Hemoglobin, Anemia, and Cognitive Function: The Atherosclerosis Risk in Communities Study

Area of Science:

• Neurology
• Hematology
• Epidemiology

Background:

• Anemia, characterized by low hemoglobin, affects cognitive function.
• Hemoglobin levels can be low, normal, or high, and anemia can be normocytic, microcytic, or macrocytic.
• Cognitive function encompasses various domains, including memory, processing speed, and verbal fluency.

Purpose of the Study:

• To investigate the relationship between hemoglobin concentrations and cognitive function.
• To examine how different types of anemia (normocytic, microcytic, macrocytic) relate to cognition.
• To assess cognitive changes over time in relation to hemoglobin levels and anemia.

Main Methods:

• Analysis of 13,133 participants from the Atherosclerosis Risk in Communities (ARIC) study.
• Cross-sectional and prospective analyses over a median of 6 years.
• Cognitive assessments included delayed word recall, digit symbol substitution, word fluency tests, and a global Z-score.

Main Results:

• Anemia was associated with lower scores on digit symbol substitution test and global Z-score cross-sectionally.
• Anemia subtypes showed similar associations with cognitive function.
• No significant association was found between anemia and cognitive change over time.

Conclusions:

• A cross-sectional, nonlinear association exists between hemoglobin and cognition, primarily driven by low hemoglobin levels (anemia).
• Anemia subtypes demonstrated comparable associations with cognitive function.
• Anemia was not prospectively associated with cognitive decline.