[Abnormality of bone mineral metabolism in elderly female patients with dementia]

In order to clarify the relationship between dementia and osteoporosis, bone mineral metabolism was studied in elderly female patients with dementia. We measured bone mineral densities of the vertebral body and the femoral neck using DEXA, and evaluated Ca-related factors in 22 patients with dementia of the Alzheimer type (DAT), 23 patients with vascular dementia (VD), and 22 age-matched controls (C). Activity of daily living was significantly poorer in VD patients than controls, but no difference was shown between DAT and C groups. Bone mineral density values of the vertebral body and the femoral neck were significantly decreased in both DAT and VD groups when compared to C group. DAT patients showed significant decreases in serum Ca and Ca2+ ion, increase in serum parathyroid hormone, and decrease in serum 1,25-dihydroxyvitamin D, a tendency towards decrease in serum calcitonin, and a tendency towards increase in urinary Ca. However, VD patients showed only significant increase in urinary Ca and a tendency towards decrease in serum 1,2-dihydroxyvitamin D, without showing other changes of Ca-regulating hormones. These results suggest that patients with dementia are more often associated with osteoporosis, and that in DAT several abnormalities of Ca-regulating factors play an important role in the development of osteoporosis, while in VD limited physical activities contribute to bone mineral loss.