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1.
There is growing evidence that immune functions are linked to the regulation of body fat. Our studies of knockout mice indicate that both endogenous interleukin (IL)-6 and IL-1 can suppress mature-onset obesity. We now investigated whether four common polymorphisms of the IL6 and IL1 systems are associated with the fat mass measured with dual-energy X-ray absorptiometry (DXA) in elderly men (n = 3,014). The study subjects were from the Swedish part of the MrOS multicenter population study and 69-81 years of age. The IL6 -174 G>C (Minor allele frequency (MAF) = 48%) gene promoter polymorphism was associated with the primary outcome total fat mass (P = 0.006) and regional fat masses, but not with lean body mass. The IL1B -31T>C (MAF = 34%) polymorphism was also associated with total fat (P = 0.007) and regional fat masses, but not lean body mass. The IL-1 receptor antagonist (IL-1ra) gene (IL1RN) +2018 T>C (MAF = 27%) polymorphism (in linkage disequilibrium (LD) with a well-studied variable number tandem repeat of 86 base pair (bp)) and IL1B +3953 C>T (MAF = 26%) polymorphism were not associated with total fat mass. In conclusion, the IL-1 and IL-6 systems, shown to suppress mature-onset obesity in experimental animals, contain gene polymorphisms that are associated with fat, but not lean, mass in elderly men.  相似文献   

2.
Detrimental changes in body composition are often associated with declining levels of testosterone. Here, we evaluated the notion that multipotent mesenchymal stem cells, that give rise to both fat and muscle tissue, can play a significant role to alter existing body composition in the adult. Transgenic mice with targeted androgen receptor (AR) overexpression in stem cells were employed. Wild-type littermate and AR-transgenic male and female mice were gonadectomized and left untreated for 2 months. After the hypogonadal period, mice were then treated with 5α-dihydrotestosterone (DHT) for 6 weeks. After orchidectomy (ORX), wild-type males have reduced lean mass and increased fat mass compared to shams. DHT treatment was beneficial to partially restore body composition. In wild-type females, ovariectomy (OVX) produced a similar change but there was no improvement with DHT. In targeted AR transgenic mice, DHT treatment increased lean and reduced fat mass to sham levels. In contrast to wild-type females, DHT treatment in female transgenic mice significantly ameliorated the increased fat and decreased lean mass changes that result after OVX. Our results show that DHT administration reduces fat mass and increases lean mass in wild-type males but not females, indicating that wild-type females are not as sensitive to androgen treatment. Because both male and female transgenic mice are more responsive than wild-type, results suggest that body composition remains linked to stem cell fate in the adult and that targeted androgen signaling in stem cells can play a significant role to reverse detrimental changes in body composition in both sexes.  相似文献   

3.
Objectives:Youth exercise is associated with improved body composition, but details regarding timing and persistence are limited. We examined pre- and circum-menarcheal organized physical activity exposure (PA) as a factor in development of early post-menarcheal lean mass, fat mass and muscle strength.Methods:Participants in a longitudinal study of musculoskeletal growth using dual energy X-ray absorptiometry (DXA) were included based on: 1) Whole body DXA scans: 0.5-1.5 years pre-menarche, 0.5-1.5 years post-menarche; 2) PA records for ≥6 months preceding the first DXA (PREPA) and for the inter-DXA interval (CIRCUMPA). Dominant arm grip strength and sit-ups tests coincided with DXA scans; PA, height and maturity were recorded semi-annually. Regressions correlated PA with lean mass/fat mass/strength, accounting for maturity, body size, and baseline values.ResultsSeventy girls [baseline: 11.8 yrs (sd 1.0), follow-up: 13.9 years (sd 1.0)] demonstrated circum-menarcheal gains of 25-29% for lean and fat mass and 33% for grip strength. PREPA correlated with pre- and post-menarcheal lean mass, sit-ups and pre-menarcheal fat mass (p<0.05), but not grip strength. CIRCUMPA correlated with only post-menarcheal sub-head lean mass (p=0.03).Conclusions:Lean mass and core strength at 1-year post-menarche were more strongly predicted by pre-menarcheal organized PA than by recent circum-menarcheal PA.  相似文献   

4.
The interaction between age at menopause and postmenopausal body composition development was tested with in 178 Viennese women aged 47 to 68 years (x=55.4 yr). Postmenopausal body composition was described using dual energy x-ray absorptiometry by absolute fat and lean mass and bone mineral content of the whole body, the arms, legs, the trunk and the head. Upper and lower amount of body fat, the fat percentages of the individual body compartments and the fat distribution index were calculated. Postmenopausal body fat and lean soft tissue mass and postmenopausal bone mineral content were significantly associated with the age at menopause. Women whose menopause occurred late showed the highest amount of body fat (31.2+/−7.7kg) and lean body mass (41.2+/−4.4 kg) postmenopausally, while women with an early menopause exhibited the lowest amount of body fat (27.5+/−8.9kg) and lean body mass (38.4+/−5.4 kg) during the postreproductive phase of life (p<0.05). Women whose menopause occurred later than 51 had a significant higher postmenopausal bone mass (2.26+/−0.9kg versus 2.09+/−0.3 kg; p<0.05). A late menopause was associated with a significantly higher value in fat mass, lean body mass and in bone mineral content. Therefore age at menopause may be assumed as an indicator for body fat and bone mineral content during postmenopause and postmenopausal fat distribution patterns.  相似文献   

5.
To examine the associations between birth weight and BMI, and total body composition, in overweight Latino adolescents. Two hundred and forty-two overweight Latino children (baseline age = 11.1 +/- 1.7 years; BMI >or= 85th percentile) were measured annually for up to 6 years (2.6 +/- 1.4 observations/child, total 848 visits). Birth weight and history of gestational diabetes were obtained by parental interview. Visceral fat and subcutaneous abdominal fat were assessed by magnetic resonance imaging, while total body fat, total lean tissue mass (LTM), trunk fat, and lean tissue trunk mass were measured by dual-energy X-ray absorptiometry. BMI and BMI percentile were calculated using the Centers for Disease Control and Prevention age appropriate cutoffs. Longitudinal linear mixed effects (LME) modeling was used to evaluate the influence of birth weight on subsequent changes in body composition and distribution of fat across puberty. Birth weight significantly predicted BMI (P < 0.001), total trunk fat (P < 0.001), total trunk LTM (P < 0.001), total fat mass (FM) (P < 0.001), and total LTM (P < 0.001), but not subcutaneous (P = 0.534) or visceral fat (P = 0.593) at age 11 years. Longitudinally, as participants transitioned into puberty, birth weight did not significantly predict any of the body composition or fat distribution measures (P > 0.05). Birth weight is significantly associated with increased adiposity and LTM and negatively associated with trunk fat mass and trunk lean mass at baseline; however these relationships did not predict rate of change of any of the variables as the children progress through adolescence.  相似文献   

6.
In the present study the menarcheal status (pre-or postmenarcheal), body composition, weight status, and socioeconomic parameters such as type of school and parental educational level as of 1752 female adolescents ageing between 12 and 18 years (x = 14.6) from rural areas of Eastern Austria were documented. Furthermore the association patterns between body composition, socioeconomic parameters and menarcheal status were analyzed. It turned out, that body composition parameters such as BMI, lean body mass and absolute and relative fat mass were significantly associated with menarcheal status. Postmenarcheal girls were taller and exhibited a higher weight status, a higher absolute and relative amount of fat mass and a higher amount of lean body mass than their premenarcheal counterparts of the same age. In contrast to the significant association between body composition and menarcheal status, no significant impact of educational level on menarcheal status, indicating socioeconomic status could be documented.  相似文献   

7.
Objective: To determine the changes in body composition (fat and lean mass) occurring in children during adiposity rebound (AR). Research Methods and Procedures: Thirty‐nine girls, 3 to 6 years of age at baseline, underwent yearly DXA scans for 2 years. An additional DXA scan was obtained 4 to 5 years after baseline. Age at AR was determined by modeling, and the velocity of change in height, weight, fat mass, and lean mass was estimated for each child using random coefficient models. Girls with an AR <5 years of age were classified as having an early AR, and those having an AR ≥5 years were classified as late AR. Results: Although body composition was similar at age 5, by age 9, girls with an early AR were significantly taller (3.5% more) and heavier (14.4%), with greater fat mass (50%) and percentage body fat (27%) than girls with a later AR. In addition, more girls were overweight according to BMI (18% vs. 6%) or percentage body fat (29% vs. 11%) at this time, despite no differences at baseline. Annual velocity of fat mass gain was over 2‐fold higher in early compared with late rebounders (17.1% vs. 6.5%, p < 0.0001), with no difference in lean mass velocity (13.1% vs. 12.5%, p = 0.116). Discussion: Differences in BMI during AR were caused specifically by alterations in body fat and not by alterations in lean mass or height. Children undergoing early AR gained fat at a faster rate than children who rebounded at a later age.  相似文献   

8.
The objective of this study was to determine whether noninvasive morphometric measurements of olive baboons (Papio cynocephalus anubis) can reliably predict lean body mass and fat mass in this species. Crown-rump length, triceps circumference, and skinfold measures at the neck, subscapular, suprailiac, and triceps sites were obtained prior to necropsy from 21 clinically normal infant baboons at 18 weeks of age and from 22 clinically normal adolescent baboons at 5 years of age. At necropsy, the lean body mass and body fat mass were measured using gravimetric methods. Pearson's correlations and regression analysis were used to test the relationship between direct measures of lean and fat mass obtained at necropsy with calculated estimates based on morphometric measures obtained prior to death. Our null hypothesis was that the morphometric measures (individually or in combination) were not related to direct measures of fat mass or lean mass. Non-linear and multiple regression estimators, by age and gender, were derived and provided increased predictability. Our results indicate that (1) morphometric measures can accurately predict lean body mass in male and female baboons; (2) morphometric measures used to predict lean body mass change with age; (3) morphometric measures are strongly associated with body fat mass at 18 weeks of age but are not as strongly associated with body fat mass in 5-year-old baboons; (4) triceps circumference provides the best single indicator of lean body mass for both genders and age periods; (5) baboons are like humans in that adolescent females tend to accumulate body fat while males of the same age tend to develop lean mass; and (6) combinations of these morphometric measurements explain between 70% and 100% of the variability and can be used to estimate lean and fat mass in baboons.  相似文献   

9.
Based on the data of 203 male and 179 female schoolchildren from Eastern Austria (Burgenland), aged between 6 and 10 years, sex typical differences in body composition (absolute and relative body fat, lean body mass) and weight status were analyzed. Body composition analyses were carried out by means of BIA method, weight status was estimated using BMI percentiles (BMI > 90th percentile defined overweight, BMI > 97th percentile defined obesity). Statistically significant sex differences were found for all body composition parameters, girls exhibited a significantly higher amount of absolute and relative body fat, whereas their male counterparts exhibited a significantly higher amount of lean body mass. Regarding weight status, no statistically significant sex differences were observable, however, a higher amount of girls could be classified as overweight or obese. Evolutionary and sociocultural explanations for these observations are discussed.  相似文献   

10.
The present study focuses on the impact of age at menarche on body composition development during adulthood. With 459 healthy middle-class women between 18 and 67 years (x = 41.5) the association between age at menarche and body composition was tested. Body composition, described by absolute and relative amount of fat mass, lean body mass, and bone mass, was estimated by means of dual energy x-ray absorptiometry. In order to exclude the influence of the menopausal transition on body composition, pre- and postmenopausal females were examined separately. The absolute amount of body fat was significantly lower within the group of women whose menarche occurred later. However, postmenopausal females exhibit less significant relations between the two trait systems than premenopausal women. This may be due to the impact of menopausal transition which affected the hormone levels and body composition development independently from the adolescent hormonal transition. While in both proband groups the quantitative amount of body fat was significantly related to menarcheal age, a significant relation between menarcheal age and adult body fat distribution could not be verified. Am J Phys Anthropol 105:9–20, 1998. © 1998 Wiley-Liss, Inc.  相似文献   

11.
The aim of this study is to investigate the relationship between sleep duration and body composition and to estimate the genetic contribution of sleep duration and body composition in a Chinese twin population. This cross-sectional analysis included 738 men and 511 women aged 21-72 year. Anthropometric and dual-energy X-ray absorptiometry (DXA) measures of body composition were used. Sleep duration was obtained from a standard sleep questionnaire. Multiple regression models were used to examine the association between sleep duration and body composition measures. Structural equation modeling was used to assess the heritability of sleep duration and body composition. Compared with individuals in the 2nd and 3rd age-specific quartiles of sleep duration (reference group), shorter (1st quartile) sleep duration among women but not men was associated with higher z-scores (0.248-0.317) for all adiposity measures--BMI, fat mass index (FMI), percent body fat mass (%BF), and percent trunk fat mass (%TF), P < 0.05 for each--and with 0.306 lower z-scores for percent body lean mass (%LM) and 0.353 lower lean/fat mass ratio (LFR), P < 0.01 for each. The heritability of sleep duration was 0.27 in men and 0.29 in women, while the heritability of body composition was as high as 0.56-0.73 after adjustment for age in both genders. Short sleep duration was associated with increased body fat and decreased lean body mass in women but not in men. Sleep duration was largely influenced by environmental factors while adiposity measures were mainly influenced by genetic factors.  相似文献   

12.
Dietary interventions that reduce accumulation of body fat are of great interest. Consumption of viscous dietary fibers cause well-known positive metabolic effects, such as reductions in the postprandial glucose and insulin concentrations. However, their effect on body composition and fuel utilization has not been previously studied. To examine this, rats were fed a viscous nonfermentable dietary fiber, hydroxypropyl methylcellulose (HPMC), for 6 weeks. Body composition was measured by dual-energy X-ray absorptiometry (DXA) and fat pad weight. Plasma adipokines, AMP kinase activation, and enzyme and mRNA analysis of key regulators of energetics in liver and soleus muscle were measured. The HPMC diet significantly lowered percent body fat mass and increased percent lean body mass, compared to a cellulose-containing diet (no viscosity). Fasting leptin was reduced 42% and resistin 28% in the HPMC group compared to the cellulose group. Rats fed HPMC had greater activation of AMP kinase in liver and muscle and lower phosphoenolpyruvate carboxykinase (PEPCK) expression in liver. mRNA expression in skeletal muscle was significantly increased for carnitine palmitoyltransferase 1B (CPT-1B), PPARγ coactivator 1α, PPARδ and uncoupling protein 3 (UCP3), as was citrate synthase (CS) activity, in the HPMC group relative to the cellulose group. These results indicate that viscous dietary fiber preserves lean body mass and reduces adiposity, possibly by increasing mitochondrial biogenesis and fatty acid oxidation in skeletal muscle, and thus represents a metabolic effect of viscous fiber not previously described. Thus, viscous dietary fiber may be a useful dietary component to assist in reduction of body fat.  相似文献   

13.
本项目采用人体测量法,测量了976名(男性528人,女性448人)湖南土家族成人的身高、体质量以及肱三头肌、肩胛下、髂前上和小腿内侧皮褶的厚度,并根据公式计算体密度、体脂率、脂肪质量、脂肪质量指数、瘦体质量和瘦体质量指数。结果显示随年龄增长,小腿内侧皮褶厚度值逐渐减小,肱三头肌、肩胛下和髂前上棘皮褶以及体脂率、脂肪质量、瘦体质量、体质量指数、脂肪质量指数和瘦体质量指数值先增大后减小,体密度值先减小后增大;各年龄组中体密度、瘦体质量及其指数值女性明显低于男性,4项皮褶厚度值以及体脂率、脂肪质量及其指数值女性高于男性;与布朗族等24个族群比较,湖南土家族成人皮褶厚度处于中等水平,与门巴族、珞巴族、僜人、彝族等族群的亲缘关系较近。  相似文献   

14.
The purpose of this investigation was to explore the relationship between velocity of lactate threshold (vLT) and various measures of body mass and composition: mass, lean mass, fat mass, percent body fat (% fat), and body surface area (BSA). We hypothesized that mass would be inversely related to vLT, and that differences in measures of body mass and composition would account for a significant amount of variability in vLT. A total of 21 healthy male runners served as subjects. Body composition was assessed by hydrostatic weighing. A significant negative relationship (r = -0.759, p < or = 0.01) was between body mass and vLT. The coefficient of determination between vLT and body mass indicated that nearly 58% of the variability in vLT was explained by body mass in these subjects. Significant relationships were also between vLT and BSA (r = -0.72, p < or = 0.01), fat mass (r = -0.70, p < or = 0.01), % fat (r = -0.59, p < or = 0.01), and lean mass (r = -0.41, p < or = 0.05). Linear regression yielded the following model: y = 369.48 - 1.7343 (X), where y = predicted vLT (m.min(-1)) and X = body mass (kilograms) (SEE = 15.45). Velocity of lactate threshold was significantly inversely related with body mass in a group of male runners. The calculated coefficient of determination suggests that nearly 58% of the variability in vLT was explained by body mass. The present data suggest consideration of categorizing participants in 'road runs' by body mass to equate competition, as is done in other sports (e.g., weightlifting).  相似文献   

15.
ABSTRACT The ability to measure body composition is critical for studying the physiological ecology of animals. This is particularly true for small mammals that have a high metabolic rate. We evaluated a nondestructive method of body composition analysis that would allow accurate assessment of body fat, body water, and lean mass. We used total body electrical conductivity (TOBEC) to estimate body composition in the little brown myotis (Myotis lucifugus). In a sample of 46 individuals, TOBEC was both accurate and precise in estimating total body water and lean mass but was less effective at estimating total body fat. Mass-independent or whole-body compartments (i.e., total body water, total body fat, lean dry mass, and lean body mass) were more accurately estimated than mass-dependent or mass-specific body composition compartments (i.e., water content, fat index, and % lean dry mass). The TOBEC measurements we made using an SA-3000 analyzer were influenced by extremes in body temperature, as well as by aluminum and incoloy wing bands. Our study also presents a new method of restraint especially suited for small mammals and birds that increases precision of TOBEC measurements. This study shows that TOBEC is a potentially valuable tool for studying changes in body composition of small mammals and may provide insight into the physiological impacts of various life history stages such as postnatal growth, reproduction, and hibernation.  相似文献   

16.
Body composition was measured in male American kestrels (Falco sparverius) beginning after a 77-day exposure to 0, 6, or 12 ppm (dry wt.) selenium as seleno-L-methionine in their diet. Total body mass, lean body mass, and body fat were compared among groups to identify potential wasting effects of selenium, as had been reported for wild waterfowl from a selenium-contaminated site. On the last day of selenium treatment, selenium concentrations in the blood of kestrels was significantly negatively correlated with lean mass. Kestrels that had been exposed to 12 ppm selenium in the diet exhibited relatively higher lean mass (relative to total body mass) and lower normalized body fat than kestrels fed 0 or 6 ppm dietary selenium. These differences persisted throughout the 6 mo study period. The effect observed on body condition of kestrels at environmentally relevant exposure levels has implications for wild birds with respect to both overwinter survival and reproductive success.  相似文献   

17.
Data are lacking regarding regional morphological changes among women after prolonged physical training. This study employed dual-energy X-ray absorptiometry to assess changes in whole body and regional (i.e., trunk, legs, arms) fat mass, lean mass, and bone mineral content body composition adaptations in 31 healthy women pre-, mid-, and post-6 mo of periodized physical training. These results were compared with those of 1) a control group of women who had not undergone the training program and were assessed pre- and post-6 mo and 2) a group of 18 men that was tested only once. Additionally, magnetic resonance imaging was used to assess changes in muscle morphology of the thigh in a subset of 11 members of the training group. Physical training consisted of a combination of aerobic and resistance exercise in which the subjects engaged for 5 days/wk for 24 wk. Overall, the training group experienced a 2.2% decrease, a 10% decrease, and a 2.2% increase for body mass, fat mass, and soft tissue lean mass, respectively. No changes in bone mineral content were detected. The women had less of their soft tissue lean mass distributed in their arms than did the men, both before and after the women were trained. Novel to this study were the striking differences in the responses in the tissue composition of the arms (31% loss in fat mass but no change in lean mass) compared with the legs (5.5% gain in lean mass but no change in fat mass). There was a 12% fat loss in the trunk with no change in soft tissue lean mass. Dual-energy X-ray absorptiometry and magnetic resonance imaging fat mass measurements showed good agreement (r = 0. 72-0.92); their lean mass measurements were similar as well, showing approximately 5.5% increases in leg lean tissue. These findings show the importance of considering regional body composition changes, rather than whole body changes alone when assessing the effects of a periodized physical training program.  相似文献   

18.
Computed tomography (CT) scans were taken of 21 middle-aged men (mean age 46.3 years) and 20 older men (mean age 69.4 years) to measure differences in body composition with age. Overall, the older men weighed 8.2 kg less than the middle-aged men, and this difference was primarily the result of their having less lean tissue. Although fat mass (by whole body potassium counting) was only slightly less in older men, there were distributional differences in fat between the age groups. Total abdomen adipose tissue area (from CT) was similar in both groups, although the subcutaneous portion of the abdomen adipose tissue was less in the older men, and they had correspondingly more adipose tissue within the abdominal cavity. Muscle areas of the leg and arm were significantly less in the older men, as were all lean tissues of the abdomen and chest. When these data were corrected for differences in body weight with age, the results were still significant, suggesting a centripetalization and internalization of fat with age. Causes of this apparent fat redistribution and decrease of lean tissue with age were not revealed by this study and are presently unknown.  相似文献   

19.
Objective: To characterize the body composition of Prader‐Willi syndrome (PWS) subjects and compare with simple obesity. Research Methods and Procedures: Seventy‐two individuals (27 PWS deletion, 21 PWS uniparental disomy, and 24 obese controls) 10 to 49 years old were studied with the use of DXA. Body composition measures were obtained, and regional fat and lean mass patterns were characterized. Significant differences were assessed with Student's t test and ANOVA adjusting for age, gender, and BMI. Results: Significant differences between the PWS and obese groups were found for lean measures of the arms, legs, and trunk. Total lean mass was significantly lower in PWS than in obese subjects for arms, trunk, and especially legs. Furthermore, two body regions (legs and trunk) showed significant differences for fat and lean measures between PWS and obese males. However, significant differences between PWS and obese females for these measures were found only for the legs. No significant differences were identified between PWS deletion and uniparental disomy subjects. Discussion: Our results demonstrate that PWS individuals do, in fact, have an unusual body composition and fatness patterns, characterized by reduced lean tissue and increased adiposity, with PWS males contributing most with fat patterns more similar to females.  相似文献   

20.
In this study, the authors investigated the physiologic effects of the altered body composition that results from surgical removal of large amounts of subcutaneous adipose tissue. Fourteen women with body mass indexes of greater than > 27 kg/m2 underwent measurements of fasting plasma insulin, triglycerides, cholesterol, body composition by dual-energy x-ray absorptiometry (DXA), resting energy expenditure, and blood pressure before and after undergoing large-volume ultrasound-assisted liposuction.There were no significant intraoperative complications. Body weight had decreased by 5.1 kg (p < 0.0001) by 6 weeks after liposuction, with an additional 1.3-kg weight loss (p < 0.05) observed between 6 weeks and 4 months after surgery, for a total weight loss of 6.5 kg (p < 0.00006). Body mass index decreased from (mean +/- SEM) 28.8 +/- 2.3 to 26.8 +/- 1.5 kg/m2 (p < 0.0001). This change in body weight was primarily the result of decreases in body fat mass: as assessed by DXA, lean body mass did not change (43.8 +/- 3.1 kg to 43.4 +/- 3.6 kg, p = 0.80), whereas DXA total body fat mass decreased from 35.7 +/- 6.3 to 30.1 +/- 6.5 kg (p < 0.0001). There were significant decreases in fasting plasma insulin levels (14.9 +/- 6.5 mIU/ml before liposuction versus 7.2 +/- 3.2 mIU/ml 4 months after liposuction, p < 0.007), and systolic blood pressure (132.1 +/- 7.2 versus 120.5 +/- 7.8 mmHg, p < 0.0002). Total cholesterol, high-density lipoprotein cholesterol, plasma triglycerides, and resting energy expenditure values were not significantly altered after liposuction.In conclusion, over a 4-month period, large-volume liposuction decreased weight, body fat mass, systolic blood pressure, and fasting insulin levels without detrimental effects on lean body mass, bone mass, resting energy expenditure, or lipid profiles. Should these improvements be maintained over time, liposuction may prove to be a valuable tool for reducing the comorbid conditions associated with obesity.  相似文献   

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