the information site on endocrine disruption

Marcia E. Hermann-Giddens, et al., Pediatrics 99(4) 1997

Secondary sexual characteristics and menses in young girls seen in office practice: A study from the pediatric research in office settings network

This is a cross sectional study reporting several variables related to sexual development from 17 077 young girls presenting in physicians offices in North Carolina. This is significant in that it presents data from a very large cohort of girls and suggests that there is a sizable subpopulation of girls whose sexual development is accelerated relative to the general population. Further, the data suggest that the relative size of this accelerated population is greater in black girls than in white girls. Dramatic results include the finding that over 7% of 4 year old black girls showed some sign of pubertal development compared to less than 1% for white girls and by 8 years of age these numbers had risen to almost 50% of black girls and almost 15% for white girls. Finally, mean age at first menses was earlier in black vs white girls (12.16 ± 1.21 and 12.88 ± 1.20, respectively). The authors discuss these results in the context of previous population based studies of female puberty and conclude that, although the age at first menses closely match historic data (back to 1948), this study suggests that age at which breast development and pubic hair are first apparent is younger, especially among black girls, compared to previous studies. These results have been cited as evidence of population-based exposure to reproductive hazard in spite of the fact that no exposures, direct or implied, were estimated for the subjects in this study. More significantly, this study has caused considerable debate about revising the normal age of puberty in girls and the clinical management of premature puberty.

However, the authors do suggest some limitations to their data the most significant being that the subjects were selected on the basis of consulting a family physician that resulted in a physical examination. There was no attempt to exclude girls where the visit was percipitated by concerns of early puberty. As there are pathological conditions that result in signs of early puberty that need to be managed clinically, the pressence of these cases in the sample will bias the results towards an earlier age of pubertal development. It is not clear to what extent this factor influenced the results. Nonetheless, this study has caused increased concern about the age at puberty and the possibility that environmental factors can influence pubertal development.


©copyright McLaughlin Centre, Institute of Population Health, University of Ottawa