High incidence of central precocious puberty in a bounded geographic area of northwest Tuscany: An estrogen disrupter epidemic?

Abstract

The potential health consequences of human exposure to environmental estrogen disrupters are not known. Because many chemical compounds are environmentally persistent, toxic and estrogen-active, they can dysregulate the hypothalamic–pituitary–gonadal axis, potentially inducing reproductive disorders such as central precocious puberty (CPP). We performed a multi-center analysis of CPP distribution in northwest Tuscany (NWT), an area of 5990 km² with 1 280 895 inhabitants. Study criteria consisted of recorded CPP diagnoses and prescriptions of gonadotropin-releasing hormone analogs from January 1, 1998 to December 1, 2003. Although similar CPP prevalences were found in four major cities of NWT (Livorno, Lucca, Massa and Pisa) (mean 30.4 per 100 000 children, standard deviation 18.6; p > 0.05), Viareggio area (< 300 km²) with 19 219 child inhabitants (0–14 years of age) had the highest CPP prevalence: more than 161 CPP cases per 100 000 children. Living in Viareggio area significantly increased the risk of CPP (relative risk (RR) 5.73, 95% confidence interval (CI) 3.5–9.3; rate/risk difference 0.133%, p < 0.05). Annual CPP incidence in the Viareggio area was relatively constant and significantly higher than in other NWT areas (RR 5.04, 95% CI 2.3–11.2; rate/risk difference 0.03%, p < 0.05). Indeed, 47% of total NWT cases were distributed in the countryside (300 km²) surrounding Viareggio. Specifically, three villages – Camaiore, Pietrasanta and Stazzema – in Viareggio presented the highest CPP frequency: 216.1, 393.5 and 274.0 CPP cases per 100,000 children, respectively (RR 9.59, 95% CI 1.71–16.6; rate/risk difference 0.26%, p < 0.05). Owing to the definite geographic distribution of CPP and because increasing distance (km) from Pietrasanta rarefied CPP frequency, we suggest environmental factors (e.g. estrogen disrupter pollution) as major CPP determinants in NWT.