Skip to main content
NCBI home page
NIHPA Author Manuscripts logoLink to NIHPA Author Manuscripts
. Author manuscript; available in PMC: 2022 Jan 1.
Published in final edited form as: Environ Res. 2020 Sep 22;192:110226. doi: 10.1016/j.envres.2020.110226

Reproductive outcomes associated with flame retardants among couples seeking fertility treatment: a paternal perspective

Mary E Ingle 1, Lidia Mínguez-Alarcón 2, Courtney C Carignan 3, Heather M Stapleton 4, Paige L Williams 5, Jennifer B Ford 2, Molly B Moravek 6, Marie S O’Neill 7, Lu Wang 8, Russ Hauser 9, John D Meeker 10,*, EARTH Study Team
PMCID: PMC7736216  NIHMSID: NIHMS1631095  PMID: 32971080

Abstract

Background.

Polybrominated diphenyl ethers (PBDEs) have been phased out of production for nearly a decade yet are still frequently detected in serum of U.S. adults. PBDE concentrations have been associated with adverse reproductive outcomes and laboratory studies suggest hydroxylated-BDEs (OH-BDEs) may act as endocrine disruptors. We set out to assess the joint effects of paternal and maternal serum PBDE concentrations on in vitro fertilization (IVF) outcomes and the association between paternal serum OH-BDE concentrations and IVF outcomes.

Methods.

This analysis included 189 couples (contributing 285 IVF cycles) recruited between 2006-2016 from a longitudinal cohort based at Massachusetts General Hospital Fertility Center who completed at least one IVF cycle and had an available blood sample at study entry. Congeners (47, 99, 100, 153, and 154) and OH-BDEs (3-OH-BDE47, 5-OH-BDE47, 6-OH-BDE47 and 4-OH-BDE49) were quantified in serum. Log-transformed PBDEs and OH-BDEs were modeled in quartiles for associations with IVF outcomes using multivariable generalized mixed models and cluster weighted generalized estimating equations.

Results.

Lipid-adjusted concentrations of PBDEs and OH-BDEs were higher in females than in male partners. There were no clear patterns of increases in risk of adverse IVF outcomes associated with PBDEs and OH-BDEs. However, some decreases in associations with IVF outcomes were observed in isolated quartiles.

Conclusions.

Our assessment of couple level exposure is unique and highlights the importance of including male and female exposures in the assessment of the influence of environmental toxicants on pregnancy outcomes.

Keywords: Flame retardants, Fertility, Reproductive health, Couple-based, Polybrominated diphenyl ether

Graphical Abstract

graphic file with name nihms-1631095-f0001.jpg

1. Introduction

Polybrominated diphenyl ethers (PBDEs) are flame retardants which have been phased out of production for nearly a decade, yet concentrations among U.S. adults remain high(1). The most frequently detected congeners (47, 99, 100, 153, and 154) are found in (but not exclusively) the PentaBDE commercial mixture, which was primarily manufactured in the U.S. until the voluntary phase out at the end of 2004 (2,3). PBDEs are not covalently bound but physically combined with materials, which allows them to leach into surrounding environments and bioaccumulate in adipose tissues, with half-lives ranging from weeks to years (4). PBDEs were added to consumer products including upholstered furniture, carpeting, electronics, and plastics as flame retardants. In the U.S., PBDE exposure is predominantly from dust due to its common use in these products, while diet is a main source of exposure in European countries where it was less commonly used (3). Hydroxylated-BDEs (OH-BDEs), products of oxidative metabolism from PBDEs in mammals, also bioaccumulate in humans and have been detected in adult serum (5). Some OH-BDEs are of a natural origin (e.g. biogenic from marine sponges) and may contribute to exposure via seafood diets (6).

PBDE exposure has been associated with adverse reproductive health outcomes in both men and women. Elevated concentrations of BDE99 and BDE153 in women have been associated with failed implantation and longer time to pregnancy (TTP) (7,8). Congeners 47, 100, 153, and 154 have also been associated with altered hormone levels and poorer semen quality in men, while low-dose in utero exposure to BDE99 in mice was associated with poor semen quality in male offspring (9-12). However, laboratory studies suggest OH-BDEs may act as endocrine disruptors and have greater toxic effects compared to PBDEs (13,14).

We have previously reported that serum PBDE and OH-BDE concentrations among women had unexpected positive associations with implantation, clinical pregnancy, and live birth (15). However, considerations for male exposure with fertility and pregnancy outcomes are pivotal in understanding the comprehensive impact of PBDE exposure on reproductive health. This analysis examines the relationship of couple (male and female) PBDE and OH-BDE exposures with fertility metrics and pregnancy outcomes.

2. Methods

2.1. Study Population

The male participants (n=189) and their female partners (n=189) included in our analysis were a subset of study participants recruited between 2006-2016 from the Environment and Reproductive Health (EARTH) study, an ongoing longitudinal prospective pre-conception cohort study of the environment, dietary, and lifestyle impacts on reproductive health (16). Men (18-55 years) and women (18-46 years) were recruited from Massachusetts General Hospital (MGH) Fertility Center. Approximately 60% of participants contacted by research staff participated in the study (17). Couples (male and female) must have contributed their own gametes, completed at least one in vitro fertilization (IVF) cycle (n=285 cycles), and provided a blood sample for flame retardant and metabolite quantification. At study entry, research staff collected demographic data and pregnancy history. Research protocols were approved by the Ethics and Research Committees of MGH, Harvard T.H. Chan School of Public Health, University of Michigan, and Duke University. The study was described in detail to participants, all questions were answered, and informed consent was obtained from all participants.

2.2. PBDE and OH-BDE Collection and Measurement

PBDE and metabolite protocols have been described in detail elsewhere (15). Briefly, 5 mL blood samples collected at study entry were aliquoted, frozen, and stored (−80° C) before shipment overnight to Dr. Stapleton’s laboratory at Duke University (Durham, NC). Five PBDE congeners: 47, 99, 100, 153, and 154 and four OH-BDE metabolites: 3-OH-BDE47, 5-OH-BDE47, 6-OH-BDE47, and 4-OH-BDE49 were quantified in serum.

Samples were weighed and spiked with internal standards (monofluorinated BDE 69, 13C BDE 209, and 13C-6-OH-BDE47). Serum was diluted with water and formic acid before solid phase extraction (SPE) (Oasis HLB, Waters Corp.). Dichloromethane (DCM) and ethyl acetate (50:50) removed both PBDES and OH-BDEs from the SPE column. Samples were dried, rejuvenated with hexane (1 mL) and extract cleaning via a 1.0 g silica column. PBDEs were removed with 10 mL of hexane and OH-BDEs with 10 mL of DCM hexane solution. PBDEs were analyzed using gas chromatography negative chemical ionization mass spectrometry (GC/ECNI-MS) and OH-BDEs were measured using liquid chromatography tandem mass spectrometry (LC/MS-MS) (18). Accuracy was verified by extracting a human serum Standard Reference Material (SRM 1957) from the National Institute of Standards and Technology (NIST). Measured values were between 73%- 97% of the certified values. Total lipids were derived from total serum cholesterol and triglycerides using the following formula: TL (g/l) = [(TC x 1.12) + (TG x 1.33) + 1.48 where TL= total lipids, TG= serum triglycerides, and TC= serum cholesterol (19). Missing total lipids (males n=4 and females n=13) were replaced with the median (males= 628.6 and females=509.15).

2.3. Clinical Protocols and Outcomes

Clinical staff collected participants’ date of birth and measured height and weight to calculate body mass index (BMI, kg/m2) at study entry. At the beginning of each cycle, clinical data are abstracted from the female partners’ electronic health records by research staff. Clinical protocols and outcomes have previously been described (20). Briefly, initial infertility diagnoses are given by a physician at MGH Fertility Centers in accordance with the Society for Assisted Reproductive Technology (SART) definitions (21,22). Depending on infertility evaluation and other clinical factors, one of three ovarian stimulation protocols was selected: (1) luteal phase gonadotrophin releasing hormone (GnRH) agonist, (2) follicular phase GnRH agonist or “flare” stimulation, or (3) GnRH antagonist. Fertilization was confirmed 17-20 hours after IVF or intracytoplasmic sperm injection (ICSI) by the presence of an oocyte with two pronuclei. Fertilization rate was defined as the number of two pronuclear embryos divided by the number of metaphase II (M2) oocytes. Successful implantation was confirmed when serum beta human chorionic gonadotropin (β-hCG) levels were > 6 mIU/mL, approximately 17 days after egg retrieval. Implantation was characterized as the presence of an intrauterine pregnancy confirmed by ultrasound and elevated β-hCG levels (approximately 6 weeks gestation). Live birth was defined as the birth of a neonate at or after 24 weeks gestation.

2.4. Statistical Analysis

Demographic characteristics for males were characterized using medians together with interquartile ranges (IQRs) for continuous variables, and frequencies together with percentages for categorical variables. PBDEs and OH-BDE concentrations below method detection limit (MDL) were imputed to MDL/√2 (21). Unadjusted and lipid-adjusted congeners and metabolites were described using geometric means (GM), 95% confidence intervals (CIs), and selected percentiles. Spearman correlation coefficients were used to assess relationships between male and female serum PBDE and OH-BDE concentrations. Distributions of congeners and metabolites were right-skewed and transformed by the natural logarithm (ln).

Concentrations of PBDEs and OH-BDEs were evaluated individually and summed. Concentrations were divided into quartiles before inclusion in regression models to account for possible non-linear relationships. The p-value for trend (P-trend) was calculated from a regression model including the median ln-transformed PBDE or OH-BDE concentration of each quartile. Associations of congeners and metabolites with fertilization rate were evaluated using multivariable generalized linear mixed models (binomial distribution and logit function), where a random intercept is introduced to account for multiple cycles per couple. Associations with PBDEs and OH-BDES with implantation, clinical pregnancy, and live birth were assessed using cluster weighted generalized estimating equation (CWGEE) models, where the weight was the inverse of the total number of cycles (cluster size) (23). CWGEE models have provided more flexibility to allow for more complex within-cluster correlations, and they only need the mean model to be correctly specified. Interpretation in CWGEE is at population level, while in contrast, interpretation in generalized linear mixed models is at individual level (23). Due to some co-elution with a few batches of 3-OH-BDE47 and 5-OH-BDE47 among female samples, male and female metabolites 3-OH-BDE47 and 5-OH-BDE47 were modeled as a sum 3&5-OH-BDE47 (15).

Demographic covariates considered for final models were male and female: total lipids, age and BMI, and male: race (White/Other), education (high school/some college, college graduate, graduate degree), smoking status (never/ever) and year of serum sample collection. Recently, alternate methods for lipid adjustment have been suggested and therefore we conducted an additional analysis for lipid adjustment where PBDE and OH-BDE concentrations were standardized and lipids were also included as a covariate in the model (24). However, we observed no increase in the validity of effect estimates from the additional analysis and thus lipid adjustment was accounted for as a covariate in the model. Reproductive characteristics considered were history of prior pregnancy, initial infertility diagnosis (female factor, male factor, or unexplained), previous intrauterine insemination (IUI) (yes/no), previous IVF (yes/no), treatment protocol (antagonist, flare, or luteal phase agonist), and ICSI (yes/no). Final covariates were included if they were associated with PBDE concentrations in our cohort, associated with PBDEs based on prior studies, and known to be a predictor of IVF outcomes (25,26). Analyses were performed using SAS 9.4 (SAS Institute Inc., Cary, NC) and R version 3.3.5. P-values < 0.05 were considered statistically significant.

3. Results

Men (n=189) were primarily White (86%), non-smokers (68%) in their mid-thirties (median= 36 yrs.) with a BMI typical of the U.S. population (median= 27 kg/m2), and they had similar demographic characteristics to a previously reported sample of men from the EARTH cohort (27) (Supplemental Table 1). Almost all men (93%) held at least a college degree. Demographic and reproductive characteristics of female partners (n=189) have been described elsewhere (15). Briefly, female partners were mostly White (86%) with a normal BMI (median=23 kg/m2) in their mid-thirties (median=35 years). Over half of the women (61%) held a graduate degree and few reported ever smoking (28%). The most common infertility diagnosis was male factor (36%) followed by unexplained infertility (35%) and female factor (29%). The majority of women underwent luteal phase agonist protocol (69%), followed by flare (18%), and antagonist (13%). Over half of fertilization was via ICSI (52%).

Descriptive statistics of unadjusted and lipid-adjusted male PBDEs and OH-BDEs are presented in Table 1. Congeners 47, 153, and 154 were frequently detected (88% >MDL). Concentrations of BDE47 (GM=12.8 ng/g serum) and BDE153 (GM=14.5 ng/g serum) were over 4-fold higher than BDE99 (GM=2.2 ng/g serum) and BDE100 (GM=2.6 ng/g serum). Metabolites 3-OH-BDE47 and 4-OH-BDE49 were also frequently detected in men (84%>MDL). Median concentrations of 3-OH-BDE47 (0.14 ng/g serum) were more than double those of 6-OH-BDE47 (median=0.06 ng/g serum). Female partners’ distributions of serum PBDE and OH-BDE concentrations have previously been described (15). Briefly, PBDEs 47, 100, 153, and metabolites 3-OH-BDE47, and 4-OH-BDE49 were frequently detected (70%>MDL) and concentrations of BDE47 and BDE153 were approximately 5-fold higher than BDE99 and BDE100. Median concentrations of 3-OH-BDE47 (0.12 ng/g serum) in women were slightly higher than 4-OH-BDE49 (median=0.09 ng/g serum) concentrations. The median of lipid-adjusted concentrations of all congeners were higher in female partners compared to males (p<0.001) (Figure 1). Lipid adjusted median concentrations of BDE47 (24.6 ng/g lipid) and BDE153 (24.5 ng/g lipid) were almost 3-fold higher among female partners compared to males (8.1 and 7.7 ng/g lipid). OH-BDE concentrations were also higher in female partners compared to males (p<0.001) (Supplemental Figure 1). Median concentrations of 4-OH-BDE49 (0.21 ng/g lipid) and 6-OH-BDE47 (0.18 ng/g lipid) were nearly three and four times (respectively) higher among female partners compared to men (0.07 and 0.04 ng/g lipid) (Supplemental Figure 1).

Table 1.

Distribution of unadjusted and lipid adjusted PBDEs and OH-BDEs among 189 men from the EARTH cohort.

Percentiles
PBDEs N > MDL (%) GM (95% CI) 25th 50th 75th 95th Max
Unadjusted (pg/g serum)
BDE47 166 87.8 12.8 (11.0, 15.0) 5.7 12.1 25.5 103.2 374.3
BDE99 109 57.7 2.2 (1.9, 2.5) <MDL 1.6 3.7 14.7 37.8
BDE100 112 59.3 2.6 (2.3, 3.0) <MDL 2.0 4.6 14.6 78.9
BDE153 181 95.8 14.4 (12.2, 16.9) 6.5 10.8 26.8 146.1 768.0
BDE154 196 96.3 3.7 (3.2, 4.1) 2.2 3.7 6.3 14.3 32.8
Total BDEs 43.6 (38.2, 49.8) 22.6 36.8 74.6 238.4 808.0
Lipid Adjusted (ng/g lipid)
BDE47 8.8 (7.1, 9.9) 3.5 8.1 17.7 60.7 224.5
BDE99 1.4 (1.2, 1.6) 0.79 1.1 2.4 8.9 46.1
BDE100 1.7 (1.5, 2.0) 0.96 1.3 3.1 9.2 47.3
BDE153 9.4 (7.9, 11.1) 4.2 7.7 18.1 94.0 530.7
BDE154 2.4 (2.1, 2.7) 1.3 2.4 4.3 12.1 18.9
Total BDEs 28.5 (24.8, 32.9) 14.5 25.4 47.1 150.0 558.4
OH-BDEs
Unadjusted (pg/g serum)
3-OH-BDE47 159 84.1 0.15 (0.13, 0.17) 0.09 0.14 0.27 0.74 1.3
5-OH-BDE-47 13 4.6 0.02 (0.02, 0.02) 0.01 0.02 0.02 0.03 0.46
6-OH-BDE47 107 56.6 0.07 (0.06, 0.08) <MDL 0.06 0.18 1.03 2.3
4-OH-BDE49 166 87.8 0.10 (0.08, 0.12) 0.04 0.10 0.24 1.1 2.1
Total OH-BDEs (0.35, 0.46) 0.19 0.34 0.73 2.2 4.4
Lipid Adjusted (ng/g lipid)
3-OH-BDE47 0.10 (0.08, 0.11) 0.05 0.09 0.17 0.51 1.8
5′OH-BDE-47 0.01 (0.01, 0.01) 0.01 0.01 0.02 0.03 0.39
6′OH-BDE47 0.05 (0.04, 0.06) 0.02 0.04 0.12 0.66 1.6
4′OH-BDE49 0.07 (0.05, 0.08) 0.02 0.07 0.17 0.75 1.6
Total OH-BDEs 0.26 (0.23, 0.30) 0.12 0.23 0.54 1.5 3.4
Open in a new tab

MDL: Method detection limit; GM: Geometric mean; CI: Confidence interval.

Figure 1.

Figure 1.

Open in a new tab

Distributions of serum PBDEs concentrations (ng/g lipid) among 189 couples from the EARTH study.

Correlations of serum PBDEs and OH-BDEs for male and female partners are presented in Figure 2. Among men, correlations for congeners 47, 99, and 100 were the strongest (r: 0.84-0.85). Correlations for BDE153 and BDE154 were slightly weaker (r: 0.38-0.54), yet still statistically significant. Metabolites 6-OH-BDE47 and 4-OH-BDE49 were strongly correlated (r=0.64). The combined metabolite 3&5-OH-BDE47 was moderately correlated with BDEs 47, 99, and 100 (r: 0.51-0.61). A detailed description of PBDE and OH-BDE correlations among female partners has been described elsewhere (28). Correlations for PBDES between females and males were strongest for BDE47 (r=0.47) and weakest for BDE153 (r=0.24). Correlations for OH-BDEs between men and their female partners were weak (r: 0.22-0.34) but statistically significant, except for the association of female 3&5-OH-BDE47 and male 6-OH-BDE47 (p>0.05). PBDE and OH-BDE concentrations among men declined between 2006 and 2007 and remained consistent throughout the study (Figure 3). The largest decline was observed for BDE47 which decreased 84% between 2006-2007. Metabolite concentrations fluctuated, yet generally declined over the study period.

Figure 2.

Figure 2.

Open in a new tab

Spearman correlation coefficients for serum concentrations of PBDEs and OHBDEs (ng/g lipid) among 189 couples from the EARTH study.

Figure 3.

Figure 3.

Open in a new tab

Geometric means of serum PBDE and OH-BDE concentrations among 189 men from the EARTH cohort by year. 2006: n=2; 2007: n=5; 2008: n=26; 2009: n=44; 2010: n=45; 2011: n=48; 2012: n=38; 2013: n=36; 2014: n=32; 2015: n=8; 2016: Only one sample collected and not included.

No associations were observed between any PBDEs or OH-BDEs and fertilization rate (Supplemental Tables 2 and 3). However, some of the quartiles, specifically quartile 2 (Q2) or Q3 were associated with poorer IVF outcomes. For instance, a 38% decrease in the probability of implantation (Relative risk (RR)=0.62; 95% CI: 0.45, 0.84; p=0.002), 39% decrease in probability of clinical pregnancy (RR=0.61; 95% CI: 0.42, 0.86; p=0.01), and 36% decrease in the probability of live birth (RR=0.64; 95% CI: 0.44, 0.91; p=0.02) was observed among female partners of men in Q2 of serum BDE99 concentrations compared to Q1 (reference group) (Figure 4). Similarly, a decrease in the probability of implantation, clinical pregnancy, and live birth was found among female partners of men in Q2 of serum BDE100 concentrations compared to Q1 (RR=0.62; 95% CI: 0.45, 0.86; p=0.004, RR=0.59; 95% CI: 0.41, 0.84, p=0.004, and RR=0.56; 95% CI: 0.37, 0.87; p=0.01, respectively). On the other hand, Q3 serum concentrations of BDE153 were associated with a 37% decrease in the probability of implantation (RR=0.63; 95% CI: 0.46, 0.86; p=0.004), 34% decrease in the probability of clinical pregnancy (RR=0.64, 95% CI: 0.47, 0.92; p=0.02), and 38% decrease in the probability of live birth (RR=0.62; 95% CI: 0.40, 0.96; p=0.03) compared to men in Q1 group of exposure. A 37% increase in the probability of implantation was observed for female partners of men in Q2 of serum BDE154 concentrations compared to men in Q1 (RR=0.63; 95%C CI: 1.01, 1.82; p=0.04). Summed serum OH-BDE concentrations in Q2 and Q4 among males were associated with an increase in the probability of live birth for female partners (RR=2.17; 95% CI: 1.34, 3.53; p=0.001 and RR=2.12; 95% CI: 1.29, 3.49; p=0.003; p-trend=0.03, respectively) compared to men with summed serum concentrations in Q1 (Figure 5).

Figure 4.

Figure 4.

Open in a new tab

Relative risk (95% CI) of clinical IVF outcomes by quartile of serum PBDE concentrations among 189 men (285 IVF cycles) from the EARTH cohort. Cluster weighted generalized estimating equations adjusted for female serum PBDE concentrations, male and female serum lipids, male and female age, male and female BMI, year of serum sample collection, and infertility diagnosis (female, male, unknown); The p-value for trend (P-trend) was calculated as the median ln-transformed PBDE concentration of each quartile; RR: Relative risk; CI: Confidence interval; * Quartile is statistically different (p<0.05) from Q1 (reference).

Figure 5.

Figure 5.

Open in a new tab

Relative risk (95% C) of clinical IVF outcomes by quartile of serum OH-BDE concentrations among 189 men (285 IVF cycles) from the EARTH cohort. Cluster weighted generalized estimating equations adjusted for female serum OH-BDE concentration, paternal and maternal lipids, paternal and maternal age, paternal BMI, year of serum sample collection, and infertility diagnosis (female, male, unknown); The p-value for trend (P-trend) was calculated as the median ln-transformed serum OH-BDE concentration of each quartile; RR: Relative risk; CI: Confidence interval; * Quartile is statistically different (p<0.05) from Q1 (reference).

4. Discussion

This study investigated associations of paternal serum concentrations of PBDEs and OH-BDEs with couples’ pregnancy outcomes while accounting for female exposure. While we found overall no significant associations, we also observed decreased probabilities of successful implantation, clinical pregnancy, and live birth among female partners of men in Q2 of serum BDE99 and BDE100 concentrations, and Q3 concentrations of BDE153, compared to men in Q1, although overall p-trends were not statistically significant. These non-linear relationships were unexpected, and possibly spurious, yet biologically plausible if PBDEs are acting as endocrine disruptors which have been associated with unconventional dose-response relationships (29,30). For instance, non-linear dose-response relationships have been observed between congeners 99, 100, and 153 and thyroid stimulating hormone levels during pregnancy (25).

Several studies have observed negative associations between sperm count, concentration, and morphology and BDE153 in men, while low doses of BDE99 in mice have been associated with decreased sperm and spermatid counts (9,10,31,32). Other studies suggest PBDEs act as an endocrine disruptor and alter male reproductive hormones. Congeners 47 and 99 have been inversely associated with inhibin B and positively associated with follicular stimulating hormone (FSH), and lower levels of inhibin B and higher levels of FSH are often observed in subfertile men (11). Reported associations between PBDEs and thyroid function is inconsistent (33-35). However, both hypo and hyperthyroidism have been associated with male infertility (36,37).

To the best of our knowledge, only one prior study has assessed the relationship of serum PBDE concentrations among couples with TTP and we are the first to evaluate pregnancy outcomes from conception to live birth. A prior study of 501 couples found no associations with the pentaBDEs and TTP yet did observe a 14% decrease in fecundability odds ratio (FOR) with elevated male serum BDE183 concentrations (38). However, there was no adjustment for female concentrations or covariates.

Couple comparison studies of PBDEs and OH-BDEs are limited. However, adjusted GMs for PBDEs were significantly higher overall in males compared to females in a pooled sample from the National Health and Nutrition Examinations Survey (NHANES) (1). Correlations for BDE153 were the weakest among our couples (r=0.24) and possibly a result of exposure through diet which can vary by individual (39,40). Differences among couples could also be a result of separate ‘workday’ microenvironments. In a sample of 20 homes in Boston, MA, congeners from the PentaBDE mixture were 72% higher in the main living area compared to the bedroom (41). Lower PentaBDE dust concentrations have also been observed in recently constructed buildings compared to older buildings in the Boston area (42).

However, we observed more comparable distributions among women and their partners for unadjusted PBDE and OH-BDE concentrations and therefore serum lipid levels may be driving the difference in lipid-adjusted concentrations. We observed statistically higher BMIs and total serum lipids in men compared to women (Supplemental Figure 2). PBDEs bioaccumulate in adipose tissue and restrict exposure to vital organs, however adipose storage and lipid metabolism varies by sex (43,44). Therefore, it is possible that lipid-adjusted concentrations were higher in females due to sex differences in lipid metabolism and fat storage. However, an inverse association was also observed for congeners 47 and 153 with increasing BMI among a sample of women from CA (45). A laboratory study observed impaired glucose homeostasis in lean mice compared to obese mice exposed to polychlorinated biphenyls (PCBs) through diet (46). Therefore, it is also possible that IVF alters the rate at which lipids are metabolized and results in increased PBDE concentrations circulating throughout females.

Serum concentrations of congeners 47, 99, 100, and 153 among our men are similar to those seen in another male cohort (n=50) in Boston (47). As far as we are aware, we are the first study to describe OH-BDEs among adult men in the U.S. Comparisons of PBDE and OH-BDE concentrations of our female partners with other studies has been described elsewhere (15). Briefly, PBDE concentrations were higher in our female partners compared to women in other cohorts. Concentrations of BDE47 among our sample were approximately double those from women in California and North Carolina, yet similar for BDE99 (7,18). BDE153 concentrations among our female partners were also higher compared to a sample of women in Canada (48). Concentrations of 6-OH-BDE47 were higher compared to pregnant women in NC, yet lower than pregnant women in IN (5,18). Concentrations of 3-OH-BDE47 and 4-OH-BDE49 were higher in our female partners compared to pregnant women in IN. Higher concentrations among our women could possibly be a result of rapid lipid peroxidation in women undergoing IVF compared to women in the general population (10).

Detection rates were high for BDEs: 47, 153, and 154 and OH-BDEs 3-OH-BDE47 and 4-OH-BDE49 (84% >MDL) in males, yet concentrations subtly declined over the 10 year study period. We observed the largest decrease in serum PBDE concentrations between 2006-2007 which is inconsistent with a previous EARTH study as well as cohorts in California which observed substantial declines in concentrations over time (1,15,49). Such a drastic decrease in the early years of the study was likely a result of the phase-out of PBDEs. Although the PentaBDE phase-out was not mandatory until 2005, many manufacturers voluntarily began to restrict these compounds a few years prior.

Although we observed statistically significant associations with several congeners and pregnancy outcomes for some exposure quartiles, a larger sample size would increase study power. Type l error is also plausible as we compared many congeners and metabolites with many outcomes. While IVF cohorts may not be as generalizable compared to TTP studies, our results are generalizable to other subfertile cohorts and possibly the general population if the biological response to PBDEs is similar for both IVF and non-IVF patients. Nevertheless, our cohort of IVF couples represents a susceptible population. Prospective pre-conception studies allow for the highlighting of specific critical windows during conception and gestation (50). Our study design expands upon other pre-conception cohorts by measuring early developmental and clinical endpoints which are not observable in studies of the general population. However, if PBDEs and OH-BDES do elicit responses through endocrine disruption, the addition of a reproductive hormone analysis could establish a biological relationship between PBDEs and OH-BDEs with pregnancy outcomes. Although typically a homogeneous population, IVF patients are highly motivated and require multiple office visits which maximize participant retention rate. Finally, infertility is a couple-based disease, and inclusion of couples allows for a more comprehensive assessment of the impact of PBDE and OH-BDEs with couple-based outcomes.

5. Conclusion

Despite a decade long phase-out, PBDEs were still widely detected and serum concentrations of PBDEs were significantly higher in female compared to male partners. Overall, we did not observe any associations between male serum PBDEs or OH-BDEs and pregnancy outcomes. Although some specific quartiles were associated with decreased probabilities of implantation, clinical pregnancy, and liver birth, overall p-trends were not statistically significant. Our assessment of couple level exposure is unique compared to the current literature and highlights the importance of including male and female exposures in the assessment of environmental toxicants with pregnancy outcomes.

Supplementary Material

1
2

Supplemental Figure 1. Distributions of OH-BDEs (ng/g lipid) among 189 couples from the EARTH study.

3

Supplemental Figure 2. Distributions of total serum lipids and BMI (kg/m2) among 189 couples from the EARTH study.

Highlights.

  • Lipid-adjusted PBDE concentrations were higher in females than in male partners.

  • Male concentrations remained relatively stable over time.

  • Outcomes were modeled using cluster weighted generalized estimating equations.

  • No clear patterns of increased risk of adverse pregnancy outcomes were observed.

  • Couple level exposure is important in the assessment of pregnancy outcomes.

Acknowledgements

We gratefully acknowledge the effort provided by our research participants. Funding for this research was supported by the National Institutes of Environmental Health Sciences (NIEHS) [R01 ES009718, ES022955, ES000002, and 009718T32ES007069].

Footnotes

Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

References

  • 1.Sjödin A, Jones RS, Wong LY, Caudill SP, Calafat AM. Polybrominated Diphenyl Ethers and Biphenyl in Serum: Time Trend Study from the National Health and Nutrition Examination Survey for Years 2005/06 through 2013/14. Environ. Sci. Technol 2019;53(10):6018–6024. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 2.Hites RA. Polybrominated Diphenyl Ethers in the Environment and in People: A Meta-Analysis of Concentrations. Environ. Sci. Technol 2004;38(4):945–956. [DOI] [PubMed] [Google Scholar]
  • 3.Dishaw L V, Macaulay LJ, Roberts SC, Stapleton HM. Exposures, mechanisms, and impacts of endocrine-active flame retardants. Curr. Opin. Pharmacol 2014;19:125–133. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.ATSDR. Toxicological Profile for Polybrominated Diphenyl Ethers (PBDEs). Atlanta; 2015. Available at: https://www.atsdr.cdc.gov/toxprofiles/tp207.pdf. Accessed October 10, 2017. [PubMed] [Google Scholar]
  • 5.Qiu X, Bigsby RM, Hites RA. Hydroxylated metabolites of Polybrominated diphenyl ethers in human blood samples from the United States. Environ. Health Perspect 2009;117(1):93–98. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 6.Malmvärn A, Zebühr Y, Kautsky L, Bergman Å, Asplund L. Hydroxylated and methoxylated polybrominated diphenyl ethers and polybrominated dibenzo-p-dioxins in red alga and cyanobacteria living in the Baltic Sea. Chemosphere 2008;72(6):910–916. [DOI] [PubMed] [Google Scholar]
  • 7.Harley KG, Marks AR, Chevrier J, Bradman A, Sjödin A, Eskenazi B. PBDE concentrations in women’s serum and fecundability. Environ. Health Perspect 2010;118(5):699–704. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 8.Johnson PI. Human Exposure to Brominated Flame Retardants and Reproductive Health. ProQuest Diss. Theses 2012. Available at: https://deepblue.lib.umich.edu/bitstream/handle/2027.42/91595/pij_1.pdf?sequence=1&isAllowed=y. Accessed August 2, 2017. [Google Scholar]
  • 9.Kuriyama SN, Talsness CE, Grote K, Chahoud I. Developmental Exposure to Low-Dose PBDE-99: Effects on Male Fertility and Neurobehavior in Rat Offspring. Environ. Health Perspect. 2005;113(2):149–154. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 10.Yu Y-J, Lin B-G, Chen X-C, Qiao J, Li L-Z, Liang Y, Zhang G-Z, Jia Y, Zhou X-Q, Chen C-R, Kan H-D, Huang W. Polybrominated diphenyl ethers in human serum, semen and indoor dust: Effects on hormones balance and semen quality. Sci. Total Environ 2019;671:1017–1025. [Google Scholar]
  • 11.Makey CM, McClean MD, Braverman LE, Pearce EN, Sjödin A, Weinberg J, Webster TF. Polybrominated diphenyl ether exposure and reproductive hormones in North American men. Reprod. Toxicol 2016;62:46–52. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 12.Meeker JD, Johnson PI, Camann D, Hauser R. Polybrominated diphenyl ether (PBDE) concentrations in house dust are related to hormone levels in men. Sci. Total Environ 2009;407(10):3425–3429. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Hamers T, Kamstra JH, Sonneveld E, Murk AJ, Visser TJ, Van Velzen MJM, Brouwer A, Bergman Å. Biotransformation of brominated flame retardants into potentially endocrine-disrupting metabolites, with special attention to 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47). Mol. Nutr. Food Res 2008;52(2):284–298. [DOI] [PubMed] [Google Scholar]
  • 14.Cao L-Y, Zheng Z, Ren X-M, Andersson PL, Guo H. Structure-Dependent Activity of Polybrominated Diphenyl Ethers and Their Hydroxylated Metabolites on Estrogen Related Receptor γ: in Vitro and in Silico Study. 2018. doi: 10.1021/acs.est.8b02509. [DOI] [PubMed] [Google Scholar]
  • 15.Ingle ME, Mínguez-Alarcón L, Carignan CC, Stapleton HM, Williams PL, Ford JB, Moravek MB, Hauser R, Meeker JD. Exploring reproductive associations of serum polybrominated diphenyl ether and hydroxylated brominated diphenyl ether concentrations among women undergoing in vitro fertilization. Hum. Reprod 2020;35(5):1199–1210. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 16.Hauser R, Meeker JD, Duty S, Silva MJ, Calafat AM. Altered semen quality in relation to urinary concentrations of phthalate monoester and oxidative metabolites. Epidemiology 2006;17(6):682–691. [DOI] [PubMed] [Google Scholar]
  • 17.Gaskins AJ, Hart JE, Mínguez-Alarcón L, Chavarro JE, Laden F, Coull BA, Ford JB, Souter I, Hauser R. Residential proximity to major roadways and traffic in relation to outcomes of in vitro fertilization. 2018. doi: 10.1016/j.envint.2018.03.029. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 18.Stapleton HM, Eagle S, Anthopolos R, Wolkin A, Miranda ML. Associations between polybrominated diphenyl ether (PBDE) flame retardants, phenolic metabolites, and thyroid hormones during pregnancy. Environ. Health Perspect 2011;119(10):1454–1459. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 19.Covaci A, Voorspoels S, Thomsen C, van Bavel B, Neels H. Evaluation of total lipids using enzymatic methods for the normalization of persistent organic pollutant levels in serum. Sci. Total Environ 2006;366(1):361–366. [DOI] [PubMed] [Google Scholar]
  • 20.Hauser R, Gaskins AJ, Souter I, Smith KW, Dodge LE, Ehrlich S, Meeker JD, Calafat AM, Williams PL. Urinary phthalate metabolite concentrations and reproductive outcomes among women undergoing in vitro fertilization: Results from the EARTH study. Environ. Health Perspect 2016;124(6):831–839. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 21.Mok-Lin E, Ehrlich S, Williams PL, Petrozza J, Wright DL, Calafat AM, Ye X, Hauser R. Urinary bisphenol A concentrations and ovarian response among women undergoing IVF. Int. J. Androl 2010;33(2):385–393. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 22.SART. National Summary Report: All SART Member Clinics. 2016. Available at: https://www.sartcorsonline.com/rptCSR_PublicMultYear.aspx?ClinicPKID=0. Accessed October 17, 2017. [Google Scholar]
  • 23.Williamson, John M, Datta S, Satten GA. Marginal Analyses of Clustered Data When Cluster Size Is Informative. Biometrics 2003;59:36–42. [DOI] [PubMed] [Google Scholar]
  • 24.O’Brien KM, Upson K, Cook NR, Weinberg CR. Environmental Chemicals in Urine and Blood: Improving Methods for Creatinine and Lipid Adjustment. Environ. Health Perspect 2016;124(2):220–227. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 25.Harley KG, Bradman A, Gharbi M, Chevrier J, Eskenazi B, Sjödin A. Polybrominated Diphenyl Ether (PBDE) Flame Retardants and Thyroid Hormone during Pregnancy. Environ. Health Perspect 2010;118(10):1444–1449. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 26.Johnson PI, Altshul L, Cramer DW, Missmer SA, Hauser R, Meeker JD. Serum and follicular fluid concentrations of polybrominated diphenyl ethers and in-vitro fertilization outcome. Environ. Int 2012;45(1):9–14. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 27.Ingle ME, Mínguez-Alarcón L, Carignan CC, Butt CM, Stapleton HM, Williams PL, Ford JB, Hauser R, Meeker JD. The association between urinary concentrations of phosphorous-containing flame retardant metabolites and semen parameters among men from a fertility clinic. Int. J. Hyg. Environ. Health 2018;221(5):809–815. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 28.Ingle ME, Mínguez-Alarcón L, Carignan CC, Stapleton HM, Williams PL, Ford JB, Moravek MB, Hauser R, Meeker JD. Exploring reproductive associations of serum polybrominated diphenyl ether and hydroxylated brominated diphenyl ether concentrations among women undergoing in vitro fertilization. Hum. Reprod 2020;35(5). doi: 10.1093/humrep/deaa063. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 29.Lagarde F, Beausoleil C, Belcher SM, Belzunces LP, Emond C, Guerbet M, Rousselle C. Non-monotonic dose-response relationships and endocrine disruptors: a qualitative method of assessment.; 2015. doi: 10.1186/1476-069X-14-13. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 30.US EPA O. Endocrine Disruption Research: Testing for Potential Low-Dose Effects.; 2017. [Google Scholar]
  • 31.Akutsu K, Takatori S, Nozawa S, Yoshiike M, Nakazawa H, Hayakawa K, Makino T, Iwamoto T. Polybrominated Diphenyl Ethers in Human Serum and Sperm Quality. Bull. Environ. Contam. Toxicol 2008;80(4):345–350. [DOI] [PubMed] [Google Scholar]
  • 32.Mumford SL, Kim S, Chen Z, Gore-Langton RE, Boyd Barr D, Louis GMB. Persistent organic pollutants and semen quality: The LIFE Study. Chemosphere 135:427–435. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 33.Turyk ME;, Persky VW;, Imm P;, Knobeloch L;, Chatterton Robert;, Anderson Chatterton R, Anderson HA. Hormone disruption by PBDEs in adult male sport fish consumers. Environ. Health Perspect 2008;116(12):1635–1641. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 34.Dallaire R, Dewailly É, Pereg D, Dery S, Ayotte P. Thyroid function and plasma concentrations of polyhalogenated compounds in inuit adults. Environ. Health Perspect 2009;117(9):1380–1386. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 35.Abdelouahab N, Ainmelk Y, Takser L. Polybrominated diphenyl ethers and sperm quality. Reprod. Toxicol 2011;31:546–550. [DOI] [PubMed] [Google Scholar]
  • 36.Wagner MS, Wajner SM, Maia AL. The role of thyroid hormone in testicular development and function. J. Endocrinol 2008;199(3):351–365. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 37.Agarwal A Thyroid Hormones in Male Reproduction and Fertility. Open Reprod. Sci. J 2011;3(1):98–104. [Google Scholar]
  • 38.Buck Louis GM, Sundaram R, Schisterman EF, Sweeney AM, Lynch CD, Gore-Langton RE, Maisog J, Kim S, Chen Z. Persistent environmental pollutants and couple fecundity: The LIFE study. Environ. Health Perspect 2013;121(2):231–236. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 39.Wu N, Herrmann T, Paepke O, Tickner J, Hale R, Harvey E, La Guardia M, McClean MD, Webster TF. Human exposure to PBDEs: Associations of PBDE body burdens with food consumption and house dust concentrations. Environ. Sci. Technol 2007;41(5):1584–1589. [DOI] [PubMed] [Google Scholar]
  • 40.Fraser AJ, Webster TF, Mcclean MD. Diet Contributes Significantly to the Body Burden of PBDEs in the General U.S. Population. Environ. Health Perspect 2009;117(10):1520–1525. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 41.Allen JG, McClean MD, Stapleton HM, Webster TF. Critical factors in assessing exposure to PBDEs via house dust. Environ. Int 2008;34(8):1085–1091. [DOI] [PubMed] [Google Scholar]
  • 42.Watkins DJ, McClean MD, Fraser AJ, Weinberg J, Stapleton HM, Webster TF. Associations between PBDEs in office air, dust, and surface wipes. Environ. Int 2013;59:124–132. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 43.Lee H-K, Kang H, Lee S, Kim S, Choi K, Moon H-B. Human exposure to legacy and emerging flame retardants in indoor dust: A multiple-exposure assessment of PBDEs. Sci. Total Environ 2020;719:137386. [DOI] [PubMed] [Google Scholar]
  • 44.Palmisano BT, Zhu L, Eckel RH, Stafford JM. Sex differences in lipid and lipoprotein metabolism. Mol. Metab 2018;15:45–55. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 45.Warner M, Rauch S, Coker ES, Harley K, Kogut K, Sjödin A, Eskenazi B. Obesity in relation to serum persistent organic pollutant concentrations in CHAMACOS women. Environ. Epidemiol 2018;2(4):e032. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 46.Baker NA, Karounos M, English V, Fang J, Wei Y, Stromberg A, Sunkara M, Morris AJ, Swanson HI, Cassis LA. Coplanar polychlorinated biphenyls impair glucose homeostasis in lean C57BL/6 mice and mitigate beneficial effects of weight loss on glucose homeostasis in obese mice. Environ. Health Perspect 2013;121(1):105–110. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 47.Makey CM, McClean MD, Sjödin A, Weinberg J, Carignan CC, Webster TF. Temporal variability of polybrominated diphenyl ether (PBDE) serum concentrations over one year. Environ. Sci. Technol 2014;48(24):14642–14649. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 48.Oulhote Y, Chevrier J, Bouchard MF. Exposure to Polybrominated Diphenyl Ethers (PBDEs) and Hypothyroidism in Canadian Women. J. Clin. Endocrinol. Metab 2016;101(2):590–598. [DOI] [PubMed] [Google Scholar]
  • 49.Zota AR, Mitro SD, Robinson JF, Hamilton EG, Park J-S, Parry E, Thomas Zoeller R, Woodruff TJ. Polybrominated diphenyl ethers (PBDEs) and hydroxylated PBDE metabolites (OH-PBDEs) in maternal and fetal tissues, and associations with fetal cytochrome P450 gene expression. Environ. Int 2018;112:269–278. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 50.Buck GM, Lynch CD, Stanford JB, Sweeney AM, Schieve LA, Rockett JC, Selevan SG, Schrader SM. Prospective pregnancy study designs for assessing reproductive and developmental toxicants. Environ. Health Perspect 2004;112(1):79–86. [DOI] [PMC free article] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

1
NIHMS1631095-supplement-1.docx (59.6KB, docx)
2

Supplemental Figure 1. Distributions of OH-BDEs (ng/g lipid) among 189 couples from the EARTH study.

NIHMS1631095-supplement-2.docx (23.5KB, docx)
3

Supplemental Figure 2. Distributions of total serum lipids and BMI (kg/m2) among 189 couples from the EARTH study.

NIHMS1631095-supplement-3.docx (20.4KB, docx)

RESOURCES