Endocrine-Disrupting Chemicals and Early Puberty in Girls

Abstract

In recent decades, pubertal onset in girls has been considered to occur at an earlier age than previously. Exposure to endocrine-disrupting chemicals (EDCs) has been associated with alterations in pubertal timing, with several reports suggesting that EDCs may have a role in the secular trend in pubertal maturation, at least in girls. However, relevant studies give inconsistent results. On the other hand, the majority of girls with idiopathic precocious or early puberty present the growth pattern of constitutional advancement of growth (CAG), i.e., growth acceleration soon after birth. Herein, we show that the growth pattern of CAG is unrelated to exposure to endocrine-disrupting chemicals and is the major determinant of precocious or early puberty. Presented data suggest that EDCs, at most, have a minor effect on the timing of pubertal onset in girls.

Keywords: constitutional advancement of growth; early puberty; endocrine-disrupting chemicals; girls; precocious puberty; puberty.

Figure 1

This girl presented at the clinic at the age of 8.1 years with a Tanner stage 2 breast and pubic hair development. Breast developed at the age of 7.4 years and pubic hair at the age of 7.8 years. Before the appearance of any signs of puberty, her height SDS (HSDS) was +1.84 SDS (lines in growth chart represent height standard deviations marked as SD) well above her Target Height (TH) of +0.25 SDS. She was born with an average birth length of 0.0 SDS, but soon after birth, she presented growth acceleration reaching a zenith percentile (close to HSDS + 2 SDS) at about 3 years of age. She continued to grow along this percentile until she entered puberty presenting a further growth acceleration thereafter. At the age of 8.2 years, her bone age was 10.3 years compatible with the biological age in which girls enter puberty. Predicted adult height was within TH. No treatment was considered necessary.