Assessing vitamin D status

To characterize methods evaluating and to summarize studies linking various serum 25-hydroxyvitamin D [25(OH)D] concentrations with health status.

Elucidation of the cell-biologic mechanism of vitamin D action, and numerous clinical trials and observational studies relating vitamin D status to health and disease.

The distinction between deficiency and insufficiency is not useful or necessary. Serum 25(OH)D values below 120  nmol/l (48  ng/ml) are associated with preventable disease and are therefore indicative of deficiency. The upper limit of the normal range can be set at 225  nmol/l (90  ng/ml), although toxicity is rare below 500  nmol/l (200  ng/ml).