Journal article
ADJUSTING FOR BIAS DUE TO INCOMPLETE CASE ASCERTAINMENT IN CASE-CONTROL STUDIES OF BIRTH DEFECTS
American journal of epidemiology, Vol.181(8), pp.595-607
04/15/2015
DOI: 10.1093/aje/kwu323
PMCID: PMC4501270
PMID: 25792608
Abstract
Case-control studies of birth defects might be subject to selection bias when there is incomplete ascertainment of cases among pregnancies terminated following prenatal diagnosis of the defect. We propose a simple method to estimate inverse probability of selection weights (IPSWs) for cases ascertained from pregnancies both ending and not ending in termination using data directly available from the National Birth Defects Prevention Study and other published information. The IPSWs can then be used to adjust for selection bias analytically. We can also allow for uncertainty in the selection probabilities through probabilistic bias analysis. We provide an illustrative example using data from National Birth Defects Prevention Study (1997–2009) to examine the association between prepregnancy obesity (body mass index ≥30 vs. <30 kg/m
2
) and spina bifida. The unadjusted odds ratio (OR) for prepregnancy obesity and spina bifida is 1.48 (95% confidence interval: 1.26, 1.73), and the simple selection bias-adjusted OR is 1.26 (95% confidence interval: 1.04, 1.53). The probabilistic bias analysis resulted in a median adjusted OR of 1.22 (95% simulation interval: 0.97, 1.47). The proposed method provides a quantitative estimate of the IPSWs and the bias introduced by incomplete ascertainment of cases among terminated pregnancies conditional on a set of assumptions.
Details
- Title: Subtitle
- ADJUSTING FOR BIAS DUE TO INCOMPLETE CASE ASCERTAINMENT IN CASE-CONTROL STUDIES OF BIRTH DEFECTS
- Creators
- Penelope P HowardsCandice Y JohnsonMargaret A HoneinW. Dana FlandersNational Birth Defects Prevention Study
- Contributors
- Paul A Romitti (Contributor) - University of Iowa, Epidemiology
- Resource Type
- Journal article
- Publication Details
- American journal of epidemiology, Vol.181(8), pp.595-607
- DOI
- 10.1093/aje/kwu323
- PMID
- 25792608
- PMCID
- PMC4501270
- ISSN
- 0002-9262
- eISSN
- 1476-6256
- Language
- English
- Date published
- 04/15/2015
- Academic Unit
- Epidemiology; Biostatistics
- Record Identifier
- 9984214957802771
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