Fat and muscle mass in different groups of pre-pubertal and pubertal rural children. Cross-cultural comparisons between Sahelian (rural Senegal) and Amazonian (Beni River, Bolivia) children

Abstract

Background: An increase in fat accretion is essential for triggering the puberty spurt. Hence, nutritional constraints may influence puberty timing.

Aim: To measure changes in fat and muscle mass in children living in natural environments but with different nutritional exposures.

Methods: Cross-comparisons of children from rural Senegal and lowland (Amazonian) Bolivia were carried out. Anthropometric measurements of stature, weight, four subcutaneous skin-folds (triceps, biceps, subscapular, supra-iliac) and arm circumference were made. Children were divided into two age groups (5–9.9-year-olds or ‘pre pubescents’ (n = 381) and 10–15-year-olds or ‘pubescents’ (n = 692)).

Results: Senegalese girls menstruated later than Bolivian girls and Senegalese boys also matured later than Bolivian boys. Bolivian children displayed more fat and muscle before puberty and during puberty than the Senegalese. They also had more fat deposited on the trunk. There were substantial differences in living conditions and nutritional patterns between both locations. In Senegal, nutritional stress is likely to appear early during in utero life and to persist throughout the growth period, including puberty. This leads to a deficit in fat accretion before and during puberty that is associated with a considerable delay in puberty occurrence. In Bolivia, such stress is far less severe.

Conclusion: Variability in puberty should be analysed taking into account these differences.

Keywords::

• Anthropometry
• nutritional stress
• puberty
• ethnic groups

Acknowledgements

We are grateful to all people of the Bolivian and Senegalese children for their kind collaboration. Special thanks are due to Carlos y Renan for their constant dedication. We warmly thank our colleagues of the IRD Marcelo Claure, Abdul Castillo, in Bolivia and Tofene Ndiaye in Senegal for their kind help during field work. The contribution of Denis Garnier who was in charge of the follow-up of adolescent Senegalese girls is fully acknowledged and appreciated.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.