Doria-Rose V Paul, Kim Han S, Augustine Elizabeth T J, Edwards Karen L
Department of Epidemiology, School of Public Health and Community Medicine, University of Washington, Seattle, WA, USA.
Am J Epidemiol. 2003 Sep 15;158(6):503-8. doi: 10.1093/aje/kwg193.
Interpretation of studies that have examined parity as a risk factor for Down's syndrome has been hindered by inadequate control for maternal age and/or failure to account for the differential use of prenatal diagnosis and pregnancy termination between low-parity and high-parity women. In this case-control study, the authors used exact matching on maternal age-minimize confounding and evaluated the potential impact of differential termination. A total of 898 cases of Down's syndrome and 4,488 controls were identified using Washington State birth certificates from 1984-1998. There was a trend towards increasing risk of Down's syndrome with increasing parity in both younger (age <35 years) and older (age > or =35 years) mothers. Restriction to women with no indication of amniocentesis (for whom differential termination is unlikely) resulted in a blunting of the odds ratios; however, a trend for parity remained. After restriction, odds ratios were as high as 1.65 (95% confidence interval: 1.13, 2.40) in younger women with a parity of three (compared with a parity of zero) and 2.41 (95% confidence interval: 1.41, 4.12) in older women with a parity of four or more. Although the odds ratios for older women were probably biased upwards because of underreporting of amniocentesis on birth certificates, these data support an association between parity and Down's syndrome.
由于对母亲年龄控制不足和/或未考虑低生育次数和高生育次数女性在产前诊断和终止妊娠方面的差异使用情况，对将生育次数作为唐氏综合征风险因素的研究解读受到了阻碍。在这项病例对照研究中，作者通过对母亲年龄进行精确匹配以尽量减少混杂因素，并评估了差异终止妊娠的潜在影响。利用1984年至1998年华盛顿州的出生证明，共识别出898例唐氏综合征病例和4488例对照。在年轻（年龄<35岁）和年长（年龄≥35岁）母亲中，唐氏综合征风险均有随着生育次数增加而上升的趋势。将研究限制在无羊膜穿刺术指征的女性（不太可能出现差异终止妊娠的情况）中，会使优势比变平缓；然而，生育次数的趋势仍然存在。限制后，生育次数为3次的年轻女性（与生育次数为0次相比）的优势比高达1.65（95%置信区间：1.13，2.40），生育次数为4次或更多次的年长女性的优势比为2.41（95%置信区间：1.41，4.12）。尽管由于出生证明上羊膜穿刺术报告不足，年长女性的优势比可能被高估，但这些数据支持生育次数与唐氏综合征之间存在关联。
