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- Bjorvang, Richelle D., et al.
(författare)
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Persistent organic pollutants, pre-pregnancy use of combined oral contraceptives, age, and time-to-pregnancy in the SELMA cohort
- 2020
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Ingår i: Environmental Health. - : BMC. - 1476-069X. ; 19:1
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Tidskriftsartikel (refereegranskat)abstract
- Background We are exposed to several chemicals such as persistent organic pollutants (POPs) in our everyday lives. Prior evidence has suggested that POPs may have adverse effects on reproductive function by disrupting hormone synthesis and metabolism. While there is age-related decline of fertility, the use of hormonal combined oral contraceptives (COCs) and its association to return of fertility remains controversial. The goal of this study is to investigate the association between exposure to POPs, both individually and as a mixture, and fecundability measured as time-to-pregnancy (TTP) according to pre-pregnancy use of COCs and age. Methods Using the SELMA (Swedish Environmental Longitudinal Mother and Child, Allergy and Asthma) study, we have identified 818 pregnant women aged 18-43 years (mean 29 years) with data on how long they tried to get pregnant and what was their most recently used contraceptive method. These data were collected at enrollment to the study (median week 10 of pregnancy). Concentrations of 22 POPs and cotinine were analyzed in the blood samples collected at the same time as the questions on TTP and pre-pregnancy use of contraceptive. Analyses were done on the association between POPs exposure and TTP measured as continuous (months) and binary (infertile for those with TTP > 12 months). To study the chemicals individually, Cox regression and logistic regression were used to estimate fecundability ratios (FRs) and odds ratios (ORs), respectively. Weighted quantile sum (WQS) regression was used to investigate the chemicals as a mixture where chemicals of concern were identified above the 7.6% threshold of equal weights. To perform the subgroup analysis, we stratified the sample according to use of COCs as the most recent pre-pregnancy contraception method and age (< 29 years, and >= 29 years). The models were adjusted for parity, regularity of menses, maternal body mass index (BMI) and smoking status, and stratified as described above. Results Prior to stratification, none of the POPs were associated with fecundability while increased exposure to HCB, PCB 74 and 118 had higher odds of infertility. Upon stratification, POP exposure was significantly associated with longer TTP in women aged >= 29 years who did not use COC. Specifically, PCBs 156, 180, 183, and 187 were associated with reduced fecundability while PCBs 99, 153, 156, 180, 183, and 187 had higher odds of infertility. As a mixture, we identified the chemicals of concern for a longer TTP include PCBs 118, 156, 183, and 187. Moreover, chemicals of concern identified with increased odds of infertility were PCB 74, 156, 183, 187, and transnonachlor. Conclusion Serum concentrations of selected POPs, both as individual chemicals and as a mixture, were significantly associated with lower fecundability and increased odds of infertility in women aged 29 years and above not using COC as their most recent pre-pregnancy contraceptive. Our findings suggest that pre-pregnancy use of oral contraceptive and age may modify the link between POPs and fecundability. The differences of specific chemicals in the individual analysis and as a mixture support the need to study combination effects of chemicals when evaluating reproductive outcomes.
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| 2. |
- Svensson, Katherine, et al.
(författare)
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EDC mixtures during pregnancy and body fat at 7 years of age in a Swedish cohort, the SELMA study
- 2024
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Ingår i: Environmental Research. - : Elsevier. - 0013-9351 .- 1096-0953. ; 48
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Tidskriftsartikel (refereegranskat)abstract
- Background: Some endocrine disrupting chemicals (EDC), are “obesogens” and have been associated withoverweight and obesity in children. Daily exposure to different classes of EDCs demands for research withmixtures approach.Objectives: This study evaluates the association, considering sex-specific effects, between prenatal exposure toEDC mixture and children’s body fat at seven years of age.Methods: A total of 26 EDCs were assessed in prenatal urine and serum samples from first trimester in pregnancyfrom 737 mother-child pairs participating in the Swedish Environmental Longitudinal, Mother and child, Asthmaand allergy (SELMA) study. An indicator for children’s “overall body fat” was calculated, using principalcomponent analysis (PCA), based on BMI, percent body fat, waist, and skinfolds measured at seven years of age.Weighted quantile sum (WQS) regression was used to assess associations between EDC mixture and children’sbody fat.Results: Principal component (PC1) represented 83.6 % of the variance, suitable as indicator for children’s“overall body fat”, with positive loadings of 0.40–0.42 for each body fat measure. A significant interaction term,WQS*sex, confirmed associations in the opposite direction for boys and girls. Higher prenatal exposure to EDCmixture was borderline significant with more “overall body fat” for boys (Mean β = 0.20; 95 % CI: − 0.13, 0.53)and less for girls (Mean β = − 0.23; 95 % CI: − 0.58, 0.13). Also, higher prenatal exposure to EDC mixture wasborderline significant with more percent body fat (standardized score) for boys (Mean β = 0.09; 95 % CI: − 0.04,0.21) and less for girls (Mean β = − 0.10 (− 0.26, 0.05). The chemicals of concern included bisphenols, phthalates, PFAS, PAH, and pesticides with different patterns for boys and girls.Discussion: Borderline significant associations were found between prenatal exposure to a mixture of EDCs andchildren’s body fat. The associations in opposite directions suggests that prenatal exposure to EDCs may presentsex-specific effects on children’s body fat.
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| 3. |
- Svensson, Katherine, et al.
(författare)
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Prenatal exposures to mixtures of endocrine disrupting chemicals and sex-specific associations with children’s BMI and overweight at 5.5 years of age in the SELMA study
- 2023
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Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 179
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Tidskriftsartikel (refereegranskat)abstract
- Background: Prenatal exposure to mixtures of endocrine disrupting chemicals (EDC) has the potential to disrupt human metabolism. Prenatal periods are especially sensitive as many developmental processes are regulated by hormones. Prenatal exposure to EDCs has inconsistently been associated with children’s body mass index (BMI) and obesity. The objective of this study was to investigate if prenatal exposure to a mixture of EDCs was associated with children’s BMI and overweight (ISO-BMI ≥ 25) at 5.5 years of age, and if there were sex-specific effects. Methods: A total of 1,105 mother–child pairs with complete data on prenatal EDCs concentrations (e.g., phthalates, non-phthalate plasticizers, phenols, PAH, pesticides, PFAS, organochlorine pesticides, and PCBs), children’s measured height and weight, and selected covariates in the Swedish Environmental Longitudinal, Mother and child, Asthma and allergy (SELMA) study were included in this analysis. The mixture effect of EDCs with children’s BMI and overweight was assessed using WQS regression with 100 repeated holdouts. A positively associated WQS index with higher BMI and odds of overweight was derived. Models with interaction term and stratified weights by sex was applied in order to evaluate sex-specific associations. Results: A significant WQS*sex interaction term was identified and associations for boys and girls were in opposite directions. Higher prenatal exposure to a mixture of EDCs was associated with lower BMI (Mean β = -0.19, 95%CI: −0.40, 0.01) and lower odds of overweight (Mean OR = 0.72, 95%CI: 0.48, 1.04) among girls with borderline significance. However, the association among boys did not reach statistical significance. Among girls, the possible chemicals of concern were MEP, 2-OHPH, BPF, BPS, DPP and PFNA. Conclusion: Prenatal exposure to a mixture of EDCs was associated with lower BMI and overweight among girls, and non-significant associations among boys. Chemicals of concern for girls included phthalates, non-phthalate plasticizers, bisphenols, PAHs, and PFAS.
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