The Vitamin D Debate: Conundrums and Complexities


Manson and Bassuk1 point to complexities in the vitamin D story, including lack of consensus on the definition of optimal 25-(OH)D concentrations, the distinction between “bioavailable” and “free” 25-(OH)D, difference in references ranges used by various laboratories, and the absence of conclusive trials. They note that several large-scale general-population vitamin D supplementation trials in treating cancer, CVD, or all-cause mortality are underway. In the meantime, “physicians would be well advised to follow current USPSTF and IOM recommendations and avoid overscreening and overprescribing supplemental vitamin D.”

Table 1: USPSTF Recommendations for Vitamin D Screening in Community-Dwelling, Nonpregnant, Asymptomatic adults (aged ≥18 years)

Risk Assessment


Persons with low vitamin D intake, decreased vitamin D absorption, and little or no sun exposure may be at increased risk for vitamin D deficiency. Obesity and darker skin pigmentation may be associated with low levels of serum 25-hydroxyvitamin D [25-(OH)D] but it is unclear whether low levels in these populations reflect vitamin D deficiency or are associated with adverse clinical outcomes.

Screening Tests


Testing methods to measure serum 25-(OH)D are available, but their accuracy is difficult to determine because of the lack of studies that use an internationally recognized reference standard and the lack of consensus on the laboratory values that define vitamin D deficiency.

Treatment and Interventions


Oral vitamin D is the most common treatment for vitamin D deficiency, including vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol). Other treatment options include increasing dietary vitamin D intake or sun exposure (which carries the risk of skin cancer).

Balance of Benefits and Risks


The current evidence is insufficient to assess the balance of benefits and harms of screening for vitamin D deficiency in asymptomatic adults.

Other Relevant USPSTF Recommendations


The USPSTF has recommendations regarding the use of vitamin D supplementation for the prevention of falls and fractures, and for the prevention of cardiovascular disease and cancer. These recommendations are available at the USPSTF website