A Motor Vehicle Crash as an Early Signal of Alzheimer's Disease and Related Dementias.

We identified 43,115 eligible individuals with incident ADRD diagnosis from 2010 to 2017.

The ADRD group was more likely to have multiple crashes in the pre-diagnosis period, but multiple events were rare overall (< 3%).

Differences were statistically significant but represented small changes in prevalence.

Crash prevalence did not reveal a clear signal of cognitive decline in the years leading up to the index diagnosis.