Without symptoms, you should not be screened for vitamin D deficiency!

The U.S. Preventive Services Task Force (USPSTF) issued a statement stating that there is currently insufficient evidence to assess the benefits and harms of screening asymptomatic adults for vitamin D deficiency.

The statement emphasized that vitamin D requirements may vary from individual to individual, and there is currently no serum vitamin D level cutoff point that defines vitamin D deficiency, nor is it clear what serum vitamin D level represents optimal status or no deficiency.

While there is insufficient evidence to support screening for vitamin D deficiency, the statement also notes that several factors are associated with lower vitamin D levels: low dietary vitamin D intake, little or no UV exposure (for example, due to winter, high altitude, or avoidance of sunlight) and older age, obesity, and ethnicity.

The statement pointed out that a large part of the variation in 25(OH)D levels between individuals cannot be explained by the above risk factors, which only account for 20% to 30% of the variation in 25(OH)D levels.

Vitamin D deficiency is usually treated with oral vitamin D. There are two common forms of vitamin D: vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol). Both are available as prescription medications or over-the-counter dietary supplements.

The statement noted that clinicians would be better off focusing on diet and supplements for those considered at risk.

The accompanying editorial also suggests that rather than raising the issue of screening for vitamin D deficiency in the general population, the focus should be on ensuring that everyone consumes the daily vitamin D intake recommended by the guidelines.

The USPSTF's updated recommendations are based on a systematic review of the benefits and harms of screening and early treatment for vitamin D deficiency in the primary care setting for asymptomatic, community-dwelling, nonpregnant adults 18 years of age or older who have no signs or symptoms of vitamin D deficiency.

The statement noted that in clinical practice, screening for vitamin D deficiency would add some unnecessary burden.

The prevalence of vitamin D deficiency varies depending on the definition of deficiency.

In some observational studies, lower vitamin D levels have been associated with increased risk of fractures, falls, functional limitations, certain types of cancer, diabetes, cardiovascular disease, depression, and death. However, these associations have been inconsistent.

This inconsistency may be because different studies use different cutoffs to define low vitamin D levels or because vitamin D requirements and the optimal cutoffs to define low vitamin D levels or vitamin D deficiency may vary among individuals or subpopulations. In addition, it is unclear whether these associations are causal.

A variety of analytical methods are available to measure 25(OH)D levels; however, accurate measurement is difficult and these analytical methods may underestimate or overestimate 25(OH)D levels.

Furthermore, current evidence is insufficient to determine whether screening and treating asymptomatic low 25(OH)D levels improves relevant clinical outcomes.

Furthermore, screening for vitamin D deficiency may misclassify patients with vitamin D deficiency, leading to overdiagnosis or underdiagnosis.

Moreover, excessive vitamin D therapy is toxic and can cause hypercalcemia, hyperphosphatemia, and hypercalciuria.

Source: Jin J. Screening for Vitamin D Deficiency in Adults. JAMA. 2021, 325(14):1480.

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