Exposure to Elements in Fetal and Early Postnatal Periods and Autistic Traits

Background:  Environmental factors likely play an important role in the etiology of autism, but are understudied. Of the many possible environmental risks, fetal and early childhood exposure to toxic metals as well as deficiencies of nutritional elements are interesting candidates for investigation as they have been associated with several adverse developmental outcomes. 

Objectives:  Using a novel tooth matrix biomarker this study examined exposure to multiple elements in relation to autistic traits. 

Methods:  Participants are members of the Roots of Autism and ADHD Twin Study in Sweden, a population based case-control twin sample recruited from nation-wide registries in Sweden. We used newly developed tooth matrix biomarkers to establish detailed temporal profiles of multiple metal toxicants and essential elements over the prenatal and early postnatal periods. Autistic- traits were assessed using the Social Responsiveness Scale-2 (SRS-2).

Results:  From the Roots of Autism and ADHD Twin Study Sweden 51 members contributed teeth samples. Manganese was inversely associated with SRS-2 (r = -0.3 to -0.5), with this association being significant over the pre- and postnatal periods, suggesting that deficiencies are associated with increasing autistic symptomatology. A significant inverse association of zinc with SRS-2 was also observed in the third trimester. The relationship of other elements, including lead and copper, and SRS-2 severity, is currently undergoing and will also be presented.

Conclusions:  Prenatal and early postnatal uptake of multiple metal toxicants and essential elements contributes to individual differences in autistic traits. Prenatal and early life excess or deficiency of elements may contribute to autism risk.