Spatial Clusters of Autism Births and Diagnoses Point to Contextual Drivers of Increased Prevalence

Spatial clusters of autism births and diagnoses point to contextual drivers of increased prevalence Although often suggested to have been crucial to the rise of autism, environmental and social contextual drivers of diagnosis have not been extensively examined. Identifying the spatial patterning of autism cases at birth and at diagnosis can help clarify which contextual drivers are affecting autism's rising prevalence. We observe significant birth and diagnostic clusters of autism independent of key individual-level risk factors. While the clusters overlap, there is a strong positive association between the diagnostic clusters and neighborhood-level, diagnostic resources. In addition, children with autism who are higher functioning are more likely to be diagnosed within a cluster than children with autism who are lower functioning. Most importantly, children who move into a neighborhood with more diagnostic resources than their previous residence are more likely to subsequently receive an autism diagnosis than children whose neighborhood resources do not change. Our findings implicate a causal relationship between neighborhood-level, diagnostic resources and spatial patterns of autism incidence. 

Mazumdar, S., Winter, A., Liu, K., & Bearman, P. (2013) Spatial clusters of autism births and diagnoses point to contextual drivers of increased prevalence. Social Science and Medicine 95: 87-96.

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