Secondary sex characteristics of boys 12 to 17 years of age: the U.S. Health Examination Survey.

Data from the United States Health Examination Survey, Cycle III, were used to describe secondary sexual characteristics and their relationship to skeletal age in a representative sample of adolescent males aged 12 to 17 years. This survey utilized a national probability sample of youths selected to represent the U.S. population with respect to age, race, sex, geographic region, and socioeconomic status. Good concordance was found between Tanner stages for pubic hair and for genitalia. Sexual characteristics developed similarly for white and black boys, and socioeconomic status did not influence this development. Skeletal age and serum urate levels were closely related to development of pubic hair and genitalia. These data permit the physician to compare the development of individual patients with a representative sample of contemporaneous U.S. boys.

A longitudinal study of body fatness in childhood and adolescence.

Data from the United States Health Examination Surveys were analyzed to determine changes in body fatness between childhood and adolescence. A national probability sample (2,177 children) was examined in both Cycle II (6 to 11 years) and Cycle III (12 to 17 years) of these surveys and comprised the study cohort. The interval between examinations was three or four years. Adiposity was measured as skinfold thickness and correlations between childhood and adolescent adiposity were explored. High rank-order correlations were found between the two examinations for each race-sex group (P less than 0.001). The relationship between childhood and adolescent fatness was independent of stature, skeletal and sexual maturation, and economic status. Childhood fatness was the most predictive factor for adolescent fatness. This strong relationship indicates that the potentially obese adolescent can be identified during childhood.