Noel Faux, PhD, of the Mental Health Research Institute, Parkville, Australia, and colleagues examined hemoglobin, iron and other blood-based measurements in the 1,112 participants (768 healthy controls, 133 MCI, 211 Alzheimer's) of the Australian Imaging Biomarkers and Lifestyle (AIBL) study of Ageing. Participants also completed questionnaires on diet and medication intake (including supplements). Results were then correlated with measures of short-term, long-term and total memory, and global cognition.

The researchers found that people with Alzheimer's in the study had significantly lower levels of hemoglobin, mean cell hemoglobin concentration (MCHC), and packed cell volume compared with healthy controls, after adjustment for age and gender. Consistent with these data, the erythrocyte sedimentation rate (ESR) was significantly higher in Alzheimer's compared to healthy controls.

Participants with anemia in the study were found to have an increased risk of Alzheimer's (odds ratio: 2.56). And people with Alzheimer's in the study were found to have an increased risk of being anemic (odds ratio: 2.61). Self reported iron intake was not different in the two groups.

"In our population, we found that people with Alzheimer's disease were more likely to be anemic, and this was not explained by dietary iron deficiency," Faux said. "This suggests that hemoglobin production is deficient in Alzheimer's patients."

"Alzheimer's had not previously been recognized as a risk factor for anemia, which is a common clinical problem for the elderly and can contribute to problems such as heart failure and renal failure," Faux continued. "The cause of anemia in Alzheimer's is still uncertain, but we speculate that Alzheimer's is a disease that affects both brain and blood. We are currently investigating this intriguing possibility."

SOURCE Alzheimer's Association