The possibility of an etiologic role of selenoprotein P in dementia etiology would be consistent with previous evidence from the few human studies available, such as the positive association observed between high brain selenium content and features of Alzheimer’s disease in autoptic studies33, and the inverse association between the highest levels of selenoprotein P and lower levels of serum β-amyloid, a marker of increased Alzheimer’s disease risk27. This evidence concerns the gene SELENOP and Alzheimer disease.