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Lean Mass (lean + mass)
Selected AbstractsKidney Function as a Predictor of Loss of Lean Mass in Older Adults: Health, Aging and Body Composition StudyJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 10 2007Linda F. Fried MD OBJECTIVES: To assess the association between kidney function and change in body composition in older individuals. DESIGN: Prospective cohort study. SETTING: Two sites, Pittsburgh, Pennsylvania, and Memphis, Tennessee. PARTICIPANTS: Three thousand twenty-six well-functioning, participants aged 70 to 79 in the Health, Aging and Body Composition Study. MEASUREMENTS: Body composition (bone-free lean mass and fat mass) was measured using dual x-ray absorptiometry annually for 4 years. Kidney function was measured at baseline according to serum creatinine (SCr). Comorbidity and inflammatory markers were evaluated as covariates in mixed-model, repeated-measures analysis. RESULTS: High SCr was associated with loss of lean mass in men but not women, with a stronger relationship in black men (P=.02 for difference between slopes for white and black men). In white men, after adjustment for age and comorbidity, higher SCr remained associated with loss of lean mass (,0.07±0.03 kg/y greater loss per 0.4 mg/dL (1 standard deviation (SD)), P=.009) but was attenuated after adjustment for inflammatory factors (,0.05±0.03 kg/y greater loss per SD, P=.10). In black men, the relationship between SCr and loss of lean mass (,0.19±0.04 kg/y per SD, P<.001) persisted after adjustment for inflammation and overall weight change. CONCLUSION: Impaired kidney function may contribute to loss of lean mass in older men. Inflammation appeared to mediate the relationship in white but not black men. Future studies should strive to elucidate mechanisms linking kidney disease and muscle loss and identify treatments to minimize loss of lean mass and its functional consequences. [source] Do Muscle Mass, Muscle Density, Strength, and Physical Function Similarly Influence Risk of Hospitalization in Older Adults?JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 8 2009Peggy Mannen Cawthon PhD OBJECTIVES: To examine the association between strength, function, lean mass, muscle density, and risk of hospitalization. DESIGN: Prospective cohort study. SETTING: Two U.S. clinical centers. PARTICIPANTS: Adults aged 70 to 80 (N=3,011) from the Health, Aging and Body Composition Study. MEASUREMENTS: Measurements were of grip strength, knee extension strength, lean mass, walking speed, and chair stand pace. Thigh computed tomography scans assessed muscle area and density (a proxy for muscle fat infiltration). Hospitalizations were confirmed by local review of medical records. Negative binomial regression models estimated incident rate ratios (IRRs) of hospitalization for race- and sex-specific quartiles of each muscle and function parameter separately. Multivariate models adjusted for age, body mass index, health status, and coexisting medical conditions. RESULTS: During an average 4.7 years of follow-up, 1,678 (55.7%) participants experienced one or more hospitalizations. Participants in the lowest quartile of muscle density were more likely to be subsequently hospitalized (multivariate IRR=1.47, 95% confidence interval (CI)=1.24,1.73) than those in the highest quartile. Similarly, participants with the weakest grip strength were at greater risk of hospitalization (multivariate IRR=1.52, 95% CI=1.30,1.78, Q1 vs. Q4). Comparable results were seen for knee strength, walking pace, and chair stands pace. Lean mass and muscle area were not associated with risk of hospitalization. CONCLUSION: Weak strength, poor function, and low muscle density, but not muscle size or lean mass, were associated with greater risk of hospitalization. Interventions to reduce the disease burden associated with sarcopenia should focus on increasing muscle strength and improving physical function rather than simply increasing lean mass. [source] Nutritional supplements combined with dietary counselling diminish whole body protein catabolism in HIV-infected patientsEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 1 2000Berneis Background Weight loss and protein malnutrition are frequent complications in HIV-infected patients. The effect of an oral nutritional supplement combined with nutritional counselling on whole body protein metabolism was assessed. Materials and methods HIV-infected individuals with a body mass index < 21 kg m,2 or CD4-T cells < 500 , L,1 in stable clinical condition were randomly allocated to [ 1] receive either oral nutritional supplements (containing 2510 kJ, complete macro- and micronutrients) and dietary counselling (n = 8), or [ 2] identical monitoring but no supplements or specific nutritional advice (controls, n = 7). Whole body leucine kinetics and leucine oxidation rate were determined by [1,13C]-leucine infusions and lean and fat mass were measured before and 12 weeks after intervention. Results Leucine oxidation (protein catabolism) decreased in the group receiving nutritional intervention from 0.33 ± 0.02 to 0.26 ± 0.02 ,mol kg,1 min,1 after 12 weeks (P < 0.05; P < 0.05 vs. control group) but remained unchanged in the control group. Whole body leucine flux showed a tendency to decrease in the intervention group from 1.92 ± 0.19 to 1.73 ± 0.14 ,mol kg,1 min,1 (P = 0.07) and remained unchanged in the control group (2.21 ± 0.16 and 2.27 ± 0.14 ,mol kg,1 min,1, respectively). Lean body mass determined by bioelectrical impedance analysis increased in the nutritional intervention group from 84 ± 2 to 86 ± 2 per cent (P < 0.05) and fat mass decreased from 17 ± 2 to 14 ± 2 per cent (P < 0.05) of total body weight whereas neither mass changed in the control group. Nutritional intervention had no significant effect on lymphocyte CD4 counts, on plasma TNFR 55, TNFR 75 and ILR 2 concentrations and on quality of life. Conclusions The data demonstrate an anticatabolic effect of nutritional supplements combined with dietary counselling in HIV-infected subjects. They suggest that diminished whole body protein catabolism resulted in a change of body composition (increased lean mass, decreased fat mass). [source] Sarcopenia is prevalent in patients with Crohn's disease in clinical remissionINFLAMMATORY BOWEL DISEASES, Issue 11 2008Stéphane M. Schneider MD Abstract Background: Patients with Crohn's disease (CD) are prone to osteoporosis. A loss of muscle mass, called sarcopenia, is responsible for an increased risk of disability. Many factors associated with osteopenia also decrease muscle mass. The aim of the present study was to measure the prevalence of sarcopenia in CD patients in remission and uncover its relationship with osteopenia. Methods: In all, 82 CD patients (43 female / 39 male; 36 ± 14 years; body mass index [BMI] 21.1 ± 3.4) and 50 healthy volunteers (30F/20M; 39 ± 13 years; BMI 22.2 ± 2.5) were studied. Body composition was assessed using dual-energy x-ray absorptiometry. Sarcopenia was defined as an appendicular skeletal muscle index (ASMI) below 5.45 kg/m2 for women and 7.26 for men. Osteopenia was defined as a T-score for bone mineral density (BMD) (g/cm2) below ,1.0. Results: In all, 60% of CD patients were found to be sarcopenic and 30% osteopenic, compared to 16% and 4% of controls, respectively (P < 0.01). ASMI was significantly lower in patients than in controls (6.0 ± 1.1 versus 6.5 ± 1.2; P < 0.05). Sarcopenic patients had significantly (P < 0.01) lower BMI (20.0 ± 3.5 versus 22.7 ± 2.8 kg/m2), lean mass (41.5 ± 9.1 versus 48.1 ± 9.1 kg), and BMD (1.09 ± 0.12 versus 1.15 ± 0.08 g/cm2) than nonsarcopenic patients; 91% of sarcopenic patients were also osteopenic. ASMI correlated with BMD (r = 0.46; P < 0.01) and BMI (r = 0.38; P < 0.01). Conclusions: The prevalence of sarcopenia is high in young CD patients and strongly related to osteopenia. These 2 phenomena may share similar mechanisms. Simultaneous screening for sarcopenia and osteopenia may be useful in CD patients. (Inflamm Bowel Dis 2008) [source] Association Between Fitness and Changes in Body Composition and Muscle StrengthJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 2 2010George A. Kuchel, [see editorial comments by Drs. Gustavo Duque, pp 37 OBJECTIVES: To examine the association between physical fitness, assessed according to ability and time to complete a 400-m walk, on changes in body composition and muscle strength over a 7-year period. DESIGN: Prospective observational cohort study. SETTING: Memphis, Tennessee, and Pittsburgh, Pennsylvania. PARTICIPANTS: Two thousand nine hundred forty-nine black and white men and women aged 70 to 79 participating in the Health, Aging and Body Composition Study. MEASUREMENTS: Body composition (fat and bone-free lean mass) was assessed using dual-energy X-ray absorptiometry in Years 1 to 6 and 8. Knee extension strength was measured using isokinetic dynamometry and grip strength using isometric dynamometry in Years 1, 2, 4, 6, and 8. RESULTS: Less fit people weighed more and had a higher total percentage of fat and a lower total percentage of lean mass than very fit men and women at baseline (P<.001). Additionally, the least fit lost significantly more weight, fat mass, and lean mass over time than the very fit (all P<.01). Very fit people had the highest grip strength and knee extensor strength at baseline and follow-up; decline in muscle strength was similar in every fitness group. CONCLUSION: Low fitness in old age was associated with greater weight loss and loss of lean mass than with high fitness. Despite having lower muscle strength, the rate of decline in the least fit persons was similar to that in the most fit. In clinical practice, a long-distance walk test as a measure of fitness might be useful to identify people at risk for these adverse health outcomes. [source] Do Muscle Mass, Muscle Density, Strength, and Physical Function Similarly Influence Risk of Hospitalization in Older Adults?JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 8 2009Peggy Mannen Cawthon PhD OBJECTIVES: To examine the association between strength, function, lean mass, muscle density, and risk of hospitalization. DESIGN: Prospective cohort study. SETTING: Two U.S. clinical centers. PARTICIPANTS: Adults aged 70 to 80 (N=3,011) from the Health, Aging and Body Composition Study. MEASUREMENTS: Measurements were of grip strength, knee extension strength, lean mass, walking speed, and chair stand pace. Thigh computed tomography scans assessed muscle area and density (a proxy for muscle fat infiltration). Hospitalizations were confirmed by local review of medical records. Negative binomial regression models estimated incident rate ratios (IRRs) of hospitalization for race- and sex-specific quartiles of each muscle and function parameter separately. Multivariate models adjusted for age, body mass index, health status, and coexisting medical conditions. RESULTS: During an average 4.7 years of follow-up, 1,678 (55.7%) participants experienced one or more hospitalizations. Participants in the lowest quartile of muscle density were more likely to be subsequently hospitalized (multivariate IRR=1.47, 95% confidence interval (CI)=1.24,1.73) than those in the highest quartile. Similarly, participants with the weakest grip strength were at greater risk of hospitalization (multivariate IRR=1.52, 95% CI=1.30,1.78, Q1 vs. Q4). Comparable results were seen for knee strength, walking pace, and chair stands pace. Lean mass and muscle area were not associated with risk of hospitalization. CONCLUSION: Weak strength, poor function, and low muscle density, but not muscle size or lean mass, were associated with greater risk of hospitalization. Interventions to reduce the disease burden associated with sarcopenia should focus on increasing muscle strength and improving physical function rather than simply increasing lean mass. [source] Association Between Testosterone and Estradiol and Age-Related Decline in Physical Function in a Diverse Sample of MenJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 11 2008Andre B. Araujo PhD OBJECTIVES: To examine the association between aging and physical function in men by testing a theoretically based model of aging, hormones, body composition, strength, and physical function with data obtained from men enrolled in the Boston Area Community Health/Bone (BACH/Bone) Survey. DESIGN: Cross-sectional, observational survey. SETTING: Population-based. PARTICIPANTS: Eight hundred ten black, Hispanic, and white randomly selected men from the Boston area aged 30 to 79. MEASUREMENTS: Testosterone, estradiol, sex hormone,binding globulin, lean and fat mass, grip strength, and summated index of physical function (derived from walk and chair stand tests). RESULTS: Measures of grip strength and physical function declined strongly with age. For instance, 10 years of aging was associated with a 0.49-point difference (scale 0,7) in physical function. Age differences in total testosterone and estradiol concentrations were smaller than age differences in their free fractions. Weak or nonsignificant age-adjusted correlations were observed between hormones and measures of physical function, although path analysis revealed a positive association between testosterone and appendicular lean mass and a strong negative association between testosterone and total fat mass. Lean and fat mass, in turn, were strongly associated with grip strength and physical function, indicating the possibility that testosterone influences physical function via indirect associations with body composition. CONCLUSION: The age-related decline in serum testosterone concentration in men has a weak association with physical strength and functional outcomes through its associations with lean and fat mass. [source] Kidney Function as a Predictor of Loss of Lean Mass in Older Adults: Health, Aging and Body Composition StudyJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 10 2007Linda F. Fried MD OBJECTIVES: To assess the association between kidney function and change in body composition in older individuals. DESIGN: Prospective cohort study. SETTING: Two sites, Pittsburgh, Pennsylvania, and Memphis, Tennessee. PARTICIPANTS: Three thousand twenty-six well-functioning, participants aged 70 to 79 in the Health, Aging and Body Composition Study. MEASUREMENTS: Body composition (bone-free lean mass and fat mass) was measured using dual x-ray absorptiometry annually for 4 years. Kidney function was measured at baseline according to serum creatinine (SCr). Comorbidity and inflammatory markers were evaluated as covariates in mixed-model, repeated-measures analysis. RESULTS: High SCr was associated with loss of lean mass in men but not women, with a stronger relationship in black men (P=.02 for difference between slopes for white and black men). In white men, after adjustment for age and comorbidity, higher SCr remained associated with loss of lean mass (,0.07±0.03 kg/y greater loss per 0.4 mg/dL (1 standard deviation (SD)), P=.009) but was attenuated after adjustment for inflammatory factors (,0.05±0.03 kg/y greater loss per SD, P=.10). In black men, the relationship between SCr and loss of lean mass (,0.19±0.04 kg/y per SD, P<.001) persisted after adjustment for inflammation and overall weight change. CONCLUSION: Impaired kidney function may contribute to loss of lean mass in older men. Inflammation appeared to mediate the relationship in white but not black men. Future studies should strive to elucidate mechanisms linking kidney disease and muscle loss and identify treatments to minimize loss of lean mass and its functional consequences. [source] Ruddy turnstones Arenaria interpres rapidly build pectoral muscle after raptor scaresJOURNAL OF AVIAN BIOLOGY, Issue 5 2006Piet J. van den Hout To cope with changes in the environment, organisms not only show behavioural but also phenotypic adjustments. This is well established for the digestive tract. Here we present a first case of birds adjusting their flight machinery in response to predation risk. In an indoor experiment, ruddy turnstones Arenaria interpres were subjected to an unpredictable daily appearance of either a raptor or a small gull (as a control). Ruddy turnstones experiencing threat induced by a flying raptor model, longer than after similar passage by the gull model, refrained from feeding after this disturbance. Pectoral muscle mass, but not lean mass, responded in a course of a few days to changes in the perceived threat of predation. Pectoral muscle mass increased after raptor scares. Taking the small increases in body mass into account, pectoral muscle mass was 3.6% higher than aerodynamically predicted for constant flight performance. This demonstrates that perceived risk factors may directly affect organ size. [source] Gizzard and other lean mass components increase, yet Basal Metabolic Rates decrease, when red knots Calidris canutus are shifted from soft to hard-shelled foodJOURNAL OF AVIAN BIOLOGY, Issue 2 2004Theunis Piersma We measured basal metabolic rate (BMR), body mass, lean mass, and gizzard mass of captive red knots Calidriscanutusislandica maintained on a trout chow diet (soft-texture, low ash and water content) for several years and then shifted to small mussels Mytilus edulis (hard-texture, high ash and water content). During a 3-week period of feeding on mussels, body mass, lean mass, and gizzard mass increased 7.3 g (+7%), 10.5 g (+12%), and 4.9 g (+213%), respectively, yet BMR decreased from 0.96 to 0.89 W (,8%). Under the new mussel regime, red knots must have reduced the metabolic intensity of some of the tissues. This suggests that the experimental red knots experienced the transition to a mussel diet as stressful and energy limiting, resulting in an energy-saving strategy by reducing BMR in spite of hypertrophy of the gizzard and other organs. [source] Bone and Muscle Development During Puberty in Girls: A Seven-Year Longitudinal Study,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2009Leiting Xu Abstract The growth of lean mass precedes that of bone mass, suggesting that muscle plays an important role in the growth of bone. However, to date, no study has directly followed the growth of bone and muscle size through puberty and into adulthood. This study aimed to test the hypothesis that the growth of muscle size precedes that of bone size (width and length) and mass during puberty. Bone and muscle properties were measured using pQCT and DXA in 258 healthy girls at baseline (mean age, 11.2 yr) and 1-, 2-, 3,4- and 7-yr follow-up. Growth trends as a function of time relative to menarche were determined from prepuberty to early adulthood for tibial length (TL), total cross-sectional area (tCSA), cortical CSA (cCSA), total BMC (tBMC), cortical volumetric BMD (cBMD), and muscle CSA (mCSA) in hierarchical models. The timings of the peak growth velocities for these variables were calculated. Seventy premenopausal adults, comprising a subset of the girl's mothers (mean age, 41.5 yr), were included for comparative purposes. In contrast to our hypothesis, the growth velocity of mCSA peaked 1 yr later than that of tibial outer dimensions (TL and tCSA) and slightly earlier than tBMC. Whereas TL ceased to increase 2 yr after menarche, tCSA, cCSA, tBMC, and mCSA continued to increase and were still significantly lower than adult values at the age of 18 yr (all p < 0.01). The results do not support the view that muscle force drives the growth of bone size during puberty. [source] Impaired Energetic Metabolism After Central Leptin Signaling Leads to Massive Appendicular Bone Loss in Hindlimb-Suspended Rats,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 12 2008Aline Martin Abstract We previously showed in rats that the leptin effects on bone were dose dependent. Positive effects were observed when serum leptin concentration was in a physiological range. In contrast, important increases in serum leptin levels led to negative effects on bone formation similar to those reported after intracerebroventricular leptin administration in mice. To clarify whether leptin effects on bone depend on administration route and/or animal model, female rats were hindlimb unloaded or not and treated either with intracerebroventricular infusion of leptin or vehicle for 14 days. By increasing cerebrospinal fluid (CSF) leptin concentration, intracerebroventricular infusion of leptin significantly reduced food intake and consequently body weight, abdominal fat, and lean mass of the animals. Leptin infusion inhibited bone elongation over the 14 days and blunted cortical bone thickening at the femoral diaphysis site. Interestingly, leptin effects were site dependent in the cancellous bone envelopes, because tibia metaphysis BMD was lower and lumbar spine BMD was higher under intracerebroventricular leptin. Treated groups showed reduced bone remodeling independently of hindlimb unloading. Multiple downstream pathways were implicated in the mediation of these negative leptin effects on bone including not only stimulation of the sympathetic nervous system but also a decrease in somatotropic axis activity. Therefore, the intracerebroventricular leptin-induced bone loss could be largely related to the concurrent alteration of energetic and metabolic status. In summary, our study supports the hypothesis of a concentration-dependent balance between peripheral and central control of leptin on bone. [source] Habitual Levels of Physical Activity Influence Bone Mass in 11-Year-Old Children From the United Kingdom: Findings From a Large Population-Based Cohort,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2007Jon H Tobias MD Abstract We examined the influence of habitual levels of physical activity on bone mass in childhood by studying the relationship between accelerometer recordings and DXA parameters in 4457 11-year-old children. Physical activity was positively related to both BMD and bone size in fully adjusted models. However, further exploration revealed that this effect on bone size was modified by fat mass. Introduction: Exercise interventions have been reported to increase bone mass in children, but it is unclear whether levels of habitual physical activity also influence skeletal development. Materials and Methods: We used multivariable linear regression to analyze associations between amount of moderate and vigorous physical activity (MVPA), derived from accelerometer recordings for a minimum of 3 days, and parameters obtained from total body DXA scans in 4457 11-year-old boys and girls from the Avon Longitudinal Study of Parents and Children. The influence of different activity intensities was also studied by stratification based on lower and higher accelerometer cut-points for moderate (3600 counts/minute) and vigorous (6200 counts/minute) activity, respectively. Results: MVPA was positively associated with lower limb BMD and BMC adjusted for bone area (aBMC; p < 0.001, adjusted for age, sex, socio-economic factors, and height, with or without additional adjustment for lean and fat mass). MVPA was inversely related to lower limb bone area after adjusting for height and lean mass (p = 0.01), whereas a positive association was observed when fat mass was also adjusted for (p < 0.001). Lower limb BMC was positively related to MVPA after adjusting for height and lean and fat mass (p < 0.001), whereas little relationship was observed after adjusting for height and lean mass alone (p = 0.1). On multivariable regression analysis using the fully adjusted model, moderate activity exerted a stronger influence on lower limb BMC compared with light activity (light activity: 2.9 [1.2,4.7, p = 0.001]; moderate activity: 13.1 [10.6,15.5, p < 0.001]; regression coefficients with 95% confidence intervals and p values). Conclusions: Habitual levels of physical activity in 11-year-old children are related to bone size and BMD, with moderate activity exerting the strongest influence. The effect on bone size (as reflected by DXA-based measures of bone area) was modified by adjustment for fat mass, such that decreased fat mass, which is associated with higher levels of physical activity, acts to reduce bone size and thereby counteract the tendency for physical activity to increase bone mass. [source] Bone Mineral Response to a 7-Month Randomized Controlled, School-Based Jumping Intervention in 121 Prepubertal Boys: Associations With Ethnicity and Body Mass Index,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2002K. J. Mackelvie Abstract We examined the effects of a 7-month jumping intervention (10 minutes, 3 times per week) on bone mineral gain in prepubertal Asian and white boys (10.3 ± 0.6 years, 36.0 ± 9.2 kg) at 14 schools randomized to control (n = 60) and intervention (n = 61) groups. Intervention and control groups had similar mean baseline and change in height, weight, lean mass and fat mass, baseline areal bone mineral density (aBMD; g/cm2), bone mineral content (BMC; g; dual-energy X-ray absorptiometry [DXA], QDR 4500W), and similar average physical activity and calcium intakes. Over 7 months, the intervention group gained more total body (TB) BMC (1.6%, p < 0.01) and proximal femur (PF) aBMD (1%, p < 0.05) than the control group after adjusting for age, baseline weight, change in height, and loaded physical activity. We also investigated the 41 Asian and 50 white boys (10.2 ± 0.6 years and 31.9 ± 4.4 kg) who were below the 75th percentile (19.4 kg/m2) of the cohort mean for baseline body mass index (BMI). Boys in the intervention group gained significantly more TB and lumbar spine (LS) BMC, PF aBMD, and trochanteric (TR) aBMD (+ ,2%) than boys in the control group (adjusted for baseline weight, final Tanner stage, change in height, and loaded physical activity). Bone changes were similar between Asians and whites. Finally, we compared the boys in the control group (n = 16) and the boys in the intervention group (n = 14) whose baseline BMI fell in the highest quartile (10.5 ± 0.6 years and 49.1 ± 8.2 kg). Seven-month bone changes (adjusted as aforementioned) were similar in the control and intervention groups. In summary, jumping exercise augmented bone mineral accrual at several regions equally in prepubertal Asian and white boys of average or low BMI, and intervention effects on bone mineral were undetectable in high BMI prepubertal boys. [source] Fitness, fatness and activity as predictors of bone mineral density in older personsJOURNAL OF INTERNAL MEDICINE, Issue 5 2002K. J. Stewart Abstract. Stewart KJ, DeRegis JR, Turner KL, Bacher AC, Sung J, Hees PS, Tayback M, Ouyang P (Johns Hopkins Bayview Medical Center, Johns Hopkins University, School of Medicine, Baltimore, MD, USA). Fitness, fatness, and activity as predictors of bone mineral density in older persons. J Intern Med 2002; 252: 381,388. Objectives. To determine relationships of bone mineral density (BMD) with fitness, physical activity, and body composition and fat distribution. Design. Cross-sectional. Setting. General Clinical Research Center, Johns Hopkins Bayview Medical Center, Baltimore, Maryland. Subjects. Men (n = 38) and women (n = 46), aged 55,75 years with high normal blood pressure or mild hypertension but otherwise healthy. Methods. Aerobic fitness (oxygen uptake) on a treadmill, muscle strength by one-repetition maximum, activity by questionnaire, abdominal obesity by magnetic resonance imaging; anthropometrics, and body composition by dual energy X-ray absorptiometry (DXA) which measured total fat and lean mass, and BMD for the total skeleton, lumbar spine (L1,L4) and total hip. Results. Aerobic fitness did not correlate with BMD. Using multivariate analysis to ascertain independent contributions to the variance in BMD, in women, with adjustment for hormone replacement therapy (HRT), total skeleton BMD was independently related to muscle strength and abdominal total fat; total hip BMD to body weight; lumbar spine BMD to abdominal total fat. HRT also influenced BMD in the lumbar spine. In men, lumbar spine BMD was independently related to abdominal total fat physical activity and total hip BMD related to lower body strength. P < 0.05 for all of these correlations. Conclusions. Abdominal obesity and muscle strength emerge as predominant correlates of BMD in older persons with stronger relationships seen in women. Body weight and HRT also explained portions of the variance in BMD in women. Whether abdominal obesity is simply a marker for general obesity or has independent protective effects on bone is yet to be determined. [source] Accuracy and precision of dual-energy X-ray absorptiometry for body composition measurements in rhesus monkeys*JOURNAL OF MEDICAL PRIMATOLOGY, Issue 2 2001Angela Black Accuracy of body composition measurements by dual-energy X-ray absorptiometry (DXA) was compared with direct chemical analysis in 10 adult rhesus monkeys. DXA was highly correlated (r-values >0.95) with direct analyses of body fat mass (FM), lean mass (LM) and lumbar spine bone mineral content (BMC). DXA measurements of total body BMC were not as strongly correlated (r-value=0.58) with total carcass ash content. DXA measurements of body FM, LM and lumbar spine BMC were not different from data obtained by direct analyses (P -values >0.30). In contrast, DXA determinations of total BMC (TBMC) averaged 15% less than total carcass ash measurements (P=0.002). In conclusion, this study confirms the accurate measurement of fat and lean tissue mass by DXA in rhesus monkeys. DXA also accurately measured lumbar spine BMC but underestimated total body BMC as compared with carcass ash determinations. [source] Palatable High-Energy Diet Decreases the Expression of Cannabinoid Type 1 Receptor Messenger RNA in Specific Brain Regions in the RatJOURNAL OF NEUROENDOCRINOLOGY, Issue 12 2009E. Timofeeva In laboratory rodents, a palatable high-energy diet (PHED) is usually consumed in a higher quantity than a standard laboratory diet, leading to the development of an obese phenotype. The central effects of PHED are not fully understood. Nonetheless, the long-term consumption of PHED can decrease cannabinoid type 1 receptor (CB1R) protein density in particular brain regions. However, little is known about the diet-dependent regulation of the brain expression of CB1R mRNA. The present study aimed to investigate the effects of the long-term consumption of PHED and short-term (12 h) food deprivation on the brain expression of CB1R mRNA. For 13 weeks, rats were fed a standard laboratory chow or PHED presented as a free choice of chow, shortcake biscuits and pork spread. In total, the food intake of PHED rats was higher than that of chow-fed animals. Expectedly, PHED rats demonstrated higher body weight than chow-fed animals. The difference in body weight between PHED- and chow-fed rats was as result of the fat but not the lean mass. PHED-fed rats had significantly higher plasma levels of leptin and insulin and significantly higher levels of expression of suppressor of cytokine signalling 3 (SOCS-3) in the arcuate hypothalamic nucleus. The long-term consumption of PHED significantly decreased the levels of CB1R mRNA expression in the cingulate (Cg) cortex, ventromedial hypothalamic nucleus and the descending/autonomic divisions of the parvocellular hypothalamic nucleus (PVH), the ventrolateral parvocellular PVH and, to a lesser extent, the dorsomedial parvocellular PVH. Acute food deprivation decreased the levels of CB1R transcript in the Cg and ventrolateral parvocellular PVH. Altogether, the present results demonstrate that long-term PHED leads to an increase in the hypothalamic expression of SOCS-3 mRNA and a decrease in expression of CB1R mRNA in the Cg cortex and specific hypothalamic regions. [source] Difference in non-weight-bearing effects on bone mineral density between trunk and peripheral fat mass in women with polycystic ovary syndromeJOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH (ELECTRONIC), Issue 2 2010Yumi Yanazume Abstract Aim:, To investigate the difference in non-weight-bearing effects on bone mineral density (BMD) between trunk and peripheral fat mass in women with polycystic ovary syndrome (PCOS). Methods:, Subjects were 123 amenorrheic PCOS women with right side dominance. Age, height, body weight, and body mass index were recorded. Trunk, peripheral (extremities), trunk,leg fat ratio as an index of body fat distribution, left arm (non-weight-bearing site) lean mass and BMD were measured by dual-energy X-ray absorptiometry. Serum testosterone and estradiol levels were measured. Relationships of BMD with trunk, peripheral fat mass, and sex hormones levels were investigated. Results:, Trunk fat mass amount was 9.8 ± 6.7 kg and was lower than the peripheral fat mass amount (12.2 ± 4.4 kg, P < 0.01). On Pearson's correlation test, trunk fat mass and left arm lean mass were positively correlated with arm BMD (r = 0.359, P < 0.001 and r = 0.501, P < 0.0001, respectively), while peripheral fat mass and serum testosterone levels were not correlated with BMD (r = 0.083 and 0.114, respectively, NS). On multiple regression analysis, trunk fat mass was positively correlated with BMD (t -value = 3.465; P < 0.001), independent of age and height. However, this relationship disappeared after additionally adjusting for left arm lean mass. Conclusion:, Trunk fat mass, despite the smaller amount, is more associated with arm BMD than peripheral fat mass is through its non-weight-bearing effects. [source] Assessment of regional body composition with dual-energy X-ray absorptiometry in Duchenne muscular dystrophy: Correlation of regional lean mass and quantitative strengthMUSCLE AND NERVE, Issue 5 2009Andrew J. Skalsky MD Abstract The purpose of this study was to assess regional body composition and its correlation with regional strength in Duchenne muscular dystrophy (DMD) subjects and able-bodied controls. Regional dual-energy X-ray absorptiometry (DEXA) measurements and isometric strength were obtained for 23 DMD subjects and 23 control subjects. DMD subjects showed a decreased regional lean mass (P < 0.001). The correlation between regional strength and regional lean mass was stronger for controls than for DMD subjects. DMD subjects had decreased regional lean mass, increased regional fat mass, and decreased strength. Muscle Nerve 39: 647,651, 2009 [source] Physical activity, sport, and pediatric diabetesPEDIATRIC DIABETES, Issue 1 2006MC Riddell Abstract:, The benefits derived from regular physical activity include improved cardiovascular fitness, increased lean mass, improved blood lipid profile, enhanced psychosocial well-being, and decreased body adiposity. The benefits for children with diabetes may also include blood glucose control and enhanced insulin sensitivity. However, for these children, engagement in vigorous physical activity and sport must be properly controlled through modifications in insulin therapy and nutritional intake so that the benefits of exercise outweigh the risks. The following review describes the various physiological and metabolic factors which occur both during exercise and during sport while describing specific recommendations to control glucose excursions by proper insulin management and diet. [source] Change in body mass index is a stronger predictor of change in fat mass than lean mass in elderly black and white womenAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 1 2009Sigurbjörn Á. Arngrímsson The aim of this study was to determine the relation between change in body mass index (BMI) and changes in fat mass (FM), lean soft tissue (LST), and percentage body fat (%Fat) in elderly (67.6 ± 6.0 years) women varying in race (53 black, 144 white) who underwent measurements of BMI, FM, LST, and %Fat at baseline and after 2 years. The group did not markedly change body composition over 2 years (BMI = ,0.1 ± 1.5 kg/m2, P = 0.53; FM = 0.0 ± 2.8 kg, P = 0.95; LST = ,0.4 ± 1.7 kg, P < 0.001; %Fat = 0.3 ± 2.0%, P = 0.06). Change in BMI predicted change in FM (r = 0.90, SEE = 1.19 kg FM, P < 0.001) but was less predictive of change in %Fat (r = 0.64, SEE = 1.54%Fat, P < 0.001). Change in BMI was curvilinearly related to change in LST adjusted for change in height (R = 0.76, SEE = 1.10 kg LST, P < 0.001). Change in BMI more strongly predicts change in FM than LST and could be used to monitor change in FM in community-dwelling women. Am. J. Hum. Biol., 2009. © 2008 Wiley-Liss, Inc. [source] PSA and body composition by dual X-Ray absorptiometry (DXA) in NHANESTHE PROSTATE, Issue 2 2010Jay H. Fowke Abstract BACKGROUND Obese men are at higher risk for advanced prostate cancer and have a poorer prognosis following treatment. Several studies also report that obese men have lower blood PSA levels, suggesting that obesity may be interfering with the ability to detect early-stage prostate cancer. METHODS Dual X-ray absorptiometry (DXA) is considered a gold-standard measurement of body composition. We investigated the association between PSA levels and body composition measured by DXA among 1,360 men participating in NHANES (2001,2004), a representative sample of the U.S. male population. RESULTS After controlling for age, race, and other factors, PSA concentration was ,15% lower for men with the highest level of total mass, lean mass, fat mass, trunk lean mass, and trunk fat mass (all P for trend <0.05). We then multiplied PSA concentration by estimated plasma volume to calculate the amount of PSA in circulation (i.e., PSA mass). Total body fat mass and fat mass located in the body trunk were not significantly associated with PSA mass, however, PSA mass was ,10,15% higher across low versus high categories of total body lean mass and bone mineral content (all P -trend <0.05). CONCLUSION Our results using DXA to measure body composition confirm that a greater body mass, not just fat mass, is associated with a lower PSA concentration. This is consistent with PSA hemodilution within men with a higher body mass index. The separate associations between measured lean and fat mass on calculated PSA mass require further investigation. Prostate 70: 120,125, 2010. ©2009 Wiley-Liss, Inc. [source] Effects of weight training on quality of life in recent breast cancer survivorsCANCER, Issue 9 2006The Weight Training for Breast Cancer Survivors (WTBS) study Abstract BACKGROUND Aerobic exercise training has been shown to have beneficial effects on quality of life (QOL) in breast cancer survivors. However, the effects of weight training on psychological benefits are unknown. We sought to examine the effects of weight training on changes in QOL and depressive symptoms in recent breast cancer survivors. METHODS A convenience sample of 86 survivors (4-36 months posttreatment) was randomized into treatment and control groups. The primary outcomes were changes in QOL (CARES short form) and depressive symptoms (CES-D) between baseline and month 6 in this randomized controlled trial. RESULTS Over 6 months the physical global QOL score improved in the treatment group compared with the control group (Standardized Difference = 0.62, P = .006). The psychosocial global score also improved significantly in the treatment group compared with the control group (Standardized Difference = 0.52, P = .02). There were no changes in CES-D scores. Increases in upper body strength were correlated with improvements in physical global score (r = 0.32; P <.01) and psychosocial global score (r = 0.30; P <.01). Increases in lean mass were also correlated with improvements in physical global score (r = 0.23; P <.05) and psychosocial global score (r = 0.24; P <.05). CONCLUSION Twice-weekly weight training for recent breast cancer survivors may result in improved QOL, in part via changes in body composition and strength. Cancer 2006. © 2006 American Cancer Society. [source] Normative dual energy X-ray absorptiometry data in Swedish children and adolescentsACTA PAEDIATRICA, Issue 7 2010Gayani Alwis Abstract Aim:, To present normative dual energy X-ray absorptiometry data in healthy young Swedes. Methods:, Included were 710 girls and 759 boys aged 6,30 years from southern Sweden. Bone mineral content, bone mineral density, bone size, lean body and fat mass were measured by dual energy X-ray absorptiometry in total body, lumbar spine, hip, arms and legs. Results:, Swedish children had similar bone mass to children in the Netherlands but higher than children in Canada and Korea. Height, weight, bone mass, bone size and lean mass increased at a constant rate from age 6 until the rapid increase in all traits at puberty. The pubertal growth spurt started earlier in girls than in boys, while the spurt in boys was larger in magnitude and occurred for a longer period. Around one-quarter of the adult total body and lumbar spine peak bone mineral content was gained during the 2 years with the fastest gain in both genders. Conclusion:, This study presents normative bone mass data in Swedish children, data that are similar to that in Dutch children but higher than in Canadian and Korean children. The gain in Swedish children seems to mimic the gain seen in children in other settings. [source] | |||||||||||||