Abstract P253: Lifetime Risk of Dementia by Midlife Vascular Risk Factor Burden: The Atherosclerosis Risk in Communities (ARIC) Study

Introduction: Vascular risk factors play an important role in the development of dementia and death over the lifecourse. However, no absolute lifetime risk of dementia by individual and composite number of vascular risk factors have been reported. Methods: We conducted a prospective cohort analysis of data from the Atherosclerosis Risk in Communities (ARIC) Study. We examined the associations of vascular risk factors with incident dementia. Risk factors were measured at visit 2 (1990-1992) and included hypertension (SBP140mmHg, DBP90mmHg or medication use), diabetes status (self-reported physician diagnosis, medication use or HbA1C6.5%) and smoking status. Incident dementia was ascertained via active surveillance involving cognitive function assessments, informant reports, hospitalization codes and death records. We performed survival analysis using age as time scale and accounted for death without dementia as a competing event. We used age 60 as the origin and age on December 31 st , 2019, as the administrative censoring endpoint. Results: Among 13,161 participants, 45%, 40%, and 15% had 0, 1 and 2+ risk factors. There was a dose-dependent association between number of risk factors and the cumulative incidence of dementia (Figure A) and death (Figure C) . In competing risk models ( Figure B ), the cumulative incidence of dementia (95% CI) in persons with 0, 1 and 2+ risk factors by age 80 was 7.5% (6.6-8.5%), 10.3% (9.2-11.5%) and 13.7% (11.5-15.7%). By age 90, due to higher risk of mortality among those with vascular risk factors, the dementia risk (95% CI) for 0, 1 and 2+ risk factors were 34.8 (32.3-37.3%), 31.2% (29.0-33.2%) and 26.7% (23.9-29.6%). Conclusion: Preventing vascular risk factors in midlife may substantially reduce the age-specific risk of dementia. However, since fewer risk factors also lead to longer survival to oldest ages where dementia risk is very high, reducing lifetime risk of dementia beyond age 90 years will require additional preventative strategies. Figure: Cumulative incidence of dementia using Kaplan Meier estimator (A), using cumulative incidence function with competing risk of death (B), and cumulative incidence of death (C), according to the number of vascular risk factors in mid-life.