Characteristics of Early-Onset Dementia in Chiba Prefecture, Japan: A Multicenter Survey

Early-onset dementia (EOD), defined as dementia onset before the age of 65 years, is relatively rare, but its social impacts are significant. This study aimed to characterize the diagnosis and clinical and social status of EOD subjects in the 11 dementia centers in Chiba Prefecture, Japan.

A retrospective 1-year survey was conducted. Collected data included clinical diagnosis, age at onset, age at survey, neuropsychological test, family history, employment, and living status.

We identified 208 EOD subjects, including 123 (59.4%), 24 (11.6%), 21 (10.1%), 17 (8.2%), and 10 (4.8%) with Alzheimer's disease (AD), vascular dementia, frontotemporal lobar degeneration (FTLD), dementia with Lewy bodies/Parkinson's disease dementia, and alcohol-related dementia, respectively. The Mini-Mental State Examination (MMSE) score <24 was observed in 50-75% of patients and was not correlated with disease duration. Twenty-four (16.4%) subjects had positive family history of EOD. EOD subjects were at risk of early retirement, and 133 subjects lived with their family, in whom 64 (30.8%) lived with their child.

In dementia centers, AD, FTLD, and Lewy body dementia had relatively large proportion. Employment, economy, and social supports are urgently needed for EOD subjects and their family.