Body size, fatness, and leanness of Mexican American children in Brownsville, Texas: changes between 1972 and 1983.

Changes in the height, weight, body mass index, triceps skinfold, and arm and estimated midarm muscle circumferences in lower socioeconomic Mexican American children, 6 through 17 years of age, from Brownsville, Texas, were documented on the basis of surveys done in 1972 and 1983. With the exception of height in youths ages 14-17, all parameters show gains at most ages, and in particular an increase in fatness. Brownsville Mexican American youth are similar in height, weight, and the body mass index to Mexican American youth in other areas of Texas. These trends confirm the large proportion of relatively short but heavy children among Mexican Americans.

Relative lower extremity length in Mexican American and in American black and white youth.

Stature, sitting height, estimated leg (subischial) length and the sitting height/stature ratio are compared in Mexican American, American White and American Black boys 9 through 14 years of age and girls 12 through 17 years of age. Mexican American youth are shorter in stature and have absolutely shorter lower extremities. The sitting height of Mexican American youth is similar to that of Black youth and shorter than that of White youth. The sitting height/stature ratio is virtually identical in Mexican American and White youth, indicating similar proportions of lower extremities to stature. In contrast, Black youth have absolutely and relatively longer lower extremities than Mexican American and White youth. These results would thus seem to suggest that reference data for the body mass index (BMI) based on American White youth can be used with Mexican American youth, while race-specific values may be necessary for American Black youth. However, ethnic variation in physique, perhaps frame size, may be a factor which should be more systematically considered in evaluating the utility of the body mass index.

Estimated overweight and obesity in Mexican American school children.

The prevalence of overweight and obesity in Mexican American children 6 to 17 years of age was estimated in 1972 (n = 1269) and 1983 (n = 868). Children were classified as overweight or obese on the basis of the body mass index (weight/stature2), the triceps skinfold, or both, relative to reference data for white children in NHANES-1. Overweight was defined as greater than or equal to 90th percentiles, while obesity was defined as greater than or equal to 95th percentiles of age- and sex-specific reference data. Over the entire age range, there was a significant increase in the prevalence of overweight and obesity between 1972 and 1983, but there was variation with age and sex. Fewer children were classified as overweight or obese when the two criteria were used together than when they were used individually. The results suggest that the body mass index and the triceps skinfold may vary in sensitivity as indicators of overweight and obesity particularly in 10- to 17-year-old children. Children classified as obese by the body mass index had significantly larger estimated midarm muscle circumferences than those classified as obese by the triceps skinfold or by both the body mass index and the triceps skinfold.

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.

Growth and body composition of Mexican-American boys 9 through 14 years of age.

The growth status and densitometric estimates of body composition are considered in a cross-sectional sample of 95 Mexican-American boys, 9 through 14 years of age, from lower socioeconomic circumstances. A series of 19 measurements were taken on each boy, including measures of size, proportions, skeletal breadths, limb circumferences, skinfolds, and grip strength. Body density was determined by underwater weighing and residual volume was predicted. Density determinations were converted to percentage body fat using the average of two estimates from the equations of Brozek et al. (1963) and Siri (1956). Relative fatness was also converted to lean body mass and fat weight in kilograms. The growth status of the boys was compared to reference data for American White boys in the U. S. Health examination Survey. The Mexican-American boys are shorter and lighter than the reference data, and smaller in all anthropometric dimensions except skinfolds, which are variable. The subscapular and midaxillary skinfolds are similar in the two samples, while the triceps, medial calf, and suprailiac skinfolds are thinner in Mexican-American boys. Regressions of the four body composition estimates on age show significant age effects only for lean body mass and fat weight. Density and percentage fat do not vary significantly with age. Compared to samples of boys in the same age range, the Mexican-American boys generally have a greater body density. Correlations between skinfold thicknesses and body density are generally lower in the Mexican-American boys compared to other samples. Two equations for the prediction of body density in Mexican-American boys are offered.

Growth, fatness, and leanness in Mexican-American children.

Height, weight, arm circumference and the triceps skinfold were measured in 1269 Mexican-American school children, 6 through 17 years of age, from Brownsville, Texas. Arm circumference was corrected for the triceps skinfold to estimate midarm muscularity and fatness. The triceps skinfold was also used to estimate the occurrence of obesity and leanness. The heights and weights of Brownsville Mexican-American children compare favorably to those for Mexican-Americans in the Texas phase of th Ten State Nutrition Survey, and approximate the 25th centile of the United States Health Examination Survey (HES) reference data. Estimated midarm fat areas for Mexican-American children are similar to or slightly below HES values, while estimated midarm muscle areas are consistently below HES medians. The differences in estimated muscle mass of the arm reflect in part the smaller body size of Mexican-American children, and perhaps their diet, which tends to be adequate in calories and less satisfactory in protein. About 5 to 7% of the Mexican-American children are classified as "obese" using HES and TEcumseh (Michigan) criteria, both sets of reference data giving comparable results except in boys 14 to 17 years. However, about 30% of the Mexican-American children are classified as "lean" by the Tecumseh criteria and only 3% by the HES criteria. Estimates of obesity and leanness in a population thus vary with the criteria used.

Secular trend in the stature and weight of Mexican-American children in Texas between 1930 and 1970.

Statures and weights for four samples of Mexican-American children in Texas, measured in 1929-1931 and 1968-1972, were evaluated for evidence of a secular trend. The age range was 6 to 18 years, with more complete data from 8 through 15 years. There is no secular increase in the statures and weights of 6 year old children, a small increase in 8 year old children, and a larger secular increase at 10, 12, 14, and 15 years of age. From about 9 or 10 years of age on, the more recent Mexican-American children tend to have greater weights for their heights. The magnitude of the secular change per decade, however, is considerably smaller than rates for US black, white, European, and Japanese children. The estimated rates of secular change in stature for Mexican-American children approximate about one-fourth to one-half of the generalized rates for European and North American children offered by Meredith ('76) and Tanner ('77). Reasons for a limited secular trend in Texas Mexican-American children are probably bound to the matrix of lower socioeconomic circumstances, poorer health conditions, and marginal nutritional status.

Androgyny of physique in female track and field athletes.

Androgyny scores (3 x biacromial breadth - bicristal breadth) were calculated for 66 female track and field five event categories and 76 female non-athletes. Runners (distance and sprinters) did not differ significantly from the non-athletes in androgyny. However, jumpers, discus/javelin throwers, and shotputters were significantly more androgynous in physique. Androgyny scores for participants in jumping and throwing events overlapped considerably those for college-age males.