Using a microsimulation algorithm that accounts for the effect on mortality, a team from Marseille, France, has shown that interventions targeting the three main vascular risk factors for dementia – hypertension, diabetes, and physical inactivity – could significantly reduce the burden of dementia by 2040.
Although these modeling results could appear too optimistic, since total disappearance of the risk factors was assumed, the authors say the results do show that targeted interventions for these factors could be effective in reducing the future burden of dementia.
Increasing prevalence
According to the World Alzheimer Report 2018, 50 million people around the world were living with dementia; a population roughly around the size of South Korea or Spain. That community is likely to rise to about 152 million people by 2050, which is similar to the size of Russia or Bangladesh, the result of an aging population.
Among modifiable risk factors, many studies support a deleterious effect of hypertension, diabetes, and physical inactivity on the risk of dementia. However, since the distribution of these risk factors could have a direct impact on mortality, reducing it should increase life expectancy and the number of cases of dementia.
The team, headed by Hélène Jacqmin-Gadda, PhD, research director at the University of Bordeaux (France), has developed a microsimulation model capable of predicting the burden of dementia while accounting for the impact on mortality. The team used this approach to assess the impact of interventions targeting these three main risk factors on the burden of dementia in France by 2040.
Removing risk factors
The researchers estimated the incidence of dementia for men and women using data from the 2020 PAQUID cohort, and these data were combined with the projections forecast by the French National Institute of Statistics and Economic Studies to account for mortality with and without dementia.
Without intervention, the prevalence rate of dementia in 2040 would be 9.6% among men and 14% among women older than 65 years.
These figures would decrease to 6.4% (−33%) and 10.4% (−26%), respectively, under the intervention scenario whereby the three modifiable vascular risk factors (hypertension, diabetes, and physical inactivity) would be removed simultaneously beginning in 2020. The prevalence rates are significantly reduced for men and women from age 75 years. In this scenario, life expectancy without dementia would increase by 3.4 years in men and 2.6 years in women, the result of men being more exposed to these three risk factors.
Other scenarios have estimated dementia prevalence with the disappearance of just one of these risk factors. For example, the disappearance of hypertension alone from 2020 could decrease dementia prevalence by 21% in men and 16% in women (because this risk factor is less common in women than in men) by 2040. This reduction would be associated with a decrease in the lifelong probability of dementia among men and women and a gain in life expectancy without dementia of 2 years in men and 1.4 years in women.
Among the three factors, hypertension has the largest impact on dementia burden in the French population, since this is, by far, the most prevalent (69% in men and 49% in women), while intervention targeting only diabetes or physical inactivity would lead to a reduction in dementia prevalence of only 4%-7%.
The authors reported no conflicts of interest.
This article was translated from Univadis France. A version appeared on Medscape.com.