抄録
Vitamin D plays an important role in regulation of calcium homeostasis and bone metabolism. Among vitamin D metabolites, serum 25-hydroxyvitamin D (25-D) concentration is a best indicator to assess the vitamin D status. It is known that a mild decrease of serum 25-D concentration (vitamin D insufficiency) leads to secondary hyperparathyroidism, which has a negative effect on bone metabolism in the elderly. Therefore, vitamin D insufficiency is thought to be one of the risk factors of osteoporosis. Vitamin D insufficiency is commonly observed in the world. In Japan, we have also confirmed that around half of elderly women were in vitamin D insufficient. Recently, several meta-analysis about vitamin D supplementation to prevent fracture and bone loss in elderly people have been reported. In the present review, current epidemiological studies about vitamin D status and prevention of osteoporosis, and requirement of vitamin D to prevent osteoporosis would be discussed.
