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Fat-free body mass is an important component of body composition which is of particular interest to nutritionists and related workers. Fat-free mass has been determined from the simple measurement of skinfold thickness and it has been demonstrated that there is a close correlation with total body nitrogen even though the test subjects had a wide range of nutritional status.
Body fat percentage (BF%) was measured in 298 Singaporean Chinese, Malay and Indian men and women using a chemical four-compartment model consisting of fat, water, protein and mineral (BF%4C). In addition, weight, height, skinfold thickness and segmental impedance (from hand to hand) was measured. Body fat percentage was predicted using prediction equations from the literature (for skinfolds BF%SKFD) and using the manufacturer's software for the hand-held impedance analyser (BF%IMP). The subjects ranged in age from 18-70 years and in body mass index from 16.0 to 40.2 kg/m2. Body fat ranged from 6.5 to 53.3%. The biases for skinfold prediction (BF%4C-BF%SKFD, mean +/- SD) were -0.4+/-3.9, 2.3+/-4.1 and 3.1+/-4.2 in Chinese, Malay and Indian women, respectively, the Chinese being different from the Malays and Indians. The differences were significant from zero (P < 0.05) in the Malays and Indians. For the men, the biases were 0.5+/-3.8, 0.0+/-4.8 and 0.9+/-4.0 in Chinese, Malays and Indians, respectively. These biases were not significantly different from zero and not different among the ethnic groups. The biases for hand-held impedance BF% were -0.7+/-4.5, 1.5+/-4.4 and 0.4+/-3.8 in Chinese, Malay and Indian women. These biases were not significantly different from zero but the bias in the Chinese was significantly different from the biases in the Malays and Indians. In the Chinese, Malay and Indian men, the biases of BF%IMP were 0.7+/-4.6, 1.9+/-4.8 and 2.0+/-4.4, respectively. These biases in Malay and Indian men were significantly different from zero and significantly different from the bias in Chinese men. The biases were correlated with level of body fat and age, and also with relative arm span (arm span/height) for impedance. After correction, the differences in bias among the ethnic groups disappeared. The study shows that the biases in predicted BF% differ between ethnic groups, differences that can be explained by differences in body composition and differences in body build. This information is important and should be taken into account when comparing body composition across ethnic groups using predictive methods.
Childhood obesity increases the risk of morbidity whether or not obesity persists into adulthood. Measurement of body fat content using bioimpedance analysis (BIA) is a useful tool in epidemiologic studies. Both tricep skinfold thickness (TST, mm) and body mass index (BMI, kg/m(2)) are indirect, simple methods and easy to perform for assessing body composition. These methods are generally accepted as good clinical measures for defining childhood obesity. The aim of our study was to evaluate fat mass (FM, kg and %) measurements using TST and BIA (50 kHz) in a cohort of 6-year-old Italian children. A total of 228 southern Italian children (121 boys, 107 girls), randomly selected in nine local primary schools, were included in the study. The correlation between methods for measuring FM was calculated. Linear regression analysis showed a significant positive correlation between FM measured with BIA and BMI ( r=0.92, p<0.001) and with TST ( r=0.79, p<0.001). We conclude that FM measurement using TST and BIA is comparable in different BMI ranges. However, BIA is a useful and alternative method for detecting body composition in children and may be a more precise tool than TST for measuring FM in epidemiological studies in pediatric populations.
In order to establish an easy and reliable method for estimating body composition, the lean body mass (LBM) and the fat mass (FM) were measured in vivo in 228 normal adults (130 women and 98 men) using dual photon (153Gd) absorptiometry. In addition, skinfold thickness was measured at two sites in each subject. Multiple regression equations of LBM and FM based on age, height, and weight were computed (r = .86 to .95, SEE = 2.1 to 2.9 kg). These correlations were only slightly improved in men, but not in women, when the results of the skinfold measurements were included in the calculations. We conclude that LBM and FM can be estimated in normal adults from age, height, and weight with a predictive error below 3 kg.
Some full-term infants with birthweights over 2500g suffer neonatal hypoglycaemia. These infants often appear to be poorly nourished, due to decreased amounts of subcutaneous fat. 100 normal term infants with birthweights over 2500g who were nursed, apparently asymptomatically, beside their mothers were chosen at random for study. As an objective indicator of malnourishment, standard deviation scores of skinfold thickness as a function of birthweight were derived from standards for each infant. Those infants with low skinfold standard deviation scores had significantly lower plasma glucose levels at four hours of age, but the correlation between plasma glucose and skinfold standard deviation scores, although significant, was too low for use as a screening method. The importance of finding an objective measurement for predicting neonatal hypoglycaemia in term neonates weighing over 2500g at birth is discussed.
BACKGROUND: Duchenne muscular dystrophy (DMD) is often associated with obesity, which worsens the handicap early in the course of the disease. Nutritional assessment, however, can be difficult and often misleading in DMD. OBJECTIVE: Two methods of estimating body composition in DMD, skinfold-thickness (ST) measurement and bioelectrical impedance analysis (BIA), were compared with a reference method, labeled water dilution (WD). DESIGN: Body composition was estimated by using ST measurements and BIA (50 kHz, 800 mAmp), as well as the WD method (1 mL H2(18)O/kg) in 11 DMD patients with a mean (+/-SD) age of 10.0 +/- 2.5 y. RESULTS: When compared with the WD method, ST measurement significantly (P < 0.01) overestimated fat-free mass (FFM) (mean +/- SD ST: 24.5 +/- 5.9 kg; mean +/- SD WD: 18.2 +/- 2.5 kg), which led to an underestimation of the percentage of fat mass (%FM) (ST: 23.3 +/- 10.4%; WD: 40.1 +/- 17.1%; P < 0.05). In contrast, estimates obtained with BIA (FFM: 21.5 +/- 4.5 kg; %FM: 31.3 +/- 13.9%) did not differ from those obtained with WD. The difference from the reference method was less for BIA (mean: 3.3 kg; 95% CI: 0.8, 4.9 kg) than for ST (6.3 kg; 2.2, 8.6 kg). WD and BIA defined 73% and 55%, respectively, of the children as obese (%FM associated with body mass index cutoffs for obesity), whereas ST measurements defined 9% as obese (P < 0.01). CONCLUSIONS: Body-composition estimates by BIA are closer to those by WD than are those by ST measurement. Early detection of fat accumulation and longitudinal monitoring of nutritional care are 2 relevant applications of BIA to prevent obesity and hence lessen the burden of DMD.
A stratified sample of normal infants born at term at Johannesburg Hospital, who attended the hospital for a routine 6-week follow-up visit, were selected to include 43 infants who were exclusively breast-fed, 42 fed a low-sodium formula and 39 fed a high-sodium formula (greater than 10 mmol sodium/l). Dynamic skinfold thickness measurements (DSTM), designed to assess the amount of interstitial fluid, were performed on each infant by the application of a skinfold caliper for a 3-second sampling period at two sites. The curves generated by these applications were recorded and analysed by microcomputer. There were no differences between any of the feeding groups for DSTM measurements of blood pressure suggesting that the range of sodium ingested by these groups of infants had no significant effects on extracellular water content. However, using multiple linear regression, both DSTM and blood pressure were best predicted by body weight and not by age or any other anthropometric measurement. Thus the normal postnatal decrease in extracellular fluid volume and increase in blood pressure appears to be most closely related to an increase in body weight.
BACKGROUND: Although body fat patterning has been related to adverse health outcomes in adults, its importance in children and adolescents is less certain. OBJECTIVE: We examined the relation of circumference (waist and hip) and skinfold-thickness (subscapular and triceps) measurements to lipid and insulin concentrations among 2996 children and adolescents aged 5-17 y. DESIGN: This was a community-based, cross-sectional study conducted in 1992-1994. RESULTS: A central or abdominal distribution of body fat was related to adverse concentrations of triacylglycerol, LDL cholesterol, HDL cholesterol, and insulin; these associations were independent of race, sex, age, weight, and height. These associations were observed whether fat patterning was characterized by using 1) waist circumference alone (after adjustment for weight and height), 2) waist-to-hip ratio, or 3) principal components analysis. Compared with a child at the 10th percentile of waist circumference, a child at the 90th percentile was estimated to have, on average, higher concentrations of LDL cholesterol (0.17 mmol/L), triacylglycerol (0.11 mmol/L), and insulin (6 pmol/L) and lower concentrations of HDL cholesterol (-0.07 mmol/L). These differences, which were independent of weight and height, were significant at the 0.001 level and were consistent across race-sex groups. CONCLUSIONS: These findings emphasize the importance of obtaining information on body fat distribution, waist circumference in particular, in children. Waist circumference, which is relatively easy to measure, may help to identify children likely to have adverse concentrations of lipids and insulin.
Forty-eight infants, including 14 premature infants who were appropriate size for gestational age (AGA), 10 full-term AGA infants, 18 full-term infants who were large for gestational age (LGA), and six premature LGA infants of diabetic mothers (IDMs), had measurements of skinfold thickness (SFT) in the first 72 h of life. For the 24 LGA infants, there was a significant positive correlation between maternal glycohemoglobin (Hb AIc) in the post-partum period and SFT (r = 0.42, p less than 0.05). Our observations in this study support those of others, demonstrating that SFT increases with increasing gestational age. In addition, they support the hypothesis that, in diabetic pregnancies, or pregnancies associated with an elevated Hb AIc, a reflection of the time-integrated blood glucose level over the weeks preceding parturition, fetal hyperglycemia and hyperinsulinemia stimulate increased triglyceride synthesis in adipose cells and lead to an increase in fetal subcutaneous fat.
Accidental immersion often involves the threat of death due to hypothermia. Clothing to control heat loss in water is generally selected to minimize bulk while providing the necessary protection. While water temperature (Tw) and possible immersion time are often considered, another relevant variable is the insulation provided by subcutaneous fat. This paper describes the use of a sophisticated computer model to explore the interactions among skinfold thickness (6-20 mm mean weighted value), clothing insulation (0.06-0.23 clo, immersed), and Tw (0-20 degrees C), in producing critical hypothermia (arterial temperature less than or equal to 34 degrees C). Results indicate that subcutaneous fat strongly affects heat loss even with heavy clothing. Discussion includes examples of the possible use of skinfold data to improve specification of protective clothing for groups and allow special clothing prescription for individuals.
OBJECTIVE: To determine the sensitivity and specificity of soft-tissue nuchal-fold measurement in the second-trimester fetus for the detection of trisomy 21. METHOD: Thirty-six investigators in 12 centers measured nuchal skinfold thickness in 3308 fetuses of 14-24 weeks' gestation. All mothers were referred for amniocentesis because of age, history of genetic disorder, or laboratory findings. Those referred with an ultrasound indication for amniocentesis, including nuchal-fold thickening, were excluded. RESULTS: Overall, nuchal skinfold was 6 mm or more in 8.5% of chromosomally normal fetuses and in 38% of those with trisomy 21. A false-positive rate below 5% was obtained by 81% of the investigators. Raising the cutoff of normality to 7 mm after 18 weeks' gestation improved specificity. CONCLUSION: Although the diagnostic value of this sign in skilled hands could allow its use as an indication for genetic amniocentesis at the second trimester, the method does not appear suitable for population screening because of the high variability in the results among the investigators.
Research to establish indirect methods of determining human body composition began during the 1940s. Renewed interest in the assessment of human body composition has stimulated the need for a balanced understanding of available methodologies of estimating fat-free mass and fat mass. Subsequently a variety of methods has been introduced. However, attempts to describe the theory and practice of individual methods have been limited. The review summarizes the background and to describe the precision or error of skinfold thickness measurement and to highlight the strengths and the limitations of bioelectrical impedance method.
This is the first comprehensive growth study of male children of Bengali parentage. The cross-sectional survey was undertaken in an urban high school situated in the north of the Metropolitan City of Calcutta during 1982 and 1983. The sample consisted of 815 healthy Bengali boys aged 7-16 years. In this paper, data on height, weight, and skinfold thicknesses are presented including patterns of change in these physical traits with increasing age. Mean values of height or weight of the boys--not representative for all school-going boys of Calcutta--are distinctly above the national standards given by the Indian Council of Medical Research. They are, however, shorter and lighter than the well-off boys of India but have a similar magnitude of subcutaneous fat on arm. Peak annual incremental growth in height and weight occurs in Bengali boys at 12-13 years and 14-15 years, respectively. This is about one year earlier than in the well-off Indian, British, or American boys.
STUDY OBJECTIVE: To determine the relationship between obesity and subsequent incidence of ischaemic heart disease (IHD). DESIGN: Prospective cohort survey. SETTING: Study of three occupational groups, with follow up examinations. SUBJECTS: 3500 people recruited between 1972 and 1978 (80% response rate), and followed up between 1978 and 1984. This report is based on subgroup of 1511 white men aged 40-64 at entry. MEASUREMENTS AND MAIN RESULTS: Information was obtained on smoking and family history of IHD. Blood pressure, weight, height, skinfold thickness at four sites, fibrinogen, factor VII activity and cholesterol were measured during follow up. Body mass index (BMI) was used as an index of obesity. BMI was found to be more strongly correlated with IHD than any of the skinfold measurements, none of which was significantly associated with IHD when BMI was allowed for. Increase in BMI by 1 SD (approximately 8 kg) was associated with a 44% increase in the risk of IHD. Of the four skinfolds, subscapular was the most closely associated with risk, confirming the relevance of central obesity. The association between obesity and IHD remained when possible mechanisms for its effects were taken into account, and its strength may increase with time: for 1 SD increase in BMI, risk of events within 5 years was increased by 28%, while risk of events after longer than 5 years was increased by 65%. CONCLUSIONS: Preventive strategies for IHD should include avoidance of obesity.
Because body composition is altered during head-down bed rest (HDBR), body mass can not be used as an index of energy balance. Consequently diet allowances should not be based on body mass evolution but on fat mass changes. Though criticized, skinfold thickness (ST) is the costless, easiest and fastest method to use for such an objective. The aim of this study was to compare the percentage of body fat (%BF) estimated by ST with the isotope dilution of H2 18O. We compiled data from three HDBR campaigns, one on women (n=8) in November 1998 and two on the same men (n=8) in December 1997 (without countermeasure) and January 1998 (with thigh-cuffs countermeasure), according to a crossover design. Body composition was assessed before and after 6 days of HDBR. %BF was derived from the biceps, triceps, sub-scapular and sup-iliac ST according to Durnin and Wormersly (1974). Fat-free mass was measured on the same day by H2 18O dilution and fat mass was calculated by the difference with body mass and expressed as a percentage. Based on precision tests, the minimum measurable change by ST was 1.1%BF for single measurement point. Both intercepts (F (4,30)=0.89, P=0.45) and slopes (F (4,30)=0.74; P=0.57) of the ST versus dilution relationships were not affected by the periods (December vs January), experimental conditions (control vs HDBR vs HDBR + thigh cuffs) or sex allowing the derivation of a common relationship %BF(st)=0.94 x %BF(dil) (F (1,47)=97.9, P<0.0001; non-significant intercept excluded) with a bias between methods of -1.7+/-2.0 %BF (95% CI: -5.8, 2.4 %BF). ST can be used to measure %BF during HDBR provided great care is placed on training and changes are higher than 1.1 %BF. If the method can be applied for in-flight energy balance monitoring given the high observed energy deficit, a tight monitoring of the individual nutritional status as needed during simulation appears, however, dubious based on this solely method.
The measurement of body composition is an important part of metabolic and epidemiological research, but most currently available methods are complex and expensive. We have, therefore, compared measurements of fat mass (FM) and lean body mass (LBM), obtained using a commercially available bioelectrical impedance monitor (The Holtain Body Composition Monitor) (IMP), and by measuring skinfold thickness (SFT), with values obtained by measuring total body potassium (TBK). Twenty subjects, 10 with a body mass index (BMI) less than 30 (kg m-2), (non-obese) and 10 with BMI greater than or equal to 30 (obese) took part in the study. There was a strongly significant linear relationship between LBM calculated from TBK and that calculated from impedance (IMP), in both non-obese and obese groups analysed separately (non-obese: r = 0.92; p less than 0.001 and obese: r = 0.92; p less than 0.001) and together (all: r = 0.89; p less than 0.001). LBM calculated from TBK was strongly linearly correlated with values derived from SFT for non-obese (r = 0.91; p less than 0.001) but not for obese subjects. Mean values of LBM of non-obese subjects derived by each method were not significantly different (TBK: 51.3 +/- 10.40 kg; IMP: 53.18 +/- 10.37 kg; SFT: 48.87 +/- 9.48 kg), but significant differences existed when the subjects were obese (TBK: 51.86 +/- 9.65 kg; IMP: 58.69 +/- 8.55 kg; SFT: 67.61 +/- 8.14 kg; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
The relation between fitness and adiposity is particularly relevant to adolescent females in whom fitness is known to decrease and fatness to increase. However, little is known about the interaction of these variables in normally active, nonobese subjects. Our major hypotheses were that adiposity would be inversely correlated with physical fitness and that even a relatively brief intervention would lead to measurable, site-specific changes in body fat. We used a cross-sectional protocol to correlate body adiposity with indexes of fitness and a prospective study design to examine body adiposity before and after a 5-wk period of endurance training in 44 nonobese females aged 15-17 y (control group, n = 22; training group, n = 22). Adiposity was assessed by magnetic resonance imaging of the abdomen and thigh as well as by standard skinfold-thickness measuring techniques. Fitness was assessed by using cycle ergometer measurements of maximal oxygen uptake (VO2max). There were significant negative correlations between VO2max normalized to body weight and subcutaneous abdominal, thigh, and skinfold estimates of fat. However, when VO2 max was normalized to muscle volume these correlations were not significant. Abdominal fat increased in direct proportion to body weight (scaling factor = 1.14 +/- 0.16) but thigh fat increased proportionately less (scaling factor = 0.38 +/- 0.12, P < 0.05). Training increased thigh muscle mass significantly only in the midmuscle region and prevented the observed fat increase in the distal thigh of the control subjects. Body fat distribution in adolescent females appeared to be affected by many factors, including overall body weight and the level of physical activity.
BACKGROUND: Body composition assessment in patients with chronic renal failure is of paramount importance since studies have demonstrated the association of protein-energy malnutrition with an increased morbidity and mortality in this population. However, practical and sensible indicators of body compartments are still needed for clinical purposes. Thus, we aimed to evaluate the simple methods of skinfold thicknesses (SKF) and bioelectrical impedance analysis (BIA), using dual-energy X-ray absorptiometry (DEXA) as a reference method, for the assessment of body fat in patients on long-term haemodialysis therapy. METHODS: We studied 30 clinically stable patients (15 men/15 women) undergoing haemodialysis at the Dialysis Unit of the Federal University of São Paulo. Body fat assessment was performed by the SKF, BIA and DEXA methods after a haemodialysis session. Analysis of variance, intra-class correlation coefficient and Bland and Altman plot analysis were used for comparative analysis among the methods. RESULTS: Body fat estimates by SKF (17.7 +/- 7.8 kg) and BIA (18.6 +/- 9.2 kg) were not significantly different from those obtained by DEXA (18.2 +/- 7.9 kg) considering the whole population. However, the BIA technique worked differently from DEXA when analysed by gender, measuring less fat content in men and higher fat content in women (P < 0.01). No differences were observed for SKF. Strong intra-class correlation coefficients (r) were found between DEXA with SKF (r = 0.94) and BIA (r = 0.91). DEXA showed a relatively good agreement with both SKF [0.47 +/- 2.8 (-5.0 to 6.0) kg] and BIA [-0.39 +/- 3.3 (-6.9 to 6.1) kg] in all patients according to the Bland and Altman plot analysis. However, considering gender, BIA showed greater mean prediction error of 1.93 +/- 2.5 (-3.0 to 6.8) kg for men and -2.71 +/- 2.3 (-7.2 to 1.8) kg for women. CONCLUSIONS: The simple and long established method of SKF was preferable over BIA, which showed gender-specific variability in the assessment of body fat in patients undergoing haemodialysis. However, more comparative and longitudinal studies are needed to evaluate the applicability of these practical methods for monitoring body composition in the routine care of patients with chronic renal failure.