Rates of new dementia cases may be falling

  • Data from the very long-running Framingham Heart Study adds to evidence that, for those with at least a high school education, the rate of dementia is declining. Improved cardiovascular health and treatment appears to be an important factor in this decline.

As we all know, people are living longer and obesity is at appalling levels. For both these (completely separate!) reasons, we expect to see growing rates of dementia. A new analysis using data from the long-running Framingham Heart Study offers some hope to individuals, however.

Looking at the rate of dementia during four distinct periods in the late 1970s, late 1980s, 1990s, and 2000s, using data from 5205 older adults (60+), the researchers found that there was a progressive decline in the incidence of dementia at a given age, with an average reduction of 20% per decade since the 1970s (22%, 38%, and 44% during the second, third, and fourth epochs, respectively).

There are two important things to note about this finding:

  • the decline occurred only in people with a high school education and above
  • the decline was more pronounced with dementia caused by vascular diseases, such as stroke.

The cumulative risk over five years, adjusted for age and gender, were:

  • 3.6 per 100 persons during the first period (late 1970s and early 1980s)
  • 2.8 per 100 persons during the second period (late 1980s and early 1990s)
  • 2.2 per 100 persons during the third period (late 1990s and early 2000s)
  • 2.0 per 100 persons during the fourth period (late 2000s and early 2010s).

Part of the reason for the decline is put down to the decrease in vascular risk factors other than obesity and diabetes, and better management of cardiovascular diseases and stroke. But this doesn't completely explain the decrease. I would speculate that other reasons might include:

  • increased mental stimulation
  • improvements in lifestyle factors such as diet and exercise
  • better health care for infectious and inflammatory conditions.

The finding is not completely unexpected. Recent epidemiological studies in the U.S., Canada, England, the Netherlands, Sweden and Denmark have all suggested that “a 75- to 85-year-old has a lower risk of having Alzheimer’s today than 15 or 20 years ago.” Which actually cuts to the heart of the issue: individual risk of dementia has gone down (for those taking care of their brain and body), but because more and more people are living longer, the numbers of people with dementia are increasing.

http://www.futurity.org/dementia-rates-decline-1119512-2/

http://www.scientificamerican.com/article/is-dementia-risk-falling/

Reference: 

Related News

An Italian study has found that a significant percentage of Alzheimer’s patients suffer from Obstructive Sleep Apnea Syndrome. This respiratory disorder, which causes people to temporarily stop breathing during their sleep, affects cerebral blood flow, promoting cognitive decline.

Data from 70 older adults (average age 76) in the Baltimore Longitudinal Study of Aging has found that those who reported poorer sleep (shorter sleep duration and lower sleep quality) showed a greater buildup of amyloid-beta plaques.

A new discovery helps explain why the “Alzheimer’s gene” ApoE4 is such a risk factor.

Analyses of cerebrospinal fluid from 15 patients with Alzheimer's disease, 20 patients with mild cognitive impairment, and 21 control subjects, plus brain tissue from

Tau protein stabilizes structures that transport supplies from the center of the cell to the extremities, but sometimes some tau is not bound to these microtubules and instead clumps together into

A study involving genetically engineered fruit flies adds to our understanding of why sleep and bioclock disruptions are common in those with Alzheimer's disease.

A new study shows that a combination of inflammation and hypoxia activates microglia in a way that persistently weakens the connection between neurons,

A new function has been found for the

New research helps explain the role of amyloid-beta plaques in the development of Alzheimer's, by finding that the

Creating amyloid-beta requires the convergence of a protein called

Pages

Subscribe to Latest newsSubscribe to Latest newsSubscribe to Latest health news