A Connection Between Blood and the Brain?

Anemia linked to dementia in long term study

/ Author:  / Reviewed by: Robert Carlson, M.D Beth Bolt, RPh

(RxWiki News) Dementia is one of those tricky conditions that can be difficult to understand. There are likely many different factors contributing to dementia, and even something as seemingly unrelated as a blood disorder may be involved.

A recent study found that individuals with anemia may be at higher risk for dementia than those without the disorder.

Anemia is a blood disorder in which the body does not make enough red blood cells, which carry oxygen throughout the body.

A higher percentage of adults with anemia developed dementia in this long-term study than those without anemia.

"Ask your doctor about signs of dementia."

This study, led by Chang Hyung Hong, MD, PhD, of the Department of Psychiatry and Institute on Aging at Ajou University School of Medicine in South Korea, aimed to find out if anemia was related to dementia.

The researchers tracked 2,552 senior adults, with an average age of 76, for 11 years. None had dementia when the study began.

The men with a hemoglobin concentration less than 13 g/dL and the women with a concentration less than 12 g/DL were categorized as having anemia in the study, following World Health Organization criteria.

At the start of the study, 392 adults, or 15.4 percent of the group, had anemia.

The adults were regarded as having developed dementia if they began taking a dementia medication, if their hospital records included the diagnosis or if they had a significant change out of the normal range in a dementia screening tool.

By the end of the study, 455 participants, or 17.8 percent, had developed dementia.

In terms of the raw numbers, 23 percent of those with anemia had developed dementia, compared to 17 percent who did not have anemia.

Then the researchers analyzed the data taking into account differences among the adults in terms of age, sex, race/ethnicity, their dementia screening score at the start of the study, other health conditions and kidney function.

The link between anemia and dementia remained even after making these adjustments.

Even when the researchers considered other criteria for anemia besides the WHO criteria and the amount of C-reactive protein (a marker of inflammation) in their analysis, the results did not change.

"Among older adults, anemia is associated with an increased risk of developing dementia," the authors wrote.

The authors wrote that anemia therefore appears to be a risk factor for dementia, but it's not clear what mechanism is behind this connection.

"Dementia can be a devastating disease. It is important that we learn more about this condition -- what causes it, how to diagnose and treat it, and ultimately how to prevent it.  The possible association between anemia and dementia could provide some direction in several areas," Dr. Shanker Dixit, Medical Director of Mountain View Hospital and Summerlin Hospital, told dailyRx News.

"We do need to understand the association between the two conditions and if strategies like keeping a patient's hemoglobin levels up could keep some people from developing the disease. One day, it could impact how we manage patients. More research is needed to better understand what this means," Dr. Dixit said. 

Further research is needed to understand whether to address factors related to anemia in preventing dementia or whether other approaches, such as improving a person's overall health, would be better.

This study was published July 31 in the journal Neurology. The research was funded by the National Institutes of Health, the National Institute of Aging and the American Health Assistance Foundation.

One author has served on data safety monitoring boards for Takeda, Inc. and consulted for Novartis. No other disclosures were reported.

Review Date: 
July 30, 2013
Last Updated:
December 30, 2013