RESUMO
OBJECTIVE: To describe longitudinal changes in plasma lipid levels and pubertal stage in youths from age 8-18 years, in Project HeartBeat! STUDY DESIGN: Fasting blood samples and pubertal stage, using physical assessment of secondary sex characteristics, were obtained every 4 months for up to 4 years in a mixed longitudinal study of 633 children (49.1% female, 20.1% black), initially aged 8, 11, and 14 years. Total cholesterol, low density lipoprotein-cholesterol, high density lipoprotein-cholesterol, triglycerides (TG), and nonhigh density lipoprotein-cholesterol measurements were obtained. Data were collected from 1991-1995. RESULTS: Pubertal stage correlations with age varied among all race-sex groups (range, r = 0.61-0.70), and a given pubertal stage could represent a range of 5 years or more of chronological age. Throughout puberty, levels of total cholesterol, low density lipoprotein-cholesterol, and nonhigh density lipoprotein-cholesterol decreased, TG in males increased, and high density lipoprotein-cholesterol and TG in females showed no changes. Within a given pubertal stage, plasma lipid levels tended to differ by race, sex, or both. CONCLUSIONS: Lipid levels change markedly by pubertal stage, and patterns differ by sex and race. Chronological age ranges widely within a given pubertal stage and is an insensitive indicator of pubertal stage and the related changes in lipid levels. Pubertal development should be considered when determining screening criteria to identify youths with adverse blood lipid levels.
Assuntos
Jejum/sangue , Lipídeos/sangue , Puberdade/sangue , Adolescente , Criança , Estudos de Coortes , Feminino , Humanos , Estudos Longitudinais , Masculino , Grupos Raciais , Fatores Sexuais , TexasRESUMO
OBJECTIVES: To estimate age-related changes for serum concentration of non-high-density lipoprotein cholesterol (HDL-C), describe non-HDL-C distribution, and examine the prevalence of high non-HDL-C levels in children and adolescents by demographic characteristics and weight status. STUDY DESIGN: Data from 7058 participants ages 6-19 years in the 2005-2010 National Health and Nutrition Examination Surveys were analyzed. A high level of non-HDL-C was defined as a non-HDL-C value ≥ 145 mg/dL. RESULTS: Locally weighted scatterplot smoothing-smoothed curves showed that non-HDL-C levels increased from 101 mg/dL at age 6 to 111 mg/dL at age 10, decreased to 101 mg/dL at age 14, and then increased to 122 mg/dL at age 19 in non-Hispanic white males. Non-HDL-C levels generally were greater in female than male subjects, lower in non-Hispanic black subjects, and similar in male and slightly lower in female Mexican American subjects, compared with non-Hispanic white subjects. The overall mean was 108 (SE 0.5), and the percentiles were 67 (5th), 74 (10th), 87 (25th), 104 (50th), 123 (75th), 145 (90th), and 158 (95th) mg/dL. Mean and percentiles were greater among age groups 9-11 and 17-19 years than others and greater among non-Hispanic white than non-Hispanic black subjects. The prevalence of high non-HDL-C was 11.8% (95% CI 9.9%-14.0%) and 15.0% (95% CI 12.9%-17.3%) for the age groups 9-11 and 17-19, respectively. It varied significantly by race/ethnicity and overweight/obesity status. CONCLUSION: Non-HDL-C levels vary by age, sex, race/ethnicity, and weight classification status. Evaluation of non-HDL-C in youth should account for its normal physiologic patterns and variations in demographic characteristics and weight classification.