Fat patterning in athletes in relation to ethnic origin and sport

Body composition characteristics of elite Australian rugby union athletes according to playing position and ethnicity

This study describes the body composition traits of modern-day elite rugby union athletes according to playing position and ethnicity. Thirty-seven international Australian rugby athletes of Caucasian and Polynesian descent undertook body composition assessment using dual-energy X-ray absorptiometry and surface anthropometry. Forwards were significantly taller, heavier and had a greater total fat mass and lean mass than backs. Backs displayed a higher percentage lean mass and lower sum of seven skinfolds and percentage fat mass. While no whole body composition differences were seen between ethnicities, significant regional differences were observed. In the periphery (arm and leg) regions, Polynesians had a greater proportion of fat mass (53.1% vs. 51.3%, P = 0.052, d = 0.5) and lean mass (49.7% vs. 48.6%, P = 0.040, d = 0.9), while in the trunk region a lower proportion of fat mass (37.2% vs. 39.5%, P = 0.019, d = 0.7) and lean mass (45.6% vs. 46.8%, P = 0.020, d = 1.1). Significant differences were also seen between Caucasian and Polynesian forwards in leg lean mass (31.4 kg vs. 35.9 kg, P = 0.014, d = 2.4) and periphery lean mass (43.8 kg vs. 49.6 kg, P = 0.022, d = 2.4). Elite Polynesian rugby athletes have different distribution patterns of fat mass and lean mass compared to Caucasians, which may influence their suitability for particular positions.

Ontogenesis changes and sex dimorphism of subcutaneous fat distribution: 12-year longitudinal study of children and adolescents from Cracow, Poland

The aim of the work was to analyze the direction and tempo of subcutaneous fat redistribution during ontogenesis, appearing sex differences and relations to puberty on the basis of 12-year longitudinal data of 270 boys and 154 girls from Cracow, Poland. They all had complete data (from 7 to 18-years old) of three trunk (subscapular, abdominal, suprailiac) and three extremity (triceps, knee, medial calf) skinfold thicknesses. The type of subcutaneous adipose tissue distribution was determined based on trunk to extremity ratio to analyze the process of fat redistribution. The analysis included medians of extremity and trunk skinfolds and medians of their sums and age altered frequency of central and peripheral type of fat distribution. To present empirical values, the median variability of the sums of three trunk and extremity skinfolds was calculated using a third degree polynomial as an age function. Polynomial regression of extremity skinfolds median explained 88% of its variability (F = 71.2, P < 0.001) and for trunk skinfolds as far as 96% (F = 111.65, P < 0.001). The median variability curves of both types of distribution crossed at the age of 11.88 in girls and 13.45 in boys directly preceding puberty stage, which indicated clear dependencies between fat redistribution and puberty. The results showed a tight connection between the process of subcutaneous fat redistribution and puberty, and also sex dimorphism of the process. More dynamic fat redistribution in boys contrasted trunk and extremity fatness, while in girls less dynamic changes resulted in more even fatness.

Comparisons of body volumes and dimensions using three-dimensional photonic scanning in adult Hispanic-Americans and Caucasian-Americans

BACKGROUND

We studied whether significant differences exist between Hispanic-Americans (H-A) and Caucasian-Americans (C-A) in body dimensions using a newly validated three-dimensional photonic scanner (3DPS).

METHODS

We compared two cohorts of 34 adult U.S.-based H-A (19 females) and 40 adult C-A (25 females) of similar age and body mass index (BMI, kg/m(2)). We measured total body volume (TBV), trunk volume (TV), and other body dimensions, including waist and hip circumferences, estimated percentage body fat (%fat), calculated TV/TBV, and waist-to-hip ratio.

RESULTS

For female cohorts, there were no significant differences in age, weight, height, and 3DPS-measured variables between the two ethnic cohorts. For male cohorts, C-A had greater height (p = 0.014), but there were no significant differences in absolute or proportional volumes or dimensions between the two cohorts.

CONCLUSIONS

Results demonstrate that, in these H-A and C-A cohorts of similar age and BMI, total and regional body volumes and dimensions, as well as their proportions, approximate each other very closely in both sexes; these variables also show similar relationships with %fat in each sex. This is in contradistinction to previous study reports using other measurement techniques.

Comparison of body composition assessment among lean black and white male collegiate athletes

Variations in the density of the fat-free mass (DFFM) across ethnic groups is a critical factor that invalidates the use of body fat equations. It has also been suggested that resistance trained athletes may have higher body densities (BDs) than untrained subjects. Thus, the validity of using anthropometric (ANT) equations, which have mainly been derived on white nonathletic groups, has been questioned for athletic white and black men. This study compared BD and percent body fat (%BF) between 34 white (20 +/- 1 yr, 184 +/- 11 cm, 84 +/- 12 kg, 25 +/- 3 BMI) and 30 black (20 +/- 1 yr, 182 +/- 9 cm, 84 +/- 12 kg, 25 +/- 2 BMI) male collegiate athletes and determined the accuracy of 5 ANT equations in estimating %BF. Subjects were underwater weighed (UWW), and skinfold measurements were obtained from the chest, mid-axillary, abdomen, suprailiac, subscapula, triceps, and thigh. BD was obtained from UWW and estimated from the five skinfold equations. From UWW, significant (P < or = 0.05) differences were found for BD (1.075 +/- 0.007 vs 1.0817 +/- 0.009), but not for %BF (10.49 +/- 2.8 vs 11.59 +/- 3.4) for white and black subjects, respectively. Differences were noted for subcutaneous skinfold sites (abdominal (vertical), suprailiac, and thigh), sum of three and seven skinfolds, and proportion of subscapular subcutaneous fat. One out of five and five out of five ANT equations (Siri conversions) yielded significantly lower estimates compared with UWW %BF for the white and black athletes, respectively. Use of the Schutte equation for the black athletes resulted in overpredictions of %BF for five out of five equations. In addition, the Schutte equation offered slightly greater accuracy than did the Siri equation for estimating %BF in black athletes. These data confirm earlier concerns that ANT equations derived on general populations may not be as accurate for athletic populations and also suggest that correction equations are necessary for converting BD into %BF for populations differing with respect to race or training status.

Fat distribution in relation to sex and socioeconomic status in children 4-19 years

Fat distribution was studied in an urban sample of boys and girls 4.5 to 19.5 years from the Basque province of Biscay by means of Principal Component Analysis (PCA) of five skinfolds. The PCA extracted four components, which explained 99.1% of the total variance. The first principal component revealed strong stability across age and sex, and was related to a pattern of central body fat distribution. The three other components, upper-lower trunk fat, lateral-medial trunk fat, and upper-lower extremity fat, showed poor stability due largely to the influence of age and, to a lesser degree, sex. In both sexes, individual scores of the four factors did not show multivariate differences by socioeconomic status when a MANOVA with age, age² and age³ as covariates was done. Nevertheless, the first factor scores were significantly higher only in the poorer socioeconomic group of girls. The results are explained in the context of either different lifestyles related to socioeconomic status, a protective effect against environmental stress on urban males, or greater plasticity of trunk fat relative to extremity fat in females. Am. J. Hum. Biol. 10:799-806, 1998. © 1998 Wiley-Liss, Inc.

Application of bioelectric impedance methodology and prediction equations to determine the volume of distribution for ethanol

In large-scale epidemiologic studies of drinking behavior there is a need for simple and reliable estimates of the body water compartment of subjects. This, in turn, provides an estimate of the volume of distribution of ingested ethanol and a better estimate of tissue exposure levels than the use of total body weight as the volume of distribution for alcohol. The volume of distribution for ethanol (total body water, TBW) was estimated in a racially mixed group of 276 alcoholics and 166 nonalcoholics (aged 20-59 years) by means of bioelectric impedance methodology (BIA) and by means of prediction equations based upon age, body weight, and height. Estimations of mean TBW from BIA were found to be only slightly higher (1-4%) than those provided by the prediction equations. TBW values generated from both prediction equations were also highly correlated with TBW values obtained by impedance methodology, with the highest correlations observed in females (particularly black) and in alcoholics (particularly female).

Adiposity in aboriginal people from Arnhem Land, Australia: variation in degree and distribution associated with age, sex and lifestyle

A number of researchers have found substantial sex, population and group differences in adiposity and fat-distribution patterns, but there is relatively little information on body fat distribution in Aboriginal groups, especially for the indigenous people of Australia. This study, the largest of its kind for Australian Aboriginal people, presents information on adiposity and fat distribution in 425 Yolngu, a group of Aboriginal people living in a number of communities representing a wide range of lifestyles, in northeast Arnhem Land, Australia. Using BMI standards developed for people of European descent, the majority of the individuals in this study were lean, and the incidence of obesity was considerably less than in other Australian groups, Aboriginal and non-Aboriginal. For the Yolngu in this study the relationship between ageing and adiposity is similar to that reported for tradition-orientated Aboriginal people, as well as for a number of other indigenous groups, viz., while the men maintain their weight into old age, the women, once they are past early adulthood, lose body fat with age. The results from the present study suggest that the age at which the Yolngu women start to gain, and subsequently lose, body fat is associated with differences in degree of acculturation. As has been found in other populations, age- and sex-related differences in body fat distribution occur, but no correlation was found between adiposity and fat distribution. The Aboriginal women and men, however, had a significantly more central distribution of subcutaneous fat than their non-Aboriginal counterparts. Our findings have implications for the health and demography of Aboriginal people in general, and the Yolngu in particular, as they continue the transition from hunting and foraging towards a more 'westernized' lifestyle.

Body fat distribution and job stress in Mexican-American men of the hispanic health and nutrition examination survey

A positive relationship between psychosocial stress and central body fat distribution has been hypothesized. To test this hypothesis, two indices derived from principal components analysis of four skinfold measurements were studied in relation to imputed job stress characteristics (decision latitude, skill discretion, decision authority, and psychological demands) in Mexican-American men of the U.S. Hispanic Health and Nutrition Examination Survey (HHANES). The two indices were fatness and central body fat distribution. Fatness was not significantly associated with any of the job stress characteristics before controlling for education. Once education was included in the equations, however, the relationship between fatness and two of the four job stress variables (decision authority and psychological demands) became statistically significant. Thus, for a given level of education, increasing job stress was associated with increasing fatness. Three of the four job stress characteristics were significantly associated with central body fat distribution before controlling for education. However, after education was entered into the regression equations as a proxy for social class, the relationships between central body fat distribution and the job stress variables were no longer significant. It thus appears that aspects of social class other than job stress are of equal or greater importance in predicting body fat distribution. © 1992 Wiley-Liss, Inc.

Socioeconomic status, sex, age, and ethnicity as determinants of body fat distribution for Guatemalan children

The distribution of subcutaneous fat at the triceps and subscapular skinfold sites is described for four groups of children living in Guatemala. These groups are high socioeconomic status (SES) children of Ladino (mixed Spanish and Indian) ancestry, high SES children of European ancestry, low SES Ladino children, and very low SES Indian children. The method of Healy and Tanner (1981) is used, employing regression and principal components analysis of log transformed skinfold values to divide "fatness" into two uncorrelated variables: size (amount of fat) and shape (fat pattern). Significant differences exist between groups in size, with lower SES groups having less fat than higher SES groups. No significant difference in fat pattern exists between the high SES Ladino and high SES European children. Significant differences do exist between the high SES groups and the low SES groups. The relative amount of subscapular fat increases from the high SES Ladinos and high SES Europeans, to the low SES Ladinos, to the very low SES Indians. In the high SES European and high SES Ladino samples, girls have significantly more arm fat than boys. There is no significant difference in fat patterning between boys and girls in the two low SES samples. Finally, the relative amount of subscapular fat tends to increase with age in all four samples. These results indicate that fatness and fat patterning are independent anatomical characteristics, SES influences fat patterning; low SES children of both Ladino and Indian ancestry show greater reductions in arm fat than in trunk fat compared to high SES children, sexual dimorphism in fat patterning is SES dependent.(ABSTRACT TRUNCATED AT 250 WORDS)

Androgyny in fat patterning is associated with obesity in adolescents and young adults

Recent work suggests that android or male-type obesity is characterized by fat cell enlargement on the trunk and upper body. This implies adult differences in patterns of body fat distribution may have developmental origins connected with differences in maturation or age of onset of obesity. To investigate this, we studied adolescent females (N = 455, 12 years), males (N = 527, 14 years) and young adults (N = 393 females and N = 413 males, 17 years) of the US Health Examination Survey. Five skinfolds and five maturity indicators were available. Individuals were classed as normal weight, overweight or obese on the basis of the body mass index (WT/HT2). Fat patterning was studied by principal components analysis of the log residual skinfold thickness at the five sites, which revealed trunk/extremity and upper/lower trunk fat distribution components in all sex/age groups studied. The means of both components were significantly (P less than 0.05) greater in obese than in normal weight individuals indicating that obesity in adolescence and young adulthood consists of fat concentrated on the upper aspect of the trunk. The effect was independent of maturity, which was a significant correlate of the trunk/extremity patterning component only and in males only. Advanced physiological maturity is probably not a determinant of adult patterns of body fat distribution, but obesity which occurs in adolescence may be.

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.