Red blood cell choline. I: Choline in Alzheimer's disease

Seventeen drug-free patients with Alzheimer's disease (AD) and 15 normal elderly controls, of which 13 age- and sex-matched pairs were included, participated in a study of red blood cell (RBC) and plasma choline. Mean values for RBC choline, plasma choline, and the ratio of RBC/plasma choline did not differ between the AD and control groups. Degree of dementia did not correlate with any blood choline measure. A correlation was found between age and RBC choline (r = 0.57; p less than or equal to 0.01) and the RBC/plasma choline ratio (r = 0.56; p less than or equal to 0.03) in normals, but not in AD patients. RBC choline correlated with plasma choline in AD patients only (r = 0.46, p less than or equal to 0.03). These results do not support the use of RBC and plasma choline concentrations as either a diagnostic tool to identify AD patients or an antemortem index of the cholinergic deficit in brains of patients with Alzheimer's disease.