um-related factors were compared in 60 elderly female subjects, who were classified into three groups as nondementia group (n = 18), groups of senile dementia of Alzheimer type (SDAT, n = 22) and of vascular type (VTD, n = 20). The group of SDAT showed significant decrease in serum calcium, and increases in serum parathyroid hormone and urinary Ca, and tendency of decrease in serum 1,25-dihydroxyvitamin D, compared to those of the nondementia group. However, the group of VTD, without showing these features, showed a tendency towards decreased serum calcitonin. These results suggest that Ca and Ca-regulating hormones may play several important and different roles in senile dementia.