采用育龄妇女叶酸补充剂加权比例法预测神经管缺陷率下降情况。
Method of weighted proportion of reproductive-aged women taking folic acid supplements to predict a neural tube defect rate decline.
作者信息
Yang Quanhe, Atkinson Michael, Erickson J David
机构信息
Division of Birth Defects and Developmental Disabilities, National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
出版信息
Birth Defects Res A Clin Mol Teratol. 2003 Dec;67(12):959-67. doi: 10.1002/bdra.10127.
BACKGROUND
Neural tube defect (NTD) rates can be lowered by increased consumption of folic acid (FA) by women before and during early pregnancy. The crude proportion of reproductive-aged women taking FA supplements has been used to predict a decline of the NTD rate in the general population. In this study we examine the potential error in using the crude proportion to predict NTD risk reduction, and offer an alternative method.
METHODS
The crude proportion measures the number of women taking FA. It ignores the substantial variability by maternal age in the probability of giving birth. Age-specific fertility rates (ASFRs) reflect the probability that a woman in a specific age group will give birth in a given year. In this study, we show how to calculate a proportion weighted by ASFRs to predict a decline in the NTD rate, and to assess the effectiveness of FA consumption in preventing NTDs.
RESULTS
Our results show that a crude proportion of 50% of women (15-49 years old) taking FA is associated with a range of 24-77% in weighted proportions. Assuming a 40% risk reduction from taking 400 microg of FA daily, the expected NTD rate decline could vary from 9.6% to 30.6%, depending on the age distribution of women taking FA.
CONCLUSIONS
The ASFR-weighted proportion estimates the proportion of babies born to women taking FA, as opposed to the crude proportion of women taking FA. We recommend using the ASFR-weighted proportion to predict an NTD rate decline and measure the success of FA education campaigns. We found that when women in high-fertility age groups increased their FA consumption, the decline in the NTD rate was greater than when women in low-fertility age groups did so. Our findings suggest that the more efficient approach to NTD prevention is to focus on women with a higher probability of giving birth. For example, by focusing on <50% of women of childbearing age (20-34 years), as much as 76% of the maximum NTD rate reduction can be achieved.
背景
在怀孕前及怀孕早期增加叶酸（FA）的摄入量可降低神经管缺陷（NTD）的发生率。使用服用FA补充剂的育龄妇女的粗略比例来预测一般人群中NTD发生率的下降情况。在本研究中，我们研究了使用粗略比例预测NTD风险降低的潜在误差，并提供了一种替代方法。
方法
粗略比例衡量服用FA的妇女人数。它忽略了产妇年龄在生育概率方面的巨大差异。特定年龄生育率（ASFRs）反映了特定年龄组的妇女在给定年份生育的概率。在本研究中，我们展示了如何计算按ASFRs加权的比例以预测NTD发生率的下降，并评估FA摄入预防NTD的有效性。
结果
我们的结果表明，50%的妇女（15 - 49岁）服用FA的粗略比例对应的加权比例范围为24% - 77%。假设每天服用400微克FA可降低40%的风险，预期的NTD发生率下降可能在9.6%至30.6%之间，具体取决于服用FA的妇女的年龄分布。
结论
ASFR加权比例估计的是服用FA的妇女生育婴儿的比例，而不是服用FA的妇女的粗略比例。我们建议使用ASFR加权比例来预测NTD发生率的下降，并衡量FA教育活动的成效。我们发现，高生育年龄组的妇女增加FA摄入量时，NTD发生率的下降幅度大于低生育年龄组的妇女。我们的研究结果表明，预防NTD更有效的方法是关注生育概率较高的妇女。例如，关注<50%的育龄妇女（20 - 34岁），可实现高达76%的最大NTD发生率降低。
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