Vitamin D is an essential vitamin that you can get from food (fatty fish, egg yolks, cheese) or from exposure to UV light. It regulates the absorption of calcium and phosphorus and has an important role in maintaining the health of the bones. Low levels of vitamin D are associated with a wide range of illnesses, such as bones fractures, falls, cardiovascular disease, colorectal cancer, depression moods and many more.
The problem is that a vitamin D deficiency is not clearly defined. The minimum levels should range between 20 and 30 nanograms per milliliter of blood, but it is difficult toproperly determine vitamin D insufficiency because of the different testing methods among labs. What is more, there are key populations, such as African-Americans, who normally have lower levels, but it is not known whether this is a sign of deficiency or not.
“Further research is needed to determine the cutpoint that defines vitamin D deficiency, the sensitivity and specificity of various assays using an internationally accepted reference standard, and whether total serum 25(OH)D is the best measure of vitamin D deficiency in all populations,”USPSTF wrote.
It is important to mention that the Task Force hasn’t yet determined whether the screening of asymptomatic people has a real merit. According to Task Force experts, there is still a lack of evidence that measuring vitamin D levels and then administering treatment will really help as long as there is not clear evidence of a disease caused by the deficiency.
Moreover, specialists are also worried about the potential harms the excess of vitamin D can do: kidney stones and toxicity, which may lead to hypercalcemia and suppressed parathyroid hormone.
On the other hand, the USPSTF recommends vitamin D supplementation for the elderly that are at a risk of falling and for those who present real signs of deficiency, such as broken bones, liver disease or multiple sclerosis.
“Unless you really are truly symptomatic, it might not be worthwhile to measure vitamin D, and tag you with the diagnosis of deficiency, when it’s not clear those levels make you deficient and you’re not at risk for disease.”
Dr. Clifford Rosen, one of the country’s foreman experts on the impact of vitamin D screening, concluded.