Summary data of serum concentrations of 32 persistent organic pollutants in young adults in relation to summary scores of persistent organic pollutants

This data article presents mean serum concentrations (wet weight and lipid standardized) of 32 persistent organic pollutants (POPs) detected in >75% of participants of the Coronary Artery Risk Development in Young Adults (CARDIA) study across levels of POPs scores, and their corresponding coefficients of determination. POPs scores were calculated as: A) the sum of each participant's log-transformed POPs concentrations (∑ of log Pops], or B) as the sum of the participants' log-transformed concentrations of each POP divided by the groups' standard deviation of the corresponding log-transformed POP (POPs summary score. Scores were calculated for both wet weight and lipid standardized concentrations and for all 32 POPs and for PCBs and organochlorine pesticides separately. POPs summary scores analyses were used in the article “Organochlorine pesticides and polychlorinated biphenyls (PCBs) in early adulthood and blood lipids over a 23-year follow-up” [Suarez-Lopez et al., 2018].


a b s t r a c t
This data article presents mean serum concentrations (wet weight and lipid standardized) of 32 persistent organic pollutants (POPs) detected in >75% of participants of the Coronary Artery Risk Development in Young Adults (CARDIA) study across levels of POPs scores, and their corresponding coefficients of determination. POPs scores were calculated as: A) the sum of each participant's logtransformed POPs concentrations ( P of log Pops], or B) as the sum of the participants' log-transformed concentrations of each POP divided by the groups' standard deviation of the corresponding log-transformed POP (POPs summary score. Scores were calculated for both wet weight and lipid standardized concentrations and for all 32 POPs and for PCBs and organochlorine pesticides separately. POPs summary scores analyses were used in the article "Organochlorine pesticides and polychlorinated biphenyls

Data
Data is presented in 6 tables providing information on wet weight concentrations and lipidstandardized concentrations (median, 25th e 75th percentile, p for trend and R 2 ) of persistent organic pollutants (POPs) in serum across quartiles of various POPs summary variables including 32 POP summary score, 8 organochlorine pesticide (OCP) summary score, 23 polychlorinated biphenyl (PCB) summary score, and sum of 32 log-transformed POPs based on both wet-weight and lipid standardized values.

Participants
POPs in serum were measured in samples collected in 1985e1986 (year-2 of follow-up) of 180 men and women from a nested case-control study within the Coronary Artery Risk Development in Young Adults (CARDIA) study [1e3]. Participants with diabetes (cases) consisted of 50% of participants (n ¼ 90). However, cases must not have been diagnosed with diabetes during at year 0 or 2 of followup. The remaining 90 participants were frequency matched to cases on body mass index (BMI) and were randomly selected from those who had fasting glucose levels below 100 mg/dL at follow-up years 0, 7, 10, 15, and 20, had not been diagnosed with diabetes before year 20 of follow-up, and were not receiving glucose-lowering medications. Additional details of recruitment and participant selection been described in detail [1,3].

Measurements
POPs concentrations of serum samples collected in year 2 of follow-up were measured using solidphase extraction and final determination using gas chromatography isotope dilution high-resolution Specifications Value of the data POPs composite scores are used in epidemiologic studies to reduce the number of associations tested, thus reducing the potential for spurious findings, and because the general population is exposed to a mixture of POPs. This article presents coefficients of determination (R 2 ) between specific POPs and various POPs scores, thus providing further exposure information of our published work using POPs summary scores. This article provides deeper insight on POPs summary scores and their relationships with specific POPs exposure levels. These data can be used by investigators who are conducting analyses using POPs score analyses and provides information to compare exposure levels between the CARDIA study and other studies.      mass spectrometry [4,5]. Nine OCPs, 35 PCB congeners, 10 polybrominated diphenyl ether (PBDE) congeners, and 1 polybrominated biphenyl (PBB) congener were measured. Of these, 32 POPs that were detected in at least 75% of participants (8 OCPs, 23 PCBs, and PBB-153, Table. 1) were included in the present article. Non-detectable concentrations were replaced with 50% of the detection limit. Total cholesterol, and triglyceride concentrations were measured using an enzymatic assay. HDL concentrations were measured via precipitation using dextran sulfate-magnesium chloride on the ABA 200 Biochromatic device. LDL concentrations were calculated using the Friedewald equation [6]. Oxidized LDL concentrations were measured using a monoclonal antibody mAb-4E6ebased competition ELISA (Mercodia, Uppsala, Sweden).

POPs scores and analysis
This article presents median POPs concentrations in serum across categories of POPs composite variables. Composite variables are used because the general population is exposed to a mixture of many POPs [7], and such variables substantially reduce the number of associations tested, thus reducing the potential for spurious findings. First, we created a summary score which consisted of the sum of logtransformed POPs concentrations for each individual ( P of 32 log POPs). Then we created composite POPs variables that would not be heavily influenced by the most prevalent POPs, considering that the 8 most prevalent POPs had 25.6 times the concentration than the 8 least prevalent in our study. This "32 POP summary score" was defined as the sum of the participants' log-transformed concentrations of each of the 32 POPs divided by the groups' standard deviation of the corresponding log-transformed POP (S[logPOP individual /logPOP standard deviation group ]). We created similar summary variables for 8 organochlorine pesticides (8 OCP summary score), and 23 PCBs (23 PCB summary score); summary variables were created for both wet weight and lipid standardized (POP concentration/total blood lipids) concentrations.
Tables 1e6 present the median and interquartile range of concentrations of each POP across quartiles of each of the POPs composite scores. Using linear regression, we calculated the p-trend for the associations between each POP concentration and POP composite score using continuous variables. We also calculated the coefficient of determination (R 2 , Pearson correlation) for each association.