Introduction: Due to the current aging of the population, dementia represents a major societal concern. Recently, downward trends in the incidence of dementia have been observed in several European countries and in the United States. This decline may be attributed to higher levels of education, improved management of vascular risk factors, and healthier lifestyles. Methods: This article reviews trends in dementia based on the literature. Findings on trends observed in France, as well as the factors involved in these trends, are presented. Results: The majority of published studies point to a downward trend, but this trend is not found in all studies and is not always statistically significant. However, many previous studies have encountered methodological challenges in examining trends in dementia. In France, a decline in the incidence of dementia, measured at 10-year intervals, is observed for women only. Discussion: These optimistic results should not obscure the fact that, even if this decline in incidence is confirmed, the number of people affected by dementia is expected to continue to rise in the coming years due to population aging. Understanding trends will enable us to better predict the future number of people with dementia in order to plan for care needs. Furthermore, identifying the factors driving this decline is essential for developing prevention strategies.