Reduced gastrointestinal absorption of calcium in dementia

Several reports have suggested that the neurodegenerative change in Alzheimer-type dementia (ATD) may be related to alterations in calcium homoeostasis. The absorption of radiocalcium (45Ca) in 26 ATD subjects and 11 patients with multi-infarct dementia (MID) was compared to 24 normal age- and sex-matched controls. The absorption of radiocalcium was significantly lower in both ATD and MID when compared to controls. The reduced 45Ca absorption in ATD occurred in the presence of normal plasma concentrations of PTH and vitamin D metabolites and the serum concentrations of calcium and aluminium were in the normal range. The data suggest that the reduced uptake of radioactive calcium observed in ATD is a non-specific derangement.