The number of people over the age of 65 who will be living with dementia is expected to double by 2030, and more than triple by 2050. The debilitating syndrome, which robs older people of memories, language, and cognitive ability, is thus predicted to become more and more of a public health problem as global populations grow and life expectancy continues to increase. But a recent study based on long-term data sets has found something surprising: the rate of dementia seems to have been declining, at least for some.
This intriguing and unexpected find concerns the set of people who have been part of the long-running Framingham Heart Study. The study began in 1948, when over 5,000 men and women from Framingham, Massachusetts, were asked to participate in an ongoing cardiovascular study. Expected to last 20 years, the study is now onto its third generation of people, and has been providing an incredible insight into public health for almost 70 years. Some of the biggest findings to come out of it have been the link between smoking and heart disease, as well as elevated blood pressure and an increased risk of stroke.
But from 1975, those involved in the study were also asked to do tests on cognitive function. Looking back on this data, the researchers have found that the rate of dementia has, for some as yet unknown reason, been declining at a rate of 20 percent per decade from the 1970s. This is as astonishing as it sounds, but how does this new data square with the projected increase of those with the syndrome to 135.5 million people globally by 2050?
Well, as the baby boomers reach the age of 65, the worldwide rate of dementia is expected to skyrocket, and put simply, the drop seen in the study will do little to mitigate this overall trend. But the findings do suggest something else: a potential that could be expanded upon with further study. “Currently, there are no effective treatments to prevent or cure dementia; however, our study offers hope that some of the dementia cases might be preventable – or at least delayed,” says Sudha Seshadri, who led the study published in The New England Journal of Medicine. “Effective prevention could diminish in some measure the projected explosion in the number of persons affected with the disease in the next few decades.”
While the outcomes of this study are fascinating, the researchers note that it is not representative. The participants come from a predominantly white area of European decent, and so it can’t be used to make broader more generalized conclusions about other communities, especially those from differing racial groups. It might not just be ethnicity that impacts the development of dementia either, as curiously the data only showed a decline in the syndrome for those educated to at least a high school level.
Either way, it seems that while the effects of dementia may not be reversible, the devastating condition could potentially be slowed or even stopped in its tracks. One trial that has been met with muted optimism is that of the drug solanezumab, which in experiments last year seem to have shown a cut in dementia's progression by around a third.