Sexual precocity after immigration from developing countries to Belgium: evidence of previous exposure to organochlorine pesticides

In a retrospective auxological study of 145 patients seen in Belgium during a 9-year period for treatment of precocious puberty, 28% appeared to be fo reign children (39 girls, one boy) who immigrated 4 to 5 years earlier from 22 developing countries, without any link to a particular ethnic or countr y background. The patients were either adopted (n = 28) or non-adopted (n = 12), the latter having normal weight and height at immigration and startin g early puberty without evidence of earlier deprivation. This led to the hy pothesis that the mechanism of precocious puberty might involve previous ex posure to oestrogenic endocrine disrupters. A toxicological plasma screenin g for eight pesticides detected p,p'-DDE, which is derived from the organoc hlorine pesticide DDT. Median p,p'-DDE concentrations were respectively 1.2 0 and 1.04 ng/ml in foreign adopted (n = 15) and non-adopted (n = 11) girls with precocious puberty, while 13 out of 15 Belgian native girls with idio pathic or organic precocious puberty showed undetectable concentrations (<0 .1 ng/ml). A possible relationship between transient exposure to endocrine disrupters and sexual precocity is suggested, and deserves further studies in immigrant children with non-advanced puberty.