Trace element analysis of hairs in patients with dementia

The trace elements of scalp hair samples from ≥60-year-old dementia patients and normal persons have been studied by X-ray absorption near-edge spectroscopy (XANES) in fluorescent mode and wavelength-dispersive X-ray fluorescence spectrometry. Comparisons of hair trace element levels of age-matched dementia patients and normal persons revealed significantly elevated amounts of calcium, chlorine and phosphorus in dementia patients relative to normal persons. The results of XANES measurements identify the chemical forms of deposited calcium and phosphorus in the hair samples of both dementia patients and normal persons to be calcium chloride (CaCl₂) and phosphate (PO₄³⁻), respectively. The amount of sulfur in hairs of dementia patients was found to be not significantly different from that in normal persons. The sulfur K-edge XANES spectra, however, show significantly higher accumulations of sulfur in the sulfate (SO₄²⁻) form in hairs of Alzheimer's disease and Parkinson's disease dementia patients. This study presents the possible roles of calcium, chlorine, phosphorus and sulfur in the etiology of dementia in elderly patients.