Objective: The incidence of idiopathic precocious puberty (IPP) might have an increasing trend. But the causes and risk factors of IPP are unknown. The objective of our study is to evaluate the effects of growth environments and two environmental endocrine disruptors (EDCs), zearalenone (ZEA), and 1,1-dichloro-2,2,bisethylene (p,p'-DDE), on patients with IPP.
Design: Case-control study.
Methods: The study consisted of 78 IPP patients at diagnosis and 100 control children matched for age and sex. A questionnaire was designed to collect data on growth environments, and serum ZEA and p,p'-DDE were tested in all subjects. We analyzed data on growth environments, two EDCs, and biological interaction between growth environments and EDCs.
Results: In growth environments, small for gestational age, maternal physical disease during pregnancy, early maternal menarche, early puberty of same-degree relatives, and father's absence in 4- to 6-year olds were risk factors for children with IPP (P<0.05). Serum ZEA concentration, ZEA, and p,p'-DDE-positive rates in the IPP group were significantly higher than those in the control group (P<0.05). There was a biological interaction between growth environments and ZEA (relative excess risk due to interaction =34.562, attributable proportion due to interaction =0.745, synergy index =4.193).
Conclusions: Results suggest possible effects of growth environments and two EDCs on the development of IPP. In addition, growth environments and ZEA have biological interaction that might increase the risk of developing IPP.