Older adults with anemia face increased dementia risk

• Anemia is a blood disorder affecting nearly a quarter of adults over 65
• Study underscores importance of warding off dementia with exercise and healthy eating
• Disorder is often treatable with supplements and change in diet

A large percentage of people over 65 have anemia, and new research suggests that the blood disorder may make them more vulnerable to dementia as they age.

The study, from the University of California-San Francisco, found that people who were anemic at the start of the 11-year study period ran a 40% higher risk of developing dementia than those without it.

Anemia, which may affect nearly a quarter of people over 65, occurs when their red blood cell count drops, or when red blood cells don't contain enough hemoglobin — the protein that carries oxygen and gives the cells their distinctive color.

Though previous research has suggested a link between anemia and problems on thinking tests, this is the first to find a long-term connection with dementia.

"These two common, age-related conditions seem to be connected in a way we had not appreciated," said Kristine Yaffe, a professor of psychiatry, neurology and epidemiology at UCSF, who led the study.

Anemia can be caused by iron deficiencies, unseen internal bleeding, diseases, or as a side effect of medications, and is known to cause heart problems. It is generally treatable, often with inexpensive supplements and a change in diet.

It makes sense that depriving the brain of oxygen would cause memory and other problems, said Rachel Whitmer, senior scientist at Kaiser Permanente Division of Research in Oakland.

"If this is happening in a chronic state, it could be that you're having this small hit to the brain over time, which can set you up to be more susceptible" to dementia, she said. This study suggests that anemia comes before dementia, but some dementias, like Alzheimer's, can take years to develop, so it's still not clear which comes first, the anemia or the dementia, Whitmer said.

Although it is not yet clear whether treating the anemia would reduce the risk of dementia, both Whitmer and Yaffe said they are hopeful it would.

Both said doctors should aggressively test for and treat anemia, for heart as well as brain health.

The link with anemia adds to a growing list of things people can do to help reduce their risk of dementia as they age, such as exercising, eating healthy plant-based diets, sleeping well, and keeping their brains active.

"We have a substantial body of evidence that there are a number of things we can do that we probably should be doing anyway for heart health, but are really important for brain health," Yaffe said.