Influence of heredity and environment in determination of skinfold thickness in children.

Triceps and subscapular skinfold thicknesses were measured in 222 pairs of like-sex twins (78 monozygotic and 144 dizygotic) aged 3-15 years. Log transformations of the measurements were standardized for age and sex and the results used to estimate heritability--that is, the proportion of total variation determined by genetic factors. The overall contribution of non-genetic familial effects was small. There were appreciable differences in heritability between limb and trunk fat and between the sexes and at different ages. Over the age of 10 heritability was high for both sites in boys and girls. In younger children environmental factors contributed more to the variation.     

Ecogeographical associations between climate and human body composition: analyses based on anthropometry and skinfolds

In the 19th century, two "ecogeographical rules" were proposed hypothesizing associations of climate with mammalian body size and proportions. Data on human body weight and relative leg length support these rules; however, it is unknown whether such associations are attributable to lean tissue (the heat-producing component) or fat (energy stores). Data on weight, height, and two skinfold thickness were obtained from the literature for 137 nonindustrialized populations, providing 145 male and 115 female individual samples. A variety of indices of adiposity and lean mass were analyzed. Preliminary analyses indicated secular increases in skinfolds in men but not women, and associations of age and height with lean mass in both sexes. Decreasing annual temperature was associated with increasing body mass index (BMI), and increasing triceps but not subscapular skinfold. After adjusting for skinfolds, decreasing temperature remained associated with increasing BMI. These results indicate that colder environments favor both greater peripheral energy stores, and greater lean mass. Contrasting results for triceps and subscapular skinfolds might be due to adaptive strategies either constraining central adiposity in cold environments to reduce cardiovascular risk, or favoring central adiposity in warmer environments to maintain energetic support of the immune system. Polynesian populations were analyzed separately and contradicted all of the climate trends, indicating support for the hypothesis that they are cold-adapted despite occupying a tropical region. It is unclear whether such associations emerge through natural selection or through trans-generational and life-course plasticity. These findings nevertheless aid understanding of the wide variability in human physique and adiposity.     

Fatness and fat patterning in relation to age changes and menarche

The present study assesses changes with age in fatness and fat patterning in a cross-sectional sample of Spanish schoolgirls from 6 to 16 years of age living in an urban area (Madrid). Arm muscle area and arm fat area were derived from middle-upper arm anthropometry. Body mass index (weight/height²) and the sum of the skinfold thicknesses at three sites (triceps, subscapular and suprailiac) were computed as indices of adiposity; and two indices of subcutaneous fat distribution were also defined: the natural logarithms of subscapular/triceps and suprailiac/triceps skinfold thickness ratios. Changes with age in these variables are described, including some pattern changes found in amount of fatness as well as in fat distribution at pubescence. At this time, there is a plateau in fat deposition, and even a fat loss the average (at triceps site). Prior to pubescence, subcutaneous fat distribution changes from «pheripheral» to a more generalized pattern, but no well-defined pattern of change is found after the onset of menarche. Furthermore, the effect of the onset of puberty on all these variables is analyzed.     

Body composition and fat distribution among older Jat females: A rural–urban comparison

The aim of the present cross-sectional study is to describe and compare age related changes in body composition and fat patterning among rural and urban Jat females of Haryana State, India. A total of 600 females (rural = 300, urban = 300), ranging in age from 40 to 70 years were selected by the purposive sampling method. Body weight, height, two circumferences (waist and hip) and skinfold thickness at five different sites (biceps, triceps, calf, subscapular, and supra-iliac) were taken on each participant. To study total adiposity, indices such as body mass index (BMI), grand mean thickness (GMT), total body fat and percentage fat were analyzed statistically. The fat distribution pattern was studied using waist/hip ratio, subscapular/triceps ratio and responsiveness of five skinfold sites towards accumulation of fat at different sites with advancing age. Results indicate a decline in almost every dimension including level of fatness between the mid-fourth and mid-fifth decades of life in both rural and urban females. Urban Jat females were heavier (57.36 kg vs. 56.07 kg, p > 0.05) and significantly taller (1553.3 mm vs. 1534.5 mm, p < 0.001) than their rural counterparts. Urban females also exhibited higher mean values for both the circumferences, five skinfold thicknesses as well as for lean body mass, total fat and percentage fat than the rural females. This is also evident from their higher mean values for body mass index and grand mean thickness. Waist/hip ratio values in rural and urban females showed upper body fat predominance, with urban females having relatively more abdominal fat. Results of subscapular/triceps ratio showed that rural and urban females gained proportionally similar amounts of subcutaneous fat at trunk and extremity sites until 45 years of age. Subsequently trunk skinfolds increased relatively more in thickness. The magnitude of this increase was comparatively greater in rural females up to 55 years and among urban females from 55 to 70 years. The profiles of subcutaneous fat accumulation and sensitivity of each skinfold site also revealed more fat deposition in the trunk region compared to extremities in both rural and urban females. The present study demonstrated differential rates of fat redistribution among rural and urban females.     

Body fat in urban and rural male college students of Eastern India

Male college students (N = 381) residing in several districts of Eastern India, classified into two groups, urban (N = 193) and rural (N = 188), were studied by anthropometric measurements of skinfold thicknesses in several sites of the body to determine their body fat content. The mean value of percentage of body fat was found to be significantly higher (P < 0.001) in the urban group of students (12.07 ± 3.04) than in the rurals (11.04 ± 2.63). The mean values of skinfold thicknesses of the biceps, triceps, and subscapular regions were also found to be higher in urbans (P < 0.01), but no such significant differences in mean values of supra-iliac and abdominal skinfolds were found between the two groups of students. Most of the subjects of both the groups had a greater thickness of the abdominal skinfold compared to thickness of the biceps, triceps, and suprailiac skinfolds. It was found that the college students of Eastern India were leaner than the youths of North America, Europe, Japan, and Northern India.     

Skinfold thicknesses in a national probability sample of U.S. males and females aged 6 through 17 years

Cycles II and III of the Health Examination Survey included measurements of the skinfolds of over 14,000 individuals 6 through 17 years of age, statistically weighted to provide an accurate national probability sample. Analyses of the triceps and subscapular skinfolds of Negroes and whites are reported here, utilizing the median in preference to the mean. Females of either racial group have thicker skinfolds at all ages studied. Whites have greater median triceps thicknesses than Negroes of the same sex and age, but there are no differences between the two racial groups in the subscapular. Since, between all but one pair of adjacent ages in males, from 12 years on, the median triceps fold decreases, but the estimated cross-sectional are of fat increases, it is strongly recommended that reductions in triceps thickness not be automatically interpreted as meaning a loss of subcutaneous fat. Since greater skewness is found in the subscapular distributions in whites, but not in the triceps, it is suggested that racial differences in triceps thickness at these ages occurs from the operation of hereditary factors, while differences in the subscapular skinfold arise from environmental causes.     

Validity of convenient indicators of obesity

A validation study of convenient indicators of obesity was undertaken in 540 male and female subjects, aged 7-14 yr. Four adiposity measures that have commonly accepted obesity classification points [relative weight, relative body mass index (BMI), sum of five skinfolds, and triceps skinfold] were derived from measures of height, weight, and five skinfold thickness measurements. Body density measures were converted to percentage of body fat using Lohman's (1986) age- and gender-specific regression equations. Using greater than or equal to 20% body fat for males and greater than or equal to 25% for females as the standard for obesity, the diagnostic utilities (sensitivity, specificity, overall accuracy, and positive and negative predictive values) of the four obesity indicators at their commonly used obesity cutoff points were determined. Preliminary analyses demonstrate that use of these indicators should not be considered independent of the gender of the subject or without reference to the purpose for classifying subjects as obese. Secondary analyses, in which the obesity cutoff point in each indicator was altered to obtain a minimum specificity level of 95%, demonstrated that a sum of skinfolds was better at identifying true obesity than all other indicators in both males and females. There is potential for inappropriate labeling with all convenient indicators of obesity, and thus they should be used with caution.     

Seasonal variation and sex differences in the nutritional status in two local populations of wild Japanese macaques

Seasonal variations and sex differences in the nutritional status in two local populations of wild Japanese macaques (Macaca fuscata fuscata) were examined. It was hypothesized that the ecological condition and/or reproductive strategies of each sex determine the nutritional condition and its seasonal fluctuation in each sex. Morphometric measures such as body mass, thoracic and femoris circumferences, skinfold thickness in four places (triceps, biceps femoris, subscapular, and abdomen), and wet mass of mesenteric and omental fat were used for comparisons between sexes, seasons, and populations. Animals of the Shimane population were larger than those of the Boso population in most morphometric measures, abdominal skinfold, and mesenteric and omental fat mass, suggesting environmental and/or genetic differences in the two populations. Females of both populations had larger skinfolds and mesenteric and omental fat mass than males, indicating that females had more fat than males. Females showed seasonality in most measures, having two peaks of body mass, thoracic and femoris circumferences, abdominal skinfold, and mesenteric and omental fat masses in early spring and late fall. In contrast, males exhibited no clear seasonal variations for most measurements, except for biceps femoris and subscapular skinfolds, which showed peaks in summer. Most morphometric measurements significantly correlated to each other, particularly in females, but most skinfolds had no correlation with other measurements. These findings suggest that sexual dimorphism in body composition and its fluctuation may be affected by the different reproductive strategies of males and females.     

湖南土家族成人的皮褶厚度和体成分分析

本项目采用人体测量法,测量了976名（男性528人,女性448人）湖南土家族成人的身高、体质量以及肱三头肌、肩胛下、髂前上和小腿内侧皮褶的厚度,并根据公式计算体密度、体脂率、脂肪质量、脂肪质量指数、瘦体质量和瘦体质量指数。结果显示随年龄增长,小腿内侧皮褶厚度值逐渐减小,肱三头肌、肩胛下和髂前上棘皮褶以及体脂率、脂肪质量、瘦体质量、体质量指数、脂肪质量指数和瘦体质量指数值先增大后减小,体密度值先减小后增大;各年龄组中体密度、瘦体质量及其指数值女性明显低于男性,4项皮褶厚度值以及体脂率、脂肪质量及其指数值女性高于男性;与布朗族等24个族群比较,湖南土家族成人皮褶厚度处于中等水平,与门巴族、珞巴族、僜人、彝族等族群的亲缘关系较近。     

达斡尔族成人的皮褶厚度及其年龄变化

测量了456例（男216,女240例）达斡尔族成人的4项皮褶（三头肌皮褶、肩胛下皮褶、髂前上棘皮褶与腓肠肌皮褶）厚度值,分析了达斡尔族成人皮褶厚度随年龄变化的特征。研究表明：（1）男性躯干皮下脂肪厚于四肢。女性肩胛下皮褶最厚,三头肌皮褶次之。（2）女性4项皮褶厚度值高于男性。（3）男性30—44岁皮下脂肪较厚,45岁以后皮褶厚度下降。女性50岁以后肩胛下皮褶值明显下降,其余3项值在40岁以后下降。（4）男性全身皮褶厚度值多呈正相关。女性这种现象不明显。（5）达斡尔族成人皮下脂肪发育逊于北京、大连城市中的汉族,但优于宁夏农村的回族。     

The Diabetes Alert study: growth, fatness, and fat patterning, adolescence through adulthood in Mexican Americans

Diabetes Alert is a multidisciplinary genetic and epidemiological study of Type II (non insulin-dependent) diabetes in Texas Mexican Americans. We report the anthropometry of 1,155 individuals 10 to 70 or more years with particular reference to overweight, fatness, and anatomical fat patterning in the sample. Children ages 10-18 of both sexes are growing at the 50th percentile of the reference data (U.S. Health and Nutrition Examination Survey-1) for height, Wt/Ht2, and triceps and subscapular skinfolds. Adults are well below median height but well above median Wt/Ht2 and skinfolds. Prevalence of obesity (Wt/Ht2 greater than or equal to 30) among adults is typically 30% or higher by age 30. Diabetics compared to age/sex-matched non diabetics have shorter sitting heights, have more upper body fat (subscapular skinfold), have less lower body fat (lateral calf skinfold), and were heavier at maximum weight and at age 18. The ratio of lower to upper body fat distribution decreases over the life cycle, being highest at adolescence and lowest at ages 40-50 in both sexes. Our results show a precipitous weight gain after maturity in the sample and an association of diabetes with differences in anatomical fat patterning. The age-related changes in fat patterning need to be explained in terms of their ecological and genetic influences.     

Gender differences in fat patterning in children living in Ankara

Body composition is an excellent indicator for assessing obesity and nutritional status of both individuals and populations. Youth obesity has important health and social implications, because a large proportion of adult obesity has its origin in childhood. Numerous studies report that adverse levels of cardiovascular diseases risk factors are associated with adiposity in children. Concerning the Turkish population there is up to now only limited information with regard to adiposity in children. The aim of this study was therefore to determine the anthropometric and body composition characteristics and to investigate sex differences in fat patterning including fat distribution in a group of children living in Ankara. The present study evaluated the body composition of 332 boys and 269 girls aged between 8 and 11 years, attending public schools. It was carried out by a cross-sectional study and was focused on that anthropometric variables, which reflect body fat and fat-free mass. Anthropometric measurements including height, weight, triceps and subscapular skinfolds thickness were carried out on these children. The body mass index (BMI) was also calculated. The measurements were used to estimate the two-compartment model of body composition: fat-free mass (FFM) and body fat (BF) from skinfold equations. The mean fat percentage in boys is highest at 11 years (16.8%) and lowest at 10 years (15.6%). In girls these figures come to 18.2% and 17.1%, respectively. Girls of these age groups have a significantly larger percentage of body fat and skinfold thickness. At this young age there is therefore clear evidence of sexual dimorphism in fat patterning, as girls are showing a greater subcutaneous adiposity, which is mainly contributed by the triceps fat. The body fat (kg) increases in both sexes all over the investigated age groups. The Pearson correlation matrix showed a high significant relation between the anthropometric measurements (p < 0.01). The present study confirms the findings that sexual dimorphism of fat patterning in children is to be seen in the age of 8 - 11 years. It furthermore presents basic data of body composition, which could serve as reference data in other studies on the Turkish population.     

Genetic and environmental correlations between various anthropometric and blood pressure traits among adult Samoans

Shared polygenic effects (i.e., pleiotropy) are assumed to exist for such obesity-related phenotypes as blood pressure and adiposity. It is possible to identify these shared genetic effects through bivariate genetic analyses. This analysis of 1,342 adult Samoans, across 801 pedigrees, indicates that significant heritable components (P < 0.05) ranging from 29-58% exist for weight, height, systolic blood pressure, diastolic blood pressure, triceps skinfold, subscapular skinfold, body mass index, and sum of skinfolds. In general, the anthropometric measurements share additive genetic effects, as do the anthropometric measures, with blood pressure. Heritabilities for central fat distribution are not significant in this population, which could be due to a lack of power. On the other hand, heritabilities have been found in Hispanics; hence the genes responsible for central fat distribution may not be evenly distributed among populations.     

Birth Weight and Its Relationship to Size Attained and Relative Fat Distribution at 7 to 12 Years of Age

The relationship between birth weight and relative subcutaneous fat distribution at school age was considered in 131 boys and 106 girls 7 to 12 years of age. Relative fat distribution at school age was estimated with the ratio of the subscapular to triceps skinfolds (S/T) for the total sample, and with the ratio of the sum of two trunk (subscapular, midaxillary) to the sum of two extremity (triceps, medial calf) skinfolds (T/E) for subsamples of 102 boys and 63 girls. There were no sex differences in the S/T ratio (mm/mm), boys 0.62 ± 0.15, girls 0.63 ± 0.18; T/E ratio (mm/mm), boys 0.58 ± 0.13, girls 0.59 ± 0.16; and BMI (kg/m²), boys 17.1 ± 2.4, girls 16.9 ± 2.2. Second order partial correlations, controlling for age and the BMI or age and sum of skinfolds, between birth weight and the skinfold ratios are, respectively, ?0.22 and ?0.20 (p<0.01) for S/T and ?0.29 and ?032 (p<0.01) for T/E in girls, and ?0.18 and ?0.17 (p<0.05) for S/T and ?0.06 and ?0.6 for T/E in boys. Though low, the correlations suggest that as birth weight decreases proportionally more subcutaneous fat is accumulated on the trunk than on the extremities, more so in females than in males. Results of stepwise multiple regression analyses indicate that birth weight accounts for from 2% to 8% of the variance in relative subcutaneous fat distribution at school age.     

Evidence for higher heritability of somatotype compared to body mass index in female twins

The influence of genetics on human physique and obesity has been addressed by the literature. Evidence for heritability of anthropometric characteristics has been previously described, mainly for the body mass index (BMI). However, few studies have investigated the influence of genetics on the Heath-Carter somatotype. The aim of the present study was to assess the heritability of BMI and somatotype (endomorphy, mesomorphy, and ectomorphy) in a group of female monozygotic and dizygotic twins from childhood to early adulthood. A total of 28 females aged from 7 to 19 years old were studied. The group included 5 monozygotic and 9 dizygotic pairs of twins. The heritability was assessed by the twin method (h(2)). The anthropometric measures and somatotype were assessed using standard validated procedures. Significant differences between monozygotic and dizygotic pairs of twins were found for height, endomorphy, ectomorphy, and mesomorphy, and the heritability for these measures was high (h(2) between 0.88 and 0.97). No significant differences were found between monozygotic and dizygotic twins for weight, and the BMI and the heritability indexes were lower for these measures (respectively 0.42 and 0.52). The results of the present study have indicated that the somatotype may be more sensible to genetic influences than the BMI in females.     

DNA Polymorphisms in the α2- and β2 Adrenoceptor Genes and Regional Fat Distribution in Humans: Association and Linkage Studies

The aim of this study was to investigate the relationships between DNA restriction fragment length polymorphisms (RFLP) in the α₂- and β₂-adrenoceptor genes and body fat distribution in humans. Skinfold thickness measurements and genetic analyses (Southern blot) were performed on 280 individuals (142 parents and 138 offsprings) from the Québec Family Study. Using the association study design in unrelated adults, women but not men carrying the 6.3-kb allele of an α_2A-adrenoceptor/DraI RFLP had a significantly higher trunk to extremity skinfold ratio (= sum of subscapular + suprailiac + abdominal skinfolddsum of biceps + triceps + medial calf skinfolds) compared to women without the allele (1.44 ± 0.52 vs. 1.12 ± 0.33; p<0.005 after adjustment for age, p<0.002 after adjustment for age and body mass index or for age and subcutaneous fat). Using the sib-pair linkage procedure, a significant inverse relationship was found between the proportion of alleles identical by descent shared by sibs at the α2A RFLP marker locus and the squared differences of thetrunk to extremity skinfold ratio (p = 0.02 after adjustment for age or for age and body mass index or for age and subcutaneous fat). For a β-adrenoceptor/ BanI RFLP, no significant association or linkage was found between fat distribution indicators and the marker. These results suggest that α_2A-adrenoceptor gene variability detected with DraI is associated with a relative subcutaneous fat pattern favoring accumulation of truncal-abdominal fat in women, and that the α_2A-adrenoceptogr ene, or a locus in close proximity, may be linked to body fat distribution in humans independently of the overall level of fatness.     

Subcutaneous adiposity and relative fat patterning in adult white and migrant asian males in Britain

A comparative study of subcutaneous adiposity and relative fat patterning in adult White (n=262) and migrant Indian (n=39) and Pakistani (n=100) males living in Peterborough, Cambridgeshire revealed no significant difference in the level of generalised adiposity (measured as body mass index) between the ethnic groups. However, Asians had significantly higher means for all five truncal skinfolds; for all upper body: upper extremity, upper body: lower extremity, central body: upper extremity and central body: lower extremity skinfold rations; more total subcutaneous adiposity; and significantly more subcutaneous fat in subscapular, suprailiac and abdomen regions relative to total subcutaneous fat. However, Asian men had significantly less subcutaneous fat in all the extremity sites relative to total subcutaneous adiposity and lower mean forearm subcutaneous adiposity. Discriminant analysis revealed that 80.6% of all individuals were correctly classfied, with Whites being grouped more correctly than Asians. Suprailiac/forearm and suprailiac/triceps skinfold ratios, height, weight, age, body mass index, and subscapular, midauxillary, chest and medial calf skinfolds were among the most important discriminating variables/ratios of the three ethnic groups.     

Anthropometric data in middle-aged women. The population study of women in G?teborg 1968-1969.

Body weight, body height, skinfolds, circumferences and weight indices in a population sample of 1462 women in ages between 38 and 60 years are presented. Significant age differences were noted. High correlations (r) were found between body weight and triceps and subscapular skinfolds (0.62 and 0.72 respectively) and between body weight and arm, waist and buttock circumferences (0.75-0.88). Age differences were mostly noted between 46 and 50 years of age. After that age there was a comparatively greater increase of the waist circumference than of the buttock circumference, while triceps skinfold seemed to decrease after the age of 50 indicating an altered adipose tissue distribution from the extremities to the trunk with increasing age. When taking data from a previous study of body weight in the same population of women into consideration it seems that the age differences in body weight found in cross-sectional study like the present one may to a large extent depend on differences between different cohorts studied.     

Sub-cutaneous tissue growth in boys of the Gaddi tribe, Himachal Pradesh, India

Gaddi boys from the Bharmour sub-tehsil of the Chamba District (Himachal Pradesh, India) aged from 4 to 20 years were studied cross-sectionally during 1974-1975 for skin and sub-cutaneous tissue thickness. The patterns of change of skinfolds at triceps and calf (limb skinfolds) are similar to each other, but different from that of the subscapular and suprailiac (trunk skinfolds), which in turn also follow a similar pattern. The trunk skinfolds decrease from 5 to 7-8 years, sharply in the beginning, but slowly thereafter, and remain almost constant until age 12 and gain in thickness during adolescence. The limb skinfolds decrease in thickness from 5 to 11-12 years, and then they increase slowly. A comparison of skinfolds of the Gaddi boys with other neighbouring as well as distant populations reveals that, by and large, the Gaddi boys possess smaller amounts of sub-cutaneous tissue. Nutritional inadequacies, hard work and adverse environmental factors of moderate altitudes seem to put great stress on the development of sub-cutaneous fat among Gaddi boys. Standards of growth of triceps skinfold for this population are provided.     

达斡尔族学生皮下脂肪发育的研究

作者内蒙古莫力达瓦达斡尔族自治旗１７５９例中小学生项项皮褶厚度及体脂发育情况进行了调查研究。结果表明：（１）达斡尔族学生进入青春期后,随着年龄的增长,男性躯干部皮变厚,四肢部皮褶变薄,女性躯干、四肢部皮褶均增厚。（２）１２岁后,女性皮褶厚度显著大于男性。（３）青春发育早期,男性体脂逐渐有下降,女性于１２－１４岁体脂迅速增加。（４）总体说来,达斡尔族学生并不偏于肥胖。