Lean Mass In Women Research Articles

Sex differences in upper and lower strength and their association with body composition among university students.

Sex strongly influences physical performance throughout adolescence, and excess fat mass is associated with several health and performance impairments. This study aimed to evaluate whether variations in strength between men and women dependent on lean mass and body fat content. This cross-sectional, quasi-experimental, non-probabilistic study involved 44 university students (22 men and 22 women, aged 19-29). Handgrip strength (HGS) was measured using an adjustable handgrip dynamometer, body composition was assessed using bioimpedance, and countermovement jumps (CMJ) were measured using a force platform. Data were analyzed using ANOVA to compare HGS and CMJ based on body mass, and the Pearson correlation coefficient was applied to examine the relationships between grip strength, body composition, and jump test performance. Strength is significantly higher in men compared to women, as is countermovement jump. The strength of women corresponded to over 50% of that of men, whereas the quantity of lean mass in women corresponded to 55% of that of men. We found a significant relationship between strength and lean mass. This study supports the idea that both upper- and lower-body strengths are strongly influenced by lean mass, thereby contributing to sex differences. The primary factor in body composition that explains the disparities in HGS and CMJ between sexes is the proportion of fat mass to lean mass. Finally, the sex disparities observed between body composition and strength depend on lean mass content.

Lean mass and associated factors in women with PCOS with different phenotypes.

Although current evidence suggests increased risk of obesity, insulin resistance, and metabolic alterations in patients with polycystic ovary syndrome (PCOS), especially of a hyperandrogenic phenotype, the impact of each one of these variables on muscle mass remains uncertain. In this case-control study, we evaluated clinical and hormonal characteristics related to lean body mass according to the different PCOS phenotypes. We performed clinical, metabolic, and hormonal assessments and evaluated body compartments by dual-energy X-ray absorptiometry in 133 women of reproductive age. Creatinine served as an indirect marker of lean mass. Median age was 28 (range, 17-37) years. Women with phenotypes A and B (n = 59) had higher body mass index (BMI) and metabolic syndrome prevalence than those with phenotype C (n = 23) and controls (n = 51) (p<0.005). Women with phenotypes A and B also had higher Ferriman-Gallwey score (p<0.001), insulin levels (p = 0.006), HOMA-IR (p = 0.008), testosterone (p = 0.008), free androgen index (FAI) (p<0.001), fat mass index (FMI) (p = 0.015), android-to-gynoid fat ratio (p = 0.036), and bone mineral density (BMD) at lumbar spine (p = 0.027) and total femur (p = 0.013) than controls. Median appendicular lean mass index (ALMI) was higher in phenotypes A and B than in controls (7.01 [IQR, 6.33-8.02] vs. 6.69 [IQR, 5.94-7.09], p = 0.024), but it did not differ significantly from that in phenotype C (6.60 [IQR, 6.16-7.22], p = 0.222). Even after adjusting for BMI, ALMI correlated positively with creatinine in women with phenotypes A and B (rho = 0.319, p = 0.023) but not in those with phenotype C (p = 0.238) or controls (p = 0.097). In multivariate linear regression analyses, ALMI was positively associated with insulin, FAI, FMI, and total femur BMD. The present results suggest that fasting insulin, FAI, fat mass, and total femur BMD were positively associated with increased lean mass in women with PCOS phenotypes A and B.

What are the most effective exercise, physical activity and dietary interventions to improve body composition in women diagnosed with or at high-risk of breast cancer? A systematic review and network meta-analysis.

Obesity has been recognized as a risk factor in the development and recurrence of breast cancer and is also associated with poor prognostic outcomes. This systematic review and network meta-analysis aimed to identify the most effective exercise, physical activity, and dietary interventions to reduce fat mass, body fat percentage and body weight as well as potentially increase lean mass in women diagnosed with or at high risk of breast cancer. A systematic search of databases was performed up to May 2022. Eligible randomized controlled trials examined the effects of exercise, physical activity and/or dietary interventions on fat mass and lean mass in women diagnosed with or at high risk of breast cancer. A random-effects network meta-analysis was conducted to determine the effects of different interventions across outcomes when sufficient studies were available. Eighty-four studies (n=6428) were included in this review. Caloric restriction and combined exercise+caloric restriction significantly reduced fat mass (range, -3.9 to -3.7kg) and body weight (range, -5.3 to -4.7kg), whereas physical activity+caloric restriction significantly reduced body fat percentage (-2.4%; 95% confidence interval [CI], -3.4% to -13%) and body mass index (-2.2kg × m-2 ; 95% CI, -3.0 to -1.4kg × m-2 ) in breast cancer patients. Resistance exercise was the most effective intervention to increase lean mass (0.7kg; 95% CI, 0.5-1.0kg) in breast cancer patients. Multimodal exercise and diet programs were the most effective interventions to reduce fat mass, body fat percentage, and body weight and increase and/or preserve lean mass.

Associations of Serum Follicle-Stimulating Hormone and Luteinizing Hormone Levels with Fat and Lean Mass during Menopausal Transition

Introduction: The association of serum follicle-stimulating hormone (FSH) levels with body fat mass remains inconclusive. Furthermore, little was known about the association of luteinizing hormone (LH) with body fat. This study aimed to investigate the associations of serum FSH and LH levels with fat and lean mass in women during menopausal transition. Methods: The data analyzed in this study were derived from the National Health and Nutrition Examination Survey from 1999 to 2002. Women aged from 35 to 60 years were eligible. Serum FSH and LH levels were assayed using the microparticle enzyme immunoassay technology. A dual energy X-ray absorptiometry was used to measure body fat mass and lean mass. Fat mass index (FMI) and fat-free mass index (FFMI) were respectively used to assess fat and lean mass. General linear regression was employed to examine the associations of serum FSH and LH levels with FMI and FFMI. Results: This study included 1,329 women. For the total participants, elevated serum FSH and LH levels were associated with an increased FMI (β = 0.004 and 0.007; 95% CI: 0.002, 0.006 and 0.004, 0.010, respectively) and a decreased FFMI (β = −0.004 and −0.007; 95% CI: −0.006, −0.002 and −0.010, −0.004, respectively). Furthermore, the significant associations of serum FSH and LH levels with FMI and FFMI were fully observed in postmenopausal women, especially in a certain range of higher serum FSH and LH quartiles. Conclusion: Elevated serum FSH and LH levels were associated with increased body fat mass but decreased lean mass in postmenopausal women but not in premenopausal women. Furthermore, only higher serum FSH and LH percentiles were associated with fat and lean mass in postmenopausal women.

Comparison of Lean Mass in Women With and Without Heart Disease.

This proof-of-concept study compared lean mass (LM) between women with heart disease (HD) and without HD. Fifty-six community-dwelling women were pair-matched by age. Heart disease was defined using criteria from the US Behavioral Risk Factor Surveillance System. Body composition was measured using multifrequency bioelectrical impedance analysis. Relative LM was calculated against height (kg/m2) as the lean mass index (LMI). Sarcopenia was defined as an LMI <15.0 kg/m2. Strength was measured with a handgrip dynamometer, arm curl test, and chair stand test. Those with HD had significantly less absolute (38.2 ± 0.8 vs 43.5 ± 1.0 kg; P < .001) and relative (15.3 ± 0.3 vs 16.2 ± 0.3 kg/m2, P = .015) LM compared with those without HD. Body mass was significantly greater for those without HD (76.1 ± 2.1 vs 68.4 ± 2.1 kg; P = .013) and there were no differences in fat mass. Upper body strength was significantly less and lower body strength was diminished but not significantly different in those with HD compared to those without HD (handgrip: P = .016; arm curl: P < .001; chair stand: P = .066). In this group of community-dwelling women, those who reported a diagnosis of HD had significantly less LM than those without HD. Although neither group was classified as sarcopenic, women with HD were at greater risk due to lower relative LM. Based on our findings, during cardiac rehabilitation clinicians should counsel women regarding resistance exercise for maintenance of LM in addition to strength.

Decline in Muscle Strength and Performance Predicts Fracture Risk in Elderly Women and Men.

Muscle strength and performance are associated with fractures. However, the contribution of their rate of decline is unclear. To assess the independent contribution of the rate of decline in muscle strength and performance to fracture risk. Community-dwelling women (n = 811) and men (n = 440) aged 60 years or older from the prospective Dubbo Osteoporosis Epidemiology Study followed from 2000 to 2018 for incident fracture. Clinical data, appendicular lean mass/height2 (ht)2, bone mineral density, quadricep strength/ht (QS), timed get-up-and-go (TGUG), 5 times repeated sit-to-stand (5xSTS), and gait speed (GS) measured biennially. Rates of decline in muscle parameters were calculated using ordinary least squares regression and fracture risk was assessed using Cox's models. Incident low-trauma fracture ascertained by x-ray report. Apart from lean mass in women, all muscle parameters declined over time. Greater rates of decline in physical performance were associated with increased fracture risk in women (Hazard ratios [HRs] ranging from 2.1 (95% CI: 1.5-2.9) for GS to 2.7 (95% CI: 1.9-3.6) for 5xSTS, while in men only the decline in GS was associated with fracture risk (HR: 3.4 [95% CI: 1.8-6.3]). Baseline performance and strength were also associated with increased fracture risk in men (HRs ranging from 1.8 (95% CI: 1.1-3.0) for QS to 2.5 (95% CI: 1.5-4.1) for TGUG, but not in women. Rate of decline in physical performance in both genders, and baseline strength and performance in men, contributed independently to fracture risk. Sit-to-stand and GS were the tests most consistently associated with fractures. Further studies are required to determine whether muscle strength and/or performance improve the predictive accuracy of fracture prediction models.

Sex-differences In Exercising Hemodynamics: Role Of Exercising Muscle Mass

Sex-differences in O2 transport include O2 content (CaO2) and quantity of muscle mass. PURPOSE: To determine their consequences on exercising hemodynamics with large (e.g., 2-leg cycling (BIKE)) vs. small (e.g., 1-leg knee extension (KE)) muscle mass. METHODS: Healthy young subjects (4M, 3W) completed BIKE and KE exercise tests. The femoral artery and vein were catheterized to measure leg blood flow (Q), CaO2, and mean arterial pressure (MAP). Vascular conductance (VC), O2 delivery, and leg O2 uptake (VO2) were calculated. Measures were normalized to the right leg (BIKE) or quadriceps (KE) lean mass. Whole body VO2 was measured with a metabolic cart. Men and women were compared at similar and maximal work rates. RESULTS: Body mass was greater in men (M: 80±6 vs. W: 59±12 kg, p=0.03). Although quadriceps mass (3.3±0.2 vs. 2.0±0.3 kg, p<0.001) and CaO2 were lower, women had a higher mass-specific Q, VC (p=0.054), O2 delivery, and leg VO2 to maintain whole body VO2 during similar KE (Table 1). These differences were maintained during maximal KE, at which women tended to achieve a higher mass-specific work rate (21±2 vs. 25±3 W·kg-1, p=0.10). They were also apparent during similar BIKE despite a lower leg lean mass in women (8.7±0.3 vs. 5.3±0.7 kg, p<0.001). However, the differences were no longer present during maximal BIKE when mass-specific work rate was similar (21±2 vs. 20±2 W·kg-1, p=0.70) and whole body VO2 was lower in women. CONCLUSION: These findings highlight a greater hemodynamic capacity for women to overcome differences in CaO2 and maintain whole body VO2 at similar work rates during exercise. They also implicate the quantity of exercising muscle in facilitating the greater hemodynamic capacity and mass-specific work rate during maximal exercise with a small but not large muscle mass. Support: The Swedish National Centre for Research in Sports, Ministerio de Educacion y Ciencia of Spain, Dr. Manuel Morales Foundation, NSERCTable 1: Exercising hemodynamics (*p<0.05, **p<0.01, ***p<0.001 men vs. women)

Lean body mass is not beneficial, but may be detrimental for glucose tolerance – Splitting body mass index according to body composition

AimsTo study the combined effect of lean mass index (LMI) and fat mass index (FMI) on glucose regulation based upon findings in an oral glucose tolerance test (OGTT) and homeostasis model assessment of insulin resistance (HOMA-IR). MethodsWe conducted a population-based, cross-sectional study including 1617 participants without diabetes born in Helsinki from 1934 through 1944. LMI and FMI were calculated as lean and fat mass (kg)/height (m2). For analysis of the association between interaction of LMI and FMI and glucose regulation the participants were divided into tertiles of FMI and LMI. ResultsIn men LMI correlated positively with (fasting plasma glucose) FPG and HOMA-IR in the middle and high FMI level with a significant interaction between FMI and LMI on HOMA-IR. In women LMI was not associated with glucose regulation.In both men and women increased FMI was associated with increased FPG and 2-h plasma glucose concentrations and HOMA-IR. ConclusionsIn men high lean mass accompanied with fatness may be detrimental for glucose tolerance, whereas in women lean mass seemed to have little effect on glucose regulation. Fatness is the major determinant of glucose intolerance.

Frequency of sarcopenia and factors associated with lean mass in women with rheumatoid arthritis

To evaluate the frequency of sarcopenia (SP) according to EWGSOP2 criteria and factors associated with low lean mass in women with rheumatoid arthritis (RA). 79 women (aged 4075 years) with RA were enrolled in the study. We analyzed clinical data: age, body mass index (BMI), disease duration, methotrexate use, glucocorticoid use, anthropometric measurements, C-reactive protein level, disease activity score in 28 joints-erythrocyte sedimentation rate, bone mineral density (BMD) of the lumbar spine, femur neck, total hip and body composition by Dual energy X-ray absorptiometry. Also, muscle strength and functional tests were performed. We analyzed the correlation between disease parameters and low lean mass with the Spearman method. 73 (92%) patients had low muscle strength, 20 (25%) patients had low muscle strength and low lean mass, among them 9 (11%) also had functional disability. There was no correlation between the age of patients and the presence of SP, while the duration of RA in women with SP was significantly greater (p=0.006). There were significant correlations between lean mass and body mass index, glucocorticoids used, methotrexate doses, creatinine and urea acid serum concentration, bone mineral density and falls number. According EWGSOP2 confirmed sarcopenia was found in 25% RA patients, among them 11% women had severe sarcopenia. Lean mass correlated with the factors related to the disease itself and some general clinical parameters, which requires further study.

Response to exercise in older adults who take supplements of antioxidants and/or omega-3 polyunsaturated fatty acids: A systematic review

BackgroundNutrition is a key factor in determining exercise response. The aim of this review is to assess the response to exercise in older adults who take supplements of antioxidants and/or omega-3 polyunsaturated fatty acids. MethodsA systematic literature search was performed (June 2009- September 2019) in MEDLINE via Pubmed. The following search strategy was used with Boolean markers: (“omega-3 fatty acids” [Major] OR “antioxidants” [Major]) AND “exercise” AND “aged” [MesH]. Fourteen articles were finally included. ResultsExercise-induced free radical and inflammatory marker blood levels, but not changed the plasma total antioxidant capacity (TAC), after administration of antioxidant supplement. The oral administration of antioxidants produced null or negative effect on endothelial function, but the infusion into the brachial artery during rhythmic handgrip exercise produced a significant improvement in muscle blood flow, due to an on increase in the availability of nitric acid derived from the nitric oxide synthase. Aerobic exercise and antioxidant supplementation improved submaximal and maximal aerobic parameters, as well as mitochondrial density and mitochondria-regulated apoptotic signaling. Antioxidant supplementation, but not omega-3 PUFA, decreased pro-inflammatory marker levels and fat oxidation induced by exercise. Strength training decreased serum B12 concentration but combined with omega-3 PUFA or antioxidant supplementation, B12 levels were maintained. Antioxidant supplementation has protective effect after fatigue in isometric exercise but improved appendicular fat-free mass just combined with resistance exercise. Omega-3 fatty acid supplement combined with exercise increased lean mass in women, but not in men. Muscle damage induced by exercise is protected by antioxidant supplementation. ConclusionsOlder people who take antioxidant and/or omega-3 PUFA supplements showed improved exercise response, as well as lower muscle damage.

Sex-specific differences in the association of vitamin D with low lean mass and frailty: Results from the Berlin Aging Study II.

Sex-specific differences in factors associated with aging and lifespan, such as sarcopenia and disease development, are increasingly recognized. The study aims to assess sex-specific aspects of the association between vitamin D insufficiency and low lean mass as well as between vitamin D insufficiency and the frailty phenotype. A total of 1102 participants (51% women) from the Berlin Aging Study II were included in this cross-sectional study. Vitamin D insufficiency was defined as a 25(OH)D level <50 nmol/L. Lean mass was assessed with dual-energy x-ray absorptiometry and corrected by body mass index. Low lean mass was defined according to the Foundations for the National Institutes of Health Sarcopenia Project criteria (appendicular lean mass/body mass index <0.789 in men and <0.512 in women) and frailty defined according to the Fried criteria. In a risk factor-adjusted analysis, the association of vitamin D insufficiency was significantly influenced by sex (P for interaction < 0.001). Men with vitamin D insufficiency had 1.8 times higher odds of having low lean mass, with no association between vitamin D insufficiency and low lean mass in women. Participants with vitamin D insufficiency had 1.5 higher odds of being prefrail/frail with no significant effect modification by sex. We found notable sex-specific differences in the association of vitamin D insufficiency with low lean mass but not of vitamin D insufficiency with frailty. Vitamin D might play a relevant role in the loss of lean mass in men but not women and might be a biological marker of an unfavorable aging process associated with early development of frailty regardless of sex.

Body composition as a predictor of physical performance in older age: A ten-year follow-up of the Helsinki Birth Cohort Study

BackgroundThis study assessed how different measures of body composition predict physical performance ten years later among older adults. MethodsThe participants were 1076 men and women aged 57 to 70 years. Body mass index (BMI), waist circumference, and body composition (bioelectrical impedance analysis) were measured at baseline and physical performance (Senior Fitness Test) ten years later. Linear regression analyses were adjusted for age, education, smoking, duration of the follow-up and physical activity. ResultsGreater BMI, waist circumference, fat mass, and percent body fat were associated with poorer physical performance in both sexes (standardized regression coefficient [β] from −0.32 to −0.40, p < 0.001). Lean mass to BMI ratio was positively associated with later physical performance (β = 0.31 in men, β = 0.30 in women, p < 0.001). Fat-free mass index (lean mass/height2) in both sexes and lean mass in women were negatively associated with later physical performance. Lean mass residual after accounting for the effect of height and fat mass was not associated with physical performance. ConclusionsAmong older adults, higher measures of adiposity predicted poorer physical performance ten years later whereas lean mass was associated with physical performance in a counterintuitive manner. The results can be used when appraising usefulness of body composition indicators for definition of sarcopenic obesity.

Comparison of predictive equations of lean mass in young and postmenopausal women

The lean mass (LM) is a predictor of functional capacity, quality of life, and mortality. In this way, the LM should be measured by reliable methods. However, it presents high cost and generally predictive equations are used in clinical practice, but little is known which is the best predictive equation of LM in women. The purpose of the present study was to verify which predictive equation of LM correctly estimates the LM in young and postmenopausal women. Eighty-one women aged 19-81 years were evaluated. Body weight, height, waist circumference, and skin folds (bicipital, tricipital, subscapular and suprailiac) were measured. The LM was evaluated by DXA and also estimated using the predictive equations of Hume I, Hume II, Salamat, Kulkarni I, and Kulkarni II. Bland-Altman analysis was performed to evaluate the over/underestimation of the LM by predictive equations. The equations of Salamat, Kulkarni II, Hume I and Kulkarni I overestimated the LM by 0.0 (7.0; -6.9) kg; 2.3 (7.5; -3.0) kg; 5.1 (9.0; 0.4) kg; and 9.7 (16.3, 3.1) kg, respectively; whereas Hume II equation underestimated the LM by -16.9 (-11.5; -22.2) kg. The equation that presented a better prediction of LM was Salamat. However, it should be used with caution in clinical practice since this equation showed elevated confidence intervals and limits of agreements, and can lead to significant errors for some individuals.

Adductor pollicis muscle thickness has a low association with lean mass in women

Lean mass (LM) is a functional component of body composition and is an important parameter of nutritional status assessment. The adductor pollicis muscle thickness (APMT) has been used as a predictor of LM, but it is not well known if this method presents a higher prediction of LM than simple anthropometric measurements, such as weight. Thus, we aimed to associate APMT (alone and plus weight) with LM in women. This cross-sectional study was conducted with 82 young and postmenopausal women. Body weight (Filizola®) and height (Welmy®) was quantified and APMT was measured by Lange® caliper. Body composition (LM and fat percentage) was estimated by dual-energy X-ray absorptiometry. APMT was positively correlated with LM (r=0.35; p=0.001), however, weight was strongly correlated with LM (r=0.81; p<0.001). APMT showed a prediction of 12% of LM (β=0.346, R2=0.120, p<0.001), and weight explained the variations of LM by 65% (β=0.808, R2=0.654, p<0.001). When weight and APMT were evaluated together, there was an increase of only 0.06% in LM prediction (β=0.820, R2=0.655, p<0.001), compared to weight alone. When compared to weight, APMT showed a low association with LM. These results suggest that a simpler anthropometric measurement, such as weight, can be a better predictor of LM than APMT.

Weakness and Low Lean Mass in Women With Hip Fracture: Prevalence According to the FNIH Criteria and Association With the Short-Term Functional Recovery.

People with hip fracture commonly have low muscle mass, reduced muscle strength, limited mobility, and limited ability to function in activities of daily living. Our aim was to assess the role of grip strength and appendicular lean mass (aLM) to predict the short-term functional recovery in women with hip fracture. For both strength and aLM, we focused on the cutoff points recently released by the Foundation for the National Institutes of Health (FNIH). In this short-term prospective observational study, we investigated 138 white women consecutively admitted to a rehabilitation hospital because of their first hip fracture. We measured aLM by dual-energy x-ray absorptiometry, grip strength with a hand dynamometer, and body mass index (BMI) at a median of 18 days after hip fracture occurrence. Functional autonomy was assessed by the Barthel index at the end of the rehabilitation course. Fifty-five of the 138 women (40%; 95% confidence interval [CI], 32%-48%) had a handgrip strength less than 16 kg, whereas 33 (24%; 95% CI, 17%-31%) had a handgrip strength/BMI less than 0.56. In both cases, the weak women had Barthel index scores significantly lower than the nonweak women (P ≤ .001). One hundred eighteen of the 138 women (86%; 95% CI, 80%-91%) had an aLM less than 15.02 kg, whereas 65 (48%; 95% CI, 39%-56%) had an aLM/BMI less than 0.512. In both cases the Barthel index scores were nonsignificantly different between the women whose aLM indexes were either below or above the cutoff points. Categorization according to the FNIH cutoff points for weakness significantly predicted the functional outcome in women with hip fracture, whereas categorization for aLM did not. Adjustments for BMI significantly changed the prevalence of either weakness or low aLM, but did not materially change their predictive roles.

Lean mass predicts the size-dependent and size-adjusted BMD better than fat mass in premenopausal females: a cross-sectional analysis

Introduction: In the human body, the influence of lean and fat masses on the bone tissue is unclear. This study was conducted to examine the association of different body compartments in order to find out the major determinant of bone mass. We used both size-dependent and size adjusted bone mass measures in the analysis Methods: A group of 128 healthy premenopausal females, aged 25-50 years was selected randomly from the local community, stratified according to their BMI. Lean mass (LM), fat mass (FM), total body bone mineral density (TBBMD) and total body bone mineral content (TBBMC) were measured using a DXA scan. TBBMD was divided by the standing height to estimate height-adjusted total body BMD (TBBMD-ht). Furthermore, TBBMD was divided by the bone area and height to estimate bone mineral apparent density (BMAD). Results: Both FM and LM showed significant and positive correlations with TBBMC and corresponding r values were 0.33 and 0.73, respectively (P Conclusions: Among these premenopausal women LM predicted bone mass stronger than FM. Magnitude and directions of the correlations between bone mass and LM were different when BMC was adjusted for bone size and height of subjects. These results support the idea that lean mass has dual effects on bone tissue where it influences both linear measurements and mineral content to different extents. Journal of the Ceylon College of Physicians, 2014,45, 22-27

Sex Differences in the Effects of Weight Loss Diets on Bone Mineral Density and Body Composition: POUNDS LOST Trial.

Weight loss is associated with reduction in bone mineral density (BMD). The objective was to address the role of changes in fat mass (FM) and lean mass (LM) in BMD decline in both sexes. A 2-year randomized controlled trial, the Preventing Overweight Using Novel Dietary Strategies (POUNDS-LOST). The setting was the general community. Enrolled were 424 overweight and obese participants (mean age, 52 ± 9 y; 57% females). Intervention included weight loss diets differing in fat, protein, and carbohydrates. Main outcome measures were change in spine, total hip (TH), and femoral neck (FN) BMD and sex differences after dietary intervention. At baseline, a stronger correlation between BMD and body composition measurements was observed in women, primarily with LM (r = 0.419, 0.507, and 0.523 for spine, FN, and TH, respectively; all P < .001). In men, only LM correlated with hip BMD (r = 0.298; P < .001). Mean weight loss at 2 years was -6.9%, without differences among diets. Two-year changes in BMD were 0.005 (P = .04), -0.014 (P < .001), and -0.014 g/cm(2) (P < .001), at the spine, TH, and FN, respectively. These changes directly correlated with changes in LM in women (r = 0.200, 0.324, and 0.260 for spine, FN, and TH, respectively), whereas FM loss correlated only with changes in TH BMD (0.274; P < .001). In men, changes in LM (-0.323; P < .001) and FM (-0.213; P = .027) negatively correlated with changes in spine BMD. Weight loss diets result in sex-specific effects on BMD. Although men exhibited a paradoxical increase in spine BMD, women tended to decrease in BMD at all sites.

Socioeconomic position across life and body composition in early old age: findings from a British birth cohort study

BackgroundPrevious studies have reported associations between lower lifetime socioeconomic position (SEP) and higher body mass index in adulthood, but few have examined associations with direct measures of fat and lean...

WISE-2005: Countermeasures to prevent muscle deconditioning during bed rest in women

The objectives of this study were to evaluate the efficacy of two separate countermeasures, exercise and protein supplementation, to prevent muscle strength and lean tissue mass losses during 60 days of bed rest (BR) in women and whether countermeasure efficacy was influenced by pre-BR muscular fitness (strength, endurance, tissue mass). Twenty-four women were assigned to an exercise (EX, n = 8), a no-exercise control (CON, n = 8), or a no-exercise protein supplementation group (PROT, n = 8). EX performed supine treadmill exercise within lower body negative pressure 3-4 days/wk and maximal concentric and eccentric supine leg- and calf-press exercises 2-4 days/wk. PROT consumed a diet with elevated protein content compared with CON and EX (1.6 vs. 1.0 g·kg(-1)·day(-1)). Knee and calf isokinetic strength and endurance, isotonic leg-press strength, and leg lean mass were measured before and after BR. Post-BR knee extensor strength and endurance, ankle strength, and leg lean mass were significantly greater and leg-press strength tended to be higher in EX than in CON and PROT. Post-BR measures in PROT were not different than those in CON. Exercise countermeasure efficacy was less, and strength, endurance, and leg lean mass losses in CON and PROT were greater, in subjects who were more fit pre-BR. An exercise protocol combining resistive and aerobic exercise training protects against losses in strength, endurance, and leg lean mass in women during BR, while a nutritional countermeasure without exercise was not effective. Exercise countermeasures may require individualization to protect higher levels of strength and endurance.

A cross-sectional study of loss of muscle mass corresponding to sarcopenia in healthy Chinese men and women: reference values, prevalence, and association with bone mass

A cross-sectional survey was conducted in Shanghai, eastern China, to evaluate the prevalence of loss of muscle mass corresponding to sarcopenia in Chinese men and women and compare the results with the prevalence in other populations. We also analyzed the differences between men and women, and assessed the effect of lean mass and fat mass of different regions on bone mass. A total of 1766 men and 1778 women aged 18-96 years participated in this study. Bone mineral density of spine and femur, and lean mass and fat mass of several body regions were measured by dual-energy X-ray absorptiometry. Class 1 and class 2 sarcopenia were defined as the appendicular lean mass (ALM) index (ALM/height(2)) 1 and 2 standard deviations below the sex-specific means for young adults. Mean values for ALM index were 7.93 for men and 6.04 kg/m(2) for women, aged 18-40 years. The reference values for classes 1 and 2 sarcopenia were 7.01 and 6.08 kg/m(2) in men and 5.42 and 4.79 kg/m(2) in women. The prevalence of sarcopenia was 4.8% in women and 13.2% in men aged 70 years and older, which is lower than that in Caucasian populations, but the same as that in Japanese and Koreans in Asia. Men demonstrated greater declines in muscle mass with aging than women, partly due to the protective effect of fat mass on lean mass in women. Leg lean mass was the strongest factor on femur bone mass; however, trunk lean mass was the strongest factor on spine bone mass. Maintaining a healthy weight is important for the elderly in order to avoid osteoporosis and sarcopenia.