William H. Mueller

The changes with age of the anatomical distribution of fat

During adolescence and the third decade of life a redistribution of bodily fat is occurring away from the extremities towards the trunk. During this time the process is occurring in both sexes although more rapidly in males than females, hence it is a masculinizing process. The process is seen in human populations from various ethnic and cultural backgrounds. Masculinizing characteristics like this one are predictors of chronic diseases such as diabetes and atherosclerosis late in life. The period from adolescence through young adulthood may be a sensitive time for the development of characteristics that predispose one to the chronic diseases of aging. Socioanthropological investigations of chronic disease related to human obesity may benefit by focusing on this developmental period.

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.

A multinational Andean genetic and health program: growth and development in an hypoxic environment.

In 1972 a multidisciplinary study sought to assess the health status of the indigenous peoples of the Department of Arica in northern Chile, the Aymara, and to relate disease, morphological, physiological and biochemical variation, to the wide changes in altitude of the region. Presented here are the morphological changes which accompany age, altitude and ethnicity amoung 1047 children and adults, permanent residents of the coast, sierra and altiplano. At comparable ages, high-altitude residents were shorter, lighter and leaner but with more expansive and rounder chests than sea-level controls. None of these effects was systematically related to ethnicity (Spanish-Aymara surname), although when stature was held constant, children with greater Aymara ancestry had largest chest circumferences and longer bones. These results suggest that (1) altitude confers allometric growth changes (expensive growth of the chest and diminished growth of the structures less related to oxygen transport); and (2) size changes associated with altitude are acquired during development while shape changes may be under genetic control. Altitude appears to account for less of the variation in growth in this relatively homogeneous Chilean sample than has been reported for other Andean samples, suggesting other concomitants confounding the effects of hypoxia in Andean South America.

Diabetes Alert Study: Weight history and upper body obesity in diabetic and non-diabetic Mexican American adults

History of adult weight gain and fat patterning is compared in Mexican American diabetics and age and sex matched non-diabetics. Diabetics differed little from non-diabetics in overall body fatness at the time of the examination. However, history of adult weight gain and current fat patterning were very different. Diabetics were heavier than non-diabetics at age 18. They subsequently gained weight faster and attained a substantially higher weight, at an earlier age, than non-diabetics. Discriminant function analysis was used to test for differences in patterning. Diabetics tend to have more trunk fat, as reflected particularly in the subscapular skinfold, and less lower extremity (leg) fat. Fat patterning in this population does not appear to be influenced by age when weight gain occurred, but is related to diabetic status, especially in women.

Genetic and environmental determinants of growth of school-aged children in a rural Colombian population

Parent-offspring correlations and heritabilities of body measurements from midparent-offspring regressions are presented for school-aged children from the village of Tenza, Colombia (N = 403 families). Parent-child correlations and midparent regressions in this subsistence farming sample, are similar in magnitude to those for well nourished, urban industrial samples, suggesting that the environmental component of variability in body size is the same regardless of the environment. Tenza children are significantly shorter and lighter than upper class Bogota children, and Tenza parents have mean heights and weights similar to those of other lower class Colombian samples. Thus, chronic undernutrition has affected the growth of parents and continues to affect the growth of the present generation. Although it has been hypothesized that heritability of growth might be reduced in samples experiencing malnutrition and its sequelae, such a reduction may only be observable where environment of parents during their development is different from that of their offspring, which is not the case here. The pattern of heritabilities with respect to different body measurements in Tenza, is similar to that seen in well nourished samples, except that measurements of breadth (biacromial, bicristal, bicondylar) have heritabilities similar in magnitude to those of linear measurements (height, sitting-height, subischial length) especially in males; and heritabilities of some measurements related to adiposity are significantly higher in daughters than in sons.

The Relation of Growth to Cognition in a Well-Nourished Preschool Population.

This paper focuses on the nature of the physical growth-behavioral development association in well-nourished as compared with undernourished populations. Multiple regression analyses were calculated to determine the magnitude of IQ variance accounted for by physical growth variables and socioeconomic status indicators in a group of 3- to 6-year-old children from Cambridge, Massachusetts. The prevalence of malnutrition within this sample was negligible. Weight-for-height percentile was the only physical growth measure that explained a significant portion of the IQ variance. This finding contrasts with what is found in undernourished populations where height is generally the most potent explanatory variable of mental test score variance. In undernourished populations height is a reflection of nutritional history; in well-nourished populations weight-for-height is an indicator of physiological maturation.

Sibling correlations in growth and adult morphology in a rural Colombian population

Correlations for body measurement between members of 207 pairs of school-aged and 116 pairs of adult siblings in a mestizo farming community of the Colombian Andes are comparable to those from previous studies of well nourished urban-industrial samples, both in magnitude and pattern of heritabilities. While the genetic potential in physical growth is impeded by undernutrition and disease in childhood in samples such as the present one, hereditary influences on the variability of growth and adult size appear to be as important in such populations as they are in well nourished ones. School-aged sibs have significantly higher correlations than adult sibs and parent-offspring pairs for some measurements, suggesting environmental contributions in physical resemblance of siblings. Fatfold correlations between adult sisters are persistently higher than those of other sib pairings when socio-economic differences, age, and seasonal variation in nutrition are held constant, implying a greater genetic basis for adipose tissue in females.

Fatness and fat patterning among athletes at the Montreal Olympic Games, 1976.

Six skinfold measurements for male and female athletes (N=456) at the 1976 Montreal Olympic Games were analyzed to identify principal components of fatness and anatomical distribution of fat, i.e., fat patterning. As in non-athletes, two principal components were evident among the athletes. All skinfolds were correlated positively with the first component, which was termed fatness, while extremity fat measurements were correlated positively and trunk measurements were correlated negatively with the second principal component, which was termed an extremity/trunk ratio component. The two principal components accounted for about 85% of the variance. The first component was related to control variables in order of descending contribution to its variance as follows: sex (21-31%), sport (19%), ethnicity (3%), and age (1-3%). Likewise, the second component (extremity/trunk ratio) was related to the control variables: sex (20-35%), age (4-7%), ethnicity (2%), and sport (2%). Fatness is more influenced by sport and by inference training than is the anatomical distribution or patterning of fat on the extremities relative to the trunk. The latter characteristic may be more dependent on biological or environmental factors unrelated to sport and training.

Anger in adolescents: sex, ethnicity, age differences, and psychometric properties.

BackgroundThe State-Trait Anger Expression Inventory (STAXI), a self-report questionnaire, is designed to measure the experience and expression of anger. Reliability and validity of the STAXI have been well established among African and European Americans aged 13 years and older. However, little is known of the use of this instrument among adolescents younger than 13 years and Hispanic American adolescents. ObjectivesObjectives were (a) to test ethnic, sex, and age group differences in STAXI scores in a sample of 11-to-16-year-old African, Hispanic, and European American adolescents; and (b) to assess the psychometric properties of the STAXI among these same adolescents with special emphasis on Hispanic youths, for whom no data are available. MethodsA cross-sectional design was used with stratified quota sampling techniques. Participants (N = 394) were African, Hispanic, and European Americans aged 11–16 years and were drawn from one public middle school and two public high schools in Houston, Texas. ResultsInternal consistency reliability for the anger scales (STAXI) ranged from 0.61 (anger-in) to 0.91 (state-anger) for the younger group (aged 11–13 years), and 0.68 (anger-in) to 0.88 (state-anger) for the older Hispanic Americans (aged 14–16). No notable differences were seen among the three ethnic groups in regards to internal consistency. Results of factor analyses of the five anger scales were similar to those reported originally by the scale author. Ethnicity and age had statistically significant main effects on the anger scales, and there was only one interaction. DiscussionThe use of the STAXI among a tri-ethnic adolescent population is warranted. The anger-in scale may be less reliable, especially among younger adolescents.

Body fat distribution in men and women of the Hispanic health and nutrition examination survey of the United States: associations with behavioural variables

Body fat distribution is a biological risk factor for cardiovascular disease and diabetes. There are known genetic factors influencing body fat distribution, but variation in this characteristic is also attributable to human behavioural and socioeconomic variables such as social class. Björntorp has proposed that these associations may be due to a series of physiological responses to psychosocial stress, most prominently chronic stimulation of the adrenal-cortical system. This system is known to affect body fat distribution. Elsewhere we have shown that general socioeconomic status is related to body fat distribution in men and women of the Hispanic Health and Nutrition Examination Survey (HHANES) of the United States. In this paper we explore the relationship with those behavioural variables available from the HHANES which could hypothetically serve as indicators of psychosocial stress: smoking, drinking and depression. For both sexes in all Hispanic ethnic groups except Puerto Rican men, as socioeconomic status declined, subcutaneous fat became more centrally distributed. This relationship continued to be significant after controlling for the behavioural variables. A positive relationship was also found between smoking and central body fat distribution which was independent of socioeconomic status. This relationship was statistically significant for all subsamples except Cuban-American women. No consistent relationships were found between body fat distribution, drinking and depression. The data support the hypothesis that body fat distribution may be linked to the social stress of low socioeconomic status, independent of the behavioural factors tested.