Trends in the Incidence of Early- and Late-Onset Dementia in 2011-2019: A Nationwide Population-Based Study

Dementia is a leading cause of disability and a growing public health challenge worldwide. Monitoring incidence trends is essential for health service planning and policy development. This study examined secular trends in the incidence of early-onset (45-64 years) and late-onset (≥65 years) dementia in Israel between 2011 and 2019, with a focus on sex-specific patterns.

A nationwide, population-based study using electronic health records from all four Israeli health maintenance organizations provides universal healthcare coverage. Incident cases were identified by International Classification of Diseases (ICD-9/10) codes and/or purchases of anti-dementia medications. Age- and sex-specific incidence rates were calculated, and Joinpoint regression models were used to assess trends over time.

Over the 9-year period, dementia incidence declined significantly in both early- and late-onset groups. Mean annual incidence per 100 individuals was 0.04 for early-onset dementia overall (0.05 in men, 0.04 in women) and 1.55 for late-onset dementia (1.35 in men, 1.72 in women). Statistically significant annual percentage changes were observed across most age-groups, with the sharpest declines in those aged 65-74 (-4.0% per year) and 75-84 (-4.1% per year). Among adults aged 85+, incidence was stable from 2011 to 2015, followed by a significant decline from 2015 to 2019 (-6.6% per year). These trends were consistent across sexes.

These findings highlight important public health and community health implications, underscoring the need for continued dementia surveillance, early detection, and evidence-based policy to support healthy aging.