中国神经管畸形高低发地区季节及性别分布特征

目的：分析中国高低发区神经管畸形(NTDs)的流行病学分布特点。方法：利用1992—1994年期间“中美预防神经管畸形合作项目”监测资料，按照国际上采用的脊柱裂高低位不同损害水平分类方法，将NTDs分为四类，即无脑畸形、脑膨出、高位和低位脊柱裂(SB)，同时再将每一类按照是否合并其他畸形分为单纯与合并型，比较中国南北方、城乡、季节、性别NTDs发生率。分析中对城乡、季节、NTDs种类、性别分别进行调整，计算调整率。结果：32 6874名新生儿(包括孕20周及以上的活产、死胎和死产)中，NTDs 784例，北方NTDs发生率为5．57‰，南方为0．88‰。各类NTDs发生率存在南北方差别(P＜0．01)。调整其他影响因素后，北方总NTDs发生率大约是南方的3—7倍；NTDs发生率存在城乡差别(P＜0．01)，调整后北方农村NTDs发生率大约是城市的3—4倍，调整后南方农村NTDs发生率大约是城市的1．6—1．9倍；北方高位阳发生率在9—11月有季节性升高现象，南方无脑畸形率9—11月低于其他季节，其他类型NTDs在南北方无明显季节变化。结论：中国北方是世界上NTDs高发地区。NTDs发生率存在南北方、城乡差别，北方高位阳发生率有季节升高现象。不同类型NTDs之间在流行病学特征和表型上存在病因异质性。

The epidemiology of neural tube defects in high-prevalence and low-prevalence areas of China

Objective To describe the epidemiology of neural tube defects (NTDs) in high-and low-prevalence areas of China. Methods Birth defects surveillance data, collected from 1992 through 1994 was analyzed. These data were collected as part of the Sino-American cooperative project on NTDs prevention. We classified NTDs as anencephaly,encephalocele, high-level and low-level spina bifida (SB) according to location of the lesion (high vs low) and whether the defect was isolated or occurred in association with other birth defects. Rates were compared in the high-prevalence (North) region and the low-prevalence (South) region, after adjusted for classification, urban and rural,season and sex,and calculated the adjusted rate of NTDs. Results Among seven hundred and eighty-four NTDs cases in 326 874 recorded births (include in livebirth,stillbirth and fetal death with a gestational age of at least 20 weeks), the overall NTDs prevalence in the North was 5.57/ 1 000 births, and in the South was 0.88/ 1 000. There were also significant differences in the prevalence of anencephaly, encephalocele, high-level and low-level SB between North ( 0.97, 0.49, 2.75 and 1.11/ 1 000 birth) and South ( 0.36, 0.15, 0.21 and 0.14/ 1 000 birth)( P < 0.01), with adjusted prevalences in the North 3-7 times higher than those in the South. There were significant difference between urban ( 2.04) and rural areas ( 6.57/ 1 000 birth) in the North ( P < 0.01), urban ( 0.52) and rural areas ( 0.95/ 1 000 birth) in the South ( P < 0.05). Adjusted prevalence rates in the rural were 3- 4 times higher than those of urban in the North and 1.6- 1.9 times higher than in theSouth ;Theseasonalrateofhigh levelSBincreasedbetweenSeptemberandNovemberintheNorth ( 3 .44 / 10 0 0birth) ,whiletheseasonalrateofanencephalydecreasedbetweenSeptemberandNovember ( 0 .18/ 10 0 0birth)intheSouth .HowevertherewerenoseasonalchangesinotherclassifiedNTDsbothinthe SouthandNorth .Conclusions ThebirthprevalenceofNTDsintheNorthofChinawasthehighestinthe world.ThereweresignificantdifferencesbetweentheNorthandtheSouth ,urbanandrural.Therewas seasonalchangeinhigh levelSBintheNorth ,whichwasinaccordancetothephenotypeofNTDs.Itwas suggestedthattheremightexistetiologicalheterogeneityamonganecephalus,low andhigh levelSB .