BACKGROUND: Little is known about the role of energetic status in the timing of puberty among males across populations. AIM: To determine the relationship of testosterone production and bioavailability to energetic status and somatic growth in a sub-Saharan population. SUBJECTS AND METHODS: Anthropometric measures, secondary sexual characteristics, blood spot and salivary samples were obtained from 441 Zimbabwe school boys, aged 12-18, from four high schools in the Harare area. RESULTS: Salivary and blood testosterone both showed their first significant increase between 14 and 15 years of age. Both salivary and blood testosterone were positively related to subscapular, but not triceps skinfold, when controlled for Tanner genital stage and age. Controlled for Tanner genital stage and age, salivary, but not blood testosterone was related to suprailiac skinfolds. Blood testosterone, but not salivary testosterone, showed a significant relationship with Tanner genital stage, controlled for age and suprailic skinfolds. Blood and salivary testosterone showed similar relationships with height and arm muscle plus bone area. CONCLUSION: These results provide support for the hypothesis that energetic status, especially abdominal fat plays a role in bioavailable testosterone during male puberty. However, they fail to demonstrate a clear effect of bioavailable testosterone on somatic growth.
BACKGROUND: Little is known about the role of energetic status in the timing of puberty among males across populations. AIM: To determine the relationship of testosterone production and bioavailability to energetic status and somatic growth in a sub-Saharan population. SUBJECTS AND METHODS: Anthropometric measures, secondary sexual characteristics, blood spot and salivary samples were obtained from 441 Zimbabwe school boys, aged 12-18, from four high schools in the Harare area. RESULTS: Salivary and blood testosterone both showed their first significant increase between 14 and 15 years of age. Both salivary and blood testosterone were positively related to subscapular, but not triceps skinfold, when controlled for Tanner genital stage and age. Controlled for Tanner genital stage and age, salivary, but not blood testosterone was related to suprailiac skinfolds. Blood testosterone, but not salivary testosterone, showed a significant relationship with Tanner genital stage, controlled for age and suprailic skinfolds. Blood and salivary testosterone showed similar relationships with height and arm muscle plus bone area. CONCLUSION: These results provide support for the hypothesis that energetic status, especially abdominal fat plays a role in bioavailable testosterone during male puberty. However, they fail to demonstrate a clear effect of bioavailable testosterone on somatic growth.