Diabetes and high blood pressure in midlife linked to an increased risk of dementia

A new long term American study suggests that middle aged people who have vascular health risk factors, including diabetes, high blood pressure and those who smoke have a much greater chance of developing dementia.

The 25 year study published in JAMA Neurology, included 15,744 people.  The participants aged between 45-64 had medical tests during their initial examinations.  Over the next 25 years they were examined 4 more times.  The researchers found the chances of developing dementia increased most strongly by age followed by the presence of a gene associated with Alzheimer's disease APOE4.  As with previous studies, an analysis of vascular risk factors showed those with high blood pressure and diabetes had a higher chance of developing dementia.  Diabetes was almost as strong a predictor of dementia as the presence of the APOE4 gene.

For the first time researchers identified a link between dementia and pre hypertension (a condition in which blood pressure levels are higher than in the normal range but lower than hypertension levels.). Researchers looked at race and education and found that smoking increased the risk for white people but not for black people.  Both white people and black people who did not graduate school had a higher chance of dementia, white people with one copy of the APOE4 gene had a greater chance of developing dementia than black people.  Overall black people had a higher chance of developing dementia than white people. 

The researchers now plan to investigate ways in which vascular problems influence the brain and why race is associated with dementia. 

NOTE:  The study was funded by The National Institutes of Health, National Institute of Neurological Disorders and Stroke, supported by the National Institute on Aging.