Percent Fat-free Mass Research Articles

ACTYBOSS: Activity, Behavioral Therapy in Young Subjects – After-School Intervention Pilot Project on Obesity Prevention

Aims: To test the feasibility of a school-based intervention, which combines an incentive-driven physical activity program with lifestyle lectures, and its potential beneficial outcome on children’s metabolic parameters. Methods: We conducted a 6-month pilot intervention in two high schools in Mallorca, Spain, consisting of a program which involved free supervised exercise sessions and nutritional lectures, where children received credit points as a reward for the hours spent exercising and attendance to the lectures. The credit-earned points obtained were exchanged for gifts. We developed personalized cards and a web application for the participants to check the gifts they were eligible for (www.actyboss.com). Percentage body fat, percentage of fat-free mass and BMI were measured. Secondary measures included fitness parameters, blood pressure and blood lipids levels. 90 children signed up the consent form and 56 completed the program until the endpoint. Results: We found a beneficial effect on body composition, fitness parameters, and systolic blood pressure in children who participated in ACTYBOSS compared to children who did not start the intervention. Conclusions: We describe the incentive-driven, after-school intervention pilot program to promote physical activity and a healthy lifestyle. The program had a positive effect on anthropometric measurements. A larger incentive-driven healthy lifestyle program is now ongoing.

The variations of body mass index and body fat in adult Thai people across the age spectrum measured by bioelectrical impedance analysis

BackgroundThe measurements of body mass index (BMI) and percentage of body fat are used in many clinical situations. However, special tools are required to measure body fat. Many formulas are proposed for estimation but these use constant coefficients of age. Age spectrum might affect the predicted value of the body composition due to body component alterations, and the coefficient of age for body fat prediction might produce inconsistent results. The objective of this study was to identify variations of BMI and body fat across the age spectrum as well as compare results between BMI predicted body fat and bioelectrical impedance results on age.MethodsHealthy volunteers were recruited for this study. Body fat was measured by bioelectrical impedance. The age spectrum was divided into three groups (younger: 18–39.9; middle: 40–59.9; and older: ≥60 years). Comparison of body composition covariates including fat mass (FM), fat free mass (FFM), percentage FM (PFM), percentage FFM (PFFM), FM index (FMI) and FFM index (FFMI) in each weight status and age spectrum were analyzed. Multivariable linear regression coefficients were calculated. Coefficient alterations among age groups were tested to confirm the effect of the age spectrum on body composition covariates. Measured PFM and calculated PFM from previous formulas were compared in each quarter of the age spectrum.ResultsA total of 2324 volunteers were included in this study. The overall body composition and weight status, average body weight, height, BMI, FM, FFM, and its derivatives were significantly different among age groups. The coefficient of age altered the PFM differently between younger, middle, and older groups (0.07; P = 0.02 vs 0.13; P < 0.01 vs 0.26; P < 0.01; respectively). All coefficients of age alterations in all FM- and FFM-derived variables between each age spectrum were tested, demonstrating a significant difference between the younger (<60 years) and older (≥60 years) age groups, except the PFFM to BMI ratio (difference of PFM and FMI [95% confidence interval]: 17.8 [12.8–22.8], P < 0.01; and 4.58 [3.4–5.8], P < 0.01; respectively). The comparison between measured PFM and calculated PFM demonstrated a significant difference with increments of age.ConclusionThe relationship between body FM and BMI varies on the age spectrum. A calculated formula in older people might be distorted with the utilization of constant coefficients.

Community based physiotherapeutic exercise in COPD self-management: A randomised controlled trial

Little is known about effects of community-based physiotherapeutic exercise programmes incorporated in COPD self-management programmes. In a randomised trial, the effect of such a programme (COPE-active) on exercise capacity and various secondary outcomes including daily activity as a marker of behaviour change was evaluated. All patients attended four 2-h self-management sessions. In addition the intervention group participated in the COPE-active programme offered by physiotherapists of private practices, consisting of a 6-month "compulsory" period (3 sessions/week) and subsequently a 5-month "optional" period (2 sessions/week). Because COPE-active was intended to change behaviour with regard to exercise, one session/week in both periods consisted of unsupervised home-based exercise training. Of 153 patients, 74 intervention and 68 control patients completed the one-year follow-up. Statistically significant between-group differences in incremental shuttle walk test-distance (35.1 m; 95% CI (8.4; 61.8)) and daily activity (1190 steps/day; 95% CI (256; 2125)) were found in favour of the intervention group. Over the 12-month period a significant difference of the chronic respiratory questionnaire (CRQ) dyspnoea-score (0.33 points; 95% CI (0.01; 0.64)) and a non-significant difference of the endurance shuttle walk test (135 m (95% CI (-29; 298)) was found. No differences were found in the other CRQ-components, anxiety and depression scores and percentage of fat free mass. This study demonstrates that a community-based reactivation programme improves exercise capacity in patients with moderately to severe COPD. Even more important, the programme improves actual daily activity after one-year which indicates behaviour change with regard to daily exercise. Registered trail number: ISRCTN81447311.

Comparative effects of continuous combined hormone therapy and tibolone on body composition in postmenopausal women

ObjectiveTo compare the effects of tibolone with those of continuous combined hormone replacement therapy (HT) on body composition in postmenopausal women.MethodsOne hundred and fifty postmenopausal women were enrolled in a randomized, controlled trial to compare the effects of tibolone with continuous combined HT on body composition. Patients were randomly allocated into three groups and followed for 9 months. Of the subjects included, 50 women received 2.5 mg tibolone plus one Cal+D tablet (500 mg calcium and 200 IU vitamin D) daily, 50 women received 0.625 mg conjugated equine estrogen and 2.5 mg medroxyprogesterone acetate (CEE/MPA) plus one Cal+D tablet daily, and the rest (50 women) received only one Cal+D tablet and served as a control group. Body composition was evaluated with measurements of body mass index (BMI), weight, waist-to-hip ratio (WHR), fat mass and fat-free mass (FFM) before and after the intervention. Measurements of body fat mass percentage, fat mass, body fat-free mass percentage and fat-free mass (FFM) were assessed by measurement of skin-fold thickness.Results Tibolone significantly increased weight, BMI and FFM and decreased WHR after the treatment in comparison with baseline (p < 0.05). However, only weight and BMI increased significantly in the CEE/MPA group after the treatment (p < 0.05). There were significant increases in weight, BMI and fat mass in the control group after 9 months. In the comparison of the parameters after the treatment between the three groups, tibolone significantly increased FFM compared with the control and CEE/MPA groups (p < 0.01).Conclusions The effect of tibolone on body composition is favorable and therefore tibolone may be regarded as an alternative to continuous combined hormone therapy in postmenopausal women.

Relationships among dual-energy X-ray absorptiometry, bioelectrical impedance and ultrasound measurements of body composition of swine

Abstract. In three separate studies (156 pigs total), dual-energy X-ray absorptiometry (DXA), bioelectrical impedance (BIA) and ultrasound were compared as methods for measuring live body composition of pigs at 60 and 100-110 kg BWt. DXA measured total body fat and lean content, BIA measurements of resistance (Rs) and reactance (Xc) were used to calculate total body lean mass and ultrasound measurements of backfat (BF) depth and longissimus muscle area (LMA) were used to calculate total carcass lean mass. Following the 100–110 kg measurements, the pigs were slaughtered and the half-carcass analyzed chemically for fat and water content. At 110 kg both DXA and ultrasound measurements were significantly correlated with the percentages of carcass fat and water, although correlations were higher for DXA. The correlations between DXA and BF measurements were higher at 110 kg than at 60 kg, whereas they were lower for DXA and LMA. For pigs measured at 100 kg there were high correlations between the DXA values and the BIA estimates for both percentage of fat-free lean mass (FFM %) and FFM kg. Furthermore, the correlations between the BIA estimates of FFM and carcass fat and water content were similar to those for DXA and the same carcass values. This study also provided a side-by-side comparison of the BIA and ultrasound lean measurements relative to DXA and carcass composition. The BIA lean measurement correlated more highly with both DXA and carcass composition than did the ultrasound lean measurement.

Effects of long-term multidisciplinary inpatient therapy on body composition of severely obese adolescents

To describe the effects of long-term multidisciplinary inpatient therapy on body composition of severely obese adolescents. A total of 728 extremely obese adolescents, including 249 boys (aged 15.25+/-1.56 years) and 479 girls (aged 15.34+/-1.59 years) received multidisciplinary therapy during a period of 3 to 9 months. The therapy consisted of reduced energy intake, dietetic education, physical exercises and psychological therapy. Body composition was assessed by bioelectrical impedance analysis, and physical capacity was assessed by the multistage cycle ergometer test. Type and duration of each activity were recorded using a daily controlled activity diary. There was a significant decrease (p < 0.05) in body mass (27.84+/-12.49 kg for boys and 21.60+/-9.87 kg for girls), body mass index (9.19+/-3.88 kg/m(2) for boys and 7.72+/-3.98 kg/m(2) for girls) and fat mass. In addition, the percentage of fat free mass increased significantly (p < 0.05) in boys (from 58.8+/-6.41 to 69.98+/-7.43%) and in girls (from 51.86+/-4.96 to 60.04+/-5.65%). Long-term multidisciplinary approach allows significant reduction in severe obesity, preserving growth and percentage of fat free mass.

Efeitos da terapia multidisciplinar de longo prazo sobre a composição corporal de adolescentes internados com obesidade severa

OBJETIVO: Descrever os efeitos da terapia multidisciplinar de longo prazo sobre a composição corporal de adolescentes obesos severos internados. MÉTODOS: Um total de 728 adolescentes obesos extremos, incluindo 249 meninos (15,25±1,56 anos) e 479 meninas (15,34±1,59 anos), recebeu terapia multidisciplinar durante um período de 3 a 9 meses. A terapia consistiu de redução da ingestão energética, orientação dietética, exercícios físicos e terapia psicológica. A composição corporal foi analisada pela bioimpedância elétrica, e a aptidão física foi avaliada pelo teste em ciclo ergômetro multiestágios. O tipo e duração de cada atividade foram avaliados através de recordatório diário de atividade física. RESULTADOS: Foi verificada redução significante (p < 0,05) na massa corporal (27,84±12,49 kg para meninos e 21,60±9,87 kg para meninas), índice de massa corporal (9,19±3,88 kg/m² para meninos e 7,72±3,98 kg/m² para meninas) e da gordura corporal. Além disso, a porcentagem de massa magra aumentou significantemente (p < 0,05) nos meninos (de 58,8±6,41 para 69,98±7,43%) e nas meninas (de 51,86±4,96 para 60,04±5,65%). CONCLUSÃO: A terapia multidisciplinar de longo prazo permite reduzir acentuadamente a obesidade severa, preservando o crescimento e a porcentagem de massa magra.

Validity Of Single-frequency Bioelectrical Impedance Method To Assess Changes In Body Composition During Exercise Training

PURPOSE: To investigate the validity of single-frequency bioelectrical impedance method (BI; Muscle-alpha, Physion) to assess body composition changes during a 12-week aerobic exercise program in comparison with dual-energy X-ray absorptiometry (DXA; QDR 4500, Hologic). METHODS: Eighteen obese men (age: 49.1 ± 11.3 years, body mass index: 28.7 ± 1.8 kg/m2) participated in this study. They enrolled in a 90-min supervised exercise program mainly consisting of aerobic exercise (60-80% of heart rate reserve) on a regular basis of 3 d/wk for 12 weeks. Percentage of fat mass (%fat), fat mass (FM) and fat-free mass (FFM) were measured before and after the program using BI and DXA. RESULTS: With -2.7 ± 2.4 kg of weight reduction during the program, %fat and FM significantly decreased (P < 0.05), but FFM remained unchanged when assessed by BI and DXA. Significant differences (P < 0.05) were observed between BI and DXA at baseline for %fat (28.2% vs. 25.4%), FM (23.5 kg vs. 21.3 kg) and FFM (59.7 kg vs. 62.6 kg). Further, significant differences (P < 0.05) were observed after the program for %fat (25.2% vs. 23.3%), FM (20.4 kg vs. 19.0 kg) and FFM (60.2 kg vs. 62.3 kg) and change in FM (-3.1 kg vs. -2.3 kg). At each time point, %fat, FM and FFM measured by BI were significantly lower (P < 0.05) than those by DXA. The correlation coefficients between BI and DXA were similar at baseline and after the program, while rather low for the change in %fat (r = 0.63, 0.69, and 0.33, respectively), FM (r = 0.81, 0.86, and 0.59, respectively) and FFM (r = 0.98, 0.98, and 0.15, respectively). A Bland-Altman analysis revealed no significant bias (change%fat: r = -0.21, standard error of estimate: SEE = 1.36, P = 0.40; changeFM: r = -0.09, SEE = 1.54, P = 0.72; changeFFM: r = -0.35, SEE = 0.96, P = 0.16). CONCLUSIONS: BI and DXA are able to track changes in %fat and FM similarly during an aerobic exercise program in obese men. Additionally, there are no significant differences in %fat and FM between the two methods, suggesting that BI can be used in a clinical setting.

Waist Circumference Measurement by Site, Posture, Respiratory Phase, and Meal Time: Implications for Methodology

Waist circumference (WC) has been advocated as a simple, reliable, and cost-effective measure to understand an individual's cardio-metabolic risk. Although several protocols exist for measuring WC, the variation induced by a few factors has not been investigated. We compared several established and experimental WC measurement protocols to identify factors that may cause variations in WC measurement. In this cross-sectional study, we examined the variations in the measurement of waist circumference (WC) measures carried out in 11 ways differing by anatomical site, posture, respiratory phase, and time since last meal, using repeated measure analysis of variance (using mixed models) after Tukey-Kramer adjustment. We estimated the proportion of variance in percentage of body fat (%BF) and fat-free mass (FFM) explained by each of the WC measures. We studied 123 apparently healthy Asian Indians (75 females), with mean (s.d.) age of 34 (8.7) years and BMI of 23.9 (4.8) kg/m(2). Overall, the mean of WCs measured using the 11 protocols were statistically different. Further, post hoc analysis showed statistically significant, yet mostly small, differences between most of the pairs. No single WC measure explained highest variance in %BF or FFM for both genders. Although, the National Institute of Health (NIH), USA, protocol was convenient and may be less prone to errors, at present it does not control for many variables tested in this study. Measures of WC measured using different protocols were statistically different. We suggest that the site of measurement, posture, phase of respiration, and time since last meal should be standardized for the development of a protocol for measurement of WC for worldwide use.

Energy Expenditure and Weight Regain in Patients Submitted to Roux-en-Y Gastric Bypass

Although Roux-en-Y gastric bypass (RYGBP) is a highly effective treatment for clinically severe obesity, not all patients achieve desirable weight loss and maintenance. There is some evidence that weight loss can induce a disproportionate reduction in resting metabolic rate (RMR). This reduction in RMR can be related to fat-free mass (FFM) loss, as FFM is the greatest responsible for variations in energy expenditure at rest. Abnormally low basal metabolic rate may predispose surgical patients to weight regain. Thirty-six individuals were divided into two groups: patients who have kept a healthy weight 2 years after surgery and patients who showed weight regain of at least 2 kg 2 years after the surgery. Selected patients have signed a consent form. Body mass index and excess weight loss were evaluated. RMR and body fat percentage were measured. FFM is a heterogeneous component that can be partitioned into muscle mass and no-muscle mass. The FFM was calculated as the result of subtracting total fat weight from total body weight in kilogram. We also wanted to know if the predictive formulas to assess RMR overestimate energy expenditure in these patients. Statistical tests were used to analyze the two groups. We found out that the RMR of the weight regain group was statistically inferior to the mean of the healthy weight group-the difference between the two groups was about 260 kcal/day. We also found out that the predictive formulas overestimate the RMR in the weight regain group. This study suggests that a lower RMR may contribute to weight regain in patients who undergo RYGBP. It is important to ensure ways to elevate energy expenditure in the patient, such as increasing the percentage of fat-free mass in the body and the practice of physical activities.

A viscerally driven cachexia syndrome in patients with advanced colorectal cancer: contributions of organ and tumor mass to whole-body energy demands

Background: Cancer cachexia–associated weight loss is poorly understood; energetically demanding tissues (eg, organ and tumor mass) and resting energy expenditure (REE) are reported to increase with advanced cancer.Objective: The objective was to quantify the potential contribution of increasing masses of energetically demanding tissues to REE with colorectal cancer cachexia progression.Design: A longitudinal computed tomography (CT) image review was performed to quantify organ size (liver, including metastases, and spleen) and peripheral tissues (skeletal muscle and adipose tissue) during colorectal cancer cachexia progression (n = 34). Body composition was prospectively evaluated by CT and dual-energy X-ray absorptiometry, and REE was determined by indirect calorimetry in advanced colorectal cancer patients (n = 18).Results: Eleven months from death, the liver (2.3 ± 0.7 kg) and spleen (0.32 ± 0.2 kg) were larger than reference values. One month from death, liver weight increased to 3.0 ± 1.5 kg (P = 0.010), spleen showed a trend to increase (P = 0.077), and concurrent losses of muscle (4.2 kg) and fat (3.5 kg) (P < 0.05) were observed. The estimated percentage of fat-free mass (FFM) occupied by the liver increased from 4.5% to 7.0% (P < 0.001). The most rapid loss of peripheral tissues and liver and metastases gain occurred within 3 mo of death. A positive linear relation existed between liver mass and measured whole-body REE (r2 = 0.35, P = 0.010); because liver accounted for a larger percentage of FFM, measured REE · kg FFM−1 · d−1 increased (r2 = 0.35, P = 0.010).Conclusions: Increases in mass and in the proportion of high metabolic rate tissues, including liver and tumor, represented a cumulative incremental REE of ≈17,700 kcal during the last 3 mo of life and may contribute substantially to cachexia-associated weight loss.

The effects of exercise and weight loss in overweight patients with hip osteoarthritis: design of a prospective cohort study

BackgroundHip osteoarthritis (OA) is recognised as a substantial source of disability, with pain and loss of function as principal symptoms. An aging society and a growing number of overweight people, which is considered a risk factor for OA, contribute to the growing number of cases of hip OA. In knee OA patients, exercise as a single treatment is proven to be very effective towards counteracting pain and physical functionality, but the combination of weight loss and exercise is demonstrated to be even more effective. Exercise as a treatment for hip OA patients is also effective, however evidence is lacking for the combination of weight loss and exercise. Consequently, the aim of this study is to get a first impression of the potential effectiveness of exercise and weight loss in overweight patients suffering from hip OA.Methods/DesignThis is a prospective cohort study. Patients aged 25 or older, overweight (BMI > 25) or obese (BMI > 30), with clinical and radiographic evidence of OA of the hip and able to attend exercise sessions will be included. The intervention is an 8-month exercise and weight-loss lifestyle program. Main goal is to increase aerobic capacity, lose weight and stimulate a low-calorie and active lifestyle. Primary outcome is self-reported physical functioning. Secondary outcomes include pain, stiffness, health-related quality of life and habitual activity level. Weight loss in kilograms and percentage of fat-free mass will also be measured.DiscussionThe results of this study will give a first impression of potential effectiveness of exercise and weight loss as a combination program for patients with OA of the hip. Once this program is proven to be effective it may lead to postponing the moment of total hip replacement.Trial Registration numberNTR1053

Validity of segmental multiple-frequency bioelectrical impedance analysis to estimate body composition of adults across a range of body mass indexes

Objective We compared body composition estimates using an eight-electrode, segmental, multiple-frequency bioelectrical impedance analysis (segmental MF-BIA) and dual x-ray absorptiometry (DXA) in a group of healthy adults with a range of body mass indexes (BMIs). Methods Percentage of body fat (%BF), fat-free mass, and fat mass assessed by DXA and segmental MF-BIA in 132 healthy adults were classified by normal (N; 18.5–24.9 kg/m 2), overweight (OW; 25–29.9 kg/m 2), and obese (OB; 30–39.9 kg/m 2) BMI. Results Compared with DXA, segmental MF-BIA overestimated %BF in the OB BMI group (3.4%; P < 0.0001). MF-BIA overestimated %BF among men (0.75%; P < 0.006) and women (0.87%; P < 0.006) and underestimated it in the N BMI group (−1.56%; P < 0.0001); %BF was not different between methods in the OW BMI group. Error in %BF determined by segmental MF-BIA and DXA increased as %BF increased ( r = 0.42, P < 0.0001). Waist circumference was the only significant predictor of systematic error in %BF between MF-BIA and DXA ( r = 0.60, P < 0.0001). Conclusion Eight-electrode, segmental MF-BIA is a valid method to estimate %BF in adults with BMI classified as N and OW, but not as OB. Estimation of trunk resistance with current segmental MF-BIA devices may explain the underestimation of %BF in the adults with OB BMI. Further examination of the effect of waist circumference and body fat distribution on the accuracy of BIA measurements is warranted.

Changes in Bone Mineral Density, Body Composition and Adiponectin Levels in Morbidly Obese Patients after Bariatric Surgery

Gastric bypass surgery (GBP) is increasingly used as a treatment option in morbid obesity. Little is known about the effects of this surgery on bone mineral density (BMD) and the underlying mechanisms. To evaluate changes on BMD after GBP and its relation with changes in body composition and serum adiponectin, a longitudinal study in morbid obese subjects was conducted. Forty-two women (BMI 45.0 +/- 4.3 kg/m(2); 37.7 +/- 9.6 years) were studied before surgery and 6 and 12 months after GBP. Percentage of body fat (%BF), fat-free mass (FFM), and BMD were measured by dual-energy X-ray absorptiometry and serum adiponectin levels by RIA. Twelve months after, GBP weight was decreased by 34.4 +/- 6.5% and excess weight loss was 68.2 +/- 12.8%. Significant reduction (p < 0.001) in total BMD (-3.0 +/- 2.1%), spine BMD (-7.4 +/- 6.8%) and hip BMD (-10.5 +/- 5.6%) were observed. Adiponectin concentration increased from 11.4 +/- 0.7 mg/L before surgery to 15.7 +/- 0.7 and 19.8 +/- 1.0 at the sixth and twelfth month after GBP, respectively (p < 0.001). Thirty-seven percent of the variation in total BMD could be explained by baseline weight, initial BMD, BF reduction, and adiponectin at the twelfth month (r (2) = 0.373; p < 0.001). Adiponectin at the twelfth month had a significant and positive correlation with the reduction of BMD, unrelated to baseline and variation in body composition parameters (adjusted correlation coefficient: r = 0.36). GBP induces a significant BMD loss related with changes in body composition, although some metabolic mediators, such as adiponectin increase, may have an independent action on BMD which deserves further study.

Vitamin B6 status improves in overweight/obese women following a hypocaloric diet rich in breakfast cereals, and may help in maintaining fat-free mass

To analyze the changes in vitamin B6 status in women following slightly hypocaloric diets based on the relative increase consumption of foods whose intakes are below those recommended, and to study how these changes influence the proportion of fat-free mass. Intervention study of two slightly hypocaloric diets: diet V (increased consumption of vegetables), or diet C (increased consumption of cereals, especially breakfast cereals). A total of 49 women with a body mass index (BMI) of 25-35 kg/m2. Dietetic, anthropometric and biochemical data were collected at the start of the study and at 2 and 6 weeks. Both the C and V subjects showed a reduction in their energy intake, body weight, BMI and fat mass. Pyridoxine intake increased in both groups and plasma pyridoxal phosphate (PLP) levels increased only with diet C. An association was found between the increase in plasma PLP at 6 weeks and the increase in pyridoxine intake (r=0.451; P<0.01). Multiple regression analysis showed a positive association between the increase in PLP at the end of the study and the increases in the pyridoxine intake, B6 density or B6/protein ratio. At the end of the study, and only in those women whose PLP levels were increased, the higher the increase in PLP level, the higher the increase in fat-free mass percentage (r=0.4426, P<0.05). Interventions aimed at weight control should also try to maintain or improve nutritional status. A diet rich in cereals (especially fortified breakfast cereals) appears to be useful in improving vitamin B6 status. Such an improvement could help maintain fat-free mass during periods of weight loss.

Physical Activity Is Associated with Risk Factors for Chronic Disease across Adult Women's Life Cycle

Objective The purpose of this study was to examine the association of age (young, midlife, and older) and activity level (active and sedentary), determined by a pedometer, with risk factors of chronic disease, including body composition, dietary intake, serum lipids, insulin, leptin, C-reactive protein (CRP), plasma glucose, and resting metabolic rate (RMR) in women across the adult life cycle. Methods Young (aged 20 to 30 years) (n=49), midlife (aged 40 to 50 years) (n=62), and older (aged 60 years and older) (n=47) women were recruited for this cross-sectional study. For 7 days, participants completed weighed food records and wore a pedometer. Based on the average number of steps per day, the women were further classified as active (≥7,500 steps per day) or sedentary (<7,500 steps per day). Height, weight, and waist circumference were determined for each participant. Fasting blood samples were taken to assess serum lipid, CRP, insulin, leptin, thyroid stimulating hormone, and plasma glucose levels. RMR and body composition (via dual-energy x-ray absorptiometry) were assessed. Results Young and midlife women had lower concentrations compared to older women for serum cholesterol ( P<0.01), low-density lipoprotein cholesterol ( P<0.01), triglycerides ( P<0.01), leptin ( P<0.01), and plasma glucose ( P<0.01); midlife women had lower serum insulin concentrations vs young and older groups ( P=0.01); young women had smaller waist circumference compared to midlife and older groups ( P<0.01); percent body fat ( P<0.01) and percent fat-free mass ( P<0.01) differed between all ages. Lower values were found in active vs sedentary women for serum insulin ( P=0.02), serum leptin ( P<0.01), waist circumference ( P<0.01) and percent body fat ( P<0.01). A higher percent fat-free mass ( P<0.01) was also found in active compared to sedentary women. No differences were found between activity groups for serum cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, CRP, plasma glucose levels, or RMR. RMR was higher in young and midlife vs the older women ( P<0.01). Significant inverse correlations were found between activity (steps per day) and body mass index, insulin level, CRP concentration, leptin level, waist circumference, and body fat. Significant positive correlations were found between age and body mass index, total serum cholesterol level, low-density lipoprotein cholesterol level, serum triglyceride level, leptin level, plasma glucose level, CRP concentration, waist circumference, and body fat. Young and midlife women reported consuming more relative energy (kilocalories per kilogram body weight) and protein (grams per kilogram body weight) than older women ( P<0.01). The midlife women reported consuming more dietary cholesterol compared to the young and older women ( P<0.01). Active women reported a higher relative energy (kilocalories per kilogram body weight) and protein (grams per kilogram body weight) intake vs the sedentary women ( P<0.01). Active women also reported a higher intake of dietary carbohydrates (grams per day, P<0.01; percent of energy, P=0.04). Conclusions Overall, these results indicate that younger age and greater physical activity, despite age, are associated with fewer risk factors for chronic disease, such as cardiovascular disease, type 2 diabetes, and obesity.

Validity of Predicted Thoracic Gas Volumes in Determining Body Composition During Air Displacement Plethysmography in Collegiate Athletes

Physical assessments are of increasing value in the development of peak conditioning in athletes. However, time constraints may often limit which assessment is performed. Measuring thoracic gas volume is an option provided during air displacement plethysmography (ADP), but adds time to the body composition (BC) assessment. Predicting lung volume may save time as less testing is required. However, what remains in question is the accuracy of using predicted lung volume in determining BC in athletes. PURPOSE: The aim of this study was to assess the validity of using predicted thoracic gas volume in determining BC during ADP in collegiate athletes. METHODS: Thirty-one subjects (5 males, 26 females) from 3 collegiate teams underwent BC procedures using ADP with the subject characteristics being height (m): 1.78 ± 0.08, body mass (kg): 78.66 ± 14.27, and BMI (kg/m2): 24.85 ± 3.70. Percent fat free mass (FFM) and percent fat mass (FM) were calculated from the assessment using predicted and measured lung volumes. Paired t-tests were used to compare the means of FFM and FM using predicted and measured measurements. A Pearson correlation coefficient calculated the relationship between subjects' predicted and measured body composition. RESULTS: A paired t-test revealed no significant difference between the mean measurements, p > 0.05. A Pearson correlation coefficient revealed a strong correlation between predicted and measured body composition in all subjects with r = 0.981, p = 0.001. CONCLUSION: Using the predicted lung volume provides a valid FFM and FM during BC testing during ADP in collegiate athletes. Time and effort may be saved by not measuring lung volume directly during ADP.Body Composition Values determined by Predicted and Measured Thoracic Lung Volumes.

Tracking Body Composition Changes Over Time: Comparison of Methods

Tracking changes in body composition (BC) is critical for observational and intervention studies. Little is known about the best approaches to tracking BC changes. PURPOSE: To compare air plethysmography (AP) and bioelectrical impedance (BI) estimates of BC in a group of college students, some who lose and some who gain body mass (BM). METHODS: 66 college students (26 males, 40 females, 18.1 y) were measured at the beginning and end of their first year at college. AP and BI were used to estimate fat mass (FM), fat-free mass (FFM), and body fat percentage (%BF). BI also assessed kg of trunk fat. BM, body mass index (BMI), and waist circumference (WC) were measured using standard procedures. Repeated measures ANOVA determined whether AP and BI yielded similar results. Bivariate correlation and multiple regression determined which variables were related to changes in BM, BMI and WC. RESULTS: There was wide variation in BC change, but the majority of individuals gained in BM, WC, and FM. On average, subjects gained 1.6±2.9 kg in BM, 1.24±3.02 cm in WC, and 0.35±1.03 kg/m2 in BMI. %BF increased by 0.64±3.42 and 1.37±2.76% according to AP and BI, respectively. AP yielded higher estimates of %BF than BI (24.0 ± 10.5% vs. 22.8 ± 8.6%, p=0.029). The change in FM estimated from AP was highly and significantly (p<0.01) related to change in BM (r=0.81), BMI (r=0.77), and WC (r=0.61). Change in FM estimated from AP was a stronger predictor of change in WC, BMI, and BM than the AP-derived change in FFM or %BF or any of the variables estimated by BI. CONCLUSION: AP and BI both reflect an increase in FM over time in college students. However, differences in estimates from the 2 methods do not allow them to be used interchangeably. The changes in FM according to AP are most reflective of the changes in BM, BMI, and WC.

Weight Loss and Body Composition During the First Postoperative Year of a Laparoscopic Roux-En-Y Gastric Bypass

Weight loss in patients undergoing gastric bypass should be primarily from fat mass (FM), minimizing the fat-free mass (FFM) loss. The aim of this study was to analyze changes in body weight and body composition during the first postoperative year in 50 morbidly obese patients undergoing a Laparoscopic Roux-en-Y gastric bypass (LRYGBP) at the Obesity Clinic of the ABC Medical Center. Patient's weight and body composition were obtained before surgery and 1 year later using bioelectrical impedance analysis (BIA). Weight, FM, FMM, and total body water (TBW) were measured before and 1 year after surgery. Changes in body composition were particularly analyzed. There were 29 females and 21 males with mean age of 41 +/- 12 years. Mean BMI before surgery and 1 year after surgery was 44.4 +/- 7.4 kg/m(2) and 28.3+/-4.3 kg/m(2), respectively. The percentage of excess body weight loss at the 1-year period was 86% for women and 79.6% for men. The percentage of FM before surgery was 47.7 +/- 5.1, and 1 year later it was 28.8 +/- 8. The percentage of FFM was 66.5 +/- 16.5 before surgery and 58.3 +/- 13 at 1 year. There is a significant weight loss in patients undergoing LRYGBP. Weight loss mainly occurs as a consequence of reduction in the FM with less impact on the FFM.

Short- and long-term beneficial effects of a multidisciplinary therapy for the control of metabolic syndrome in obese adolescents

Visceral fat is highly correlated with metabolic syndrome in obese adolescents. The aims of this study were to determine the prevalence of metabolic syndrome and to assess the effect of a long-term (1 year) intervention with multidisciplinary therapy in predicting metabolic syndrome among obese adolescents, as well as to compare short- with long-term therapy. Eighty-three postpuberty obese adolescents were recruited, including 37 boys (body mass index [BMI], 36.19 ± 3.85 kg/m 2) and 46 girls (BMI, 35.73 ± 4.42 kg/m 2). Body composition was measured by plethysmography using the BOD POD body composition system (version 1.69, Life Measurement Instruments, Concord, CA), and visceral fat was analyzed by ultrasound. Metabolic syndrome was determined according to the World Health Organization criteria. Patients were assigned to a weight loss multidisciplinary intervention consisting of nutritional, exercise, psychological, and clinical therapy. At the beginning of therapy, we found that 27.16% of the obese adolescents presented metabolic syndrome, whereas only 8.3% did so after intervention. Indeed, in boys, BMI (36.19 ± 3.85 to 32.06 ± 5.85 kg/m 2), visceral fat (4.88 ± 1.35 to 3.63 ± 1.71 cm), homeostasis model assessment of insulin resistance (4.77 ± 3.41 to 3.18 ± 2.33), and percentage of body fat (38.24% ± 6.54% to 30.02% ± 13.43%) presented a statistically significant reduction; and their fat-free mass percentage increased (62.14% ± 5.78% to 69.17% ± 12.37%). In girls, after long-term therapy, BMI (35.73 ± 4.42 to 33.62 ± 3.78 kg/m 2), visceral fat (3.70 ± 1.40 to 2.75 ± 1.01 cm), and percentage of body fat (46.10% ± 5.66% to 39.91% ± 5.59%) showed a statistically significant reduction; and their fat-free mass increased (53.61% ± 5.65% to 59.82% ± 5.78%). In conclusion, long-term multidisciplinary therapy was effective in promoting beneficial changes in some predictors and decreasing the prevalence of metabolic syndrome in obese adolescents.