To Örebro University

Where we live can affect the balance of genetic and environmental influences on many developmental disorders and traits. For example, some genetic influences may be drawn out specifically by urban or rural environments. We used two different approaches to investigate the influence of location on autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD), on both national and local scales.

First, using data from Sweden’s Child and Adolescent Twin Study, we used spACE structural equation models to estimate spatial patterns of genetic, shared environmental and non-shared environmental influences on symptoms of ASD and ADHD at ages 9 and 12 for thousands of locations across the country. We compared the maps to our previous analyses in the UK’s Twins Early Development Study.

Second, we explored how polygenic risk for ASD and ADHD varies across a single city-region using data at age 10 from the Avon Longitudinal Study of Parents and Children (ALSPAC) in Bristol, UK. We obtained effect estimates at multiple locations across the study area using weighted linear regression models of polygenic risk.

We found geographical variation in genetic and non-shared environmental influences for both ASD and ADHD in Sweden, paralleling our previous results from the UK. We also found evidence of geographical variation in polygenic risk on a local scale in Bristol and surrounding areas. The maps produced by these analyses may inform the discovery of novel environments that draw out or mask genetic risk, facilitating the discovery of genetic variants and the development of targeted environmental interventions.