Using linked educational attainment data to reduce bias due to missing outcome data in estimates of the association between the duration of breastfeeding and IQ at 15 years.
Using linked educational attainment data to reduce bias due to missing outcome data in estimates of the association between the duration of breastfeeding and IQ at 15 years.
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DOI：
10.1093/ije/dyv035
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发表时间：
2015-06
影响因子：
7.7
通讯作者：
Macleod J
中科院分区：
文献类型：
--
作者：
Cornish RP;Tilling K;Boyd A;Davies A;Macleod J
背景：大多数流行病学研究都缺少信息，导致功效降低和潜在偏差。如果结果变量非随机缺失 (MNAR)，则暴露-结果关联的估计通常会有偏差。与包含缺失研究结果代理的管理数据的关联可以评估该结果是否为 MNAR 并评估偏倚。我们研究了婴儿母乳喂养与 15 岁时智商之间的关系，其中智商的代理可以通过与学校成绩数据的联系获得。方法：受试者是 1990-91 年参加雅芳家长和儿童纵向研究的人（n = 13 795），其中 5023 人在 15 岁时测量了智商。对于智商缺失的人，7030 人（79%）通过连接国家学生数据库获得了 16 岁时的教育程度信息。使用完整的病例分析、多重插补和逆缺失概率加权来估计母乳喂养持续时间和智商之间的关联；然后将这些估计值与通过关联分析得出的估计值进行比较。结果：15 岁时的智商为 MNAR——即使在调整了社会人口因素之后，成绩较高的人丢失智商数据的可能性也较小。与关联分析相比，所有方法都低估了母乳喂养和智商之间的关联。结论：与包含结果变量代理的管理数据的联系允许测试 MNAR 假设并进行更有效的分析。在某些情况下，这可能会产生公正的结果。
Background: Most epidemiological studies have missing information, leading to reduced power and potential bias. Estimates of exposure-outcome associations will generally be biased if the outcome variable is missing not at random (MNAR). Linkage to administrative data containing a proxy for the missing study outcome allows assessment of whether this outcome is MNAR and the evaluation of bias. We examined this in relation to the association between infant breastfeeding and IQ at 15 years, where a proxy for IQ was available through linkage to school attainment data. Methods: Subjects were those who enrolled in the Avon Longitudinal Study of Parents and Children in 1990–91 (n = 13 795), of whom 5023 had IQ measured at age 15. For those with missing IQ, 7030 (79%) had information on educational attainment at age 16 obtained through linkage to the National Pupil Database. The association between duration of breastfeeding and IQ was estimated using a complete case analysis, multiple imputation and inverse probability-of-missingness weighting; these estimates were then compared with those derived from analyses informed by the linkage. Results: IQ at 15 was MNAR—individuals with higher attainment were less likely to have missing IQ data, even after adjusting for socio-demographic factors. All the approaches underestimated the association between breastfeeding and IQ compared with analyses informed by linkage. Conclusions: Linkage to administrative data containing a proxy for the outcome variable allows the MNAR assumption to be tested and more efficient analyses to be performed. Under certain circumstances, this may produce unbiased results.