Journal article
Quantification of selection bias in studies of risk factors for birth defects among livebirths
Paediatric and perinatal epidemiology, Vol.34(6), pp.655-664
11/2020
DOI: 10.1111/ppe.12650
PMCID: PMC7541428
PMID: 32249969
Abstract
Background
Risk factors for birth defects are frequently investigated using data limited to liveborn infants. By conditioning on survival, results of such studies may be distorted by selection bias, also described as “livebirth bias.” However, the implications of livebirth bias on risk estimation remain poorly understood.
Objectives
We sought to quantify livebirth bias and to investigate the conditions under which it arose.
Methods
We used data on 3994 birth defects cases and 11 829 controls enrolled in the National Birth Defects Prevention Study to compare odds ratio (OR) estimates of the relationship between three established risk factors (antiepileptic drug use, smoking, and multifetal pregnancy) and four birth defects (anencephaly, spina bifida, omphalocele, and cleft palate) when restricted to livebirths as compared to among livebirths, stillbirths, and elective terminations. Exposures and birth defects represented varying strengths of association with livebirth; all controls were liveborn. We performed a quantitative bias analysis to evaluate the sensitivity of our results to excluding terminated and stillborn controls.
Results
Cases ranged from 33% liveborn (anencephaly) to 99% (cleft palate). Smoking and multifetal pregnancy were associated with livebirth among anencephaly (crude OR [cOR] 0.61 and cOR 3.15, respectively) and omphalocele cases (cOR 2.22 and cOR 5.22, respectively). For analyses of the association between exposures and birth defects, restricting to livebirths produced negligible differences in estimates except for anencephaly and multifetal pregnancy, which was twofold higher among livebirths (adjusted OR [aOR] 4.93) as among all pregnancy outcomes (aOR 2.44). Within tested scenarios, bias analyses suggested that results were not sensitive to the restriction to liveborn controls.
Conclusions
Selection bias was generally limited except for high mortality defects in the context of exposures strongly associated with livebirth. Findings indicate that substantial livebirth bias is unlikely to affect studies of risk factors for most birth defects.
Details
- Title: Subtitle
- Quantification of selection bias in studies of risk factors for birth defects among livebirths
- Creators
- Dominique Heinke - Harvard UniversityJanet W Rich‐Edwards - Brigham and Women’s HospitalPaige L Williams - Harvard UniversitySonia Hernandez‐Diaz - Harvard UniversityMarlene Anderka - Massachusetts Department of Public HealthSarah C Fisher - New York State Department of HealthTania A Desrosiers - University of North Carolina Gillings School of Global Public HealthGary M Shaw - Stanford UniversityPaul A Romitti - The University of IowaMark A Canfield - Texas Department of State Health ServicesMahsa M Yazdy - Massachusetts Department of Public Health
- Resource Type
- Journal article
- Publication Details
- Paediatric and perinatal epidemiology, Vol.34(6), pp.655-664
- DOI
- 10.1111/ppe.12650
- PMID
- 32249969
- PMCID
- PMC7541428
- NLM abbreviation
- Paediatr Perinat Epidemiol
- ISSN
- 0269-5022
- eISSN
- 1365-3016
- Number of pages
- 10
- Grant note
- Health Resources and Services Administration (T03MC07648) Eunice Kennedy Shriver National Institute of Child Health and Human Development (T32HD060454) National Center on Birth Defects and Developmental Disabilities (5U01DD000491; U01DD000493; U01DD001037)
- Language
- English
- Date published
- 11/2020
- Academic Unit
- Epidemiology; Biostatistics
- Record Identifier
- 9984066110002771
Metrics
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