Anaemia, or low levels of red blood cells, may increase the risk of dementia in elderly people, a US study has said.

"Anaemia is common in the elderly and occurs in up to 23 percent of adults aged 65 and older," Xinhua quoted study author Kristine Yaffe of the University of California San Francisco as saying.

"The condition has also been linked in studies to an increased risk of early death."

In the study, researchers examined 2,552 older adults between the ages of 70 and 79 for over 11 years.

Of those, 393 had anaemia at the start of the study. At the end of the study, 445, or about 18 percent of participants, developed dementia.

The study found that people who had anaemia at the start of the study had a nearly 41 percent higher risk of developing dementia than those who were not anaemic.

The link remained after considering other factors, such as age, race, sex and education, according to the study published in the US journal Neurology.

Of the 393 people with anaemia, 89 people (or 23 percent) developed dementia, compared to 366 of the 2,159 people (or 17 percent) who did not have anaemia, the study said.

"There are several explanations for why anaemia may be linked to dementia," Yaffe said.
"For example, anaemia may be a marker for poor health in general, or low oxygen levels resulting from anaemia 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."