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At least 1,099 records · Page 61Linked to original sources

PubMed1998

Lack of an association between insulin-like growth factor-I and body composition, muscle strength, physical performance or self-reported mobility among older persons with functional limitations.

OBJECTIVE: The hypothesis that decreased growth hormone (GH) secretion contributes to the functional decline that occurs with aging is far from substantiated. There have been few studies addressing the distribution and correlates of IGF-I, an indicator of GH activity, in nonclinical populations. As part of a growth hormone intervention trial, we examined the cross-sectional relations between IGF-I levels and multiple measures of physical function, body composition, and strength in a group of older men and women exhibiting mild to moderate reductions in measured physical performance. METHODS: Using a variety of advertising techniques, 155 older subjects were recruited from a metropolitan area to participate in a growth hormone and exercise intervention study. At baseline, all subjects had blood drawn for IGF-I and underwent testing of body composition using dual X-ray absorptiometry, muscle strength using isokinetic dynamometry, and functional assessment using timed performance measures and self-report. Associations between levels of IGF-I, body composition, strength, and physical function were assessed after dividing men and women separately into tertiles of IGF-I as well as treating IGF-I as a continuous variable. RESULTS: Men had higher IGF-I levels than women, and a significant inverse correlation was observed between age and IGF-I in men (r=-0.29, P=.009). There were no clear trends for associations between tertiles of IGF-I, and any of the variables tested. Linear regression models with IGF-I treated as a continuous measure were not associated significantly with any of the measures of physical function, body composition, or strength (all P > 0.05). CONCLUSIONS: In conclusion, although IGF-I levels declined with age in men, these data did not demonstrate an association between IGF-I and measures of muscle strength, body composition, or physical functioning. These findings support the growing body of evidence that IGF-I levels may not be an indicator of growth hormone activity in older persons.

Aged↗

PubMed1995

Physical activity, body composition and bone density in ballet dancers.

The main purpose of the present study was to examine factors that affect bone mineral density (BMD) in female ballet dancers. Training history, Ca intake, body composition, total body BMD (TBMD) and site-specific BMD, and bone mineral content were described in twenty-four female ballet dancers (mean age 22.6 (SD 4.5) years). Training history was determined by questionnaires, Ca intake by 7 d dietary record, BMD and bone mineral content by dual-energy X-ray absorptiometry (DXA), total body water by 2H dilution, extracellular water by bromide dilution, body fat by underwater weighing (UWW; two-component model), DXA, and the four-component (4C) model. Dancers had a significantly lower body mass index (BMI 18.9 (SD 1.0) kg/m2) than controls (21.3 (SD 1.9) kg/m2), with significantly lower percentage body fat (17.4 (SD 3.9) v. 24.4 (SD 5.1)) but comparable fat-free mass. Mean TBMD (1.147 (SD 0.069) g/cm2) was significantly higher (6%) compared with that of a reference population. These high values could be attributed to the high BMD of legs and pelvis, the weight-bearing sites of the dancer's body. No relationship was found between age, start of ballet classes, period (years) of dancing, Ca intake, and BMD (total and site-specific). However, TBMD was positively related to BMI, and negatively related to the age of menarche. BMD of the legs was significantly related to BMI, and negatively related to the age of menarche. BMD of the legs was significantly related to daily period (h) of training. Depending on the method used the percentage body fat ranged from 16.4 (by DXA) to 18.3 by the 4C model. These differences were significantly related to the TBMD. Percentage body fat by the different methods was not significantly different, except for DXA and 4C model. The present study showed that, despite the factors that have a negative effect on BMD, such as low body mass and late menarche, BMD in female ballet dancers was relatively high. These high values were probably caused by high levels of weight-bearing physical activity.

Absorptiometry, Photon↗

PubMed2000

Relationship between energy deficits and body composition in elite female gymnasts and runners.

PURPOSE: The purpose of this study was to evaluate energy balance and body composition in 42 gymnasts (mean age = 15.5 yr) and 20 runners (mean age = 26.6 yr), all of whom were on national teams or were nationally ranked. METHODS: Athletes were assessed for body composition using DEXA and skinfolds, and energy balance was determined with a Computerized Time-Line Energy Analysis (CTLEA) procedure. RESULTS: Results from the CTLEA were assessed as the number of within-day energy deficits (largest and frequency) and within-day energy surpluses (largest and frequency). There was a significant difference (P = 0.000) in the mean number of hourly energy deficits > 300 kcal experienced by gymnasts (9.45 +/- 6.00) and runners (3.70 +/- 5.34). There was also a significant difference (P = 0.001) in the mean number of hourly energy surpluses > 300 kcal experienced by gymnasts (1.40 +/- 3.04) and runners (6.20 +/- 5.50). The mean largest daily energy deficit was 743 (+/- 392) kcal for gymnasts and 435 (+/- 340) kcal for runners. The mean largest daily energy surplus was 239 (+/- 219) kcal for gymnasts, and 536 (+/- 340) kcal for runners. There was a significant relationship between the number of daily energy deficits > 300 kcal and DEXA-derived body fat percent for gymnasts (r = 0.508; P = 0.001) and for runners (r = 0.461; P = 0.041). There was also a negative relationship between the largest daily energy surplus and DEXA-derived body fat percentage for gymnasts (r = -0.418; P = 0.003). Using the energy balance variables, age, and athlete type (artistic gymnast, rhythmic gymnast, middle-distance runner, long-distance runner) as independent variables in a forward stepwise regression analysis, a small but significant amount of variance was explained in DEXA-derived (P = 0.000; R2 = 0.309) and skinfold-derived (P = 0.000; R2 = 0.298) body fat percent by the number of energy deficits > 300 kcal and age. CONCLUSIONS: These data suggest that within-day energy deficits (measured by frequency and/or magnitude of deficit) are associated with higher body fat percentage in both anaerobic and aerobic elite athletes, possibly from an adaptive reduction in the REE. These data should discourage athletes from following restrained or delayed eating patterns to achieve a desired body composition.

Adolescent↗

PubMed2001

Longitudinal changes in body mass index and body composition over 3 years and relationship to health outcomes in Hong Kong Chinese age 70 and older.

OBJECTIVES: To determine longitudinal changes in body mass index (BMI) and body composition with age and the relationship between these changes with mortality, morbidity, functional capacity, and other health outcome measures. DESIGN: A 3-year longitudinal study of a random sample of community-living subjects. SETTING: Older Chinese in the Hong Kong Special Administrative Region of China. PARTICIPANTS: Two thousand and thirty-two Chinese subjects age 70 and older recruited territory-wide by proportional random sampling. MEASUREMENTS: Baseline information collected included medical history, self-perceived health, Barthel Index, Geriatric Depression Score, time taken to complete a 16-foot walk, height, weight, mid-arm circumference, arm skin-fold thickness, and waist/hip ratio. Body composition was calculated from prediction equation. Outcome measures included mortality, development of new diseases, Barthel Index, time taken for 16-foot walk, self-perceived health, and Geriatric Depression Score. RESULTS: All parameters, with the exception of triceps skin-fold thickness in men, decreased, regardless of presence or absence of disease. The decrease in arm circumference, triceps skin-fold thickness, and total body fat (TBF) was greater in women than in men, whereas men had a greater decrease in fat-free mass (FFM). Even in the absence of disease, three times as many subjects lost > or =5kg in weight as gained > or =5kg (15% vs. 5%), and only age could be identified as a contributing factor to this weight loss. In the absence of disease, lower anthropometric indices were associated with greater mortality, development of new disease (in women only), dependency, and poor performance measure. Waist-hip ratio was not associated with mortality or any other health outcomes. Decrease in both FFM and TBF were associated with worse outcomes, the effect being more marked in women. CONCLUSION: In the older population, changes in weight and body composition occur even in the absence of disease and are associated with mortality and physical functioning level. Weight loss rather than weight gain appears to be more important in this population, and promotion of life-style interventions targeted at weight maintenance would be important.

Activities of Daily Living↗

PubMed2004

[Genetic location of body composition traits in pigs].

To detect quantitative trait loci (QTL) for body composition traits in pigs, a resource family with three-generation was developed by using Large White grand sires and Meishan grand dams. A total of 81 F(2) progenies were phenotyped for body composition. All animals were genotyped for microsatellite markers. The main results are as follows:, the strongest linkages at genome-wise level of lean meat percentage and total meat content were detected on SSC1 and 4. QTLs for loin eye area were located on SSC1, 2 and 4, QTLs for loin eye height on SSC 1 and 4, and QTLs for loin eye width on SSC 6. The best positions estimated for QTLs of skin percentage and of skin weight were in the same marker interval. Two QTLs significant at genome-wise level or highly significant at chromosome-wide level for carcass length were located on SSC6 and 7.

Animals↗

PubMed1994

Bioelectrical impedance and body composition: present status and future directions.

Single-frequency bioelectrical impedance analyzers used to assess body composition are being replaced by multiple-frequency analyzers. At low frequencies, the current flows primarily through extracellular fluids; at high frequencies, it completely penetrates all body tissues. Measures of bioelectrical impedance at multiple frequencies can differentiate total and extracellular fluid compartments in the body. This has considerable value for assessing clinical and nutritional status. Impedance measures at a single frequency contain only a small window of the available impedance spectrum information, which may explain the difficulty in discriminating among individuals. The impedance spectrum and its analysis may provide a much clearer picture of individual differences in body water and body composition. With increasing clinical uses of bioelectrical impedance in individuals and sample populations, the use of multiple-frequency impedance may help to elucidate differences that are not discernible with single-frequency impedance.

Body Composition↗

PubMed1979

Body composition of rugby union football players.

The components of body composition were studied in 56 second class rugby union football players: 28 forwards and 28 backs. Fowards were found to have 19.5% TBF (TOTAL BODY FAT) and 80.5% LBM (LEAN BODY MASS); backs 12.2% TBF and 87.8% LBM. It was felt that greater attention should be given to the ratio of TBF to LBM in determining body weight and that there should be an increased emphasis of the LBM at the expense of TBF.

Adult↗

PubMed1998

Whole body protein metabolism estimated by 15N tracer experiments and body composition of mice selected for different growth parameters.

Whole body protein synthesis was investigated in growing male mice which were long-time selected for high carcass protein amount (DU-6P, protein line) or for high body weight (DU-6, growth line) and in the unselected randomly bred control (DU-Ks). Six mice/line were housed singly in metabolic cages for the estimation of N balance, whole body protein synthesis (end-product method, single dose of 15N-labelled amino-acid mixture), and N distribution in the body. Another six mice/line were used for the determination of the body composition. All mice had free access to a commercial stock diet (crude protein 268 g, gross energy 19 MJ/kg dry matter) and to water. Body weight of both selection lines was about twice that of control mice at the same age. Selection for high body weight resulted in higher body fat content. Scaled to the corresponding body protein pools, the protein synthesis rates of selected mice were significantly higher than in controls, but were not significantly different between both selection lines in contrast to the protein deposition rates. The higher protein accretion in the protein line in comparison to the growth line seems to be due to a combination of a lower protein breakdown and an increased protein synthesis rate.

Animals↗

PubMed2002

Growth performance and whole-body composition of pigs experimentally infected with Mycoplasma hyopneumoniae.

Mycoplasma hyopneumoniae (Mh) is the primary infectious pathogen responsible for enzootic pneumonia in pigs. Although Mh is thought to impair growth performance, whole-body composition, and fat and protein accretion in pigs with pneumonia have not been reported and the mechanism through which Mh reduces growth is unknown. The objectives of this study were to evaluate the effects of Mh on growth performance, whole-body composition, and protein and fat accretion in nursery pigs and to determine whether Mh infection increases the expression of interleukin (IL)-1beta, IL-6, and tumor necrosis factor-alpha (TNF-alpha). Sixty-four 2-wk-old Mh-free pigs were used (two trials) in a randomized complete block design. In each trial, two pigs were housed in each of 16 disease-containment chambers. At 4 wk of age, pigs were inoculated intratracheally with 3 mL of Mh broth (P5722-3, 10(7) cfu/mL) or sterile Friis culture medium. Clinical signs of disease and feed intake were monitored daily and body weight was determined weekly for 4 wk. Whole-body composition was determined from pigs killed 0, 14, and 28 d after inoculation, and the comparative slaughter technique was used to estimate protein and fat accretion. At death, gross lung lesions were quantified, and lung tissue was collected to verify the presence or absence of Mh, and to determine cytokine mRNA levels. Control pigs displayed no overt signs of infection and were Mh-negative and free of pulmonary lesions. Pigs inoculated with Mh showed pneumonic coughing (P < 0.005), were Mh-positive, and had pulmonary lesions that affected 4.5% (P < 0.01) and 14.1% (P < 0.001) of total lung surface area at 14 and 28 d, respectively, after inoculation. Ribonuclease protection assays revealed increased IL-1beta (P < 0.04) and TNF-alpha (P < 0.06) mRNA in lung tissue collected from a lesion site compared with tissue collected 10 cm from a lesion site or from control pigs. Interestingly, Mh did not depress weight gain or feed efficiency during any week of the 28-d study (P > 0.10). Moreover, Mh did not affect whole-body fat or protein accretion (P > 0.10). Thus, in spite of inducing disease and expression of inflammatory cytokines, Mh alone did not affect growth performance and whole-body composition of nursery pigs during the 4-wk experiment. The ability of pigs to contend with Mh may have resulted from the absence of other pathogens that generally co-exist with Mh under commercial conditions.

Animals↗

PubMed1997

Effect of sex and age on bone mass, body composition and fuel metabolism in humans.

The mechanism(s) governing the gain of upper-body fat and its relationship to the decrease in bone mass with age is still unclear. Therefore, four groups of subjects matched for weight, height, and body mass index (n = 119; 60 women, 59 men), but differing in age (above and below 50 y) and sex were investigated using dual energy x-ray absorptiometry (DXA) to assess body composition (bone, lean, and fat mass as well as its distribution) and indirect calorimetry to determine resting fuel metabolism. Fat mass of trunk and arms (P < 0.01), but not legs, increased with advancing age in males, resulting in a continuous increase in the ratio of upper- to lower-body fat (r = 0.45, P < 0.001). In contrast, total fat mass remained stable in women, irrespective of menopause, but a redistribution of fat occurred with advancing age (r = 0.43, P < 0.001), resulting in a higher upper- to lower-body fat ratio (P < 0.05) in older than in younger women. Total lean soft-tissue mass of all segments of the body was greater in men than in women irrespective of age (P < 0.001), and lower in the older groups than in the younger ones irrespective of sex. In males, but not females, lean soft-tissue mass in arms and legs decreased (r = 0.57, P < 0.001), whereas the ratio of total fat to lean soft-tissue mass increased (r = 0.53, P < 0.001) with age. Bone mineral content correlated with total body fat in both groups of women and in young males (r > 0.5, P < 0.001), but not in older males. With advancing age, the proportion of lean soft-tissue mass occupied by total skeleton declined in women (n = 59, P < 0.001), but remained stable in males. Resting energy expenditure decreased with age in both sexes. Protein and carbohydrate oxidation were similar in all four groups of subjects. Total fat oxidation and fat oxidation per kilogram of lean soft-tissue mass decreased with age (r > 0.36, P < 0.01) in males, but not in females, whereas it increased with increasing fat mass in females (r > 0.32, P < 0.03), but not in males. In contrast, fat oxidation per kilogram of fat mass decreased with fat mass in males (r = 0.61, P < 0.001), but not in females. Our results suggest that aging affects body composition and fuel metabolism differently in each gender, leading to reduced fat oxidation and accumulation of upper-body fat with loss of striated muscle in men, and to an increased ratio of upper- to lower-body fat and bone loss in women, the latter depending on fat mass.

Absorptiometry, Photon↗

PubMed2007

Effect of calorie restriction with or without exercise on body composition and fat distribution.

CONTEXT: There is debate over the independent and combined effects of dieting and increased physical activity on improving metabolic risk factors (body composition and fat distribution). OBJECTIVE: The objective of the study was to conduct a randomized, controlled trial (CALERIE) to test the effect of a 25% energy deficit by diet alone or diet plus exercise for 6 months on body composition and fat distribution. DESIGN: This was a randomized, controlled trial. SETTING: The study was conducted at an institutional research center. PARTICIPANTS: Thirty-five of 36 overweight but otherwise healthy participants (16 males, 19 females) completed the study. INTERVENTION: Participants were randomized to either control (healthy weight maintenance diet, n = 11), caloric restriction (CR; 25% reduction in energy intake, n = 12), or caloric restriction plus exercise (CR+EX; 12.5% reduction in energy intake + 12.5% increase in exercise energy expenditure, n = 12) for 6 months. MAIN OUTCOME MEASURES: Changes in body composition by dual-energy x-ray absorptiometry and changes in abdominal fat distribution by multislice computed tomography were measured. RESULTS: The calculated energy deficit across the intervention was not different between CR and CR+EX. Participants lost approximately 10% of body weight (CR: - 8.3 +/- 0.8, CR+EX: - 8.1 +/- 0.8 kg, P = 1.00), approximately 24% of fat mass (CR: - 5.8 +/- 0.6, CR+EX: - 6.4 +/- 0.6 kg, P = 0.99), and 27% of abdominal visceral fat (CR: 0.9 +/- 0.2, CR+EX: 0.8 +/- 0.2 kg, P = 1.00). Both whole-body and abdominal fat distribution were not altered by the intervention. CONCLUSION: Exercise plays an equivalent role to CR in terms of energy balance; however, it can also improve aerobic fitness, which has other important cardiovascular and metabolic implications.

Abdominal Fat↗

PubMed2005

Association of body composition and lung function in children with cystic fibrosis.

Survival in cystic fibrosis has improved significantly in the last 30 years, with major therapeutic goals of delaying the progressive loss of pulmonary function and maintaining normal growth. Dual-energy X-ray absorptiometry (DEXA) was performed in children with cystic fibrosis (CF) to assess both bone mineral density and body composition. We hypothesised that there would be an association between body composition and pulmonary function in children with CF. Fifty subjects with CF (28 males), mean age 12.7 years, participated in the study. Body composition was determined by DEXA. Body mass index (BMI) was calculated from the ratio of weight/height2 (kg/m2). Lung function was assessed by spirometry. Most patients (78%) had mild lung disease. The mean forced expired volume in 1 sec percent predicted (FEV1% predicted) for the 50 patients was 79.2% (range, 24-117%). There was a strong association between FEV1% predicted and BMI (R=0.59, P=0.0001). Fat-free mass had positive association with pulmonary function tests (R=0.30, P=0.03). Although fat mass showed a positive correlation with pulmonary function, this association did not reach statistical significance. In our group of children with CF and mild lung disease, pulmonary function was more strongly associated with BMI than with fat and fat-free mass.

Absorptiometry, Photon↗

PubMed1989

Comparisons of body composition derived from anthropometric and bioelectrical impedance methods.

This study compared bioelectrical impedance analysis (BIA) measurements with current bedside techniques for determination of body composition in 18 normal volunteers to evaluate the relative usefulness of these methods as adjuncts to assessment in surgical nutrition. Anthropometrics (weight, height, and two skinfold thicknesses) and age and sex were used to derive body density (D) or total body water (TBW) by two methods. Method 1: D was calculated from the logarithm of skinfold thickness according to Durnin and Womersley, adapted for age and sex. Method 2: TBW was calculated from height, weight, and sex according to Hume and Weyers. Resistance and reactance were measured with a four terminal impedance plethysmograph; from these data plus height, weight, and sex, lean body mass (LBM) was derived. In each instance, Siri's and Pace and Rathburn's equations were used to derive the remaining parameters of body composition: D, total body fat (TBF), TBW, and LBM. Using the paired t-test, no statistically significant differences were seen in any parameter determined by the different methods. These results show that D, TBW, TBF, and LBM in a population of healthy individuals under steady-state conditions can be estimated by anthropometric-derived formulas with the same relative accuracy as that provided from estimates based upon BIA measurements.

Adult↗

PubMed2003

Synergistic effects of testosterone and growth hormone on protein metabolism and body composition in prepubertal boys.

During human puberty there is a substantial increase in growth hormone (GH) and sex steroidal hormone concentrations, as well as in GH production rates and insulin-like growth factor-I (IGF-I) These studies were designed to investigate some of the interactions of testosterone (T) and GH in the metabolic changes of puberty. Ten boys with severe GH deficiency (GHD) were studied (mean age, 12.5 +/- 0.5 years) using stable isotope infusions, indirect calorimetry, and body composition analysis. After the baseline study, they received 2 doses of T enanthate (50 to 75 mg, intramuscular [IM]), and they were studied again 4 weeks later. The boys were then begun on daily subcutaneous (SC) GH (0.3 mg/kg/wk), while T therapy was continued for another 4 weeks and the studies repeated a third time. The treatment order was randomized. Protein oxidation rates decreased after T alone (-28%, P <.01), decreasing further after combined T/GH treatment (-36% v baseline, P <.01). The nonoxidative leucine disposal (NOLD), a measure of whole body protein synthesis, increased significantly after combined T/GH regardless of treatment order. The combination of T/GH also resulted in greater changes in body composition than T alone, with comparable decreases in %FM and corresponding increases in fat free mass (FFM). Measures of carbohydrate (CHO) metabolism, including glucose production and oxidation rates, were unaffected by either T or T/GH combination. Plasma IGF-I concentrations increased after T treatment and even more after T/GH combination, regardless of the treatment order. In conclusion GH and T are synergistic on whole body protein anabolism and body composition in males, even at a young age, but the positive effects of T on protein anabolism and body composition appear to need a basal amount of GH for those effects to be observed. GH and T both potentiate the development of the full body composition and metabolic changes of puberty.

Body Composition↗

PubMed2003

Body composition changes following laparoscopic gastric banding for morbid obesity.

Most reports of outcome following obesity surgery report weight and co-morbidity changes only. We studied body composition changes in 17 adult patients (15 F, 2 M, age 43+/-2 years, range 28-58 years), with morbid obesity (initial BMI 40.4+/-4.9 kg/m(2), range 34.7-48.8) who were managed surgically by laparoscopically inserting an adjustable gastric band. Body composition was studied before and after surgery (mean interval of 909+/-51 days, range 441-1155 days) using anthropometry (abdominal circumference, AC, sum of four skinfold thicknesses, SFSUM), whole-body potassium counting (TBK), in vivo neutron activation analysis total body nitrogen (TBProtein) and whole-body dual-energy ray absorptiometry (total body percent fat TBF%, and total body bone mineral density TBBMD). Weight loss over the study period was 23.4+/-2.5 kg. ( p<0.0003) with an AC reduction of 20.0+/-4.5 cm ( p<0.008). Both SFSUM and TBF% were significantly reduced ( p<0.02 and p<0.0005 respectively). Both TBK and TBProtein after normalization for sex and height, were significantly ( p<0.0054 and p<0.001 respectively) reduced, but the ratio of loss of fat mass to fat-free mass, at 4.4:1 was usual for weight loss, and there was no significant changes in the ratio of potassium to protein. TBBMD, after normalization relative to a young same sex adult, was not significantly changed. In this group of patients, most of the substantial weight loss over a 2- to 3-year period was due to loss of fat mass, with relatively less reduction in the components of fat-free mass. Adjustable laparoscopic gastric banding induces fat loss without significant other deleterious effects on body composition.

Absorptiometry, Photon↗

PubMed2005

The relationship between body composition and knee cartilage volume in healthy, middle-aged subjects.

OBJECTIVE: Although obesity is widely accepted as a risk factor for knee osteoarthritis, it is not clear whether individual components of body composition, such as the mass and distribution of muscle and fat, are associated with development of the disease. This study examined the effect of measures of body composition on the longitudinal change in tibial cartilage volume. METHODS: Body composition, assessed via dual x-ray absorptiometry, and tibial cartilage volume, assessed via magnetic resonance imaging, were measured in 86 healthy men and women who were mid-life in age. Change in tibial cartilage volume was assessed by imaging each knee 2 years after the baseline measurement and determining the difference from baseline in tibial cartilage volume. Correlations were determined between the muscle and fat mass of the arm, leg, and total body and the volume of the lateral- and medial-tibial cartilage, as well as the change in tibial cartilage volume over 2 years, after adjusting for confounders. RESULTS: There was a significant association between muscle mass and the medial-tibial cartilage volume, independent of age, sex, body mass index, tibial bone area, and level of physical activity. Although there was a positive association between muscle mass and the lateral-tibial cartilage volume, this did not persist after adjustment for confounders. Loss of muscle mass was associated with an increased loss of medial- and lateral-tibial cartilage over 2 years, after adjusting for confounders. No relationship was apparent between fat mass and either medial- or lateral-tibial cartilage volume, or between fat mass and change in either medial- or lateral-tibial cartilage volume over 2 years, after adjusting for confounders. CONCLUSION: Muscle mass is an independent predictor of medial-tibial cartilage volume in healthy people in mid-life and is associated with a reduction in the rate of loss of tibial cartilage. This suggests that increased muscle mass may be protective against the onset of osteoarthritis.

Absorptiometry, Photon↗

PubMed2001

Housing conditions influence the survival and body composition of ageing rats.

Ad libitum fed male Sprague-Dawley rats were randomly assigned to be housed individually (n=32) or four in each cage (n=32) from five to 23 months of age. Body weight and body composition by bioimpedance analysis were monitored longitudinally. An equation for analysis of body composition was developed. Deaths and causes of death were recorded. Of the individually housed animals (H1) 16 percent died, while 44 percent of those housed four in a cage (H4) died, the most common causes of death being circulatory failure, nephritis and tumours of the hypophysis.Body weight increased in both groups over time, significantly more for H4 from 6months of age. Both fat free mass and total body fat increased in both groups over time. Fat in percent of body weight increased up to an age of 14months. H4 animals had significantly more fat from 11 to 20 months of age but lost weight, mostly fat when approaching 23months of age. The occiput-sacrum length of the animals increased up to 11months of age and stayed then constant. Animals in both groups grew also in the cross-sectional dimension. The H1 animals continued to grow all the time, while the growth of the H4 animals stopped at the age of 17 months, when the mortality started to become pronounced. It is concluded that housing conditions can modulate the outcome of the ageing of sedentary and otherwise not treated rats in long-term experiments. Further, the feasibility of monitoring body composition longitudinally with bioimpedance analysis was demonstrated.

Aging↗

PubMed1997

Body composition in appropriate and in small for gestational age infants.

The body composition of 70 appropriate for gestational age newborn infants whose gestational age ranged from 32 to 41 weeks was determined by dual-energy X-ray absorptiometry during the first 48 h of life. The evolution of the bone mineral content, fat and lean mass was well correlated with gestational age (r = 0.66, r = 0.66 and r = 0.82, respectively) but even more closely with birthweight (r = 0.85, r = 0.91 and r = 0.97, respectively). The body composition of 20 symmetric small for gestational age infants (mean gestational age +/- SD = 38.1 +/- 1.2 weeks; mean birthweight +/- SD = 2117 +/- 183 g) was also studied. The total body fat, the lean mass and the bone mineral content of small for gestational age infants were decreased significantly in comparison with those of appropriate for gestational age infants with the same gestational age (p < or = 0.05, p < or = 0.0001 and p < or = 0.05) but was not significantly different from those observed in appropriate for gestational age infants of the same birthweight.

Absorptiometry, Photon↗