Källén B, Löfkvist E
J Epidemiol Community Health. 1984 Jun;38(2):103-7. doi: 10.1136/jech.38.2.103.
The spina bifida rate in Sweden from 1947 to 1981 has been studied using various sources of information, including two central computerised registers. During the period the rate approximately halved, but the decline was not smooth and occurred in three "waves." When the geographical location of high risk areas within each wave was studied, they were found to differ. The findings are discussed in the light of an environmental aetiology hypothesis of this malformation.
利用包括两个中央计算机化登记册在内的各种信息来源,对1947年至1981年瑞典脊柱裂发病率进行了研究。在此期间,发病率大约减半,但下降并不平稳,出现了三次“浪潮”。当研究每一波中高风险地区的地理位置时,发现它们各不相同。根据这种畸形的环境病因假说对这些发现进行了讨论。