28kg in males and < 18kg in females. Low muscle mass was defined as an appendicular lean mass index of < 7.0kg/m2 in males and < 5.7kg/m2 in females. Eighty-eight patients (mean age 52.3 ± 10.1years) were analyzed. The mean phase angle of pre-transplantation was 5.0 ± 1.0°. Body fat percentage was significantly higher at 6 and 12months after transplantation than pre-transplantation (P < 0.0001). Twelve months after kidney transplantation, the prevalence of low HGS decreased (pre-transplantation vs. 12months post-transplantation: 28.4% vs. 17.0%), and the prevalence of low muscle mass (pre-transplantation vs. 12months post-transplantation: 21.6% vs. 28.4%) increased. The pre-transplantation phase angle was significantly associated with low muscle mass at 12months after kidney transplantation (odds ratio [OR]: 0.34; 95% confidence interval [CI]: 0.16-0.72; P = 0.005). The pre-transplantation phase angle was not significantly associated with low HGS (OR: 0.37; 95% CI 0.12-1.17; P = 0.090) 12months after kidney transplantation. Pre-transplantation phase angle can predict muscle mass status 12months after kidney transplantation.

Co-morbid sarcopenia and low bone mineral density in young paediatric cancer survivors.

Sarcopenia and low areal bone mineral density (aBMD) are prevalent musculoskeletal complications after paediatric cancer treatment. However, their relationship has not been examined in young paediatric cancers survivors. This study aimed to evaluate aBMD differences according to sarcopenia status and the risk of low aBMD Z-score in young paediatric cancer survivors with sarcopenia confirmed/probable. This cross-sectional study included 116 paediatric cancer survivors (12.1±3.3years old; 42.2% female). Handgrip strength was used to assessed muscle strength. Dual-energy X-ray absorptiometry estimated aBMD (g/cm2) and appendicular lean mass index (ALMI, kg/m2). 'No sarcopenia' was defined when muscle strength was >decile 2. 'Sarcopenia probable' was defined when muscle strength was ≤ decile 2 and ALMI Z-score was > -1.5 standard deviation (SD). 'Sarcopenia confirmed' was defined when muscle strength was ≤ decile 2 and ALMI Z-score ≤ -1.5 SD. Analysis of covariance and logistic regression, adjusted for time from treatment completion, radiotherapy exposure, calcium intake, and physical activity, was used to evaluate aBMD and estimate the odds ratios (ORs) of low aBMD (aBMD Z-score < -1.0). Survivors with sarcopenia confirmed had significantly lower aBMD than those without sarcopenia at total body (-1.2 [95% CI: -1.5 to -0.8] vs. 0.2 [-0.2 to 0.6], P<0.001), lumbar spine (-0.7 [-1.1 to -0.3] vs. 0.4 [0.0 to 0.8], P<0.001), total hip (-0.5 [-0.9 to -0.2] vs. 0.4 [0.1 to 0.8], P<0.001), and femoral neck (-1.0 [-1.4 to -0.6] vs. 0.1 [-0.3 to 0.4], P=0.001). Compared with survivors with sarcopenia probable, survivors with sarcopenia confirmed had significantly lower aBMD Z-score at total body (-1.2 [-1.5 to -0.8] vs. -0.2 [-0.7 to 0.4], P=0.009), total hip (-0.5 [-0.9 to -0.2] vs. 0.5 [-0.1 to 1.0], P=0.010), and femoral neck (-1.0 [-1.4 to -0.6] vs. 0.1 [-0.5 to 0.7], P=0.014). Survivors with sarcopenia confirmed were at higher risk of low aBMD Z-score at the total body (OR: 6.91, 95% CI: 2.31-24.15), total hip (OR: 2.98, 1.02-9.54), and femoral neck (OR: 4.72, 1.72-14.19), than those without sarcopenia. Survivors with sarcopenia probable were at higher risk of low aBMD Z-score at the total body (OR: 4.13, 1.04-17.60) than those without sarcopenia. Young paediatric cancer survivors with sarcopenia present higher risk of low aBMD. Resistance training-based interventions designed to mitigate osteosarcopenia in this population should be implemented at early stages.

Sarcopenia definitions and their association with injurious falls in older Swedish women from the Sahlgrenska University Hospital Prospective Evaluation of Risk of Bone fractures (SUPERB) study.

To investigate the association between three commonly used sarcopenia definitions and the risk of injurious falls in a population of older Swedish women. A total of 2,883 75-80-year-old women with complete data on relevant sarcopenia definitions from the Swedish SUPERB cohort were studied. Sarcopenia was defined based on the Sarcopenia Definitions and Outcomes Consortium (SDOC: low handgrip strength and gait speed), revised European Working Group on Sarcopenia in Older People (EWGSOP2: low appendicular lean mass index (ALMI, dual-energy X-ray absorptiometry (DXA)-derived), appendicular lean mass (kg)/height (m2), hand grip strength (kg), or low chair stand time (s)), and Asian Working Group for Sarcopenia (AWGS: low ALMI and hand grip strength (kg) or low gait speed (m/s)). Questionnaires captured the occurrence of falls in the past 12months. Incident injurious falls were identified using national registers. Cox regression (hazard ratios (HR) and 95% confidence intervals (CI)) analyses were performed without adjustment and after adjustment for age, body mass index, previous falls, and the Charlson comorbidity index. During a median (IQR) follow-up time of 7.06 (6.2-7.9) years, there were 491 injurious falls without fracture and 962 injurious falls when also including falls resulting in a fracture. Sarcopenia according to EWGSOP2 and AWGS was not associated with an increased risk of injurious falls. Individuals with sarcopenia defined by SDOC had a higher risk of injurious falls with and without fracture (HR 2.11; 95% CI, 1.63-2.73 and HR, 2.16; 95% CI, 1.55-3.02, respectively). Sarcopenia definitions confined to muscle function and strength such as SDOC, rather than including DXA-determined ALMI (EWGSOP2 and AWGS), are associated with incident injurious falls with and without fractures in older women.

Identifying Risk Factors for Presarcopenia in Early Middle Age

ObjectiveThis study aimed to determine whether risk factors for presarcopenia can be identified in a sample of early middle-aged men and women. DesignProspective study. SettingLongitudinal data from the Dunedin Multidisciplinary Health and Development Study were used to investigate the relationship between presarcopenia at age 45 years and selected early markers at ages 26, 32, and 38 years. ParticipantsLongitudinal data from N=899 participants from the Dunedin Multidisciplinary Health and Development Study. InterventionsNot applicable. Main Outcome MeasuresPresarcopenia was defined as low relative appendicular lean mass index assessed by dual energy x-ray absorptiometry and low strength assessed by grip strength. Logistic regressions were used to describe the association between selected markers and presarcopenia at age 45 years. ResultsMultivariate logistic regression revealed that a higher body mass index (BMI) at ages 26, 32, and 38 years was associated with lower likelihood of presarcopenia at age 45 years in both men and women (odds ratio [OR] range, 0.46-0.64). Higher age-normative grip strength at age 38 years in both men and women (OR range, 0.88-0.92) was also associated with lower likelihood for presarcopenia. Lastly, lower self-perceived physical fitness level in men at age 38 years was associated with an increased likelihood of presarcopenia at age 45 years (OR, 9.35; 95% confidence interval, 3.28-26.70). ConclusionsBMI and strength were associated with lower likelihood of presarcopenia during middle age. A higher likelihood of presarcopenia was associated with sex-specific lower self-perceived physical fitness. These modifiable biomarkers may serve as targets for clinical screening and early intervention aimed at slowing or preventing progression to sarcopenia in old age.

The Nutritional Burden of Cancer: Nutritional Status and Body Composition Differences Between Children with Acute Lymphoblastic Leukemia and their Siblings in Guatemala

During treatment, children with acute lymphoblastic leukemia (ALL) gain fat mass and lose skeletal muscle mass. The great majority live in low- and middle-income countries with few studies of their body composition and none addressing the hypothesis that the disease itself contributes to nutritional morbidity. At diagnosis, children with ALL were compared to their siblings on socioeconomic status (SES). Nutritional status was assessed by mid-upper arm circumference (MUAC)-for-age Z scores and body composition by dual energy x-ray absorptiometry (DXA). Median SES scores for the patients (47.5) and their siblings (47.0) were very similar (P = 0.5). MUAC Z scores for patients aged >5 years were lower than for siblings (P < 0.001). On DXA siblings had a higher mean appendicular lean mass index Z score, a surrogate of skeletal muscle mass, than patients (P = 0.019). A logistic model to estimate the odds ratio (OR) of being severely/moderately under-nourished (classified by MUAC Z score) by SES revealed that, compared with siblings (n = 49), children with ALL (n = 60) had a higher probability of being under-nourished (OR 5.25, 95% CI 1.44–25.95, P = 0.02). The results support the hypothesis that children at diagnosis of ALL in Guatemala are more nutritionally depleted than their apparently healthy siblings.

Growth and physical development of children at apparent risk of sarcopenia.

The consequences of sarcopenia on growth have received little attention. We analysed the potential risk resulting from the low lean mass for age expressed through the appendicular lean body mass index (aLBMI) and the ratio aLBM/trunk fat mass (trFM). The sample consisted of 580 participants 10-13 yrs evaluated twice in a 12-month interval: height, trFM, total and aLBM, whole-body bone mineral density less head (WBLH BMD), tibia and radius SOS, maturity and handgrip strength were measured. All variables except maturity and BMI were standardised according to sex and age group (Z-score) using the sample as a reference. A high risk of sarcopenia was identified for Z-scores ≤ -1 on aLBMI (Group B) or aLBM/trFM (Group C), while Z-scores > -1 on both markers were considered at low risk for sarcopenia (Group A). The ANCOVA adjusted for maturity was used to compare the three groups. Girls showed a more significant decrease in the total BMC/LBM ratio in Group B and a minor increase in WBLH BMD in Group C (p < 0.050); boys in Group B showed a tendency to gain less height (p = 0.053). The high risk of sarcopenia expressed through aLBMI or aLBM/trFM Z-score ≤ -1 compromises bone mineralisation in girls. The findings emphasise the necessity of implementing routine screening protocols for sarcopenia risk within clinical environments and educational institutions. Such screenings should extend beyond merely assessing body mass index to encompass broader body composition variables like lean body mass. By integrating these assessments into routine health evaluations, healthcare professionals and educators can proactively identify at-risk individuals and initiate timely interventions for suboptimal physical growth and development.

Predictive value of sarcopenia components for all-cause mortality: findings from population-based cohorts

BackgroundLow grip strength and gait speed are associated with mortality. However, investigation of the additional mortality risk explained by these measures, over and above other factors, is limited.AimWe examined whether grip strength and gait speed improve discriminative capacity for mortality over and above more readily obtainable clinical risk factors.MethodsParticipants from the Health, Aging and Body Composition Study, Osteoporotic Fractures in Men Study, and the Hertfordshire Cohort Study were analysed. Appendicular lean mass (ALM) was ascertained using DXA; muscle strength by grip dynamometry; and usual gait speed over 2.4–6 m. Verified deaths were recorded. Associations between sarcopenia components and mortality were examined using Cox regression with cohort as a random effect; discriminative capacity was assessed using Harrell’s Concordance Index (C-index).ResultsMean (SD) age of participants (n = 8362) was 73.8(5.1) years; 5231(62.6%) died during a median follow-up time of 13.3 years. Grip strength (hazard ratio (95% CI) per SD decrease: 1.14 (1.10,1.19)) and gait speed (1.21 (1.17,1.26)), but not ALM index (1.01 (0.95,1.06)), were associated with mortality in mutually-adjusted models after accounting for age, sex, BMI, smoking status, alcohol consumption, physical activity, ethnicity, education, history of fractures and falls, femoral neck bone mineral density (BMD), self-rated health, cognitive function and number of comorbidities. However, a model containing only age and sex as exposures gave a C-index (95% CI) of 0.65(0.64,0.66), which only increased to 0.67(0.67,0.68) after inclusion of grip strength and gait speed.ConclusionsGrip strength and gait speed may generate only modest adjunctive risk information for mortality compared with other more readily obtainable risk factors.

Appendicular lean mass index and motor function in ambulatory patients with Duchenne muscular dystrophy.

Appendicular lean mass index (ALMI) has been linked to motor function in patients with Duchenne muscular dystrophy (DMD). However, quantification of the relationship between ALMI and disease-specific clinical outcome assessment trajectories is needed. The purpose of this study was to determine associations between dual-energy x-ray absorptiometry (DXA) derived estimates of ALMI and motor function in ambulatory patients with DMD. A retrospective analysis of longitudinal clinical visit data from 137 glucocorticoid-treated patients with DMD collected via structured motor assessment protocol evaluated associations between ALMI and motor function indexed by the North Star Ambulatory Assessment (NSAA) and 10 Meter Walk/run Test (10MWT). Body composition was assessed using DXA. ALMI was calculated by dividing arm and leg lean mass by height in m2; fat mass index (FMI) was calculated by dividing whole body fat mass by height in m2. Linear mixed-effects models were used to estimate associations between ALMI and motor function, controlling for age and FMI. The full prediction model (age, age,2 ALMI, and FMI) explained 57% of the variance in NSAA scores and 63% of the variance in 10MWT speed. A 1 kg/m2 higher ALMI value predicted a 5.4-point higher NSAA score (p < .001) and 0.45 m/s faster 10MWT speed (p < .001). A 1 kg/m2 higher FMI value predicted a 1.5-point lower NSAA score (p < .001) and 0.14 meters/second slower 10MWT speed (p < .001). DXA-derived estimates of ALMI and FMI are associated with motor function in DMD and may explain variation in DMD disease progression.

Risk of low bone mineral density in young pediatric cancer survivors with sarcopenia.

10070 Background: Required treatments to cure pediatric cancer at such a young age increase the risk of later health-related complications. Early exposure to DNA damaging agents, during a vital period of active skeletal growth, interferes with accrual of bone mass. Treatments not only impair bone health, but also affect skeletal muscle function and mass. Long-term pediatric cancer survivors present these limitations due to myofibrillary atrophy caused by degradation of myosin heavy chain and decrease in myosin synthesis death. Muscle weakness (both muscle strength deficits and low lean mass hereafter referred to as sarcopenia) and low areal bone mineral density (aBMD) have been observed to coexist in adult survivors of paediatric cancer. However, in young pediatric cancers survivors, associations between sarcopenia and low aBMD are not well described. Therefore, this study aimed to examine the risk of low aBMD in young pediatric cancer survivors with sarcopenia confirmed/probable, compared to not having sarcopenia. Methods: This cross-sectional study included 116 pediatric cancer survivors (12.1±3.3 years old; 42% female) enrolled on a randomized controlled trial designed to improve bone health (iBoneFIT project). Handgrip strength was used to assessed muscle strength. Dual-energy X-ray absorptiometry estimated aBMD (g/cm2) at the total body (less head), lumbar spine, total hip and femoral neck, and appendicular lean mass index (ALMI, kg/m2). Sarcopenia status was determined using age and sex specific international reference data from a healthy population. “No sarcopenia” was defined when muscle strength was &gt;decile 2. “Sarcopenia probable” was defined when muscle strength was ≤decile 2 and ALMI Z-score was &gt; -1.5 standard deviation (SD). “Sarcopenia confirmed” was defined when muscle strength was ≤decile 2 and ALMI Z-score ≤-1.5 SD. Logistic regression, adjusted for time from treatment completion and radiation exposure, was used to evaluate the risk of low aBMD (age-, sex- and race-specific aBMD Z-score &lt; -1.0) by sarcopenia status. Results: More than one-third of survivors met criteria for sarcopenia confirmed (37.9%); 19.0% met criteria for sarcopenia probable. Survivors with sarcopenia confirmed had higher risk of low aBMD at the total body (odd ratio [OR]: 6.91, 95% confidence interval [CI]: 2.31-24.15), total hip (OR: 2.98, 95% CI: 1.02-9.54) and femoral neck (OR: 4.72, 95% CI: 1.72-14.19) than those without sarcopenia. Survivors with sarcopenia probable had higher risk of having low aBMD only at the total body (OR: 4.13, 95% CI: 1.04-17.60) than those without sarcopenia. Conclusions: Over one-third of young paediatric cancer survivors presented sarcopenia confirmed with higher risk of low aBMD. These findings suggest that interventions to mitigate osteosarcopenia in this population should be implemented at early stages after treatment completion.

Comparisons between dual-energy X-ray absorptiometry and bioimpedance devices for appendicular lean mass and muscle quality in Hispanic adults.

The purpose of this study was to compare single- and multi-frequency bioimpedance (BIA) devices against dual-energy X-ray absorptiometry (DXA) for appendicular lean mass (ALM) and muscle quality index (MQI) metrics in Hispanic adults. One hundred thirty-one Hispanic adults (18-55 years) participated in this study. ALM was measured with single-frequency bioimpedance analysis (SFBIA), multi-frequency bioimpedance analysis (MFBIA) and DXA. ALMTOTAL (left arm + right arm + left leg + right leg) and ALMARMS (left arm + right arm) were computed for all three devices. Handgrip strength (HGS) was measured using a dynamometer. The average HGS was used for all MQI models (highest left hand + highest right hand)/2. MQIARMS was defined as the ratio between HGS and ALMARMS. MQITOTAL was established as the ratio between HGS and ALMTOTAL. SFBIA and MFBIA had strong correlations with DXA for all ALM and MQI metrics (Lin's concordance correlation coefficient values ranged from 0·86 (MQIMFBIA-ARMS) to 0·97 (Arms LMSFBIA); all P < 0·001). Equivalence testing varied between methods (e.g. SFBIA v. DXA) when examining the different metrics (i.e. ALMTOTAL, ALMARMS, MQITOTAL and MQIARMS). MQIARMS was the only metric that did not differ from the line of identity and had no proportional bias when comparing all the devices against each other. The current study findings demonstrate good overall agreement between SFBIA, MFBIA and DXA for ALMTOTAL and ALMARMS in a Hispanic population. However, SFBIA and MFBIA have better agreement with DXA when used to compute MQIARMS than MQITOTAL.

Sex-specific association of low-renin hypertension with metabolic and musculoskeletal health in Korean older adults.

Low-renin hypertension (LRH) accounts for approximately one-third of patients with hypertension and are more prevalent in women and the older adult population. Previous study has found a link between the renin-angiotensin-aldosterone system (RAAS) and sex hormones. However, there are insufficient data on the relationship between LRH and metabolic or musculoskeletal outcomes in older adults. Among the 343 participants from a population-based cohort study conducted between May 2018 and August 2019, a total of 256 (86 men older than 50 years and 170 postmenopausal women) were included. The presence of LRH was defined as plasma renin activity (PRA) <1 ng/mL/h and systolic blood pressure (BP) ≥130 or diastolic BP ≥80 mmHg based on the 2017 ACC/AHA guidelines. Individuals with missing data, and those who had used medications that could affect PRA within the past six months were excluded. Bone mineral density (BMD), trabecular bone score (TBS), and appendicular lean mass (ALM) index were assessed using dual-energy X-ray absorptiometry; degraded TBS was defined as partially degraded to degraded levels (≤1.350). Muscle function was assessed according to the Asian Working Group for Sarcopenia guidelines. PRA was measured using radioimmunoassay. The median age was 66 [61-72] years, and the body mass index (BMI) was 24.7 [23.0-26.4] kg/m2. Individuals with LRH, accounting for 34.8%, had lower diabetes mellitus; more dyslipidemia; and poorer muscle function, BMD, and TBS than those in the non-LRH group. In addition, PRA was positively correlated with C-peptide, HOMA-IR, TBS, and ALM index. After adjusting for covariates including age and BMI, LRH was negatively associated with femur neck T-score (adjusted β = -0.30, 95% CI [-0.55 to -0.05], p = 0.021) and the presence of LRH was significantly associated with degraded TBS in women (adjusted odds ratio = 3.00, 95% CI [1.36-6.58], p = 0.006). Our findings suggest that LRH can influence clinical features and metabolic risk in older adults. Notably, LRH in postmenopausal women was linked to lower femur neck T-scores and degraded TBS, indicating sex-specific effects of LRH on bone health. Larger prospective studies are required to elucidate how changes in the RAAS affect metabolic and musculoskeletal outcomes in older adults.

Sarcopenia definitions and their association with fracture risk in older Swedish women.

The purpose of this study was to investigate the prevalence of three sarcopenia definitions and their associations with fracture risk in older Swedish women when adjusted for fracture risk assessment (FRAX)-based risk factors; 2,883 women with a mean age of 77.8years were included. Sarcopenia was defined based on the Sarcopenia Definitions and Outcomes Consortium (SDOC; low handgrip strength [kg] and gait speed (m/s)), revised European Working Group on Sarcopenia in Older People (EWGSOP2; low appendicular lean mass index, appendicular lean mass [ALM]/height; kg/m2], and hand grip strength [kg]), and Asian Working Group for Sarcopenia (AWGS; low ALM (kg), and hand grip strength [kg]) definitions. Femoral neck T-score was obtained from dual-energy X-ray absorptiometry. All fractures, confirmed by X-ray or medical record review, were subsequently categorized as major osteoporotic fractures (MOFs) and hip fractures. Deaths were verified through regional registers. The total follow-up time was 6.4 ± 1.3 (mean ± SD) yr. Cox regression (hazard ratios [HR] and 95% CIs) analyses were performed with adjustment for age, FRAX variables, and femoral neck T-score. Sarcopenia prevalence was 4.5% (n = 129) according to SDOC, 12.5% (n = 360) for EWGSOP2, and 10.3% (n = 296) defined by AWGS. Individuals with sarcopenia defined by SDOC had a higher mortality risk than individuals without sarcopenia (HR: 3.41; 95% CI: 2.51, 4.62) after adjusting for age and FRAX variables. Sarcopenia according to EWGSOP2 and AWGS was not associated with an increased fracture risk after adjusting for age and FRAX variables. Individuals with sarcopenia defined by SDOC had a higher risk for any fractures (HR: 1.48; 95% CI: 1.10, 1.99) and MOF (HR: 1.42; 95% CI: 1.03, 1.98) compared with individuals without sarcopenia after adjusting for clinical risk factors used in FRAX. In conclusion, sarcopenia defined by SDOC, incorporating muscle function/strength, was the only sarcopenia definition associated with fracture risk in older women.

Paediatric dominant and non-dominant handgrip reference curves and the association with body composition

Background Lack of paediatric reference data limits the utility of handgrip strength as a measure of fitness and well-being. Aim To develop paediatric handgrip reference curves and evaluate associations with body size and composition and race/ethnicity group. Subjects and methods Handgrip, body size and composition data were obtained from National Health and Nutrition Examination Survey 2011–2014 participants aged 6–20 years. Densitometry-derived fat and appendicular lean soft tissue mass index Z-scores (FMIZ, ALSTMIZ) were generated in participants >8 years. Dominant and non-dominant handgrip reference curves were created using the LMS method. Analyses included sample weights to produce nationally representative estimates. Results Differences in handgrip strength according to hand dominance increased with age. Handgrip strength was associated with height and arm length Z-scores (R = 0.42 to 0.47) and ALSTMIZ (R = 0.54). Handgrip strength was higher in the non-Hispanic Black group and lower in the Mexican American compared to non-Hispanic White group. Group differences were attenuated when adjusted for height, arm length or ALSTMIZ. Conclusion Paediatric handgrip reference curves were generated from which individual Z-scores can be calculated separately for dominant versus non-dominant hand and adjusted for body size. Association with ALSTMIZ suggests handgrip Z-score may be used as a measure of functional body composition.

Association between serum estradiol level and appendicular lean mass index in middle-aged postmenopausal women.

Previous studies investigating the association between loss of estrogen at menopause and skeletal muscle mass came to contradictory conclusions. To evaluate the association between serum estradiol level and appendicular lean mass index in middle-aged postmenopausal women using population-based data. This study included 673 postmenopausal women, aged 40-59 years, from the National Health and Nutrition Examination Survey between 2013 and 2016. Weighted multivariable linear regression models were used to evaluate the association between serum E2 Level and appendicular lean mass index (ALMI). When non-linear associations were found by using weighted generalized additive model and smooth curve fitting, two-piecewise linear regression models were further applied to examine the threshold effects. There was a positive association between serum E2 level and ALMI. Compared to individuals in quartile 1 group, those in other quartiles had higher ALMI levels. An inverted U-shaped curve relationship between serum E2 Level and ALMI was found on performing weighted generalized additive model and smooth curve fitting, and the inflection point was identified as a serum E2 level of 85 pg/mL. Our results demonstrated an inverted U-shaped curve relationship between serum E2 levels and ALMI in middle-aged postmenopausal women, suggesting that low serum E2 levels play an important in the loss of muscle mass in middle-aged postmenopausal women.

Opposite causal effects of birthweight on myocardial infarction and atrial fibrillation and the distinct mediating pathways: a Mendelian randomization study

BackgroundPrevious observational studies have documented an inverse association of birthweight with myocardial infarction (MI) but a positive association with atrial fibrillation (AF). However, the causality of these associations and the underlying mediating pathways remain unclear. We aimed to investigate the causal effects of birthweight, incorporating both fetal and maternal genetic effects, on MI and AF, and identify potential mediators in their respective pathways.MethodsWe performed Mendelian randomization (MR) analyses using genome-wide association study summary statistics for birthweight (N = 297,356 for own birthweight and 210,248 for offspring birthweight), MI (Ncase=61,000, Ncontrol=577,000), AF (Ncase=60,620, Ncontrol=970,216), and 52 candidate mediators (N = 13,848-1,295,946). Two-step MR was employed to identify and assess the mediation proportion of potential mediators in the associations of birthweight with MI and AF, respectively. As a complement, we replicated analyses for fetal-specific birthweight and maternal-specific birthweight.ResultsGenetically determined each 1-SD lower birthweight was associated with a 40% (95% CI: 1.22–1.60) higher risk of MI, whereas each 1-SD higher birthweight was causally associated with a 29% (95% CI: 1.16–1.44) higher risk of AF. Cardiometabolic factors, including lipids and lipoproteins, glucose and insulin, blood pressure, and fatty acids, each mediated 4.09-23.71% of the total effect of birthweight on MI, followed by body composition and strength traits (i.e., appendicular lean mass, height, and grip strength) and socioeconomic indicators (i.e., education and household income), with the mediation proportion for each factor ranging from 8.08 to 16.80%. By contrast, appendicular lean mass, height, waist circumference, childhood obesity, and body mass index each mediated 15.03-45.12% of the total effect of birthweight on AF. Both fetal-specific birthweight and maternal-specific birthweight were inversely associated with MI, while only fetal-specific birthweight was positively associated with AF. Psychological well-being and lifestyle factors conferred no mediating effect in either association.ConclusionsCardiometabolic factors mainly mediated the association between lower birthweight and MI, while body composition and strength traits mediated the association between higher birthweight and AF. These findings provide novel evidence for the distinct pathogenesis of MI and AF and advocate adopting a life-course approach to improving fetal development and subsequent causal mediators to mitigate the prevalence and burden of cardiovascular diseases.

Association of change in fat and lean mass with incident cardiovascular events for women in midlife and beyond: A prospective study using dual-energy x-ray absorptiometry (DXA).

To determine whether changes in fat and lean mass over time, quantified using dual-energy x-ray absorptiometry (DXA), are related to incident cardiovascular events. Previous studies using surrogate anthropometric methods have had inconsistent findings. Prospective, longitudinal observational study of women aged 40 to 80 randomly selected from the electoral roll and stratified into decades: 40-49, 50-59, 60-69 and 70-79years. Changes in anthropometric measurements (body mass index and waist-to-hip ratio) and DXA-quantified fat mass and lean mass between the first and fifth years of the study. Incident cardiovascular events recorded from the sixth to the 12th year. In total 449 participants (87.9%) were analyzed. A 10% or greater decrease in total fat mass index was associated with a 67% lower likelihood of any cardiovascular event (OR=0.33, 95%CI 0.15-0.71); no association was observed for an increase. A 10% or greater decrease in abdominal fat mass index was associated with a 62% lower likelihood of incident stroke (OR=0.38, 95%CI 0.16-0.91); no association was observed for an increase. A 10% or greater decrease in appendicular lean mass index resulted in increased odds ratio of 2.91 for incident peripheral artery events (OR=2.91, 95%CI 1.18-7.20). Reducing fat mass for women in midlife and beyond may decrease the risk of cardiovascular events. An increase in fat mass may not contribute to additional cardiovascular events. A reduction in limb muscle mass may provide an independent marker for cardiometabolic risk and peripheral artery disease. No independent association was found using anthropometric measurements and incident cardiovascular events.

Body composition in male lifelong trained strength, sprint and endurance athletes and healthy age-matched controls.

Aging involves many physiological processes that lead to decreases in muscle mass and increases in fat mass. While regular exercise can counteract such negative body composition outcomes, masters athletes maintain high levels of exercise throughout their lives. This provides a unique model to assess the impact of inherent aging. The present study compared lean mass and fat mass in young and masters athletes from different sports to age-matched non-athletic individuals. Participants included young (20-39 years, n = 109) and older (70-89 years, n = 147) competitive male athletes, and 147 healthy age-matched controls (young = 53, older = 94 males). Athletes were separated into strength (e.g., weightlifters, powerlifters), sprint (e.g., sprint runners, jumpers) and endurance (e.g., long-distance runners, cross-country skiers) athletic disciplines. Body composition was assessed by dual-energy x-ray absorptiometry (DXA). Upper and lower limb lean mass was combined for appendicular lean mass as well as appendicular lean mass index (ALMI; kg/m2). Individuals' scores were assessed against established cut-offs for low muscle mass, obesity, and sarcopenic obesity to determine prevalence in each group. ALMI was greater in young strength (0.81-2.36 kg/m2, ∼15% and 1.24-2.74 kg/m2, ∼19%) and sprint (95% CI = 0.51-1.61 kg/m2, ∼11% and 0.96-1.97 kg/m2, ∼15%) athletes than in endurance and controls, respectively (all P < 0.001). In masters athletes, only strength athletes had greater ALMI than endurance athletes, but both older strength and sprint athletes had greater ALMI than older controls (0.42-1.27 kg/m2, ∼9% and 0.73-1.67 kg/m2, ∼13%, respectively, both P < 0.001). Fat mass was significantly lower in sprint and endurance athletes compared to strength athletes and controls in both age-groups. Sarcopenic obesity was identified in one young (2%) and eighteen (19%) older controls, while only two older endurance athletes (3%) and one older strength athlete (2%) were identified. Lifelong competitive sport participation leads to lower prevalence of sarcopenic obesity than a recreationally active lifestyle. This is achieved in strength athletes by emphasizing muscle mass, while sprint and endurance athletes demonstrate low fat mass levels. However, all older athlete groups showed higher fat mass than the young groups, suggesting that exercise alone may not be sufficient to manage fat mass.