Risk of dementia and related neurocognitive disorders among autistic and non-autistic older adults: Role of established risk factors

Neurocognitive disorders (i.e. dementia) are a leading cause of cognitive decline and loss of independence among older adults. While reported rates are higher among autistic adults, it is unclear whether this disparity persists after accounting for known risk factors.

We compared neurocognitive disorder risk between autistic and non-autistic older adults after adjusting for known risk factors and evaluated whether risk factors moderated this disparity. We replicated our analyses among subsets of autistic older adults with and without co-occurring intellectual disability (ID).

Retrospective longitudinal cohort study.

National Medicare Standard Analytical Files (2013–21).

The sample included 9201 autistic and 18 356 non-autistic older adults aged 65 or older, who were matched on demographic and clinical characteristics.

Our dependent variable was time to neurocognitive disorder, defined as years between age 65 or older and the date of first diagnosis.

Autistic older adults had a 20% higher adjusted risk of neurocognitive disorders than non-autistic older adults (95% CI = 14%–25%; P < .001). Risk was highest among autistic adults with co-occurring ID [adjusted subhazard ratio (SHR) = 1.46; 95% CI = 1.36–1.57]. The disparity between cohorts was amplified in the presence of most known risk factors, notably hypertension (SHR = 2.04; 95% CI = 1.79–2.32), high cholesterol (SHR = 1.60; 95% CI = 1.46–1.75), depression (SHR = 1.52; 95% CI = 1.42–1.62), and type 2 diabetes (SHR = 1.45; 95% CI = 1.36–1.55).

Autistic older adults, particularly those with ID, face significantly higher risk of neurocognitive disorders even after adjusting for known risk factors. These findings emphasise that risk factors may impact the autistic population differently and highlight the need for early screening and tailored prevention strategies.