Abstracts: ISEE 21st Annual Conference, Dublin, Ireland, August 25-29, 2009: Poster Presentations
*University of California, Berkeley, California, United States; and †Centers for Disease Control and Prevention, Atlanta, Georgia, United States.
Abstracts published in Epidemiology have been reviewed by the organizations of Epidemiology. Affliate Societies at whose meetings the abstracts have been accepted for presentation. These abstracts have not undergone review by the Editorial Board of Epidemiology.
To examine the association of maternal exposure to polybrominated diphenyl ethers (PBDEs) with time to pregnancy (TTP).
The study population comprised 225 pregnant women participating in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study, a cohort study of low-income, predominantly Mexican women living in an agricultural region of California. Concentrations of 10 PBDE congeners were measured in serum collected from the women near the end of the second trimester of pregnancy using gas chromatography and isotope dilution high resolution mass spectrometry. Analyses were limited to four PBDE congeners (BDE-47, −99, −100 and −153) that were detected in more than 75% of women. TTP was defined as the number of months it took to become pregnant, censored at 13 months. Women who were using contraceptives at the time of conception (i.e. contraceptive failures) were excluded. We analyzed the association of TTP with lipid-adjusted PBDEs as continuous variables using discrete-time Cox proportional hazards models, to obtain fecundability odds ratios (fOR). PBDE levels were log transformed and levels below the limit of detection (LOD) were given the values of the LOD/2. All analyzes were adjusted for covariates.
Median TTP was 3 months (range: 0–180 months). All four PBDE congeners were associated with longer time to pregnancy (i.e. fOR < 1). Each 10-fold increase in BDE-153 was associated with a 50% decreased odds of conceiving each month (adjusted fOR = 0.5, P = 0.001). Similar results were seen for BDE-47 (adjusted fOR = 0.7, P = 0.05), −99 (adjusted fOR = 0.7, P = 0.08), and −100 (adjusted fOR = 0.6, P = 0.006).
Higher maternal PBDE levels during pregnancy were associated with longer time to pregnancy in this population.