Clinical guidelines for the treatment of osteoporosis in Japan

Abstract

In Japan, unlike in the United States and Europe, where osteoporosis is synonymous with postmenopausal osteoporosis, the need for treatment of osteoporosis has been emphasized only for elderly women with established disease. This may be because women in the immediate postmenopausal period in Japan are virtually free of symptoms such as lumbago and signs such as spinal compression fracture. Osteoporosis typically does not manifest itself until about age 65; therefore, postmenopausal osteoporosis with vertebral fracture below the age of 60 is quite rare in Japan. Unique features of treatment for osteoporosis in Japan include rare use of estrogen replacement therapy, common use of vitamin D derivatives (especially lα(OH) vitamin D) without notable side effects, and use of calcitonin almost exclusively in a low-dose intermittent regimen (20 U/week). Similarly, the use of ipriflavone is common, and calcium supplementation, especially with an active absorbable algae calcium with high bioavailability (AAACa), is effective and popular. The emphasis on the use of calcium, vitamin D, and calcitonin in the treatment of osteoporosis may be explained by an extremely low dietary calcium intake in Japan. Other factors that favor reliance on the calcium-focused approach and avoidance of estrogen include a fatalistic and naturalistic view toward menopause; an uneasiness with hormone replacement therapy; an older female population who seek osteoporosis treatment because of uneventful immediate postmenopausal periods; and the efficient absorption of calcium from the intestine with favorable response to exogenous vitamin D due to a longstanding calcium deficiency and possibly a low incidence of vitamin D-receptor abnormalities.