Association of type 1 diabetes and age at diagnosis of type 2 diabetes with brain volume and risk of dementia in the UK Biobank: A prospective cohort study of community‐dwelling participants

Aims To investigate the association of type 1 diabetes (T1D) and age at diagnosis of type 2 diabetes (T2D) with brain structure and incident dementia. Methods Our analysis was based on the UK Biobank. We included 1376 participants with diabetes and 2752 randomly selected controls for brain volume analysis, and 25,141 participants with diabetes and 50,282 randomly selected controls for dementia analysis. Brain volume was measured using magnetic resonance imaging. Dementia was identified using hospital inpatient records and mortality register data until January 2021. Results T2D diagnosed at a younger age was associated with larger reductions in brain volume. After adjustment for glycated haemoglobin (HbA1c) and other covariates, only T2D diagnosed