Contribution of Modifiable Midlife and Late-Life Vascular Risk Factors to Incident Dementia

Area of Science:

• Neurology
• Epidemiology
• Cardiovascular Health

Background:

• Midlife vascular risk factors are linked to increased dementia risk.
• The cumulative impact of vascular risk factors across midlife and late life on dementia remains unclear.

Purpose of the Study:

• To quantify the proportion of dementia cases attributable to modifiable vascular risk factors in midlife and late life.
• To investigate disparities in dementia risk based on apolipoprotein ε4 genotype, race, and sex.

Main Methods:

• Prospective cohort analysis of the Atherosclerosis Risk in Communities (ARIC) study with 33 years of follow-up.
• Analysis included Black and White participants, measuring risk factors (hypertension, diabetes, smoking) at ages 45-54, 55-64, and 65-74.
• Population attributable fractions for incident dementia were estimated by age 80 and after.

Main Results:

• Between 21.8% and 44.0% of dementia cases by age 80 were attributable to vascular risk factors identified in midlife and late life.
• Attributable fractions were higher in apolipoprotein ε4 noncarriers, Black individuals, and female individuals across different age groups.
• Vascular risk factors accounted for only 2% to 8% of dementia cases occurring after age 80.

Conclusions:

• A substantial proportion of dementia cases by age 80 are linked to modifiable vascular risk factors.
• Optimizing vascular health throughout life may significantly mitigate dementia risk.
• Findings highlight the importance of lifelong vascular risk factor management for dementia prevention.