Racial differences in subcutaneous fat patterns in children aged 7–15 years

In a stratified random sample of 278 children aged 7–15 years of an entire biracial community, skinfold measurements were taken on six standard body sites. We found that white children had generally thicker skinfolds than blacks for the same body weight, with a consistent exception: the subscapular skinfold was relatively thicker in blacks. It is suggested that this racial difference in distribution of fat may manifest a genetic adaptive trait developed under circumstances demanding both a caloric reserve and facilitation of convective heat loss in tropical climates.     

Skin reflectance relationships with temperature and skinfolds

Skin reflectance measurements were taken with six filters at a site on the medial aspect of the upper arm (underarm) prior to and following topical application of a cold compress. Skinfolds were measured at the underarm and triceps sites. The experiment was designed to test for effects of skin surface temperature and subcutaneous fat variations on skin color as determined by reflectometry. Topical cold-induced erythema of the skin produced marked declines in % reflectance at the shorter visible wavelengths over the range of violet, blue, and green, and only slight declines in % reflectance at the longer visible wavelengths (red range). This is consistent with the observation from past work that there is little hemoglobin absorptance at the red end of the visible spectrum. A positive relationship between the change in % reflectance following topical cold application and underarm skinfold was recorded. Hence, the thickness of fat deposits may contribute to variation in skin reflectance. Since only large temperature differences influenced skin reflectance measurements, the need is not great for fieldworkers to control for surface temperature at the underarm site during skin reflectance survey.     

A multivariate analysis of fatness and relative fat patterning.

Skinfold measurements (triceps, subscapular, suprailiac and medial calf) in four samples (376 boys, 352 girs, 338 men and 380 women from rural Colombia) were subjected to principal components analysis to identify components of obesity and relative fat patterning. Three components emerged which were similar in the four samples: a first component of fatness explaining 70-80% of the variance and two fat pattern components each explaining 10-15% of the variance: trunk-extremity and upper-lower body. Fatness and the trunk-extremity pattern components changed with age in children (7-12 years), but none of the components changed with age in adults (25-60+). The fatter tended to be more patterned in both age groups. Canonical correlation analysis revealed that socioeconomic status was more related to fatness than to patterning. With the exception of brothers, all first degree relatives (sib, parent-off-spring) and spouses were correlated in fatness. Some of the correlations between relatives--usually sibs, but not spouses--were also significant for the pattern components, suggesting a genetic basis for the known stability of this characteristic (Garn, '55a). Principal components analysis is a useful multivariate alternative for quantitative studies of anthropometric patterning.     

Anthropometric measures, body composition, body fat distribution, and knee osteoarthritis in women

Objective: Increased BMI is a well‐recognized risk factor for radiographic knee osteoarthritis (rKOA); however, the contributions of the components of body composition, body fat distribution, and height to this association are not clear. Research Methods and Procedures: We examined 779 women ≥45 years of age from the Johnston County Osteoarthritis Project. Body composition was assessed using DXA, and rKOA was defined as Kellgren‐Lawrence grade ≥2. Logistic regression models examined the association between rKOA and the fourth compared with the first quartiles of anthropometric, body composition, and fat distribution measures adjusting for age, ethnicity, and prior knee injury. Results: The adjusted odds ratios and 95% confidence interval of BMI and weight were 5.27 (3.05, 9.13) and 5.28 (3.05, 9.16), respectively. In separate models, higher odds of rKOA were also found for fat mass [4.54 (2.68, 7.69)], percent fat mass [3.84 (2.26, 6.54)], lean mass [3.94 (2.22, 6.97)], and waist circumference [4.15 (2.45, 7.02)]. Waist‐to‐hip ratio was not associated with rKOA [1.45 (0.86, 2.43)], and percent lean mass was associated with lower odds [0.20 (0.11, 0.35)]. Taller women had higher odds of rKOA after adjustment for BMI [1.77 (1.05, 3.00)]. Discussion: This study confirms that BMI and weight are strongly associated with rKOA in women and suggests that precise measurements of body composition and measures of fat distribution may offer no advantage over the more simple measures of BMI or weight in assessment of risk of rKOA.     

Androgens and body fat distribution

An important sex difference in body fat distribution is generally observed. Men are usually characterized by the android type of obesity, with accumulation of fat in the abdominal region, whereas women often display the gynoid type of obesity, with a greater proportion of their body fat in the gluteal-femoral region. Accordingly, the amount of fat located inside the abdominal cavity (intra-abdominal or visceral adipose tissue) is twice as high in men compared to women. This sex difference has been shown to explain a major portion of the differing metabolic profiles and cardiovascular disease risk in men and women. Association studies have shown that circulating androgens are negatively associated with intra-abdominal fat accumulation in men, which explains an important portion of the link between low androgens and features of the metabolic syndrome. In women, the low circulating sex hormone-binding globulin (SHBG) levels found in abdominal obesity may indirectly indicate that elevated free androgens are related to increased visceral fat accumulation. However, data on non SHBG-bound and total androgens are not unanimous and difficult to interpret for total androgens. These studies focusing on plasma levels of sex hormones indirectly suggest that androgens may alter adipose tissue mass in a depot-specific manner. This could occur through site-specific modulation of preadipocyte proliferation and/or differentiation as well as lipid synthesis and/or lipolysis in mature adipocytes. Recent results on the effects of androgens in cultured adipocytes and adipose tissue have been inconsistent, but may indicate decreased adipogenesis and increased lipolysis upon androgen treatment. Finally, adipose tissue has been shown to express several steroidogenic and steroid-inactivating enzymes. Their mere presence in fat indirectly supports the notion of a highly complex enzymatic system modulating steroid action on a local basis. Recent data obtained in both men and women suggest that enzymes from the aldoketoreductase 1C family are very active and may be important modulators of androgen action in adipose tissue.     

Relationship of fat patterning to coronary artery disease risk in obese adolescents

Fatness and fat patterning of 27 male and 33 female obese adolescents were identified by principal-components analysis of five skinfolds (triceps, subscapular, iliac, abdominal, and thigh). Correlations were computed between the component scores, based on the eigen vectors, and anthropometric and physiological variables. Overall fatness, component I, was highly correlated with all anthropometric and body composition variables. Also, component I significantly correlated with fasting insulin and VO2 max for both sexes and with basal metabolism and HDL-cholesterol for females and males, respectively. Extremity fat patterning, component II, was poorly correlated with all the anthropometric and physiological variables except diastolic blood pressure for the females. Upper-lower body fat patterning, component III, was correlated with the fewest physiological variables.     

Comparison of ultrasound and skinfold measurements in assessment of subcutaneous and total fatness

Ultrasound (A-scan mode) and skinfold methods were evaluated in the measurement of subcutaneous fat thickness and prediction of total fat weight (by whole body potassium counting). Based on intraobserver correlations on 39 men at 15 body sites, skinfold caliper measurements were more reproducible than ones obtained by ultrasound. Measurements made with the two techniques at the same site typically produced different mean estimates of fat thickness. However, scores were often highly correlated with each other, indicating similar relative rankings of subjects by each technique. Skinfolds were more highly correlated with total fat weight than were ultrasound measurements, but body weight and anthropometric measures had even higher correlations with total fat weight. Anthropometric measurements were highly correlated with fatness because of their association with body weight, and when this relationship was statistically controlled for, they typically lost their predictive effectiveness. Multiple regression analyses revealed that the best predictors of fat weight were body weight along with skinfold and ultrasound measurements. These results suggest that skinfolds are a more effective means of assessing subcutaneous fat than ultrasound, especially when the large difference in cost of equipment is considered.     

Relative body fat and anthropometric prediction of body density of female athletes

Ninety-one percent (n = 182) of the female members of South Australian representative squads in 14 sports volunteered to act as subjects. Twenty-seven percent of them had represented Australia. The underwater weighing method together with the measurement of residual volume (RV) by helium dilution were used to determine body density (BD); the percent body fat (% BF) was then computed according to Siri. A stepwise multiple regression analysis yielded a correlation coefficient (R) of 0.863 between the criterion (BD) and the best weighted sum of predictors (anthropometric variables): BD (g X cm-3) = 1.14075-0.04959 (log10 sigma triceps, subscapular, supraspinale and calf skinfolds in mm) + 0.00044 (age in decimal years)-0.000612 (waist girth in cm) + 0.000284 (height in cm)-0.000505 (gluteal girth in cm) + 0.000331 (breast girth in cm). Only those predictors which resulted in a statistically significant increase in R (p less than or equal to 0.05) were included. The standard error of estimate of 0.00597 g X cm-3 was equivalent to 2.7% BF at the mean. This equation was shown to be largely population specific. There was a range of 7.6-35.8% of BF and the overall mean 18.5% was significantly lower (p less than 0.001) than that of 23.4% obtained on a moderately active reference sample of similar age (n = 135). If group sizes of only one or two are regarded as too small for meaningful comparison, then the lowest mean of 13.5% was achieved by the long-distance runners (n = 14). The highest averages were registered by the heavyweight rowers (24.2%; n = 7) and soccer players (22.0%; n = 11). The overall average for games players (n = 107) was 19.4%.     

Effect of body fat and gender on body temperature distribution

It is well known that body composition can influence peripheral heat loss and skin temperature. That the distribution of body fat is affected by gender is well known; however, there is little information on how body composition and gender influences the measure of skin temperature. This study evaluated skin temperature distribution according to body fat percentage (BF%) and gender. A sample of 94 apparently healthy volunteers (47 women and 47 men) was assessed with Dual-Energy X-Ray Absorptiometry (DXA) and infrared thermography (mean, maximum and minimum temperatures – T_Mean, T_Max and T_Min). The sample was divided into groups, according to health risk classification, based on BF%, as proposed by the American College of Sports Medicine: Average (n = 58), Elevated (n = 16) or High (n = 20). Women had lower T_Mean in most regions of interest (ROI). In both genders, group High had lower temperature values than Average and Elevated in the trunk, upper and lower limbs. In men, palms and posterior hands had a tendency (p < 0.05) for increased temperature along with increased BF%. T_Mean, T_Max and T_Min of trunk, upper and lower limbs were negatively correlated with BF% and the fat percentage of each segment (upper limbs, lower limbs and trunk). The highest correlations found in women were between posterior trunk and BF% (rho = −0.564, p < 0.001) and, in men, between anterior trunk and BF% (rho = −0.760, p < 0.001). Overall, this study found that women have lower skin temperature than men, which was related with higher BF%. Facial temperature seems not to be influenced by body fat. With the future collection of data on the relationship between BF% and skin temperature while taking into account factors such as body morphology, gender, and ethnicity, we conclude that measurement of BF may be reliably estimated with the use of thermal imaging technology.     

Age changes in skinfolds, body fat and lean body mass in Jat-Sikh and Bania females during 20 to 80 years

The present paper reports the changes in body fat and lean body mass during 20 to 80 years. The data consist of 502 Jat-Sikh and 510 Bania females. The body fat has been calculated by applying Durnin & Womersley's (1974) formulae. The body fat reaches a maximum value of 20.06 kg at age-group 60-64 in Jat-Sikh females and 22.15 kg at age-group 45-49 in Bania females followed by a decline, reaching a value of 15.28 kg in Jat-Sikhs and 14.93 kg in Banias in the 70+ age group. The redistribution of fat with ageing has also been observed from skinfold measurements and changing body contours. The lean body mass reaches a maximum value of 35.64 kg in Jat-Sikhs and 36.22 kg in Bania at age-group 35-39 followed by a steady decrease reaching a value of 30.47 kg in Jat-Sikhs and 28.27 kg in Banias at age-group 70+. The females of the present study possess significantly lesser body fat and lean body mass as compared to American and British females. But in terms of percentages the Jat-Sikh females of the present study possess the largest lean body mass and the least body fat.     

Sodium-lithium countertransport and body fat distribution.

The relationship between erythrocyte sodium-lithium countertransport (Na-Li CT) and body fat distribution is analyzed in a sample (n = 101) of normotensive and untreated hypertensive men participating in an epidemiological study of coronary heart disease risk factors. Na-Li CT is significantly and positively associated with both subscapular skinfold and waist to hip ratio, but not with triceps skinfold. The univariate correlation between Na-Li CT and blood pressure is diminished when adjusted for body mass index and waist to hip ratio. These findings support the existence of an association between Na-Li CT and central body fat distribution and suggest that the metabolic abnormalities associated with centrally distributed body fat could explain, at least in part, the association between Na-Li CT and blood pressure. The maximal velocity of the sodium-lithium countertransport (Na-Li CT) in erythrocytes has been reported to be directly associated with blood pressure and hypertension in numerous reports from both clinical and epidemiological studies. In most of these studies, indices of weight and/or adiposity (body mass index, in particular) have been shown to be among the most important correlates of Na-Li CT. Adiposity is an important determinant of blood pressure, and there is evidence suggesting that the patterning of the fat cells in the body is linked to a number of metabolic disturbances that could lead to hypertension and an increase in other CHD risk factors. The present report analyses the relationship between Na-Li CT and body fat distribution in a sample of normotensive and untreated hypertensive men participating in an epidemiological study.     

Age variations in the relation of body mass indices to estimates of body fat and muscle mass

In some chronic disease studies, distinctions have been made regarding the importance of body mass index (BMI) as a risk factor in younger versus older men and women. In order to determine the significance of these differences in BMI-disease associations, we determined the extent of age-dependent variations in the relation of BMIs to body composition in large probability samples of U.S. men and women from the First and Second U.S. National Health and Nutrition Examination Surveys (NHANES I and II). BMIs are more highly correlated with estimates of body fat in younger than in older men and women, and with muscle mass in older than in younger adults. Caution should be exercised in interpreting the significance of BMI as a risk factor for chronic disease, particularly in comparison of age groups.     

Relationship of the body mass index with skinfolds,girths, and bone breadths in canadian men and women aged 20–70 years

The relationships of Quetelet index (w/h²), or body mass index (BMI), with the sum of skinfolds at five sites, two skinfold-corrected limb girths, and two bone breadths were studied in a cross-sectional sample of 12,282 men and 6,593 women aged 20–70 years. The correlations of the BMI with skinfolds (0.50), bone breadths (0.51), and girths (0.58) were too low for individual prediction. Contingency tables of the BMI and sum of skinfold categories further indict its use for the purpose of assessing adiposity status or monitoring change in individuals.     

Monogenic disorders of obesity and body fat distribution.

Recently, great progress has been made towards understanding the molecular basis of body fat regulation. Identification of mutations in several genes in spontaneous monogenic animal models of obesity and development of transgenic models have indicated the physiological roles of many genes in the regulation of body fat distribution. In humans, mutations in leptin, leptin receptor, prohormone convertase 1 (PC1), pro-opiomelanocortin (POMC), melanocortin 4-receptor (MC4-R), and peroxisome proliferator-activated receptor (PPAR) gamma2 genes have been described in patients with severe obesity. Most of these obesity disorders exhibit a distinct phenotype with varying degrees of hypothalamic and pituitary dysfunction and a recessive inheritance, whereas MC4-R mutation has a nonsyndromic phenotype with dominant inheritance. These mutations suggest the critical role of central signaling systems composed of leptin/leptin receptor and alpha-melanocyte stimulating hormone/MC4-R in human energy homeostasis. Although the genetic basis of monogenic disorders of body fat distribution, such as congenital generalized lipodystrophy and familial partial lipodystrophy, Dunnigan variety, is still unknown, the genes for these have recently been localized to chromosomes 9q34 and 1q21-22, respectively. The advances in our knowledge of the phenotypic manifestations and underlying molecular mechanisms of genetic body fat disorders may lead to better treatment and prevention of obesity and other disorders of adipose tissue in the future.     

The effect of body fat percentage and body fat distribution on skin surface temperature with infrared thermography

This study aimed to search for relations between body fat percentage and skin temperature and to describe possible effects on skin temperature as a result of fat percentage in each anatomical site. Women (26.11±4.41 years old) (n =123) were tested for: body circumferences; skin temperatures (thermal camera); fat percentage and lean mass from trunk, upper and lower limbs; and body fat percentage (Dual-Energy X-Ray Absorptiometry). Values of minimum (T_Mi), maximum (T_Ma), and mean temperatures (T_Me) were acquired in 30 regions of interest. Pearson's correlation was estimated for body circumferences and skin temperature variables with body fat percentage. Participants were divided into groups of high and low fat percentage of each body segment, of which T_Me values were compared with Student's t-test. Linear regression models for predicting body fat percentage were tested. Body fat percentage was positively correlated with body circumferences and palm temperatures, while it was negatively correlated with most temperatures, such as T_Ma and T_Me of posterior thighs (r =−0.495 and −0.432), T_Me of posterior lower limbs (r =−0.488), T_Ma of anterior thighs (r =−0.406) and T_Mi and T_Me of posterior arms (r =−0.447 and −0.430). Higher fat percentages in the specific anatomical sites tended to decrease T_Me, especially in posterior thighs, shanks and arms. Skin temperatures and body circumferences predicted body fat percentage with 58.3% accuracy (R =0.764 and R² =0.583). This study clarifies that skin temperature distribution is influenced by the fat percentage of each body segment.     

Capsaicin-sensitive intestinal mucosal afferent mechanism and body fat distribution

This report summarizes clinical and experimental data in support of the hypothesis that capsaicin-sensitive intestinal mucosal afferent mechanism plays a role in regulating body fat distribution. Epidemiological data have revealed that the consumption of foods containing capsaicin is associated with a lower prevalence of obesity. Rural Thai people consume diets containing 0.014% capsaicin. Rodents fed a diet containing 0.014% capsaicin showed no change in caloric intake but a significant 24% and 29% reduction in the visceral (peri-renal) fat weight. Increase in intestinal blood flow facilitates nutrient energy absorption and decrease in adipose tissue blood flow facilitates storage of nutrient energy in adipose tissue. Stimulation of intestinal mucosal afferent nerves increases intestinal blood flow, but decreases visceral (mesenteric) adipost tissue blood flow. In in vitro cell studies capsaicin has a direct effect on adipocytes. Intravenous capsaicin produces measurable plasma level and subcutaneous capsaicin retards accumulation of adipose tissue. The data on a direct effect of oral capsaicin on adipose tissue at remote sites, however, are conflicting. Capsaicin absorbed from the gut lumen is almost completely metabolized before reaching the general circulation. Oral capsaicin significantly increases transient receptor potential vanilloid type-1 (TRPV1) channel expression as well as TRPV1 messenger ribonucleic acid (mRNA) in visceral adipose tissue. In TRPV1 knockout mice on a high fat diet the body weight was not significantly different in the absence or presence of oral capsaicin. In rodent experiments, daily intragastric administration of capsaicin for two weeks led to defunctionalization of intestinal mucosal afferent nerves, manifested by loss of acute mucosal capsaicin-induced effects; but not the corneal afferent nerves, with preservation of the paw wiping reflex of the eye exposed briefly to dilute capsaicin. The latter indicated the absence of an oral capsaicin effect at one remote site. There was an accompanying decrease and an increase in the proportion of body fat in visceral and subcutaenous compartments, respectively. Taken together, if oral capsaicin could regulate adipose tissue distribution, the process might involve the effect of intestinal mucosal afferent nerves in modulating intestinal and visceral adipose tissue blood flow. The hypothesis that the intestinal mucosal afferent mechanism is a plausible therapeutic target for abating visceral obesity deserves to be further evaluated.