Who should be treated with vitamin D?
Vitamin D supplementation is recommended for people who:
- have uncomplicated moderate or severe vitamin D deficiency (serum 25-hydroxyvitamin D concentration lower than 30 nanomol/L), particularly if symptomatic
- are starting drug therapy for osteoporosis and have a serum 25-hydroxyvitamin D concentration lower than 50 nanomol/L (see also Vitamin D and osteoporosis)
- have osteomalacia or rickets.
In patients with mild vitamin D deficiency without symptoms or complications (ie not associated with rickets, osteomalacia or hyperparathyroidism), evidence that vitamin D supplementation improves outcomes is limited and inconsistent. Lifestyle changes to improve sun exposure are usually sufficient; however, supplementation for mild deficiency is also reasonable and unlikely to cause harm.
Healthy people with a serum 25-hydroxyvitamin D concentration above 50 nanomol/L are not deficient, and there is no evidence that vitamin D supplements prevent long-term disease in these people.
The use of vitamin D to improve outcomes not related to bone or muscle health is not recommended. In a large randomised placebo-controlled study, vitamin D supplementation did not result in a lower incidence of cancer or cardiovascular events1.
If a patient is found to be vitamin D deficient, also review calcium intake and supplement if needed. See here for information on calcium intake.