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Developmental neurotoxicants and the vulnerable male brain: a systematic review of suspected neurotoxicants that disproportionally affect males

Janet K. Kern, David A. Geier, Kristin G. Homme, Paul G. King, Geir Bjørklund, Salvatore Chirumbolo, Mark R. Geier

Acta Neurobiologiae Experimentalis, 2017

110 citations

Abstract

The prevalence of neurodevelopmental disorders (NDs), including autism spectrum disorder, attention‑deficit/hyperactivity disorder, tic disorder, obsessive‑compulsive disorder, and emotional disturbances, has increased notably in the past few decades. To date, debate continues as to the origins of NDs. Increases in widespread exposure to and bioaccumulation of chemical neurotoxicants have paralleled the upsurge in NDs, and are suggested to be causal agents for NDs. One consistent aspect of NDs is the male preponderance. This review considers the issue of male preponderance by reviewing the gender‑specific neurotoxic effects of recognized neurotoxicant chemicals to assess their possible etiology in NDs. This investigation consisted of a systematic literature review of original studies published from 1970-2016 on suspected neurotoxicants, to examine whether they have a disproportionate adverse effect based on gender. Based on that review, the neurotoxicants exhibiting consistent gender‑specific effects, with exposed males being more affected (than similarly exposed females), were: lead, Thimerosal/ethylmercury, some organochlorine pesticides (e.g., dieldrin, endosulfan, and heptachlor), and air pollution. The next group identified were neurotoxicants exhibiting gender‑specific neurotoxic effects, with males being somewhat (but not consistently) more affected than females: mercury vapor, polychlorinated biphenyls (PCBs), and organophosphate pesticides. Finally, there was a…

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Evidence Hub reads this as a systematic review. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid.

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