Anaemia, or low levels of red blood cells, may increase the risk of dementia, a new study has found.
US researchers tested 2,552 older adults between the ages of 70-79 for anaemia. The participants also underwent memory and thinking tests over 11 years.
Of those, 393 had anaemia at the start of the study. At the end of the study, 445, or about 18 per cent of participants, developed dementia.
The research found that people who had anaemia at the start of the study had a nearly 41 per cent 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.
Of the 393 people with anaemia, 89 people, or 23 per cent, developed dementia, compared to 366 of the 2,159 people who did not have anaemia, or 17 per cent.
"Anaemia is common in the elderly and occurs in up to 23 per cent of adults ages 65 and older," said study author Kristine Yaffe, with the University of California - San Francisco and a member of the American Academy of Neurology.
"The condition has also been linked in studies to an increased risk of early death," Yaffe said.
"There are several explanations for why anaemia may be linked to dementia. 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," said Yaffe.
The study was published in the journal of the American Academy of Neurology.
