Is Dementia on the Rise? Maybe Not.
You may have seen fear inducing headlines such as:
CBS News: Dementia cases worldwide to triple by 2050
The Guardian: Middle-age obesity will lead to a surge in dementia case
BBC New: Experts Predict Dementia Epidemic
While it is true that the overall number of dementia cases will increase in the United States and elsewhere in the coming years, that isn’t the whole story. The headline you don’t often see is that the proportion of older adults with dementia is actually decreasing. We need to define a couple of terms epidemiologists, people who study disease and health in populations, use to describe health trends in the population.
1. Prevalence – proportion of the population with a particular condition
2. Incidence – the number of cases in a given time period
For example, the incidence of people wearing cowboy hats in Los Angeles, CA is far higher than it is in Bandera, TX. While Bandera, TX has been called the Cowboy Capital of the World there are only 856 people who call it home whereas Los Angeles, CA has almost 4 million people. Even in only 1 in 30,000 people where a cowboy that they will have a higher incidence, even though the proportion of people wearing cowboy hats is much lower in LA.
For example, say you want to learn something new (e.g. the list of presidents or how to play a new song on the guitar) – think of that skill as a destination (e.g. Boston). Once you’ve learned that skill, you’ve built a neural pathway to Boston. Keep doing it, and you’ve soon created a better, faster freeway to get there. However, stop using that road, and eventually potholes develop, and you won’t be able to get there as fast, or at all. In other words …
While it is true that the incidence or the number of new cases of dementia is increasing because we now have more older adults and people are living longer. For example, in the past decade the number of people with dementia in the United States has increased by over 1 million, and that sounds kind of scary. But the prevalence or the proportion of the population in the United States and Western Europe has actually decreased! A 2013 study published in the journal Lancet reported that the percentage of people 65 and older with dementia has plummeted 25% in the past 20 years from 8.3% to 6.2%. Similar results have been measured in the United States.
Why is the prevalence or proportion of people with dementia gone down so much? We don’t know for sure but it could be a combination of lifestyle changes and medical advances.
- Controlling cardiovascular risk factors
- Cholesterol screening and drugs
- Blood pressure
- Better education and possibly more cognitive stimulation
- Greater awareness of the importance of physical exercise
- Greater awareness of the importance of good nutrition, omega 3 fatty acids, and diet
It appears that the increased awareness of how lifestyle affects our health might already be affecting dementia rates, but we still have a long way to go. We could further reduce dementia and delay the onset of it by doing the things that we know can maximize memory ability. We haven’t discovered a magic drug to prevent dementia yet, but we are making progressing finding some of the controllable factors that matter.
By Dr. Rob Winningham
Dr. Rob Winningham is a Professor of Psychology and Gerontology at Western Oregon University. For the past 20 years he has researched human memory and ways to enhance cognitive abilities. His brain stimulation activities are used by thousands of retirement communities and have been shown to improve memory ability.