Calcium, vitamin D and involutional osteoporosis

Abstract

Previous studies suggest that combined calcium and vitamin D supplementation decreases the risk of fractures in older people, particularly those living in care homes, but trials of vitamin D alone in fracture prevention have generated inconsistent results. This review examines the physiological functions of calcium and vitamin D, and the contrasting views of what constitutes an adequate dietary calcium intake and vitamin D sufficiency in adults, and highlights the results of recent large studies of calcium and vitamin D supplementation. The RECORD study shows that calcium (1000 mg/day) and vitamin D (800 IU/day), either alone or in combination, are ineffective in the secondary prevention of osteoporotic fractures in older men and women living in the community. The Northern and Yorkshire Study also suggests that calcium (1000 mg/day) and vitamin D (800 IU/day) are of no benefit in the primary prevention of fractures in community-dwelling older women. Furthermore, the Wessex study demonstrated no reduction in fractures in older people living in the community treated with annual IM injections of vitamin D (300 000 IU). The latest studies highlight that vitamin D, either alone or in combination with calcium supplementation, is ineffective in the primary or secondary prevention of fractures in community-dwelling older people. In contrast, calcium and vitamin D supplementation prevents fractures in institutionalized elderly people, who commonly have vitamin D deficiency and secondary hyperparathyroidism.