The Etiology And Environment Factors Of Congenital Hypothyroidism In Zhejiang Province, China

Aims:To investigate the geographical distribution and risk factors of congenital hypothyroidism(CH) in Zhejiang Province.Method:All data about CH were collected from the Centre of Zhejiang newborn screening program.From Oct 2003 to Sep 2008,a total of 1276 CH patients were diagnosed from a total of 2 142 274 newborn babies were enrolled in this study.Ptients in 26 selected areas were divided into 4 regions groups as city(n=100),plain(n=62), island(n=13)and mountainous area(n=97),respecting of their natural and social environment.Result:The average incidence among these 5 years was 1 in 1679 live births. Compared with the incidences of city(1/2037),plain(1/1989),and island areas (1/2223),the incidence of mountainous area(1/1020) were significantly higher(P＜0.01, respectively).The distribution of gestational weeks,birth weight and the sexual ratio of patients showed no difference among those 4 regions(P＞0.05).Compared with the patients with normal size and shaped thyroid gland,patients with hypoplastic gland were more from city or island,but not from mountainous area(P＜0.05),and had female preponderance(P＜0.001).Compared patients with hypoplastic thyroid gland,patients with goiter were more from mountainous area than from plain(P＜0.05).Conclusion:The incidence of CH varies according to different natural and social environment.The natural and social environment may be related to the etiology of hypothyroidism.