Whole blood lead concentrations in children undergoing autism assessment in a community paediatric clinic: a retrospective cross-sectional study.

Objective: To investigate blood lead concentrations (BLCs) in children presenting with autistic spectrum disorder (ASD) and associations with clinical presentation (pica, motor delay, language delay and anaemia), age and social deprivation.

Setting: Community-based autism assessment clinics, north Bristol, UK (single-centre, retrospective cross-sectional study).

Patients: Children with autism who had BLC measured as part of an autism assessment during a 4-year period from November 2019 to November 2023.

Main outcome measures: Data were collected from electronic case notes for children who underwent an assessment for ASD during this period, including diagnoses and investigations.

Results: 13/102 (13%) children with a diagnosis of autism had BLC ≥0.24 µmol/L, which is above the UK Health Security Agency threshold to trigger further investigation and identification of sources of exposure. Elevated BLC was not associated with the presence of pica or other clinical features including developmental delay.

Conclusion: Pica and developmental delay were not useful indicators of children with elevated BLC. Their absence could lead to cases of elevated BLC being missed in children with autism. This lends weight to an argument that lead should be screened for routinely in the preschool autism population alongside other common causes of behavioural difficulties and developmental delay such as anaemia.