[Precocious puberty in children adopted from foreign countries]

Precocious puberty has been more frequently observed in the population of children adopted from abroad. A study was therefore carried out to assess the prevalence of this early onset of puberty.

In this study, 13 cases of precocious puberty have been examined in ten adopted girls and three adopted boys, and the clinical characteristics and other contributing factors have been described. In this study group, three of the cases were familial. In addition, a questionnaire was also completed by 99 French families with children adopted from abroad, and analyzed to determine the frequency of early pubertal development. The parameters included were age, weight and height at the time of adoption, date of onset of puberty, for the girls age at first menstruation, and current height and weight.

It was determined that the 13 children had a very high growth recovery rate from the time that they arrived in France. For the period from time of adoption to the onset of puberty, mean height increased from -1.3 to +1.5 standard deviation score (SDS) and the mean weight-for-height factor increased from +1.2 to 1.9 SDS. The weight-height recovery rate following adoption seems to be the direct cause of early pubertal development in certain children, notably in those with a particularly rapid growth rate (between 6 years 6 months and 8 years 9 months for the girls, and between 8 and 10 years for the boys). In children adopted at an early age, a 'biological memory' seems to exist regarding the renutrition phenomenon which was instrumental in accelerating the onset of puberty some years after adoption. An analysis of the survey on the adoptive families showed that the frequency of precocious puberty was 44.9% in the group of 49 girls compared to only 8.6% in the group of 35 adopted boys, and that it mainly concerned children from Africa (57%), followed by those from South and Central America (57%), Asia (45%), and Eastern Europe (29%).

A higher rate of precocious puberty was found in the adopted girls, with a significantly lower rate in the adopted boys. The etiological factors involved seemed to be mainly nutritional, and influenced by leptin and insulin-like growth factor 1 (IGF1) levels. The role of the latter and their interaction with other factors, particularly the ethnic aspect, remains to be determined via the study of a larger series of adopted children.