Cuckle H
Institute of Epidemiology and Health Services Research, Research School of Medicine, Leeds, U.K.
Prenat Diagn. 1995 Nov;15(11):1057-65. doi: 10.1002/pd.1970151111.
A new method is described for calculating maternal serum marker distribution parameters which will improve risk estimation when screening for Down's syndrome. The approach is to calculate parameters using data from the local screened population and data obtained by meta-analysis from all published studies. The local data are used to derive the variance and covariance in unaffected pregnancies. The meta-analysis is used for the mean level in Down's syndrome pregnancies together with the differences in variance and covariance between affected and unaffected pregnancies. Forty-four published studies were analysed. The mean level for Down's syndrome in multiples of the normal median was 0.73 for alpha-fetoprotein (AFP) in total of 1140 pregnancies, 0.73 for unconjugated oestriol (uE3) in 613, 2.02 for human chorionic gonadotropin (hCG) in 850, and 2.30 for free beta-hCG in 477. For all four markers, the variance in Down's syndrome was higher than in unaffected pregnancies; for AFP and uE3, the covariances were also higher in Down's syndrome, but for the other markers they were lower. The method was illustrated using data from 6387 pregnancies screened in Leeds.
本文描述了一种计算母体血清标志物分布参数的新方法，该方法在唐氏综合征筛查时可改善风险评估。具体做法是利用当地筛查人群的数据以及通过对所有已发表研究进行荟萃分析得到的数据来计算参数。利用当地数据得出未受影响妊娠的方差和协方差。荟萃分析用于获取唐氏综合征妊娠的平均水平以及受影响和未受影响妊娠之间方差和协方差的差异。对44项已发表研究进行了分析。在总共1140例妊娠中，甲胎蛋白（AFP）在唐氏综合征中的平均水平为正常中位数的0.73倍；在613例妊娠中，未结合雌三醇（uE3）为0.73倍；在850例妊娠中，人绒毛膜促性腺激素（hCG）为2.02倍；在477例妊娠中，游离β-hCG为2.30倍。对于所有这四种标志物，唐氏综合征中的方差均高于未受影响的妊娠；对于AFP和uE3，唐氏综合征中的协方差也更高，但对于其他标志物则更低。利用利兹筛查的6387例妊娠数据对该方法进行了说明。
