Rosano A, Smithells D, Cacciani L, Botting B, Castilla E, Cornel M, Erickson D, Goujard J, Irgens L, Merlob P, Robert E, Siffel C, Stoll C, Sumiyoshi Y
International Centre for Birth Defects, Rome, Italy.
J Epidemiol Community Health. 1999 Oct;53(10):630-5. doi: 10.1136/jech.53.10.630.
To examine time trends in neural tube defects (NTD) prevalence from 1987 to 1996 in relation to the primary prevention policies for folic acid supplementation strategies in different countries.
Retrospective time trends analysis of NTD prevalence.
11 birth defect registries of congenital malformations participating in the International Clearinghouse for Birth Defects Monitoring System, in the period from 1 July 1987 to 30 June 1996.
8207 live births, stillbirths and terminated pregnancies affected by anencephaly or spina bifida registered by the 11 participating centres 1987-1996.
Prevalence rate ratios based on the annual rates, using the Poisson regression model.
During the study period a significant fall in prevalence rates for all NTD is present in Atlanta (USA), England and Wales, Hungary and Japan, and a significant rise in Norway and South America. After adjusting for the secular trends observed in the earlier years of the study, no significant trend can be attributed to preventive strategies. Data on NTD prevalence are supplemented with information on folate awareness among some of the populations studied.
There is no evidence that, up to the middle of 1996, any change in time trend was attributable to the introduction of national folate supplementation policies. The possible effectiveness of folate supplementation policies for the reduction of NTD clearly needs to be tried and studied for several more years. Considering that in the Western world about 50% of pregnancies are unplanned, a policy that rests on action taken before conception can only have limited success. Strategies based on food enrichment, such as was introduced in the USA from the beginning of 1998, may prove to be more successful.
研究1987年至1996年期间神经管缺陷（NTD）患病率的时间趋势，及其与不同国家叶酸补充策略一级预防政策的关系。
对NTD患病率进行回顾性时间趋势分析。
1987年7月1日至1996年6月30日期间，11个参与国际出生缺陷监测系统信息交换中心的先天性畸形出生缺陷登记处。
1987 - 1996年期间，11个参与中心登记的8207例受无脑儿或脊柱裂影响的活产、死产和终止妊娠病例。
基于年发病率，采用泊松回归模型计算患病率比值。
在研究期间，美国亚特兰大、英格兰和威尔士、匈牙利和日本所有NTD的患病率显著下降，而挪威和南美洲则显著上升。在对研究早期观察到的长期趋势进行调整后，没有显著趋势可归因于预防策略。NTD患病率数据辅以部分研究人群中叶酸知晓情况的信息。
没有证据表明，截至1996年年中，时间趋势的任何变化可归因于国家叶酸补充政策的实施。叶酸补充政策对降低NTD的可能有效性显然还需要再进行数年的试验和研究。考虑到在西方世界约50%的妊娠是意外妊娠，基于受孕前采取行动的政策只能取得有限的成功。从1998年初开始在美国实施的基于食物强化的策略可能会更成功。
