Incident traumatic spinal cord injury and risk of Alzheimer’s disease and related dementia: longitudinal case and control cohort study

Retrospective case/control longitudinal cohort study Prevalent traumatic spinal cord injury (TSCI) is associated with Alzheimer’s disease and related dementia (ADRD). We examined the hazard ratio for ADRD after incident TSCI and hypothesized that ADRD hazard is greater among adults with incident TSCI compared with their matched control of adults without TSCI. Using 2010–2020 U.S. national private administrative claims data, we identified adults aged 45 years and older with probable (likely and highly likely) incident TSCI (n = 657). Our controls included one-to-ten matched cohort of people without TSCI (n = 6553). We applied Cox survival models and adjusted them for age, sex, years of living with certain chronic conditions, exposure to six classes of prescribed medications, and neighborhood characteristics of place of residence. Hazard ratios were used to compare the results within a 4-year follow-up. Our fully adjusted model without any interaction showed that incident TSCI increased the risk for ADRD (HR = 1.30; 95% CI, 1.01–1.67). People aged 45–64 with incident TSCI were at high risk for ADRD (HR = 5.14; 95% CI, 2.27–11.67) and no significant risk after age 65 (HR = 1.20; 95% CI, .92–1.55). Our sensitivity analyses confirmed a higher hazard ratio for ADRD after incident TSCI at 45–64 years of age compared with the matched controls. TSCI is associated with a higher hazard of ADRD. This study informs the need to update clinical guidelines for cognitive screening after TSCI to address the heightened risk of cognitive decline and to shed light on the causality between TSCI and ADRD.