Influence of Low-Level Prenatal Exposure to PCDD/Fs and PCBs on Empathizing, Systemizing and Autistic Traits: Results from the Duisburg Birth Cohort Study

Abstract

BackgroundPolychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) are assumed to act as endocrine disruptor chemicals. Prenatal exposure to these pollutants might influence fetal steroid hormone levels, which are thought to be related to sex-typical development and autistic traits.ObjectivesWe examined associations of prenatal levels of PCDD/Fs and PCBs with autism traits and sex-typical behaviour in childhood.MethodsWe measured levels of PCDD/Fs and PCBs in maternal blood samples during pregnancy using gas chromatography/high-resolution mass spectrometry. Sex-typical behaviour was assessed at 9 years of age (n = 96) and autistic traits at 10 years of age using the Social Responsiveness Scale (SRS; n = 100). Multiple regression analyses were conducted to estimate the associations between prenatal exposure and outcome variables.ResultsBlood concentrations (WHO2005-TEq) of ƩPCDD/Fs ranged from 2.93–46.45 pg/g lipid base (median = 12.91 pg/g lipid base) and concentrations of ƩPCBs were in the range of 1.24–25.47 pg/g lipid base (median = 6.85 pg/g lipid base) which is within the range of German background exposure. We found significant negative associations between PCDD/F levels in maternal blood and SRS scores in the whole group (β = -6.66, p < .05), in girls (β = -10.98, p < .05) and, in one SRS subscale, in boys (β = -6.86, p < .05). For PCB levels, associations with one SRS subscale were significant for the whole study group as were associations with two subscales in girls. We did not find significant associations between PCDD/F or PCB levels and sex-typical behaviour for either sex.ConclusionsIn an earlier part of this study, prenatal exposure to PCDD/Fs and PCBs was found to be associated with lower testosterone levels, therefore, our findings are consistent with the idea that autism spectrum conditions are related to fetal androgen levels. Several possible mechanisms, through which PCDD/Fs and PCBs might influence autistic behaviour, are discussed.

Sex Differences in Autism Spectrum Disorder: a Review

“…This is an interesting finding that may relate to the liability-threshold model and FPE models (discussed earlier), but the sample sizes were small and the implications should be considered carefully. Finally, maternal blood levels of an endocrine disruptor, which has been shown to decrease testosterone levels, were negatively correlated with social responsiveness in boys and girls at 9 and 10 years of age [76]. …”

Autism genes are selectively targeted by environmental pollutants including pesticides, heavy metals, bisphenol A, phthalates and many others in food, cosmetics or household products

“…Dioxin toxicity, including TCDD, also related to autism and neurodevelopmental problems in a follow-up Vietnamese study. [24] Dioxin and polychlorinated biphenyl maternal blood levels also related to autistic traits in a German study [25]. polychlorinated dibenzo-p-dioxin exposure during the brain growth spurtextending from the third trimester of pregnancy to age 2 related to autism: Reviewed in [3] relatively low doses of four endocrine disruptors , atrazine (10mg/kg), perfluorooctanoic acid (0.1mg/kg), bisphenol-A (50 µg/kg), 2,3,7,8-tetrachlorodibenzo-p-dioxin (0.25 µg/kg) alone or combined in a mixture, from gestational day 7 until weaning produce behavioural toxicity , which for mixture effects was predominantly seen in male mice offspring [26].…”

Cumulative Impact of Polychlorinated Biphenyl and Large Chromosomal Duplications on DNA Methylation, Chromatin, and Expression of Autism Candidate Genes

“…PCBs are identified as probable environmental risk factors for neurodevelopmental disorders, and remain a significant children's health concern because of their inadvertent production by various industrial processes and contamination of indoor air, especially in schools across the United States (Grimm et al, 2015; Herrick et al, 2016; Landrigan et al, 2012; Pessah et al, 2010; Stamou et al, 2013). Additionally, PCB exposures have recently been linked to autistic mannerisms in humans (Nowack et al, 2015). …”