Short-term trends in dementia prevalence in Germany between the years 2007 and 2009.

Recent studies have been cautiously optimistic about declining trends in dementia prevalence and incidence. Newly available claims data from a German public health insurance company covering 30% of the total population permitted us to explore short-term trends based on millions of observations up to the highest ages. Diagnoses stemmed from the inpatient and outpatient services and covered both the community-dwelling population and those living in nursing homes. Data spanning more than 3 years were examined, and the examination revealed a significant yearly reduction between 1% and 2% in the prevalence of dementia among women aged 75 to 84 years. The extent of the reduction was comparable with reports from earlier studies. A similar tendency existed among men, however, statistically not significant. Trends in medical, lifestyle, and societal risk factors of dementia may have contributed to this decline.