Figà-Talamanca I, Tarquini M, Lauria L
Dipartimento di Biologia Animale e dell'Uomo, Università degli Studi di Roma La Sapienza.
G Ital Med Lav Ergon. 2003 Jul-Sep;25 Suppl(3):52-3.
The sex ratio at birth (male births/total births) seems to be influenced by both biological and environmental factors. Endocrine Disrupters such as dioxin, DBCP and other pesticides have been studied as possible determinants of the decline in the sex ratio observed in some western countries. High serum concentration of dioxin in about two hundred fathers exposed during the well-known Seveso accident (1976), have been found associated with a significant decline in male births. The present study examines the possible variation of the sex ratio at birth in the offspring of the entire populations residing in the municipalities around the site of the Seveso accident. We observed a reduction of male births in the eight years following the accident (1977-1984) in the two municipalities with the highest level of contamination (Meda and Seveso). This effect was no longer detectable in the subsequent decades. No reduction in the sex ratio was observed when all considered municipalities are grouped in three exposure categories, according to their distance from the centre of the contaminated area. It is concluded that variations of the sex ratio may be detected only in populations with high exposure to dioxin, but this effect is concealed when the analysis of the sex ratio is based on large populations, with lower levels of exposure.
出生性别比（男婴出生数/总出生数）似乎受到生物和环境因素的双重影响。二噁英、二溴氯丙烷及其他杀虫剂等内分泌干扰物已被作为一些西方国家观察到的出生性别比下降的可能决定因素进行研究。在著名的塞韦索事故（1976年）期间暴露的约200名父亲中，发现高血清二噁英浓度与男婴出生数显著下降有关。本研究调查了居住在塞韦索事故现场周边市镇的全部人群后代的出生性别比可能存在的变化。我们观察到，在污染程度最高的两个市镇（梅达和塞韦索），事故发生后的八年（1977 - 1984年）间男婴出生数减少。在随后几十年中，这种效应不再可检测到。根据与污染区域中心的距离，将所有考虑的市镇分为三类暴露组时，未观察到出生性别比下降。得出的结论是，仅在高暴露于二噁英的人群中可检测到出生性别比的变化，但当基于暴露水平较低的大量人群进行出生性别比分析时，这种效应会被掩盖。
