August 1, 2013
Anemia Increases Dementia Risk In Elderly
Brett Smith for redOrbit.com - Your Universe Online
A new American study published in the journal Neurology has found that anemia, a potentially dangerous condition marked by a low red blood cell count and fatigue, can lead to an increased risk of dementia.
In the study, scientists from several US institutions followed over 2,500 adults in their 70s for eleven years and found that those who were diagnosed with anemia at the start of the study had a 65 percent higher chance of developing dementia by the end.
"Anemia is common in the elderly and occurs in up to 23 percent of adults ages 65 and older," said study author Dr. Kristine Yaffe, a psychiatrist at the University of California, San Francisco. "The condition has also been linked in studies to an increased risk of early death."
Previous research has tentatively linked anemia and dementia, but the latest study is the first to effectively track anemia patients over time to see if they developed dementia, Yaffe told Reuters Health.
Study participants were tested for anemia at the start of the study and were given cognitive tests over the study's duration. Almost one-quarter of the approximately 400 people with anemia at the study's beginning developed dementia, as opposed to 17 percent of the 2,000 who were not anemic, making those with anemia 41 percent more likely to develop the cognitive disorder.
"I think doctors should be aware of this important connection especially as both anemia and dementia are common with aging," Yaffe said.
The researchers pointed out that their study did not establish a cause-and-effect relationship, only a potential association. Yaffe noted that an association makes sense because fewer red blood cells could mean less oxygen traveling to the brain.
"There are several explanations for why anemia may be linked to dementia," said Yaffe. "For example, anemia may be a marker for poor health in general, or low oxygen levels resulting from anemia may play a role in the connection. Reductions in oxygen to the brain have been shown to reduce memory and thinking abilities and may contribute to damage to neurons."
The California psychiatrist said a condition like chronic kidney disease could also cause both conditions and the study authors tried to consider that when reaching their findings.
Dr. Ruth Peters, a dementia expert at Imperial College London who was not involved in the study, told Reuters that while the findings do not establish a causal relationship, they do paint a more complete picture of the cognitive disorder.
"There are many risk factors that are associated with dementia and these kinds of studies are very useful in identifying and clarifying these," she said. "Each individual will have their own mosaic of risk factors."
In addition to kidney disease, anemia can also result from poor nutrition, bleeding disorders or cancer. To combat the disease, doctors often check their older patients for low iron levels and recommend an iron-rich diet to those who are at risk.
Yaffe recommended that future research should look into determining whether treating anemia also improves cognition.