Interaction between manganese and in relation to autism spectrum disorder while controlling for exposure to mixture of lead, mercury, arsenic, and cadmium.

BACKGROUND: We previously reported a significant interactive association between polymorphisms of and blood manganese concentrations (BMC) with autism spectrum disorder (ASD) in Jamaican children. In this paper, we investigate the same interactive association with ASD while adjusting for the mixture of four metals (lead, mercury, cadmium, and arsenic).

METHOD: We used data from 163 case-control pairs of children 2-8 years of age from our autism project in Jamaica, in which we collected blood for heavy metals analysis at enrollment. To minimize potential multicollinearity between concentrations of the four metals, we generated a mixture index using generalized weighted quantile sum regression, which was used in conditional logistic regression models to control for the four metals while assessing the interactive association between and BMC with ASD.

RESULTS: Similar to the findings we reported previously, we found that in co-dominant and dominant models for among children with the Ile/Ile genotype, those with BMC > 12μg/L had 4.6 and 4.27 times higher odds of ASD compared to those with BMC

CONCLUSIONS: After adjusting for the mixture of four metals, the interactive association of BMC and with ASD remained significant with similar magnitude of associations. Results should be interpreted cautiously.