LIPIDS AND APOPROTEINS IN RELATION TO PARTICIPATION IN ORGANIZED SPORT ACTIVITIES AND PUBERTAL DEVELOPMENT IN BOYS

This study considers changes in the plasma lipid and apoprotein profil es of boys in relation to participation in organized sport activities and to testosterone (T) levels. Fifty boys, aged 9.9 +/- 0.6 years (me an +/- S.D.), participated in the study. During a 3 year follow-up, th e following measurements were taken twice a year: stature, weight, and skinfolds. Blood samples for lipids and apoproteins and sex hormone l evels, 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 (ape A-I). The changes of the profile over time in more active boys (participation rate >3 hr/wk) were similar to those of le ss active boys (participation rate <1 hr/wk) (MANOVA, repeated measure s, not significant). Consistent relationships between sex hormones and lipids and apoproteins were restricted to T with total cholesterol (T C), HDL-C, and apo A-I, respectively. The common variance ranged from 5.8% (r(T,TC)) to 18.5% (r(T,HDL-C)) (P less than or equal to 0.05). W hen the boys who reached advanced puberty during the follow-up period (n = 21) were studied apart from those who did not (n = 29), differenc es were found in TC, apo A-I, and HDL-C. TC decreased from 4.6 +/- 0.6 5 to 4.3 +/- 0.58 mmol/l in the more advanced pubertal boys, and incre ased from 4.6 +/- 0.90 to 4.8 +/- 0.79 mmol/l in the others; apo A-I d ecreased from 185 +/- 28.3 to 156 +/- 20.4 mg/dl and from 179 +/- 20.6 to 176 +/- 27.7 mg/dl, respectively (MANOVA, repeated measures, P les s than or equal to 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, respectiv ely; P less than or equal to 0.05). The lack, of a relationship with r egular physical activity may be due to the high levels of HDL-C and ap o A-I at the beginning 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 activity. (C) 1995 Wiley-Liss, Inc .