[Epidemiology of neurocognitive disorders in France]

Neurocognitive disorders are common: every year, any physician or health professional comes into contact with patients or relatives with early symptoms of dementia. Nevertheless, their epidemiology remains difficult to estimate, due to real differences in risk factors within a country or region (average age, genetics, level of education, socio-economic level, etc.), differences in data collection, in the interpretation of these data with regard to scientific findings and changes in diagnostic criteria. In this review, we present a state of knowledge of the epidemiology of dementia in France. Epidemiological data on neurocognitive disorders in France come mainly from 3 sources: two prospective cohorts (PAQUID and 3C) and large databases (SNIIRAM, RSI data, PMSI). Neurocognitive disorders are estimated to directly affect more than 1.2 million people in France and about 2 out of 3 cases are attributed to Alzheimer's disease. The prevalence rate is estimated at about 40/1,000 people after 60 years of age and gradually increases to 180/1,000 after 75 years of age, reaching almost one in two people after 90 years of age. The incidence rate is estimated at between 13 and 19/1,000 person-years, and seems to decrease slightly over the decades. The PAQUID and 3C cohorts are coming to an end; despite the development of large databases (SNIIRAM, PMSI, etc.), it seems necessary to continue to set up new prospective cohorts in the general population to monitor the epidemiology of neurocognitive disorders in France.