Anemia Associated with Mild Cognitive Impairment

A European study has found a link between anemia (deficiency in hemoglobin or red blood cells) and mild cognitive impairment, which is often a precursor to Alzheimer’s disease.

The findings are meaningful as anemia is often treatable, a practice that the research suggests could prevent or slow cases of cognitive decline.

The large population health study found that in a group of randomly selected participants in Germany, participants with anemia showed lower performances in verbal memory and executive functions. Moreover, researchers discovered mild cognitive impairment (MCI) occurred almost twice more often in participants diagnosed with anemia.

For the study, anemia was defined as defined as hemoglobin <13 g/dl in men and <12 g/dl in women.

Study results appear in the Journal of Alzheimer’s Disease.

Deficits in mental acuity often occur over time, beginning with mild cognitive impairments then culminating in dementia. In the current study, researchers focused on early stages of cognitive impairment as MCI represents an intermediate and possibly modifiable stage between normal cognitive aging and dementia.

Although persons with MCI have an increased risk of developing dementia or Alzheimer’s disease (AD), they can also remain stable for many years or even revert to a cognitively normal state over time. This modifiable characteristic makes the concept of MCI a promising target in the prevention of dementia.

Investigators used four criteria to diagnose MCI:

  1. participants have to report a decline in cognitive performance over the past two years;
  2. participants have to show a cognitive impairment in objective cognitive tasks that is greater than one would expect taking their age and education into consideration;
  3. this impairment is not as pronounced as in demented individuals since persons with MCI can perform normal daily living activities or are only slightly impaired in carrying out complex instrumental functions;
  4. cognitive impairment is insufficient to fulfill criteria for dementia.

The concept of MCI distinguishes between amnestic MCI (aMCI) and non-amnestic MCI (naMCI). In the former, impairment in the memory domain is evident, most likely reflecting Alzheimer’s disease pathology. In the latter, impairment in non-memory domains is present, mainly reflecting vascular pathology but also frontotemporal dementia or dementia with Lewy bodies.

Data was reviewed from the Heinz Nixdorf Recall (Risk Factors, Evaluation of Coronary Calcium and Lifestyle) study, an observational, population-based, prospective study that examined 4,814 participants (50 percent men) between 2000 and 2003 in the metropolitan Ruhr Area.

After five years, a second examination was conducted with 92 percent of the participants taking part. The publication reports cross-sectional results of the second examination.

The investigators first reviewed 163 participants with anemia and 3,870 participants without anemia were included to compare the performance in all cognitive subtests. Interestingly, anemic participants showed more pronounced cardiovascular risk profiles and lower cognitive performance in all administered cognitive subtests.

After adjusting for age, anemic participants showed a significantly lower performance specifically in the immediate recall task and the verbal fluency task.

The second part of the study included 579 participants diagnosed with MCI (299 participants with aMCI and 280 with naMCI) and 1,438 cognitively normal participants. The subsets were included to compare the frequency of MCI and MCI subtype diagnosis in anemic and non-anemic participants.

Investigators discovered MCI occurred almost twice more often in anemic than in non-anemic participants. Similar results were found for MCI subtypes, indicating that low hemoglobin level may contribute to cognitive impairment via different pathways.

Researchers believe the results suggest that anemia is associated with an increased risk of MCI even in the absence of traditional cardiovascular risk factors.

Experts believe the discovery of the association is important as anemia can be effectively treated, potentially preventing or delaying cognitive decline.

Source: IOS Press