Body shape in relation to socio-economic status in young adults from the basque Country.

Body shape has a great variability determined, partly, by energy intake and physical activity, as well as by gender and age. The aim of this research was to analyse the relation between socio-economic status (SES) and body shape estimated through the somatotype, in a sample of university students. The sample included 316 males and 635 females aged 18-33. Somatotype was estimated by the Heath-Carter anthropometric technique. The information included data of SES. A MANOVA test was used to test differences among groups. The mean somatotypes were 4.0-4.4-2.3 in males and 5.4 -3.4-2.2 in females. Sexual dimorphism for the whole somatotype was found (p < 0.001). There is a greater stability of the body shape in females regarding SES and more variability in males. Males' somatotype was significantly related to SES, low socioeconomic levels were associated with high values of endomorphy and mesomorphy.

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.

Overweight and obesity: prediction by silhouettes in young adults.

The present study analyzes the prevalence of overweight/obesity in a sample of young adults from the University of the Basque Country (Spain), and tests the efficiency of the silhouettes to predict overweight/obesity. This cross-sectional study was conducted in a sample of volunteer university students from the University of the Basque Country (356 men and 745 women, age: 18-33 years), who came to the Physical Anthropology laboratory where a standardized questionnaire was administered and anthropometric measurements were taken by a well-trained anthropometrist. Height and weight were obtained. BMI was calculated as weight/height(2) (kg/m(2)) and it was used as a reference method. Using a questionnaire, based on the standard figural stimuli, subjects were asked to choose the silhouette which was closest to his/her usual appearance (current body size). The accuracy of the Williamson et al.'s silhouettes as an overweight-obesity indicator was analyzed by gender-specific receiver operating curve (ROC). The cutoff figure to distinguish between nonoverweight and overweight-obese individuals corresponded to number 7 in men and 6 in women. These cutoff values matched optimal sensitivity and specificity, with few nonoverweight subjects selecting silhouettes bigger than 7 in the case of men or 6 for women. In conclusion, the figural stimuli allows the identification of populations at overweight/obesity risk with the simple use of silhouettes, at least in this rank of age, where the overweight and obesity are yet little frequent.

Sex differences in skinfold variability across human populations and during the life cycle.

BACKGROUND: Subcutaneous fat measurements have been recently found to show sex differences in variability (dispersion dimorphism) in young adult samples from two extant unrelated European populations, with males more variable than females. AIM: This paper aims to investigate potential sex-by-age interaction and to verify its presence and possible different expression in various populations. SUBJECTS AND METHODS: Biceps, triceps, subscapular, suprailiac, abdominal, midthigh and calf skinfolds were analysed in two European samples from the Basque Country (4176 subjects, 8-50 years) and from Sardinia (2491 subjects, 14-100 years). Data on triceps and subscapular skinfolds in Non-Hispanic Whites (1799 subjects, 8-75 years), Mexican Americans (3133 subjects, 8-85 years), Other samples (1733 subjects, 8-70 years) from NHANES (2001-2002) were also included in the analysis. The significance of the difference between male and female coefficients of variation was performed by means of a suitable non-parametric bootstrap test. RESULTS: Skinfold coefficients of variation were greater in males than in females in 79.8% of comparisons with 27.2% significant differences. Dispersion dimorphism was particularly evident in peripheral subcutaneous fat depots. The results do not show appreciable variations across population samples and age classes. CONCLUSION: Skinfold dispersion dimorphism seems to exist throughout most of the life cycle, and be widespread in European and non-European human populations. It involves especially accumulation sites of the gynoid pattern known to be relevant in female reproduction. More 'standardized' fatty reserves in women might represent a selective advantage. On the other hand, skinfold dispersion dimorphism might also be related to cultural factors affecting the extent of female variability by means of enhanced environmental homogeneity.

Dispersion dimorphism in human populations.

The aim of this paper is to verify the existence of dispersion (or variability) dimorphism in several anthropometric traits, i.e., some skeletal, muscular, and adipose dimensions, and to provide an evaluation of this scarcely considered aspect of sex differences. This research focuses on two human samples from two different European regions, Sardinia (Italy) and the Basque Country (Spain). Twenty-three anthropometric measurements were taken. A first qualitative analysis was carried out comparing the profiles of the coefficients of variation of each variable in both sexes. Secondly, the equality of variability was verified with different tests. In the normal case, Student's t-test, as proposed by Sokal and Braumann ([1980] Syst. Zool. 29:50-63), was applied. In the more general case, it was necessary to resort to resampling techniques. A suitable bootstrap test was constructed and the results were compared, when possible, with those obtained by other methods. The measurements showed parallel trends in the two populations. In particular, subcutaneous skinfolds showed significant dispersion dimorphism, with the greatest coefficients of variation in men. We suggest that this result was linked to stronger canalization in female dimensions related to the reproductive function and influenced by sociocultural factors. We also suggest defining dispersion dimorphism, whose existence is confirmed by the results presented in this paper, as a descriptive pattern of phenotype variability in both sexes that can be specific of a given class of anthropometric traits.

Comparison of predicted body fat percentage from anthropometric methods and from impedance in university students.

The objective of the present study was to compare different methods for evaluating body fat percentage (BF%) (anthropometric methods and bioelectrical impedance analysis) in university students. Subjects were 653 healthy students whose mean age, body height, body weight and BMI were 21.1 (SD 2.5) years, 166.0 (SD 8.4) cm, 62.8 (SD 11.0) kg and 22.7 (SD 3.1) kg/m(2), respectively. Results showed that BMI is a poor predictor of body fatness since the sensitivity was low in comparison with the reference method (Siri equation). The lowest values of BF% were obtained using the reference method (Siri equation) (21.8 (SD 6.8)%). The two methods with the highest agreement were Siri and Lean (mean difference, -0.5), followed by Brozek (mean difference, -1.4) and Deurenberg (mean difference, -1.5). The largest mean difference for BF% was between Siri and impedance (-4.5). Although the methods and/or equations used in the present study have been commonly utilised to estimate BF% in young adults, the results must be interpreted with caution in the diagnosis and monitoring of overweight and obesity.