Dementia trends in England and Wales

Because the most prominent risk factor for dementia is aging, the urgent need to address the public health challenges of dementia is heightened by the “greying” of societies worldwide. In 2015, nearly 47 million people around the world had dementia. If age and sex specific prevalence of dementia stays constant over time, there will be 130 million cases by 2050.1

And yet changes over time in both dementia incidence (the rate at which new cases arise in a population over a specified period, among people at risk) and duration (time from the overt clinical onset to death) are plausible, so dementia prevalence, which is the product of incidence and average duration, could remain stable, decrease, or increase accordingly. In a linked paper, Ahmadi-Abhari and colleagues (doi:10.1136/bmj.j2856) develop a Markov model to estimate the direction and magnitude of these and other trends to 2040 in England and Wales.2

Trends in prevalence3 and incidence of dementia4 have been previously reported in the Medical Research Council’s Cognitive Function and Ageing Study (CFAS), …