Maturity and its relationship to plasma lipid and lipoprotein levels in adolescents: The Fels longitudinal study.

During adolescence, changes in lipid and lipoprotein levels have been reported to be associated with changes in body composition and changes in endogenous testosterone and estradiol. These hormone levels are directly correlated with sexual and skeletal maturity levels. The purpose of the present study was to determine if there are associations during pubescence and adolescence, independent of chronological age, between measures of maturity and body composition or plasma lipid and lipoprotein cholesterols. Skeletal maturity was measured on the basis of skeletal assessments of the bones of the knee joint. Age at peak height velocity was determined from serial stature measurements and, in girls, age at menarche was recorded. These measures of maturity, as well as measures of percent body fat, total body fat, total body fat mass, fat-free mass from underwater weighing, and plasma cholesterol, triglyceride, highdensity lipoprotein-cholesterol, and low-density lipoprotein-cholesterol levels from 502 observations on 174 boys and girls enrolled in the Fels Longitudinal Study were used in the analysis. Within annual chronological age groups, no associations were found between level of maturity and lipid and lipoprotein level or percent body fat in boys or girls. However, changes in lipid and lipoprotein levels over time appeared to be more apparent when age grouping were based on skeletal age than when they were based on chronological age.