03. Time-Varying Covariate Analysis of Dementia Risk Between Autistic and Non-Autistic Older Adults in Medicare

Prior studies have demonstrated heightened dementia risk among autistic older adults. Understanding disparities in dementia risk is increasingly important as more autistic individuals reach older adulthood. While research suggests autistic older adults experience heightened risk for most physical and mental health conditions compared with their non-autistic peers, it remains unclear the extent to which these risk factors play a role in the heightened dementia risk observed in autistic older adults.
While logistic regression is commonly used to model binary outcomes, it fails to account for the timing of disease onset or the dynamic nature of risk exposure. Using a national Medicare sample, we modeled the association between autism and dementia using a Cox proportional hazards model with time-varying covariates for known dementia risk factors 9 years of follow-up data. Risk factors for dementia in the general population have been well-documented and include hypertension, hearing loss, type 2 diabetes, obesity, high cholesterol, TBI, depression, alcohol use, and tobacco use.
Our findings suggest that, even after accounting for these factors as time-dependent exposures, autistic older adults remain at significantly elevated risk for dementia. These results suggest that known risk factors only partially explain the disparity and that additional contributors may underlie the increased risk of dementia observed in the autistic population.

survival analysis

Cox regression

time-varying covariates

secondary data

Medicare

Autism 

Mid-Level

Knowledge

Women in Statistics and Data Science 2025