Perinatal Lead Exposure and Risk of ASD: A Multiyear Natural Experiment at the US State Level

Prevalence of autism spectrum disorder (ASD) is continuing to rise unabated worldwide; however, the origins of this epidemic and the drivers of its sustained momentum remain elusive. While exposure to air pollution and abnormal metal levels in children with ASD have been identified as environmental risk factors of ASD, these studies have failed to explain the emergence of the epidemic. Paramount to protecting against future cases of this neurodevelopmental disorder is a better understanding of its etiology. Here, in part one of a series of ecological studies, we demonstrate at the US state level that perinatal lead exposure is inversely associated with ASD and is likely a potent inhibitor of autism. These results contrast with how lead is typically perceived, namely, as detrimental to normal neurodevelopment. Lead’s disuse in the last several decades, while benefiting the physiological health of children in many ways, has likely prompted the current epidemic by leaving infants more exposed to other metal toxicants