Spatial relative risk patterns of autism spectrum disorders in Utah.

Heightened areas of spatial relative risk for autism spectrum disorders (ASD), or ASD hotspots, in Utah were identified using adaptive kernel density functions. Children ages four, six, and eight with ASD from multiple birth cohorts were identified by the Utah Registry of Autism and Developmental Disabilities. Each ASD case was gender-matched to 20 birth cohort controls. Demographic and socioeconomic characteristics of children born inside versus outside ASD hotspots were compared. ASD hotspots were found in the surveillance area for all but one birth cohort and age group sample; maximum relative risk in these hotspots ranged from 1.8 to 3.0. Associations were found between higher socioeconomic status and birth residence in an ASD hotspot in five out of six birth cohort and age group samples.