[Using two-dimensional graphic cluster method to study the geographic distribution pattern of patients with anorectal...

To investigate the geographic distribution pattern of patients with anorectal atresia/stenosis in China, in order to provide clue for research on its etiology.

Data were collected from Chinese Birth Defects Monitoring Network (CBDMN), which was a hospital-based congenital malformations registry system. From 2001 to 2005, all fetuses with more than 28 weeks of gestation and neonates up to 7 days of age, were monitored. Two-dimensional graphic cluster method was used to divide monitoring stations into different classes with the incidence rates of anorectal atresia/stenosis.

The overall incidence of anorectal atresia/stenosis was 3.17 per 10,000 during 2001 to 2005. The incidence was higher in Eastern than that in Mid or Western parts of China and the difference was statistically significant (z = 2.50, 3.69; P = 0.012, < 0.001). The monitoring stations were grouped into 6 classes. Class I was with Heilongjiang, Jilin and Liaoling; Class II was with Fujian, Guangdong, Hainan, Guangxi, and South Hunan and Jiangxi; Class III was with Beijing, Tianjin, Hebei, Shandong, and North Jiangsu and Anhui; Class IV was with Zhejiang, Shanghai, South Anhui and Jiangsu, North Hunan and Jiangxi, Hubei, Henan, Shanxi and Inner Mongolia, Class V was with Ningxia, Gansu and Qinghai; and Class VI was with Shaanxi, Sichuan, Chongqing, Yunnan, Guizhou, Xinjiang and Tibet.

Our findings discovered the geographic distribution patterns of patients with anorectal atresia/stenosis in China. It is important to further analyze the relevant environmental factors attached to it so a better regional monitoring system for anorectal atresia/stenosis can be operated.