Lipids and apoproteins in relation to participation in organized sport activities and pubertal development in boys.

Abstract

This study considers changes in the plasma lipid and apoprotein profiles of boys in relation to participation in organized sport activities and to testosterone (T) levels. Fifty boys, aged 9.9 ± 0.6 years (mean ± S.D.), participated in the study. During a 3 year follow-up, the following measurements were taken twice a year: stature, weight, and skinfolds. Blood samples for lipids and apoproteins and sex hormone levels, and information on participation in sport activities were also obtained. No relationship was found between participation in organized sport activities and high density lipoprotein cholesterol (HDL-C) or apoprotein A-I (apo A-I). The changes of the profile over time in more active boys (participation rate > 3 hr/wk) were similar to those of less active boys (participation rate < 1 hr/wk) (MANOVA, repeated measures, not significant.) Consistent relationships between sex hormones and lipids and apoproteins were restricted to T with total cholesterol (TC), HDL-C, and apo A-I, respectively. The common variance ranged from 5.8% (rT,TC ) to 18.5% (rT,HDL-C ) (P ⩽ 0.05.) When the boys who reached advanced puberty during the follow-up period (n = 21) were studied apart from those who did not (n =29), differences were found in TC, apo A-I, and HDL-C, TC decreased from 4.6 ± 0.65 to 4.3 ± 0.58 mmol/l in the more advanced pubertal boys, and increased from 4.6 ± 0.90 to 4.8 ± 0.79 mmol/l in the others; apo A-I decreased from 185 ± to 28.3 to 156 ± 20.4 mg/dl and from 179 ± 20.6 to 176 ± 27.7 mg/dl, respectively (MANOVA, repeated measures, P ⩽ 0.05) HDL-C was lower in advanced pubertal boys at the end of follow-up (1.4 ± 0.33 and 1.7 ± 0.38 mmol/l, respectivel; P ⩽ 0.05). The lack of a relationship with regular physical activity may be due to the high levels of HDL-C and apo A-I at the begining of the study. On the other hand, the effect of the increasing T levels on HDL-C and apo A-I may have overwhelmed the presumed effect of regular physical activitiy. © 1995 Wiley-Liss, Inc.