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PubMed1995

Age-related patterns in body composition for men aged 20-79 yr.

Fat-free body mass has been reported to decline by 30% between the ages of 30 and 70 yr, whereas body weight increases until age 50 yr. This study examined the age-related patterns in body composition, specifically its two components, fat-free body mass and fat mass, in 157 men aged 20-79 yr. Total body composition was assessed by hydrodensitometry and subcutaneous fat was measured with skinfolds. Approximately 15 men were tested in each of the 12 5-yr age groups (20-24, 25-29, 30-34, ... 75-79 yr). Body density, as determined by underwater weighing, was lower successively from the youngest to oldest age groups; men below age 40 yr had significantly higher (P < 0.01) body densities than the older men. Although there was a gradual decline in fat-free body mass with increasing age, there was not a significant age group effect until age 70 yr. Fat mass gradually increased with increasing age; men above age 40 yr had significantly higher (P < 0.01) total body fat when compared to the younger men. Subcutaneous body fat was similar at the distal limb locations for each age group; however, the proximal trunk locations, especially the abdomen, demonstrated significantly (P < 0.01) higher skinfold thicknesses with increasing age. In conclusion, fat-free body mass was maintained to a later age than previously reported; thus, the age-related decline in body density could be attributed to an age-related increase in body fat.

Adipose Tissue↗
PubMed2006

Walking, body composition, and blood pressure dose-response in African American and white women.

PURPOSE: The purpose of this study was to evaluate body composition and blood pressure (BP) responses to a 16-week dose of brisk walking in sedentary and obese African American (AA) and White women. METHODS: Seventy-five sedentary women (45 AA and 30 White) between the ages of 18 and 50 years and body fat > or =27% signed institutional approved informed consent forms and volunteered to participate in this study. The participants were divided into four groups (AA exercisers [AAE], AA control [AAC], White exercisers [WE], White controls [WC]). The exercisers walked three miles a day, three days a week. Body composition and BP were measured before and after the training intervention. Food records were collected before, during, and after the intervention. RESULTS: Following training, only the WE experienced a reduction in body weight and body fat (P<.05). However, the energy intake of the AAE increased 4.7% during and 16% at the conclusion of the intervention and contributed to them neither losing nor gaining weight or fat. Both exercise groups experienced reductions (P<.05) in systolic (AAE 5.7 mm Hg, WE 11.3 mm Hg) and diastolic BPs (AAE 3.0 mm Hg, WE 3.6 mm Hg) following training, but the reductions for the WE were greater (P<.05) than for the AAE. There were no changes in body composition or BP for either AAC or WC. CONCLUSIONS: These results indicate that a 16-week walking intervention provides body composition and BP benefits for both AA and White women, but the benefits are greater for White women.

Adult↗
PubMed1996

Circadian rhythms in human body composition.

The study investigates how the human body composition (BC) changes as a function of the day-night cycle. The BC was investigated using bioelectrical impedance analysis (BIA) of 10 clinically healthy subjects (CHS), monitored in supine position (readings at 2-h intervals), avoiding mealtimes, dietary abuses, and bladder and intestinal retention. Time series data were analyzed for their temporal characteristics and circadian rhythm (CR). All the variables of BC (lean body mass, fat body mass, body cell mass, total body water, intracellular and extracellular body water, sodium and potassium exchangeable pool) showed a within-day variability with nighttime crests. Such an oscillatory synchronism corroborates the hypothesis that the rest time plays a fundamental role, via its anabolic effects, in conferring the nocturnal phase to the CR of the human BC.

Adipose Tissue↗
PubMed1976

Serum testosterone, body composition, and strength of young adults.

The relationship between serum testosterone (ST), body composition, and static strength was studied in 26 college females and 16 male college football players. In addition, the transient effect of weight training on ST was studied in 10 college males (5 skilled and 5 unskilled weight trainers), 12 male high school students, and 5 female college students. ST, measured by radioimmunoassay, ranged from 333.7 to 848.1 ng/100 ml in males, and from 32.8 to 121.5 n/100 ml in females. The high school subjects had significantly lower levels of ST. Correlations between serum testosterone, body composition (measured by densitometry), and static strength (grip and backlift) were nonsignificant in males and females. Comparisons of subjects with the highest and lowest levels of testosterone within each sex showed no significant differences in strength or body composition. Serum testosterone increased 111.4 +/- 96.l ng/100 ml (X +/- SX) following a weight training session in the male college group, but failed to increase in the college females or high school males. There were no significant differences in testosterone increases between the skilled and unskilled male weight trainers. Maximal exertion may be necessary for an increase in serum testosterone to occur. Lack of an increase in testosterone by high school males or college females may have been due to a submaximal effort during the weight training exercise.

Adolescent↗
PubMed1995

The influence of body composition on left ventricular mass and other echocardiographic and Doppler measurements in 70-year-old males.

Heart morphology and function are often related to body size. The most common way to standardize for body composition is to divide these measures by body surface area (BSA). It has, however, been suggested that left ventricular mass (LV mass) ought to be indexed for height and that cardiac output is influenced by the body fat distribution. As part of a health screening programme of 70-year-old males in Uppsala, Sweden, 100 consecutive men were investigated with echocardiography and Doppler with regard to cardiac morphology and function. These measures were related to an evaluation of body composition using an X-ray method (dual energy X-ray absorptiometry). Lean body mass was strongly related to BSA and body weight (r = 0.90 and 0.89, respectively; P < 0.0001), and to a lesser degree to height (r = 0.70, P < 0.0001). In the healthy part of the population (n = 39), relationships between LV mass on the one hand and lean body mass, BSA and height on the other were seen (r = 0.51, 0.51 and 0.50, respectively; P < 0.01). Stroke volume calculated according to Teichholtz (but not when calculated with Doppler) showed a significant correlation to lean body mass (r = 0.38, P < 0.05). Also, left ventricular diameter and the thickness of the free wall were related to lean body mass (r = 0.40 and 0.39, respectively; P < 0.05). All of the evaluated relationships were generally weaker and in most cases no longer significant when evaluated in part of the population with diseases known to affect the heart. No significant correlations were seen between the size of the left atrium, septal thickness or indices of diastolic function (E/A-ratio, isovolumic relaxation time, deceleration time) and the indices of body composition. No measures of cardiac morphology and function were significantly related to the amount of body fat or body bone. LV mass, stroke volume and left ventricular diameter were found to be correlated with lean body mass, but not with the amount of fat, in healthy 70-year-old males. Theoretically, it is optimal to adjust for lean body mass, but in clinical practice, BSA is to be preferred.

Aged↗
PubMed2004

Brain size scaling and body composition in mammals.

Brain size scales with body size across large groups of animals, but exactly why this should be the case has not been resolved. It is generally assumed that body size is a general proxy for some more important or specific underlying variable, such as metabolic resources available, surface area of the body, or total muscle mass (which is more extensively innervated than is, e.g., adipose tissue). The present study tests whether brain size in mammals scales more closely with muscle mass (and other components of lean body mass) than with total fat. Felsenstein's independent comparisons method was used to control for phylogenetic effects on body composition in organ weight data taken from a previously published comparative sample of 39 species in 8 different orders of mammals, all collected and processed by the same researchers. The analysis shows that the size of the central nervous system (CNS) is more closely associated with components of fat-free weight than it is to fat weight. These results suggest a possible explanation for why metabolic resources and brain size both share the same general relationship with body size across mammals. They also suggest that some measure of lean body mass is a more appropriate scaling parameter for comparing brain size across species than is overall body weight.

Animals↗
PubMed1999

Impact of lactation on maternal body weight and body composition.

Women worldwide generally lose weight and body fat during lactation. This loss, although increased by longer, more intensive breastfeeding, is modest and may be reduced by increased food intake and decreased activity. Higher parity and older age are associated with greater weight loss postpartum among poorly nourished women. Well-nourished women or those who breastfeed only for a limited time may not return to their prepregnant weight or body composition by the end of the lactation period. Those who are overweight or obese may have difficulty initiating or maintaining lactation. For the majority of women in the world, lactation is unlikely to represent a threat to their health. To advise women on how to optimize their health and lactational performance, one must consider all of the changes in maternal nutritional status that occur during a reproductive cycle, which may or may not compensate for the modest decreases in body weight associated with lactation.

Body Composition↗
PubMed1996

Applications of bioelectrical impedance analysis for body composition to epidemiologic studies.

Bioelectrical impedance analysis (BIA) is a promising tool in the evaluation of body composition in large population studies because it is fast, is inexpensive, and does not require extensive operator training or cross-validation. The empiric nature of the relation between resistance and reactance measured by BIA and body composition has led to the development of equations that translate the raw data into liters of body water or kilograms of fat-free mass (FFM) or fat mass. These equations may not be easily transferred from one population to another if the populations differ significantly in important determinants of body composition such as age, obesity, and illness. I review two recent studies from the Framingham Heart Study in which BIA was first compared with dual-energy X-ray absorptiometry (DXA) as a validation technique, and then compared with the body mass index (BMI, in kg/m2) as an alternative estimate of body fat. BIA was a good predictor of DXA-derived FFM (r = 0.85-0.88, P < 0.001) and was superior to BMI as an estimator of body fat.

Adipose Tissue↗
PubMed1999

Physical activity and the progressive change in body composition with aging: current evidence and research issues.

PURPOSE: The purpose was to review studies that have examined the effect of aerobic (AEX) or resistance exercise (REX) on body composition in older individuals (>55 yr). Our goal was to examine the effect of these two exercise paradigms on fat mass and fat-free mass and to consider those factors that may explain variability in findings among studies. METHODS: We conducted a literature search (Medline, 1984-1999) for intervention studies (at least 2 months in duration) that have examined the independent effect of either REX or AEX on body composition in older individuals. RESULTS: AEX decreased fat mass (range: -0.4 to -3.2 kg) but had little effect on fat-free mass. The change in fat mass with AEX was related to the duration of the exercise program (r = 0.51; P < 0.02) but not to body composition methodology. In contrast, REX reduced fat mass (range: -0.9 to -2.7 kg) and increased fat-free mass (range: 1.1 to 2.1 kg). Changes in body composition with REX were not related to body composition methodology or the duration of the exercise program. CONCLUSION: Both AEX and REX appear to be beneficial in reducing body fat. REX appears to have the additional benefit of increasing fat-free mass.

Aging↗
PubMed1996

Incremental changes in total and regional body composition of growing pigs measured by dual-energy x-ray absorptiometry.

The pig was used as a model for the application of dual-energy x-ray absorptiometry (DXA) for measuring changes in total and regional body composition that accompany body growth. Ten pigs were scanned at the beginning of the study (26.3 +/- 8.2 kg) and at 14 day intervals until reaching a final weight of 88.6 +/- 2.3 kg. Final body composition was validated by chemical analysis of the carcass. DXA fat and lean tissue measurements were corrected by using values based on previous calibration studies. From individual growth curves, rates of fat (295 +/- 50 g/d), lean (531 +/- 50 g/d) and bone mineral (16.7 +/- 1.4 g/d) deposition rates were estimated. Furthermore, using regional analysis these tissue deposition rates partitioned into front legs, back legs and body trunk. The final DXA measurements of 87.5 kg for total tissue mass, 27.9% for percent body fat and 24.4 kg for total fat mass were not significantly different (P > .05) from direct or chemical measurements. The DXA measurement of bone mineral content 1912 g (2.18%) was similar to the estimate based on total body ash, 1980 g (2.23%). Also, from the final DXA values for lean tissue mass, it was predicted that the body contained 13.5 kg or 15.4% protein and 45.74 kg or 52.3% water. These results indicate that DXA could be an appropriate method for studies involving sequential measurements of body composition during growth.

Absorptiometry, Photon↗
PubMed2005

[The influence of long-term growth hormone replacement therapy on body composition, bone tissue and some metabolic parameters in adults with growth hormone deficiency].

A syndrome of growth hormone deficiency in adults (GHDA) is a syndrome characterised by metabolic deviations, body composition abnormalities, fatigue, decreased quality of life and some cardiovascular changes. The aim of the study was to assess the influence of the growth hormone (GH) replacement therapy on body composition, bone changes, serum lipids levels and some parameters of sugar metabolism in the course of 7-year monitoring. We followed 34 individuals of mean age of 41.73 +/- 2.49 years (mean +/- SE). Severe deficiency of GH was demonstrated by performing stimulation insulin tolerance test. Duration of treatment was 4.13 +/- 0.36 years (mean +/- SE). Patients were examined before the initiation of replacement therapy, after 6 months and further in yearly visits. To determine a statistical level of significance in individual parameters we compared initial baseline status (before drug administration) with the status in individual time intervals. The body composition was examined by anthropometric methods, bioelectric impedance and by densitometry, bone changes were examined by means of DEXA. There were no statistically significant changes of weight, but the waist circumference significantly decreased (p < 0.05), as well as the sum of skinfold thickness (p < 0.05) within the whole treatment period. The percentage of body fat mass measured by the BIA method was significantly changed after the period of 3 years (p < 0.05). Upon the densitometrical measurement of the body composition a significant decrease in kilograms of body fat mass (FM) occurred in the first year of the treatment (p < 0.05) and an increase in lean body mass (LBM) in kilograms during our complete monitoring (p < 0.05). A statistically significant increase in bone density was found in the whole-body BMD and BMC after the first year of the treatment. In the examination of peripheral bone changes a statistically significant increase in BMD occurred (expressed as a Z score) in the area of proximal femur after the first year and collum femoris after three years (p < 0.05), there was a significant increase in BMD of the lumbar spine already after one year of the treatment (p < 0.05) and changes were significant also in further four years. There were found no statistically significant changes related to the sugar metabolism. In the field of lipid metabolism a decrease of total and LDL cholesterol occurred already after a half of the year of the treatment (p < 0.05), changes were significant also in further four years. HDL cholesterol levels have had a progressive tendency, but they were not statistically significant. Positive changes of body composition, an increase in bone density and a decrease of total and LDL cholesterol were demonstrated in the course of the growth hormone replacement therapy.

Adult↗
PubMed2003

Body composition in adolescent girls with type 1 diabetes.

AIMS: To compare body composition in adolescent girls with Type 1 diabetes with healthy controls. RESEARCH DESIGN AND METHODS: In this population-based study, body composition was examined, using dual-energy X-ray absorptiometry (DXA) and skinfold measurements, in 18 adolescent post-menarcheal females, 16-19 years of age, with Type 1 diabetes since childhood in comparison to age-matched healthy control subjects. RESULTS: Body mass index was 2.7 kg/m2 higher in diabetic patients (26.3 +/- 2.6 vs. 23.6 +/- 3.8; P < 0.05). The overweight consisted almost entirely of increased fat mass, as evaluated by both skinfold measurements and DXA. Bone mineral density did not differ between the two groups. In diabetic females, the distribution of the fat mass was increased in the upper part of the body. The fat distribution, expressed as the abdominal-to-leg ratio, was significantly correlated to glycated haemoglobin (HbA1c) (r = 0.69; P < 0.005), daily dosage of insulin expressed per kilogram body weight (r = 0.78; P < 0.0005) and total cholesterol (r = 0.60; P < 0.001). CONCLUSIONS: The observed overweight in adolescent females with Type 1 diabetes is explained by an increased fat mass. Abdominal fat accumulation was associated with poor glycaemic control, increased need for insulin and elevated blood lipids.

Absorptiometry, Photon↗
PubMed1994

Resting energy expenditure and body composition in morbidly obese, obese and control subjects.

Resting energy expenditure (REE) was investigated by indirect calorimetry in relation to body composition and to different degrees of obesity in order to assess if a defective energy expenditure contributes to extra body fat accumulation. Differences were found between control subjects (group C; BMI 23 +/- 0.5 kg/m2, REE 5890 +/- 218 kJ/day; mean +/- SEM) and obese subjects (group O; BMI 34.2 +/- 0.9 kg/m2, REE 7447 +/- 360 kJ/day; P < 0.0001) and between group C and morbidly obese subjects (group MO; BMI 49.9 +/- 1.6 kg/m2, REE 8330 +/- 360 kJ/day; P < 0.0001); REE was not significantly different between groups O and MO. Body composition data were obtained by means of body impedance analysis. Even though group MO had a fat mass higher than group O, body cell mass, the metabolically active body compartment, was similar in groups O and MO, and this fact may have contributed to the similar REE in the two groups. Multiple regression analysis gave the following equation as the best predictor of REE: REE (kJ/day) = 1591 +/- 49BW + 74BCM - 737G (R2 = 0.88), where BW is body weight, BCM is body cell mass and G is a dummy variable coding group membership (group C = 1; group O = 2; group MO = 3). Thus the analysis showed a negative impact of obesity on REE beyond body composition variables.

Adult↗
PubMed1988

Accurate assessment of body composition in obese females.

Although several generalized regression equations exist for body composition assessment the accuracy of these equations for special populations is uncertain. This study examined the ability to predict body composition variables from girth measurements in obese women. Girth measurements were taken on 156 obese women at abdomen 1 and abdomen 2 (mean value of the two was used), buttocks, and right thigh. Stepwise multiple-regression analysis generated on 110 randomly assigned subjects yielded the following equations: density (g/cc) = -0.00020(mean abdomen) - 0.00032(wt) + 0.00039(ht) + 0.97783 (R = 0.76, SEE = +/- 0.00061); % fat = 0.11077(mean abdomen) - 0.17666(ht) + 0.14354(wt) + 51.03301 (R = 0.76, SEE = +/- 2.9); fat wt (kg) = 0.62039(wt) - 0.17844(ht) + 0.09495(mean abdomen) + 5.88874 (R = 0.96, SEE = +/- 2.9); and lean body wt (kg) = 0.37939(wt) + 0.17898(ht) - 0.09494(mean abdomen) - 6.00423 (R = 0.89, SEE = +/- 3.0). Data from the remaining 46 women were used for cross-validation. These equations were valid, with validity coefficients for fat weight and lean body weight of r = 0.92 (SE = +/- 3.3 kg) and r = 0.86 (SE = +/- 3.3 kg), respectively, with no significant mean differences between actual and predicted values. The use of girth measurements is a simple and practical method of estimating fat weight and lean body weight in obese women.

Adult↗
PubMed2000

Validation of whole-body magnetic resonance spectroscopy as a tool to assess murine body composition.

OBJECTIVE: To evaluate proton magnetic resonance spectroscopy (MRS) as a tool for the non-invasive assessment of murine body composition. DESIGN: Twenty C57/BL6 male mice with a wide range of body adiposities underwent both pre- and post-mortem whole-body MRS to assess body composition. MRS measures were compared to the results obtained by chemical carcass analysis, the current 'gold standard' for determination of body composition. MEASUREMENTS: Areas under the curve (AUC) for lipid and water peaks of whole body MRS spectra (AUClipid and AUCH2O, respectively) were used to determine percentages of body fat (%FATMRS) and fat free mass by MRS (%FFMMRS). Total body fat, total body water, fat free mass, and total lean mass were determined by chloroform/methanol extraction of lipid from dessicated whole carcass and compared to MRS measures (%FATMRS, %FFMMRS, AUClipid, and AUCH2O). The variability of the MRS technique was assessed by determining the coefficients of variation (COV) associated with %FATMRS, AUClipid, and AUCH2O for mice of three different adiposities. RESULTS: %FATMRS in live mice was highly correlated with body fat percentage (r=0.994, P<0.001) and total body fat (r=0.980, P<0.001) derived from chemical carcass analysis over a broad range of adiposities (7-48% body fat content by carcass analysis). There was no difference in %FATMRS measured pre- vs post-mortem (r=1.00, P<0.001). AUClipid was highly correlated with chemically derived total fat mass (r=0.996, P<0.001) and body fat percentage (r=0.981, P<0.001), while %FFMMRS was strongly correlated to chemical determinations of percentage body water (r=0.994, P<0. 001), percentage fat free mass (r=0.993, P<0.001), and percentage lean mass (r=0.792, P<0.001). AUCH2O was strongly associated with carcass analysis determinations of total body water (r=0.964, P<0. 001), total fat free mass (r=0.953, P<0.001), and total lean mass (r=0.89, P<0.001). In mice of 6%, 12%, and 43% body fat, COVs determined for %FATMRS and AUClipid were less than 10%. The COVs for AUCH2O were less than 2%. CONCLUSIONS: MRS provides precise, accurate, rapid, and non-invasive measures of body fat, body water, fat free mass, and lean mass in living mice with a broad range of adiposities.

Adipose Tissue↗
PubMed1989

Body composition of children recovering from severe protein-energy malnutrition at two rates of catch-up growth.

Twenty-two children with severe protein-energy malnutrition were randomly assigned to dietary treatments that permitted either moderate (4-6 g.kg-1.d-1) rates of weight gain (MG, n = 11) or rapid (12-16 g.kg-1.d-1) rates of weight gain (RG, n = 11) to test the hypothesis that restoration of weight deficits by the RG group restores reference body composition. Final total body water was 60 +/- 4% of body weight in the MG group and 62 +/- 3% in the RG group (NS) indicating reference body composition was attained by both groups. Composition of weight gained was measured by energy and nitrogen balance from doubly labeled water and metabolic collection data. In early recovery, the percent (+/- SEM) protein, fat, and water in weight gain was 20 +/- 1%, 40 +/- 8%, and 40 +/- 10% in the MG group and 14 +/- 1%, 43 +/- 4%, and 43 +/- 12% in the RG group. In late recovery these were 13 +/- 1%, 42 +/- 7%, and 47 +/- 14% in the MG group and 12 +/- 1%, 46 +/- 4%, and 42 +/- 6% in the RG group. We conclude that the nutritional therapy used to promote rapid weight gain restores reference body composition and significantly reduces time required for catch-up growth.

Anthropometry↗
PubMed1998

Body composition in institutionalized elderly people in Granada (Spain). Relation with other nutritional parameters.

Anthropometric characteristics and body composition were assessed in a group of 93 institutionalized elderly people, mean age 80.9 +/- 7.6 years, in Granada (Spain). The body composition was measured by the bioelectrical impedance technique. The influence of dietary energy intake, lifestyle, physical activity and health data were studied. Forty-five per cent of the women and 17% of the men were obese (BMI > 30 kg/m2) and 78% of the women and 54% of the men were overweight (BMI > 25 kg/m2). Only 12% of men and 4% of women suffered from undernutrition (BMI < 20 kg/m2). No significant correlations (P > 0.05) were found between BMI or body fat percentage and energy intake. Lifestyle and health data do not affect the BMI or body composition, but a significant negative correlation (P < 0.05) was found between the physical handicap level and the energy intake in all the sample (r = -0.26) and in the women (r = -0.16).

Aged↗