Bias Analyses to Investigate the Impact of Differential Participation: Application to a Birth Defects Case-Control Study

Citation

Petersen, Julie M.; Kahrs, Jacob C.; Adrien, Nedghie; Wood, Mollie E.; Olshan, Andrew F.; Smith, Louisa H.; Howley, Meredith M.; Ailes, Elizabeth C.; Romitti, Paul A.; & Herring, Amy H., et al. (Online ahead of print). Bias Analyses to Investigate the Impact of Differential Participation: Application to a Birth Defects Case-Control Study. Paediatric and Perinatal Epidemiology.

Abstract

BACKGROUND: Certain associations observed in the National Birth Defects Prevention Study (NBDPS) contrasted with other research or were from areas with mixed findings, including no decrease in odds of spina bifida with periconceptional folic acid supplementation, moderately increased cleft palate odds with ondansetron use and reduced hypospadias odds with maternal smoking.
OBJECTIVES: To investigate the plausibility and extent of differential participation to produce effect estimates observed in NBDPS.
METHODS: We searched the literature for factors related to these exposures and participation and conducted deterministic quantitative bias analyses. We estimated case-control participation and expected exposure prevalence based on internal and external reports, respectively. For the folic acid-spina bifida and ondansetron-cleft palate analyses, we hypothesized the true odds ratio (OR) based on prior studies and quantified the degree of exposure over- (or under-) representation to produce the crude OR (cOR) in NBDPS. For the smoking-hypospadias analysis, we estimated the extent of selection bias needed to nullify the association as well as the maximum potential harmful OR.
RESULTS: Under our assumptions (participation, exposure prevalence, true OR), there was overrepresentation of folic acid use and underrepresentation of ondansetron use and smoking among participants. Folic acid-exposed spina bifida cases would need to have been

URL

http://dx.doi.org/10.1111/ppe.13026

Reference Type

Journal Article

Year Published

Online ahead of print

Journal Title

Paediatric and Perinatal Epidemiology

Author(s)

Petersen, Julie M.
Kahrs, Jacob C.
Adrien, Nedghie
Wood, Mollie E.
Olshan, Andrew F.
Smith, Louisa H.
Howley, Meredith M.
Ailes, Elizabeth C.
Romitti, Paul A.
Herring, Amy H.
Parker, Samantha E.
Shaw, Gary M.
Politis, Maria D.

Article Type

Regular

Data Set/Study

National Birth Defects Prevention Study (NBDPS)

Continent/Country

United States

State

Nonspecific

ORCiD

Olshan - 0000-0001-9115-5128