Is Dementia Actually on the Decline?

Dementia rates were thought to be on the rise but new research suggests things are not getting worse

/ Author:  / Reviewed by: Robert Carlson, M.D

(RxWiki News) The medical world is abuzz with data to come out of a longitudinal study about the prevalence of dementia. It may be possible that advances in blood pressure and cholesterol medications are keeping the brain safer.

Researchers aren’t saying that dementia rates are dropping significantly, but the lack of increasing rates is encouraging. Better health practices and brain health seem to coincide with positive results.

"Overall good health contributes to lowering chances for dementia."

Dr. E.M.C. Schrijvers MD., from the Department of Epidemiology and Neurology at the Erasmus MC University Medical Center, Rotterdam, the Netherlands, lead a team for a longitudinal study about whether the rates of dementia have changed over the last 20 years.

The Rotterdam study is gaining attention in the press for claiming dementia numbers are not on the rise like the medical community had thought. While the length and size of this study are good for reliable data, the geographic limitation is notable.

This study was constructed with data from Rotterdam only, which means that the numbers do no reflect environmental international dementia rates.

Dr. Schrijvers team took two separate groups of dementia free 60-69 year olds: 5,727 from the year 1990 and 1,769 from 2000. Following these participants for up to five years each.

The 1990 group resulted in 286 cases of dementia, and the 2000 group provided 49 cases. That’s .0499 percent and .0276 percent respectively.

Based on the percentage rates the group from 2000 had fewer cases of dementia than the group from 1990. When other health factors like hypertension and obesity were taken into account, those rates were lower in the 2000 group as well.

The advancement of better and more common use of blood pressure and cholesterol lowering pharmaceuticals over the course of those 10 years very likely affected those numbers according to the study.

The group from 2000 also had larger total brain volumes, and in the females: less cerebral small vessel disease than the 1990 group.

Due to the evidence, authors concluded: “Although the differences in dementia incidence were non-significant, our study suggests that dementia incidence has decreased between 1990-2005.

This study was published in the journal for the American Academy of Neurology, Neurology, May 2012. Funding for the research was provided by the Erasmus Medical Center and Erasmus University Rotterdam, the Netherlands Organization for Scientific Research (NWO), the Netherlands Organization for Health Research and Development (ZonMw),

The Research Institute for Diseases in the Elderly (RIDE), the Ministry of Education, Culture and Science, the Ministry of Health, Welfare and Sports, the European Commission (DG XII), the Municipality of Rotterdam, and a grant from the Netherlands Heart Foundation. No conflicts of interest were found.

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Review Date: 
May 10, 2012
Last Updated:
July 5, 2012