Separate models were run using uncorrected and specific gravity-corrected urinary BPA concentrations as the dependent variables. We assessed several sociodemographic click here factors, maternal characteristics, and dietary factors as potential
predictors of exposure including those previously reported in the published literature (Braun et al., 2011, Calafat et al., 2008, Cao et al., 2011, Lakind and Naiman, 2010 and Mahalingaiah et al., 2008). Potential predictors of BPA exposure considered in the models included: maternal age, education, parity, pre-pregnancy body mass index (BMI), income poverty ratio (ratio of family income to the respective poverty threshold based on 2000 U.S. Census data), years spent living in the United States, consumption of: soda, alcohol, canned fruit, bottled water, pizza, fish, and hamburgers during pregnancy; gestational age at the time of urine sample collection,
and collection time of each urine sample provided. Information on demographic characteristics and pre-pregnancy BMI was collected at the first prenatal visit. Pre-pregnancy BMI (kg/m2) was calculated based on self-reported weight and measured height. Information on dietary consumption throughout the pregnancy SCH727965 cost was extracted from the food frequency questionnaire administered in the second prenatal visit. This food frequency questionnaire was originally designed to document women’s nutrient intake during pregnancy and lists 124 food items but has limited information about food packaging. Thus, of the 124 food items, we only included the
limited number of available food items previously associated with BPA or potentially packaged in containers with BPA. Time-varying covariates included in the models were gestational age at the time the urine samples were collected, Nitroxoline maternal smoke exposure (personal and second hand exposure), soda consumption, and alcohol consumption. Information on these time-varying covariates was collected at the time of each urine collection (e.g., at the first interview, mothers were asked about soda consumption habits since they became pregnant and at the second interview they were asked about these habits since the first interview). With the exception of gestational age, collection time, and income poverty ratio, covariates were examined as categorical variables in our GEE model; variables were categorized as specified in Table 1. Values for missing covariates (≤ 5%) were randomly imputed based on observed probability distributions. All potential predictors of BPA exposure were included in the GEE models as independent variables; statistical significance of individual predictors was considered as a p-value < 0.05. All statistical analyses were conducted using Stata 10 for Windows (StataCorp, College Station, TX). Mothers were primarily young (mean + SD: 25.6 + 5.