Sarcopenia and increased adipose tissue infiltration of muscle in elderly African American women

BACKGROUND: Aging is associated with metabolic, physiologic, and functional impairments, in part through age-related changes in body composition. During the later adult years, skeletal muscle mass decreases and body fat becomes centralized. OBJECTIVE: The goal of the study was to investigate body composition over time ( +/- SD: 2.04 +/- 0.6 y) in healthy, ambulatory, elderly African American women. The hypothesis that a reduction in total-body skeletal muscle (SM) and increases in visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and intermuscular adipose tissue (IMAT) are ongoing in healthy, weight-stable elderly was tested. DESIGN: The study was a longitudinal evaluation of 26 women (age at baseline: 75.5 +/- 5.1 y) with a body mass index (in kg/m(2)) of 27.0 +/- 4.0. Body composition was measured by using whole-body magnetic resonance imaging for the quantification of SM, total adipose tissue (TAT), VAT, SAT, and IMAT. RESULTS: SM (P < 0.001) and bone (P < 0.05) masses decreased, and regional analyses showed a decrease in dual-energy X-ray absorptiometry-derived leg SM (P < 0.05). VAT (P = 0.011) and IMAT (P < 0.001) increased. No changes occurred in TAT (P = 0.45), SAT (P = 0.96), physical function, or food intake. CONCLUSION: These data show an age-related remodeling of body composition with reductions in SM and corresponding increases in VAT and IMAT. Changes in the previously unstudied depot of IMAT may be involved in the deterioration of metabolic values frequently observed during aging.     

Postmenopausal hormone therapy and body composition--a substudy of the estrogen plus progestin trial of the Women's Health Initiative

BACKGROUND: It has been suggested that hormone therapy may help counter undesirable changes in body composition in older women. OBJECTIVE: This study was designed to test whether estrogen plus progestin (E+P) therapy favorably affects age-related changes in body composition in postmenopausal women. DESIGN: The substudy was composed of 835 women from the estrogen plus progestin trial of the Women's Health Initiative who were randomly assigned to receive either E+P therapy (n = 437) or placebo (n = 398). The women had a mean age of 63.1 y and, on average, were 13.8 y past menopause. More than 17% of the participants were from an ethnic minority. No significant differences in baseline body composition (measured with dual-energy X-ray absorptiometry) by intervention assignment were observed. RESULTS: After 3 y of intervention, the women who received active E+P therapy lost less lean soft tissue mass (-0.04 kg) than did the women who received placebo (-0.44 kg; P = 0.001). Additionally, the women in the E+P group had less upper-body fat distribution than did the women in the placebo group (change in ratio of trunk to leg fat mass: -0.025 for the E+P group and 0.004 for the placebo group; P = 0.003). A sensitivity analysis, which was conducted on the women who took > or = 80% of the study medication during the intervention period, corroborated the findings from the intent-to-treat analysis. CONCLUSIONS: A 3-y E+P intervention significantly reduced both the loss of lean soft tissue mass and the ratio of trunk to leg fat mass in postmenopausal women. However, the effect sizes were small, and whether these changes in body composition lead to significant health benefits remains to be confirmed.     

Age, sex, ethnicity, body composition, and resting energy expenditure of obese African American and white children and adolescents

BACKGROUND: African Americans may have a lower resting energy expenditure (REE) than do whites, although the data are limited for obese children and adolescents and for boys. Differences in bone density and trunk lean body mass may account for some of these measured differences in REE. OBJECTIVE: We assessed the REE and body composition of obese African American and white children and adolescents. DESIGN: Obese, 5-17-y-old children and adolescents were evaluated (n = 203). Body composition was assessed by dual-energy X-ray absorptiometry. REE was measured by open-circuit calorimetry. African American and white children were compared. The relation between REE and the independent variables (age, sex, ethnic group, fat mass, and fat-free mass or lean tissue mass) was assessed. RESULTS: Of those evaluated, 66% were girls and 34% were African American. Age, sex, pubertal status, and body composition did not differ significantly by ethnic group. All the independent variables were significantly associated with REE. Using lean tissue mass to account for differences in bone density did not significantly alter the results. REE decreased with age and was lower in the girls than in the boys and in the African Americans than in the whites. When trunk fat-free mass was included in the model in place of whole-body fat-free mass, the ethnic difference in REE decreased. CONCLUSIONS: Adjustment for trunk lean tissue mass partially explains the lower REE of obese African American children and adolescents. The lower relative REE of older obese children suggests the importance of early intervention in the prevention of childhood obesity. The lower REE of girls and of African Americans may contribute to the difficulty in weight management in these groups.     

Regional changes in body composition by time of year in healthy postmenopausal women.

We examined regional changes in fat, lean, and bone tissue for greater than 1 y in 125 postmenopausal women. Duplicate whole-body scans were performed at 6-mo intervals. Period 1 was June or July to December or January and period 2 was December or January to the following June or July. Lean and bone tissue mass in the arms, legs, trunk, and whole body increased in period 1 and decreased in period 2 [eg, lean tissue in legs increased 1.84 +/- 0.41% (mean +/- SE) in period 1 and decreased 2.84 +/- 0.39% in period 2, P less than 0.001]. In each region except the arms, fat tissue decreased in period 1 and increased in period 2. Quadriceps muscle strength was correlated with lean tissue mass of the legs [rp (controlled for height) = 0.24, P V 0.02] and physical activity was correlated with quadriceps strength. Overall, body weight did not change significantly (0.17 +/- 0.41% increase, P greater than 0.20); however, there was a net loss of 1.08 +/- 0.39% (P less than 0.01) in lean tissue in the legs and a net increase of 3.43 +/- 1.12% (P less than 0.01) in fat tissue in the trunk.     

Obesity and sarcopenia after menopause are reversed by sex hormone replacement therapy

OBJECTIVE: Menopause is linked to an increase in fat mass and a decrease in lean mass exceeding age-related changes, possibly related to reduced output of ovarian steroids. In this study we examined the effect of combined postmenopausal hormone replacement therapy (HRT) on the total and regional distribution of fat and lean body mass. RESEARCH METHODS AND PROCEDURES: Sixteen healthy postmenopausal women (age: 55 +/- 3 years) were studied in a placebo-controlled, crossover study and were randomized to 17beta estradiol plus cyclic norethisterone acetate (HRT) or placebo in two 12-week periods separated by a 3-month washout. Total and regional body composition was measured by DXA at baseline and in the 10th treatment week in both periods. Changes were compared by a paired Student's t test. RESULTS: The change in body weight during HRT was equal to the change during placebo (-24.6 g vs. -164 g, p = 0.42), but relative fat mass was significantly reduced (-0.5% vs. +1.24%, p < 0.01). During HRT, compared with during placebo, lean body mass increased (+347 g vs. -996 g, p < 0.01) and total fat mass decreased (-400 g vs. +836 g, p = 0.06). Total bone mineral content increased (+28.9 g vs. -4.4 g, p = 0.04) and abdominal fat decreased (-185 g vs. +253 g, p = 0.04) during HRT compared with placebo. DISCUSSION: HRT is linked to the reversal of both menopause-related obesity and loss of lean mass, without overall change in body weight. The increase in lean body mass during HRT is likely explained by muscle anabolism, which in turn, prevents disease in the elderly.     

Effects of birth cohort and age on body composition in a sample of community-based elderly

BACKGROUND: The effect of the recent obesity epidemic on body composition remains unknown. Furthermore, age-related changes in body composition are still unclear. OBJECTIVE: The objective was to simultaneously examine the effects of birth cohort and age on body composition. DESIGN: A total of 1786 well-functioning, community-based whites and blacks (52% women and 35% blacks) aged 70-79 y from the Health, Aging, and Body Composition Study underwent dual-energy X-ray absorptiometry annually from 1997 to 2003. RESULTS: At baseline, mean +/- SD percentage body fat, fat mass, and lean mass (bone-free) were 28 +/- 5%, 24 +/- 7 kg, and 56 +/- 7 kg, respectively, for men and 39 +/- 6%, 28 +/- 9 kg, and 40 +/- 6 kg for women. Mixed models were used to assess the effects of cohort and age-related changes on body composition. Later cohorts in men had a greater percentage body fat (0.32% per birth year, P < 0.0001) than did earlier cohorts. This cohort effect was due to a greater increase in fat mass than in lean mass (0.45 kg and 0.17 kg/birth year, respectively). With increasing age, percentage body fat in men initially increased and then leveled off. This age-related change was due to an accelerated decrease in lean mass and an initial increase and a later decrease in fat mass. Similar but less extreme effects of cohort and age were observed in women. CONCLUSIONS: The combination of effects of both birth cohort and age leads to bigger body size and less lean mass in the elderly.     

Racial differences in energy expenditure and aerobic fitness in premenopausal women

BACKGROUND: Aerobic fitness, or maximal oxygen uptake (f1.gif" BORDER="0">O(2)max), and energy expenditure (EE) may be lower in African Americans than in whites. OBJECTIVE: The objective of this study was to compare sleeping EE (SEE), resting EE (REE), free-living total EE (TEE), and f1.gif" BORDER="0">O(2)max in African American and white women after adjustment for body composition and free-living activity-related energy expenditure (AEE). DESIGN: Eighteen African American and 17 white premenopausal women were matched for weight, percentage body fat, and age. SEE and REE were measured in a room calorimeter and f1.gif" BORDER="0">O(2)max was measured on a treadmill. Fat-free mass (FFM) and fat mass (FM) (4-compartment model), AEE (doubly labeled water and SEE), and regional lean tissue (dual-energy X-ray absorptiometry) were used as adjustment variables in SEE, REE, TEE, and f1.gif" BORDER="0">O(2)max comparisons. RESULTS: The African American women had significantly more limb lean tissue and significantly less trunk lean tissue than did the white women. The African American women also had significantly lower SEE (6.9%), REE (7.5%), TEE (9.6%), and f1.gif" BORDER="0">O(2)max (13.4%) than did the white women. Racial differences persisted after adjustment for f1.gif" BORDER="0">O(2)max, AEE, FFM, and limb lean tissue but disappeared after adjustment for trunk lean tissue. The f1.gif" BORDER="0">O(2)max difference was independent of all body-composition variables and of AEE. CONCLUSIONS: African American women had lower aerobic fitness than did white women, independent of differences in lean tissue or AEE. Diminished racial differences in SEE, REE, and TEE after adjustment for trunk lean tissue suggest that low EE in African American women is mediated by low volumes of metabolically active organ mass.     

Body composition studies in patients with wasting associated with tuberculosis

OBJECTIVE: Wasting is a well-recognized manifestation of tuberculosis (TB), but little is known about the alterations in body composition that occur. Therefore, we measured regional and whole-body composition in patients with TB and wasting. METHODS: Body composition was measured by dual-energy x-ray absorptiometry in 18 patients with newly diagnosed TB and wasting (10 coinfected with human immunodeficiency virus [HIV]) and 22 controls (10 coinfected with HIV). RESULTS: Patients with TB and wasting had significantly lower body weight (48.6 versus 62.0 kg), lean body mass (39.6 versus 45.6 kg), and fat mass (6.2 versus 12.6 kg) than did controls. Patients with TB had significantly reduced lean tissue in the limbs (15.2 versus 19.1 kg) and trunk (21.3 versus 23.2 kg) and significantly higher trunk-to-limb lean ratio (1.41 versus 1.22) compared with controls. Patients with TB had significantly reduced fat in the limbs (3.4 versus 6.1 kg) and trunk (2.1 versus 5.7 kg) and significantly lower trunk-to-limb fat ratio (0.52 versus 0.92) compared with controls. Body composition measurements were no different in patients with and without HIV coinfection. CONCLUSIONS: Wasting in TB is associated with depletion of whole-body lean and fat tissue in approximately equal proportions overall, but lean tissue depletion is greater in the limbs and fat tissue depletion is greater in the trunk. HIV coinfection does not affect the magnitude or distribution of the body composition changes.     

Comparison of energy-restricted very low-carbohydrate and low-fat diets on weight loss and body composition in overweight men and women

OBJECTIVE: To compare the effects of isocaloric, energy-restricted very low-carbohydrate ketogenic (VLCK) and low-fat (LF) diets on weight loss, body composition, trunk fat mass, and resting energy expenditure (REE) in overweight/obese men and women. DESIGN: Randomized, balanced, two diet period clinical intervention study. Subjects were prescribed two energy-restricted (-500 kcal/day) diets: a VLCK diet with a goal to decrease carbohydrate levels below 10% of energy and induce ketosis and a LF diet with a goal similar to national recommendations (%carbohydrate:fat:protein = ~60:25:15%). SUBJECTS: 15 healthy, overweight/obese men (mean +/- s.e.m.: age 33.2 +/- 2.9 y, body mass 109.1 +/- 4.6 kg, body mass index 34.1 +/- 1.1 kg/m2) and 13 premenopausal women (age 34.0 +/- 2.4 y, body mass 76.3 +/- 3.6 kg, body mass index 29.6 +/- 1.1 kg/m2). MEASUREMENTS: Weight loss, body composition, trunk fat (by dual-energy X-ray absorptiometry), and resting energy expenditure (REE) were determined at baseline and after each diet intervention. Data were analyzed for between group differences considering the first diet phase only and within group differences considering the response to both diets within each person. RESULTS: Actual nutrient intakes from food records during the VLCK (%carbohydrate:fat:protein = ~9:63:28%) and the LF (~58:22:20%) were significantly different. Dietary energy was restricted, but was slightly higher during the VLCK (1855 kcal/day) compared to the LF (1562 kcal/day) diet for men. Both between and within group comparisons revealed a distinct advantage of a VLCK over a LF diet for weight loss, total fat loss, and trunk fat loss for men (despite significantly greater energy intake). The majority of women also responded more favorably to the VLCK diet, especially in terms of trunk fat loss. The greater reduction in trunk fat was not merely due to the greater total fat loss, because the ratio of trunk fat/total fat was also significantly reduced during the VLCK diet in men and women. Absolute REE (kcal/day) was decreased with both diets as expected, but REE expressed relative to body mass (kcal/kg), was better maintained on the VLCK diet for men only. Individual responses clearly show the majority of men and women experience greater weight and fat loss on a VLCK than a LF diet. CONCLUSION: This study shows a clear benefit of a VLCK over LF diet for short-term body weight and fat loss, especially in men. A preferential loss of fat in the trunk region with a VLCK diet is novel and potentially clinically significant but requires further validation. These data provide additional support for the concept of metabolic advantage with diets representing extremes in macronutrient distribution.     

Impact of age on leptin and adiponectin independent of adiposity

Age-related changes in leptin and adiponectin levels remain controversial, being affected by inconsistent normalisation for adiposity and body fat distribution in the literature. In a cross-sectional study on 210 Caucasians (127 women, eighty-three men, 18-78 years, BMI 16.8-46.8 kg/m2), we investigated the effect of age on adipokine levels independent of fat mass (FM measured by densitometry), visceral and subcutaneous adipose tissue volumes (VAT and SAT assessed by whole-body MRI). Adiponectin levels increased with age in both sexes, whereas leptin levels decreased with age in women only. There was an age-related increase in VAT (as a percentage of total adipose tissue, VAT%TAT), associated with a decrease in SAT(legs)%TAT. Adiposity was the main predictor of leptin levels, with 75.1 % of the variance explained by %FM in women and 76.6 % in men. Independent of adiposity, age had a minor contribution to the variance in leptin levels (5.2 % in women only). The variance in adiponectin levels explained by age was 14.1 % in women and 5.1 % in men. In addition, independent and inverse contributions to the variance in adiponectin levels were found for truncal SAT (explaining additional 3.0 % in women and 9.1 % in men) and VAT%TAT (explaining additional 13.0 % in men). In conclusion, age-related changes in leptin and adiponectin levels are opposite to each other and partly independent of adiposity and body fat distribution. Normalisation for adiposity but not for body fat distribution is required for leptin. Adiponectin levels are adversely affected by subcutaneous and visceral trunk fat.     

Effect of highly active antiretroviral therapy on fat, lean, and bone mass in HIV-seropositive men and women.

BACKGROUND: Alterations in body composition have been reported in HIV-positive adults receiving highly active antiretroviral therapy (HAART), but the magnitude and potential determinants of these changes are unclear. OBJECTIVE: We compared total and regional body composition, as measured by dual-energy X-ray absorptiometry, in 203 HIV-positive men and 62 HIV-positive women according to HAART. DESIGN: This was a cross-sectional analysis of a cohort study of nutrition and HIV infection. RESULTS: After adjustment for age, weight, race, and exercise habits, total weight and fat mass did not differ significantly in men or women by HAART. Trunk fat was greater in men (1.0 kg; P < 0.001) and women (1.4 kg; P = 0.005) and leg fat was lower in men (-1.0 kg; P < 0.001) and women (-1.5 kg, P = 0.005) receiving HAART than in those not. This corresponded to a greater percentage of total fat mass located in the trunk (men: 7.5%, P < 0.001; women: 5.1%, P = 0.02). Lean mass was also greater with longer duration of HAART in men (P < 0.002). In men receiving HAART, total and regional bone mineral content were less than in the men not receiving HAART (P < 0.001). These effects increased with longer duration of HAART. Protease inhibitors were associated with the largest differences in regional fat. CONCLUSIONS: HAART is associated with redistribution of fat mass from the legs to the trunk, despite no significant differences in total fat mass or weight. In men, HAART is also associated with a reduction in bone mineral content, suggesting that HAART increases the risk of central obesity and osteoporosis.     

Dietary restriction and walking reduce fat deposition in the midthigh in obese older women

BACKGROUND: It is suggested that fat deposition within midthigh muscle, represented by low-density lean tissue, increases with deconditioning and obesity and is associated with risk factors for cardiovascular disease (CVD) in women. OBJECTIVE: We determined the effects of a 6-mo weight loss and walking (3 times/wk) program (WL+AEX) on midthigh low-density lean tissue and glucose and lipid metabolism in 24 sedentary, obese [body mass index (kg/m(2)): 32 +/- 1 (mean +/- SEM)] postmenopausal women aged 58 +/- 1 y. DESIGN: Total body fat and fat-free mass were measured by using dual-energy X-ray absorptiometry. Intraabdominal fat (IAF), subcutaneous abdominal fat (SAF), midthigh fat, midthigh muscle, and midthigh low-density lean tissue areas were measured by using computed tomography. Glucose and insulin responses were determined with a 3-h oral-glucose-tolerance test. RESULTS: Body weight decreased 8% (P: < 0.001) and maximal aerobic capacity increased 8% (P: < 0.001) with the weight loss and walking program. Total body fat decreased by 15% (P: < 0.001) whereas fat-free mass did not change. IAF and SAF decreased by 18% and 16%, respectively (P: < 0. 001). Midthigh fat and midthigh low-density lean tissue decreased by 16% and 18%, respectively (P: < 0.001), and midthigh muscle area increased by 7% (P: < 0.05). Fasting plasma insulin decreased by 12% and total glucose and insulin areas under the curve decreased by 6% and 24%, respectively (P: < 0.05). HDL-cholesterol concentrations increased 8% (P: < 0.05) and triacylglycerol concentrations decreased 19% (P: < 0.001). CONCLUSION: Increased physical fitness and weight loss reduce midthigh low-density lean tissue and improve glucose and lipid metabolic risk factors for CVD in obese postmenopausal women.     

Body composition in asymptomatic HIV-infected men: cross-sectional and prospective assessment

Data on body composition changes in HIV infected patients is sparse and controversial. The aim of this study was to assess body composition in asymptomatic HIV-infected men with normal body weight in comparison to healthy HIV-negative control men and to investigate possible body composition changes in HIV-positive patients over a 2-year observation period. One hundred eight asymptomatic seropositive men, aged 19-62 years, and 20 healthy sex, age and weight - matched controls were recruited for the cross-sectional part of the study. Fifty-eight of the HIV+ patients were followed up for 2 years. Body weight, BMI, Bone Mineral Content (BMC), body Fat mass (Fat), % Fat, body Lean mass (Lean) and % Lean was recorded for each subject at the beginning and at the end of the follow-up period. The same analysis was repeated separately for arms, trunk and legs. HIV+ men had increased fat mass and reduced lean mass compared to controls (%Fat in HIV+ 24.3, %Fat in controls 19.2, p=0.012; %Lean in HIV+ 72.1, %Lean in controls 77.0, p=0.014). Lean mass was lower in extremities while fat mass was higher in the trunk region in HIV+ in comparison to controls, irrespective of antiretroviral therapy. Longitudinally, patients with higher baseline %Fat (>24.2, median) presented 20% decrease in fat mass while patients with lower baseline %Fat (< or =24.2) showed a smaller, non-significant decrease in fat mass accompanied by a significant decrease (2.52%) in lean mass. Fat loss occurred in all subjects predominantly in the extremities (16.5-36.45% loss), with relative preservation of trunk fat. It is concluded that otherwise asymptomatic HIV+ men exhibit subtle body composition changes involving reduced lean mass and increased central fat mass. The pattern of weight loss over time depends on baseline fat store: patients with adequate fat stores lose predominantly fat while patients with lower baseline fat stores lose both fat and lean mass. In the entire cohort, there is a tendency towards central adiposity, with the majority of fat being lost from the extremities, a picture resembling metabolic x syndrome.     

Opposite contributions of trunk and leg fat mass with plasma lipase activities: the Hoorn study

OBJECTIVE: Lipoprotein lipase (LPL) and hepatic lipase (HL) are essential in hydrolysis of triglyceride-rich lipoproteins. LPL activity is negatively, whereas HL activity is positively, associated with total body fat. We determined the associations of trunk and leg fat mass with plasma LPL and HL activities in a cross-sectional study. RESEARCH METHODS AND PROCEDURES: LPL and HL activities were determined in post-heparin plasma in a sample of 197 men and 209 women, 60 to 87 years of age. A total body DXA scan was performed to determine trunk and leg fat mass. RESULTS: In women, but not in men, trunk fat mass was negatively associated with LPL activity, whereas leg fat mass was positively associated, after mutual adjustment and adjustment for age. Standardized betas (95% confidence interval) for trunk and leg fat mass were -0.24 (-0.41; -0.08) and 0.14 (-0.02; 0.31), respectively (interaction by sex, p = 0.03). Larger trunk fat mass was associated with higher HL activity in men [0.48 (0.28; 0.68)] and women [0.40 (0.24; 0.56)]. A negative association of leg fat mass and HL activity was observed in men, although not statistically significant [-0.13 (-0.33; 0.06)], and in women [-0.28 (-0.38; -0.18)]. DISCUSSION: Abdominal fat is associated with unfavorable and femoral fat with favorable LPL and HL activities in plasma.     

Familial resemblance of body composition in prepubertal girls and their biological parents

BACKGROUND: Heritability estimates for body mass index (BMI; in kg/m(2)) in children generally have been derived from twin and adoption studies. However, BMI does not reflect total or regional body composition. OBJECTIVE: We evaluated the familial resemblance of body composition between prepubertal girls of normal weight and body fatness and their parents by using state-of-the-art technology. DESIGN: The subjects were 101 girls [mean age: 8.5 +/- 0.4 y; percentage body fat (%BF): 12-30%] and their biological parents. Weight, height, and body composition [fat mass (FM), fat-free mass (FFM), and %BF] were measured with dual-energy X-ray absorptiometry (DXA) and total body potassium (TBK). RESULTS: Weight, height, and BMI showed low-to-moderate similarity between the girls and both their parents (r = 0.29-0.44, P < 0.01). The girls' FM, FFM, and %BF were significantly related to both parents' body composition. Cross-generational equations were developed for DXA, eg, child's %BF = 12.4 + (0.158 paternal %BF) + (0.145 maternal %BF) (adjusted r(2) = 0.16, P < 0.001). Regional analysis with DXA showed that the adjusted r(2) values for the arm, trunk, and leg regions, respectively, were 0.17, 0.33, and 0.31 for lean tissue mass and 0.11, 0.14, and 0.09 for FM. TBK showed a similar relation between parents and girls (r = 0.28-0.47, P < 0.01). Significant heritability (h(2) +/- SE) was detected for BMI (0.35 +/- 0.17, P = 0.03) and %BF measured with DXA (0.50 +/- 0.12, P = 0.0001). CONCLUSION: The body composition of prepubertal girls of normal weight and body fatness is significantly related to the body composition of both biological parents.     

Prediction and validation of total and regional fat mass by B-mode ultrasound in Japanese pre-pubertal children

The present study was performed to develop regression-based prediction equations for fat mass by ultrasound in Japanese children and to investigate the validity of these equations. A total of 127 healthy Japanese pre-pubertal children aged 6-12 years were randomly separated into two groups: the model development group (fifty-four boys and forty-four girls) and the validation group (eighteen boys and eleven girls). Total body, trunk, arm and leg fat masses were initially determined by dual-energy X-ray absorptiometry (DXA, Delphi A-QDR whole-body scanner; Hologic, Inc., Bedford, MA, USA). Then, fat thickness was measured by B-mode ultrasound (5 MHz scanning head) at nine sites (arm: lateral forearm, anterior and posterior upper arm; trunk: abdomen and subscapular; leg: anterior and posterior thigh, anterior and posterior lower leg). Regression analyses were used to describe the relationships between the site-matched fat masses (total body, arm, trunk and leg) obtained by DXA and ultrasound in the development group. When these fat mass prediction equations were applied to the validation group, the measured total and regional fat mass was very similar to the predicted fat mass (mean difference calculated as predicted - measured fat mass ± 2 SD; total body 0·1 (SD 0·5) kg, arm 0·1 (SD 0·3) kg, trunk - 0·1 (SD 0·3) kg, leg 0·1 (SD 0·5) kg for boys; total body 0·5 (SD 1·3) kg, arm 0·0 (SD 0·3) kg, trunk 0·1 (SD 0·8) kg, leg 0·3 (SD 0·6) kg for girls), and the Bland-Altman analysis did not indicate a bias. These results suggest that ultrasound-derived prediction equations for boys and girls are useful for estimating total and regional fat mass.     

Resting energy expenditure can be assessed by fat-free mass in female athletes regardless of body size

Energy requirements can be estimated from resting energy expenditure (REE). However, little is known about factors influencing REE in Japanese female athletes. This study was performed to evaluate the relationship between REE and body composition in Japanese female athletes with a wide range of body sizes. Ninety-three athletes (age 20.3±1.2 y, height 162.8±6.4 cm, body weight (BW) 57.0±9.2 kg, fat-free mass (FFM) 45.4±6.2 kg) were classified into three groups according to BW: small-size (S) (n=34), medium-size (M) (n=34), and large-size (L) (n=25). Systemic and regional body compositions (skeletal muscle (SM), fat mass (FM), bone mass (BM), and residual mass (RM)) were estimated by dual energy X-ray absorptiometry (DXA). Measured resting energy expenditure (REEm) was evaluated by indirect calorimetry. Marked differences were found in REEm (S: 1,111±150, M: 1,242±133, L: 1,478±138 kcal/d), and systemic and regional body compositions among the three groups. REEm was strongly correlated with FFM, and absolute values of RM and SM increased significantly according to body size. There was good agreement between REEm and estimated REE (REEe) from the specific metabolic rates of four major organ tissue level compartments. These data indicate that REE for female athletes can be attributed to changes in organ tissue mass, and not changes in organ tissue metabolic rate. That is, change in REE can be explained mainly by the change in FFM, and REE can be assessed by FFM in female athletes regardless of body size.     

Increased consumption of dairy foods and protein during diet- and exercise-induced weight loss promotes fat mass loss and lean mass gain in overweight and obese premenopausal women

Weight loss can have substantial health benefits for overweight or obese persons; however, the ratio of fat:lean tissue loss may be more important. We aimed to determine how daily exercise (resistance and/or aerobic) and a hypoenergetic diet varying in protein and calcium content from dairy foods would affect the composition of weight lost in otherwise healthy, premenopausal, overweight, and obese women. Ninety participants were randomized to 3 groups (n = 30/group): high protein, high dairy (HPHD), adequate protein, medium dairy (APMD), and adequate protein, low dairy (APLD) differing in the quantity of total dietary protein and dairy food-source protein consumed: 30 and 15%, 15 and 7.5%, or 15 and <2% of energy, respectively. Body composition was measured by DXA at 0, 8, and 16 wk and MRI (n = 39) to assess visceral adipose tissue (VAT) volume at 0 and 16 wk. All groups lost body weight (P < 0.05) and fat (P < 0.01); however, fat loss during wk 8-16 was greater in the HPHD group than in the APMD and APLD groups (P < 0.05). The HPHD group gained lean tissue with a greater increase during 8-16 wk than the APMD group, which maintained lean mass and the APLD group, which lost lean mass (P < 0.05). The HPHD group also lost more VAT as assessed by MRI (P < 0.05) and trunk fat as assessed by DXA (P < 0.005) than the APLD group. The reduction in VAT in all groups was correlated with intakes of calcium (r = 0.40; P < 0.05) and protein (r = 0.32; P < 0.05). Therefore, diet- and exercise-induced weight loss with higher protein and increased dairy product intakes promotes more favorable body composition changes in women characterized by greater total and visceral fat loss and lean mass gain.     

Influence of distribution of lean body mass on resting metabolic rate after weight loss and weight regain: comparison of responses in white and black women

BACKGROUND: Little is known about the effect of weight change on regional lean body mass (LBM) distribution or on racial differences in resting metabolic rate (RMR). OBJECTIVE: The study compared total and regional LBM patterns in white and black women after weight loss and regain and assessed the influence of regional LBM on variances in RMR. DESIGN: Eighteen white and 22 black women who did not differ in age, weight, and height were studied 3 times: in the overweight state, after weight reduction to the normal-weight state, and after 1 y without intervention. Total and regional lean and fat masses were assessed by dual-energy X-ray absorptiometry. RESULTS: White and black women did not differ significantly in mean (+/- SD) weight loss (13.4 +/- 3.6 and 12.7 +/- 3.2 kg, respectively) and regain (6.1 +/- 5.5 and 6.4 +/- 5.4 kg, respectively). Black subjects had significantly less trunk LBM and significantly more limb LBM at each time point (P < 0.05). In both races, weight regain was associated with significant increases in limb LBM (P < 0.05) but not in trunk LBM (P = 0.21). RMR, adjusted for total LBM and fat mass, was significantly higher in white women after weight loss (P < 0.01) and regain (P < 0.01). However, no racial difference was found when RMR was adjusted for LBM distribution. CONCLUSIONS: In both races, trunk LBM decreased with weight loss and remained lower, despite significant weight regain, which potentially reflected decreased organ mass. Regional LBM distribution explained the racial difference in RMR.     

Total and regional body composition across age in healthy Hispanic and white women of similar socioeconomic status

BACKGROUND: Indirect measures of body composition suggest that Hispanic women have an excess prevalence of overweight and obesity compared with white women. Socioeconomic status (SES) is a potentially confounding factor in such studies. OBJECTIVE: Our aim was to determine whether Hispanic ethnicity is associated with higher total and regional adiposity and lower fat-free mass (FFM) in healthy women across the adult age range. DESIGN: We used a prospective cross-sectional design to examine total and regional body composition in 54 Hispanic women (primarily of Mexican descent) and 56 white women of similar SES. RESULTS: The groups were not significantly different in mean age, body mass, or SES, although the Hispanic women were shorter (P<0.05). Body mass index (in kg/m(2); 25.2+/-0.5 compared with 23.9+/-0.5; P<0.05), percentage body fat (38.4+/-0.8% compared with 34.9+/-1.3%; P<0.05), and total fat mass (25.0+/-1.0 compared with 23.0+/-1.2 kg; P = 0.10) were or tended to be higher in the Hispanic women. The greater total adiposity of the Hispanic women was primarily the result of higher percentage fat and fat mass in the trunk (P<0.05); within the trunk region, abdominal and subscapular skinfold thicknesses were 30-40% greater in the Hispanic women (P<0.01). Total FFM was slightly but significantly lower in the Hispanic women (38.9+/-0.6 compared with 40.9+/-0.6 kg; P = 0.01), primarily because of a smaller FFM in the trunk region (P<0.05). CONCLUSION: Among healthy women, Hispanic (Mexican American) ethnicity may be associated with modestly higher levels of adiposity and slightly lower amounts of FFM overall and in the trunk region in particular.