| 1. |
- Bonde, Jens Peter, et al.
(författare)
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The epidemiologic evidence linking prenatal and postnatal exposure to endocrine disrupting chemicals with male reproductive disorders : A systematic review and meta-analysis
- 2016
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Ingår i: Human Reproduction Update. - 1355-4786. ; 23:1, s. 104-125
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: More than 20 years ago, it was hypothesized that exposure to prenatal and early postnatal environmental xenobiotics with the potential to disrupt endogenous hormone signaling might be on the causal path to cryptorchidism, hypospadias, low sperm count and testicular cancer. Several consensus statements and narrative reviews in recent years have divided the scientific community and have elicited a call for systematic transparent reviews. We aimed to fill this gap in knowledge in the field of male reproductive disorders. OBJECTIVE AND RATIONALE: The aim of this study was to systematically synthesize published data on the risk of cryptorchidism, hypospadias, low sperm counts and testicular cancer following in utero or infant exposure to chemicals that have been included on the European Commission's list of Category 1 endocrine disrupting chemicals defined as having documented adverse effects due to endocrine disruption in at least one intact organism. SEARCH METHODS: A systematic literature search for original peer reviewed papers was performed in the databases PubMed and Embase to identify epidemiological studies reporting associations between the outcomes of interest and exposures documented by biochemical analyses of biospecimens including maternal blood or urine, placenta or fat tissue as well as amnion fluid, cord blood or breast milk; this was followed by meta-analysis of quantitative data. OUTCOMES: The literature search resulted in 1314 references among which we identified 33 papers(28 study populations) fulfilling the eligibility criteria. These provided 85 risk estimates of links between persistent organic pollutants and rapidly metabolized compounds (phthalates and Bisphenol A) and male reproductive disorders. The overall odds ratio (OR) across all exposures and outcomes was 1.11 (95% CI 0.91-1.35). When assessing four specific chemical subgroups with sufficient data for meta-analysis for all outcomes, we found that exposure to one of the four compounds, p,p'-DDE, was related to an elevated risk: OR 1.35 (95% CI 1.04-1.74). The data did not indicate that this increased risk was driven by any specific disorder. WIDER IMPLICATIONS: The current epidemiological evidence is compatible with a small increased risk of male reproductive disorders following prenatal and postnatal exposure to some persistent environmental chemicals classified as endocrine disruptors but the evidence is limited. Future epidemiological studies may change the weight of the evidence in either direction. No evidence of distortion due to publication bias was found, but exposure-response relationships are not evident. There are insufficient data on rapidly metabolized endocrine disruptors and on specific exposure-outcome relations. A particular data gap is evident with respect to delayed effects on semen quality and testicular cancer. Although high quality epidemiological studies are still sparse, future systematic and transparent reviews may provide pieces of evidence contributing to the narrative and weight of the evidence assessments in the field.
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| 4. |
- Gaml-Sørensen, Anne, et al.
(författare)
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Maternal vitamin D levels and male reproductive health : a population-based follow-up study
- 2023
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Ingår i: European Journal of Epidemiology. - : Springer Science and Business Media LLC. - 0393-2990 .- 1573-7284. ; 38:5, s. 469-484
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Tidskriftsartikel (refereegranskat)abstract
- Maternal vitamin D levels during pregnancy may be important for reproductive health in male offspring by regulating cell proliferation and differentiation during development. We conducted a follow-up study of 827 young men from the Fetal Programming of Semen Quality (FEPOS) cohort, nested in the Danish National Birth Cohort to investigate if maternal vitamin D levels were associated with measures of reproductive health in adult sons. These included semen characteristics, testes volume, and reproductive hormone levels and were analysed according to maternal vitamin D (25(OH)D3) levels during pregnancy. In addition, an instrumental variable analysis using seasonality in sun exposure as an instrument for maternal vitamin D levels was conducted. We found that sons of mothers with vitamin D levels < 25 nmol/L had 11% (95% CI − 19 to − 2) lower testes volume and a 1.4 (95% CI 1.0 to 1.9) times higher risk of having low testes volume (< 15 mL), in addition to 20% (95% CI − 40 to 9) lower total sperm count and a 1.6 (95% CI 0.9 to 2.9) times higher risk of having a low total sperm count (< 39 million) compared with sons of mothers with vitamin D levels > 75 nmol/L. Continuous models, spline plots and an instrumental variable analysis supported these findings. Low maternal vitamin D levels were associated with lower testes volume and lower total sperm count with indications of dose-dependency. Maternal vitamin D level above 75 nmol/L during pregnancy may be beneficial for testes function in adult sons.
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| 5. |
- Hærvig, Katia Keglberg, et al.
(författare)
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Fetal exposure to maternal cigarette smoking and male reproductive function in young adulthood
- 2022
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Ingår i: European Journal of Epidemiology. - : Springer Science and Business Media LLC. - 0393-2990 .- 1573-7284. ; 37:5, s. 525-538
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Tidskriftsartikel (refereegranskat)abstract
- Maternal smoking during pregnancy constitutes a potential, major risk factor for adult male reproductive function. In the hitherto largest longitudinal cohort, we examined biomarkers of reproductive function according to maternal smoking during the first trimester and investigated whether associations were mitigated by smoking cessation prior to the fetal masculinization programming window. Associations between exposure to maternal smoking and semen characteristics, testicular volume and reproductive hormones were assessed among 984 young men from the Fetal Programming of Semen Quality (FEPOS) cohort. Maternal smoking was assessed through interview data and measured plasma cotinine levels during pregnancy. We applied negative binomial, logistic and linear regression models to estimate differences in outcomes according to levels of maternal smoking. Sons of light smokers (≤ 10 cigarettes/day) had a 19% (95% CI − 29%, − 6%) lower sperm concentration and a 24% (95% CI − 35%, − 11%) lower total sperm count than sons of non-smokers. These estimates were 38% (95% CI − 52%, − 22%) and 33% (95% CI − 51%, − 8%), respectively, for sons of heavy smokers (> 10 cigarettes/day). The latter group also had a 25% (95% CI 1%, 54%) higher follitropin level. Similarly, sons exposed to maternal cotinine levels of > 10 ng/mL had lower sperm concentration and total sperm count. Smoking cessation prior to gestational week seven was not associated with a higher reproductive capacity. We observed substantial and consistent exposure–response associations, providing strong support for the hypothesis that maternal smoking impairs male reproductive function. This association persisted regardless of smoking cessation in early pregnancy.
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| 6. |
- Hærvig, Katia Keglberg, et al.
(författare)
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Fetal exposure to paternal smoking and semen quality in the adult son
- 2020
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Ingår i: Andrology. - : Wiley. - 2047-2919 .- 2047-2927. ; 8:5, s. 1117-1125
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Tidskriftsartikel (refereegranskat)abstract
- Background: The negative impact of maternal smoking during pregnancy on offspring semen quality is well established. Less is known about the impact of paternal smoking. Methods: We estimated differences in semen parameters and testicle size according to paternal smoking in 772 adult sons of women enrolled in the Danish National Birth Cohort when pregnant. Parents’ smoking was reported around gestational week 16, and analyses were adjusted for parents’ ages at conception, maternal pre-pregnancy body mass index, maternal alcohol and caffeine intake, family occupational status, ejaculatory abstinence time, clinic of semen analysis, and season. Results: Sons of smoking fathers and non-smoking mothers had a 10% (95% confidence interval: −24%, 7%) lower semen concentration and 11% (95% confidence interval: −27%, 8%) lower sperm count than sons of non-smoking parents. Having two smoking parents was associated with 19% reduction in sperm count (95% confidence interval: −37%, 3%). Paternal smoking was not associated with volume, motility, or morphology. Adjusting for maternal smoking, paternal smoking was associated with a 26% increased risk of small testicular volume (95% confidence interval: 0.89, 1.78). Discussion: Exclusion of sons with a history of testicular cancer, chemotherapy, orchiectomy, and with only one or no testicles may have caused us to underestimate associations if these men's reproductive health including semen quality are in fact more sensitive to paternal smoking. Conclusion: The study provides limited support for slightly lower sperm concentration and total sperm concentration in sons of smoking fathers, but findings are also compatible with no association.
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| 7. |
- Hærvig, Katia Keglberg, et al.
(författare)
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Fetal programming of semen quality (Fepos) cohort – a dnbc male-offspring cohort
- 2020
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Ingår i: Clinical Epidemiology. - 1179-1349. ; 12, s. 757-770
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Tidskriftsartikel (refereegranskat)abstract
- Background: Prenatal exposures may contribute to male infertility in adult life, but large-scale epidemiological evidence is still lacking. The Fetal Programming of Semen quality (FEPOS) cohort was founded to provide means to examine if fetal exposures can interfere with fetal reproductive development and ultimately lead to reduced semen quality and reproductive hormone imbalances in young adult men. Methods: Young adult men at least 18 years and 9 months of age born to women in the Danish National Birth Cohort living in relative proximity to Copenhagen or Aarhus and for whom a maternal blood sample and two maternal interviews during pregnancy were available were invited to FEPOS. Recruitment began in March 2017 and ended in December 2019. The participants answered a comprehensive questionnaire and underwent a physical examination where they delivered a semen, urine, and hair sample, measured their own testicular volume, and had blood drawn. Results: In total 21,623 sons fulfilled eligibility criteria of whom 5697 were invited and 1058 participated making the response rate 19%. Semen characteristics did not differ between sons from the Copenhagen and Aarhus clinics. When comparing the FEPOS semen parameters to similar cohorts, the median across all semen characteristics was slightly lower for FEPOS participants, although with smaller variation. Conclusion: With its 1058 young adult men, the FEPOS cohort is the largest population-based male-offspring cohort worldwide specifically designed to investigate prenatal determinants of semen quality. Wide-ranging information on maternal health, lifestyle, socioeconomic status, occupation, and serum concentrations of potential reproductive toxicants during pregnancy combined with biological markers of fertility in their sons collected after puberty allow for in-depth investigations of the ‘fetal origins of adult disease hypothesis’.
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| 8. |
- Hærvig, Katia Keglberg, et al.
(författare)
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Maternal Exposure to Per- and Polyfluoroalkyl Substances (PFAS) and Male Reproductive Function in Young Adulthood : Combined Exposure to Seven PFAS
- 2022
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Ingår i: Environmental Health Perspectives. - 1552-9924. ; 130:10, s. 107001-107001
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Concerns remain about the human reproductive toxicity of the widespread per- and polyfluoroalkyl substances (PFAS) during early stages of development. OBJECTIVES: We examined associations between maternal plasma PFAS levels during early pregnancy and male offspring reproductive function in adulthood. METHODS: The study included 864 young men (age range:18.9-21.2 y) from the Fetal Programming of Semen Quality (FEPOS) cohort established between 2017 and 2019. Plasma samples from their mothers, primarily from the first trimester, were retrieved from the Danish National Biobank and levels of 15 PFAS were measured. Seven PFAS had detectable levels above the limit of detection in formula presented of the samples and were included in analyses. Semen quality, testicular volume, and levels of reproductive hormones and PFAS were assessed in the young men. We used weighted quantile sum (WQS) regression to estimate the associations between combined exposure to maternal PFAS and reproductive function, and negative binomial regression to estimate the associations of single substances, while adjusting for a range of a priori-defined fetal and postnatal risk factors. RESULTS: By a 1-unit increase in the WQS index, combined maternal PFAS exposure was associated with lower sperm concentration (formula presented ; 95% CI: formula presented ), total sperm count (formula presented ; 95% CI: formula presented ), and a higher proportion of nonprogressive and immotile sperm (5%; 95% CI: 1%, 8%) in the young men. Different PFAS contributed to the associations with varying strengths; however, perfluoroheptanoic acid was identified as the main contributor in the analyses of all three outcomes despite the low concentration. We saw no clear association between exposure to maternal PFAS and testicular volume or reproductive hormones. DISCUSSION: In a sample of young men from the general Danish population, we observed consistent inverse associations between exposure to maternal PFAS and semen quality. The study needs to be replicated in other populations, taking combined exposure, as well as emerging short-chain PFAS, into consideration. https://doi.org/10.1289/EHP10285.
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| 10. |
- Høyer, Birgit Bjerre, et al.
(författare)
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Exposure to perfluoroalkyl substances during pregnancy and child behaviour at 5 to 9 years of age
- 2018
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Ingår i: Hormones and Behavior. - : Elsevier BV. - 0018-506X. ; 101, s. 105-112
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Tidskriftsartikel (refereegranskat)abstract
- We examined associations between prenatal exposure to perfluorohexane sulfonic acid (PFHxS), perfluoroheptanoic acid (PFHpA), perfluorononanoic acid (PFNA), and perfluorodecanic acid (PFDA) - and child behaviour (SDQ-total) and hyperactivity (sub-scale) at 5–9 years of age in birth cohorts from Greenland and Ukraine. Pregnancy serum samples (N = 1023) were analysed for perfluoroalkyl substances (PFASs) and categorised into tertiles and also used as continuous exposure variables. Problem behaviour and hyperactivity were assessed, using the Strength and Difficulties Questionnaire (SDQ) and categorised as normal/borderline and abnormal. Associations were analysed using multiple logistic and linear regression. High compared to low prenatal PFHxS exposure was associated with 1.16 (95% confidence interval (CI): 0.08; 2.25) point higher SDQ-total (more problem behaviour) in Greenland and 0.80 (CI: 0.06; 1.54) point higher SDQ-total in the combined analyses, whereas no association was present in Ukraine alone. One natural log-unit increase in prenatal PFNA exposure was associated with 0.90 (CI: 0.10; 1.71) points higher SDQ-total in Greenland and 0.72 (CI: 0.13; 1.31) points higher in the combined analysis and no association in Ukraine. Prenatal PFAS exposure was unrelated to problem behaviour (abnormal SDQ-total). In the combined analysis, odds ratio (OR) (CI) for hyperactivity was 1.8 (1.0; 3.2) for one natural log-unit increase in prenatal PFNA and 1.7 (1.0; 3.1) for one natural log-unit increase in prenatal PFDA exposure. Findings are compatible with weak effects on child behaviour of prenatal exposure to some PFASs although spurious results are not entirely unlikely. The associations were strongest in Greenland.
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