Multicenter population-based study on the prevalence of early onset dementia in Japan: vascular dementia as its prominent cause.

AIM: In Japan, the government and media have become aware of the issues of early onset dementia (EOD), but policies for EOD have not yet been established and support systems are inadequate. To provide practical data about EOD, a two-step postal survey was performed. METHODS: A questionnaire requesting information on EOD cases was sent to target institutions in five catchment areas in Japan. According to the answers from the institutions, we estimated the prevalence of EOD using census data and determined the illnesses causing EOD. As a quality control study, the authors reviewed every diagnosis in a quarter of the reported cases using the medical and psychiatric records and neuroimaging data. This study was conducted from 2006 to 2007. RESULTS: Information from 2469 patients was collected from 12,747 institutions, and 2059 subjects with EOD were identified. The estimated prevalence of EOD was 47.6 per 100,000 (95% confidence interval, 47.1-48.1) for all of Japan. Of the illnesses causing EOD, vascular dementia (VaD) was the most frequent (39.8%), followed by Alzheimer's disease. CONCLUSIONS: The prevalence of EOD in Japan appeared to be similar to that in Western countries. However, unlike previously reported international experience, VaD was the most frequent cause of EOD in all catchment areas in Japan.

Cerebrospinal fluid levels of phosphorylated tau and Aß1-38/Aß1-40/Aß1-42 in Alzheimer's disease with PS1 mutations.

We studied seven cases of Alzheimer's disease (AD). Six of the patients had presenilin 1 (PS1) mutations (PS1AD). Three novel PS1 mutations (T99A, H131R and L219R) and three other missense mutations (M233L, H163R and V272A) were found in the PS1AD group. We measured the levels of phosphorylated tau (ptau-181, ptau-199) and Aß (Aß1-42, Aß1-40 and Aß1-38) in the cerebrospinal fluid (CSF) of PS1AD patients, early-onset sporadic AD (EOSAD), late-onset sporadic AD (LOSAD) and non-demented subjects (ND). The CSF levels of Aß1-42 in the three AD groups were significantly lower than those of the ND group (p < 0.0001). CSF levels of Aß1-42 in the PS1AD group were significantly lower than those in the two sporadic AD groups. The Aß1-40 and Aß1-38 levels in the CSF of the PS1AD group were significantly lower than those of the three other groups (p < 0.0001, respectively). The levels of Aß1-40, Aß1-38 and Aß1-42 in the CSF of the PS1AD group remained lower than those of the ND group for 4 years. Not only CSF Aß1-42, but also Aß1-40 and Aß1-38 decreased in the advanced stages of PS1AD.