Evaluating vitamin D status. Implications for preventing and managing osteoporosis and other chronic diseases.

Recent studies have added new dimensions to the fund of knowledge on vitamin D. In addition to the classic role of vitamin D in preventing rickets and osteomalacia, a preventive effect against osteoporotic fractures has been convincingly established, and abundant evidence suggests a role in preventing malignancies and autoimmune diseases. Serum 25-OH-vitamin D assay is a simple test for evaluating vitamin D status. However, recent review articles indicate that current reference ranges for serum 25-OH-vitamin D are too low. An appropriate lower normal limit may be between 50-100 nmol/l (20-40 ng/ml). Standard supplement dosages may fail to provide concentrations above this range.