Impact of sample collection participation on the validity of estimated measures of association in the National Birth Defects Prevention Study when assessing gene-environment interactions

To better understand the impact that nonresponse for specimen collection has on the validity of estimates of association, we examined associations between self-reported maternal periconceptional smoking, folic acid use, or pregestational diabetes mellitus and six birth defects among families who did and did not submit buccal cell samples for DNA following a telephone interview as part of the National Birth Defects Prevention Study (NBDPS). Analyses included control families with live born infants who had no birth defects (N = 9,465), families of infants with anorectal atresia or stenosis (N = 873), limb reduction defects (N = 1,037), gastroschisis (N = 1,090), neural tube defects (N = 1,764), orofacial clefts (N = 3,836), or septal heart defects (N = 4,157). Estimated dates of delivery were between 1997 and 2009. For each exposure and birth defect, odds ratios and 95% confidence intervals were calculated using logistic regression stratified by race-ethnicity and sample collection status. Tests for interaction were applied to identify potential differences between estimated measures of association based on sample collection status. Significant differences in estimated measures of association were observed in only four of 48 analyses with sufficient sample sizes. Despite lower than desired participation rates in buccal cell sample collection, this validation provides some reassurance that the estimates obtained for sample collectors and noncollectors are comparable. These findings support the validity of observed associations in gene-environment interaction studies for the selected exposures and birth defects among NBDPS participants who submitted DNA samples

Factors affecting maternal participation in the genetic component of the National Birth Defects Prevention Study—United States, 1997–2007

As epidemiological studies expand to examine gene–environment interaction effects, it is important to identify factors associated with participation in genetic studies. The National Birth Defects Prevention Study is a multisite case–control study designed to investigate environmental and genetic risk factors for major birth defects. The National Birth Defects Prevention Study includes maternal telephone interviews and mailed buccal cell self-collection kits. Because subjects can participate in the interview, independent of buccal cell collection, detailed analysis of factors associated with participation in buccal cell collection was possible

Estimated Maternal Pesticide Exposure from Drinking Water and Heart Defects in Offspring

Our objective was to examine the relationship between estimated maternal exposure to pesticides in public drinking water and the risk of congenital heart defects (CHD). We used mixed-effects logistic regression to analyze data from 18,291 nonsyndromic cases with heart defects from the Texas Birth Defects Registry and 4414 randomly-selected controls delivered in Texas from 1999 through 2005. Water district-level pesticide exposure was estimated by linking each maternal residential address to the corresponding public water supply district’s measured atrazine levels. We repeated analyses among independent subjects from the National Birth Defects Prevention Study (NBDPS) (1620 nonsyndromic cases with heart defects and 1335 controls delivered from 1999 through 2005). No positive associations were observed between high versus low atrazine level and eight CHD subtypes or all included heart defects combined. These findings should be interpreted with caution, in light of potential misclassification and relatively large proportions of subjects with missing atrazine data. Thus, more consistent and complete monitoring and reporting of drinking water contaminants will aid in better understanding the relationships between pesticide water contaminants and birth defects

Maternal Occupational Exposure to Polycyclic Aromatic Hydrocarbons: Effects on Gastroschisis among Offspring in the National Birth Defects Prevention Study

Background: Exposure to polycyclic aromatic hydrocarbons (PAHs) occurs in many occupational settings. There is evidence in animal models that maternal exposure to PAHs during pregnancy is associated with gastroschisis in offspring; however, to our knowledge, no human studies examining this association have been conducted

The national birth defects prevention study: A review of the methods: NBDPS METHODS REVIEW

The National Birth Defects Prevention Study (NBDPS) is a large population-based multi-center case-control study of major birth defects in the United States

Interpreting and communicating risk of medications in pregnancy, using SSRIs as an example

Background: Often we consider publishing our research as the last step in the process. However, women considering pregnancy, women who are pregnant and health care providers caring for these women need to be able to interpret and use our research to make treatment decisions for their health and the infant's. We may consider ourselves to be scientists and not policy makers, but, if we do not clearly describe and interpret our results others will interpret it for us. This abstract is submitted on behalf of the Medications in Pregnancy SIG. Objectives: To be aware of the challenges that health care providers, who care for women with chronic conditions such as depression, face. To learn how to write scientific manuscripts and press releases that are as helpful as possible for health care providers, the general public and policy makers. Description: A moderator and four speakers will discuss the challenges of interpreting the scientific data that is out there. The first speaker will briefly discuss the existing literature on SSRIs and major birth defects, and the potential reasons for conflicting results, or conflicting interpretation of results. The second speaker will provide the clinical perspective of a provider who treats women with depression who might want to get pregnant or who already are pregnant. Someone from a teratogen information center will provide insight into what aspects of communication are important to inform and educate in a transparent way, for instance by using absolute risks. Someone from a regulatory agency will discuss what aspects of publications on medications in pregnancy are most important to them as they regulate. Lastly a journalist will share with us what factors influence whether a paper will be considered for coverage in a media outlet and what information is useful for them to write their articles. Participants can be involved by providing specific examples and working together to come up with improved ways to present data