Epidemiology of Frontotemporal Lobar Degeneration in Northern Finland

BACKGROUND: Frontotemporal lobar degeneration (FTLD) is responsible for as many as every fifth case of early-onset dementia. Very few epidemiological studies of FTLD have been conducted; there are no published epidemiological data of FTLD from Finland or the other Nordic countries. The C9ORF72 expansion-associated FTLD is common in Finland; thus, the prevalence of FTLD is expected to be high in this population. METHODS: We retrospectively evaluated the incidence and prevalence of FTLD in university hospital settings in Northern Finland. RESULTS: The mean 1-year incidence of FTLD was 5.54/100,000 (range 1.9-11.3/100,000) in the population aged 45-65 years. The prevalence of FTLD in the same age group was 20.5/100,000. CONCLUSION: The incidence and prevalence of FTLD in Finland seem to be the highest in Europe. However, studies from different countries may not be directly mutually comparable due to methodological issues.