Sex and Ethnicity Disparities in Autism Diagnosis: Population-Level Findings from Linked Health and Education Data

There is limited robust population-level evidence on the widely reported disparities in autism diagnosis by sex and ethnicity. Universal measures of school readiness, particularly the domains measuring social and emotional development, have been proposed as early indicators of developmental need, but whether the disparities in formal diagnoses across demographic groups are reflected in these population-level measures remains unclear. This study examined how sex, ethnicity, and their intersection were associated with the frequency and timing of childhood autism diagnoses and whether school readiness measures were associated with subsequent diagnosis across demographic groups. Linked health and education records for 55,054 children from a Northwest District of England were analysed using Poisson regression. Children from minoritised ethnic backgrounds and females were less like to receive an autism diagnosis and experienced significantly longer times to diagnosis than males and White British children. South Asian heritage females showed the greatest disadvantage. These patterns were not reflected across distributions of school readiness scores, suggesting diagnostic disparities by sex and ethnicity may reflect structural inequalities within identification pathways rather than true differences in underlying need. Developmental differences are evident and measurable by age five across demographics, highlighting the opportunity for earlier identification and support.