Comparison of blood lipids, lipoproteins, anthropometric measures, and resting and exercise cardiovascular responses in children, 6--7 years old.

The purpose of this investigation was to determine sex differences and interrelationships in anthropometric, blood lipids and lipoproteins, steady rate and maximal bicycle ergometric measures in boys (IV = 38) and girls (N = 28) ages 6 to 7 years. After adjusting for a significantly (P i 0.05) higher sum of skinfold measure for the girls, significant (P < 0.05) sex differences were obtained for high-density lipoprotein cholesterol (HDL-C), resting heart rate, and steady-rate heart rate. Lower HDL-C values (43.3 vs 49.6 m&il) for the girls accounted for their lower cholesterol since no sex differences were found for low-density lipoprotein cholesterol (LDL-C). Following 4 min of steady-rate bicycling at 90 kgm, girls had higher heart rates (131 vs 119 beats.min-‘) whereas no differences (P > 0.05) existed in preexercise and maximal heart rates. Multiple regression analyses resulted in weak but significant (P C 0.05) prediction equations for cholesterol and cumulative work performed on the bicycle. A significant (P < 0.05) negative correlation between HDL-C vs triglycerides (r = 0.46) was obtained for the girls. These data indicate that sex differences exist for selected ergometric, anthropometric, and blood lipid and lipoprotein measures as early as 6 years. Also, the association among blood lipid and lipoprotein measures may differ between boys and girls.