Incidence of epilepsy in a racially diverse, community-dwelling, elderly cohort: results from the Einstein aging study

OBJECTIVE: To determine age-specific incidence and cumulative incidence of epilepsy in a well-defined cohort of elderly people, and to examine how rates of epilepsy are modified by sex, race, stroke, dementia, head injury, and depression. METHODS: The authors examined data from a reconstructed cohort based on 1919 community-dwelling volunteers, followed as part of a large ongoing prospective aging study. RESULTS: Age-specific incidence was 10.6 (per 100,000 person-years) between ages 45 and 59, 25.8 between ages 60 and 74, and 101.1 between ages 75 and 89. Cumulative incidence was 0.15% from age 45 to age 60, 0.38% to age 70, 1.01% to age 80, and 1.47% to age 90. In addition, the difference in cumulative incidence among African-American subjects approached statistical significance (57.6/100,000 person-years versus 26.1 in Caucasian, p=0.10), and the difference in incidence among subjects reporting a history of stroke was significantly elevated (p=0.029). Incidence of epilepsy was not statistically elevated among males, those with dementia, or individuals reporting a history of head injury or treatment for depression. Among "healthy" subjects without history of stroke, head injury, or dementia, we observed a cumulative risk of epilepsy with onset after age 60 of only 1.1%. CONCLUSIONS: The incidence of epilepsy was low in this relatively healthy cohort of elderly people, especially among subjects without known risk factors. In this study we identified African-American race as a risk factor in the elderly for epilepsy independent of stroke.