Vitamin D Deficiency Epidemic: Fiction or Reality?

According to a recent study, 75% of Spaniards have a vitamin D deficiency (VD). But this situation of apparent deficiency is also questioned by many experts who wonder if there really is an “epidemic of hypovitaminosis” or if what is happening is that the parameters considered optimal are not properly calibrated. That is, if the limits considered “healthy” today are too high and that is why so many people are below the optimal threshold.

This is exactly what was suggested by Spanish researchers, who Attention was drawn to the large number of patients with low PV who were found to have“Most of this vitamin is synthesized by exposure to the sun, so in a country like ours, where the weather is usually so good, we found this very curious. That’s how the idea for this study came about,” says Juan José Perales, a doctor at the biochemistry department at the Lozano Blesa Hospital in Zaragoza.

Thus, a paper with the instructive title “This is not a real vitamin D deficiency pandemic,” published in the journal Biochemia Medica, concludes that values ​​above 12 ng/mL may be appropriate for healthy people. If this value were taken as a standard, “the incidence of vitamin D deficiency would be halved.”“This will therefore affect thousands of people who are currently ‘affected’,” says Marta Fabre of the Aragon Health Research Institute and author of the study.

“Some authors argue that This hypovitaminosis pandemic is due to reference values ​​being misinterpreted from the US Institute of Medicine, published in NEJM in 2016, would set the threshold for sufficiency at values ​​that are virtually impossible to achieve and that correspond to a minority of the population, Perales continues. This situation has led to a dramatic increase in the number of VD reports in recent years, from around 20,000 a few years ago to the more than 60,000 we currently perform at our center.

To add fuel to the fire, the Endocrine Society just published an updated version of its guidelines in which it removes the traditional 30 ng/mL cutoff below which a person is considered to have low levels of the vitamin, and recommends against screening the general population, but only members of various at-risk groups such as children and adolescents (to prevent rickets), pregnant women, people over 74, or people with diabetes.

As Juan José Diez and Elena Carrillo, Director and Deputy Director of the Endocrinology Service at the Puerta de Hierro Hospital in Madrid, explain, “considering the latest scientific work, the Society excludes considering the DV level of 20-29 ng/ml as ‘insufficient’, since there is no convincing evidence to establish analytical thresholds for DV. which indicate potential benefit of treatment in a healthy populationHowever, this highlights the need for more high-quality research to help refine these recommendations in the future.

The Endocrine Society’s new guidelines eliminate the reference range for optimal levels.

And one of the main problems is the lack of agreement. Currently, there is no consensus among scientific societies regarding the reference values ​​that should be adopted for VD. no cutoff point indicating insufficiency. For example, the Japanese Endocrine Society considers values ​​below 30 ng/ml insufficient, and the United States, as we have already said, has stopped supporting this threshold. On the other hand, the Mayo Clinic, a renowned clinical organization, considers values ​​below 20 ng/ml insufficient. At the national level, the Spanish Society of Endocrinology and Nutrition (SEEN) suggests maintaining values ​​above 30 ng/ml.

The key to this issue, as explained by Esteban Yodar, a member of SEEN’s Mineral and Bone Metabolism Group, is that DV levels are generally not measured in the population, so the actual situation is unknown.“Indications for VD measurement and supplementation today are limited to patients with risk factors such as calcium changes, osteoporosis, or certain clinical conditions or medications that affect their absorption or metabolism,” he explains.

Except, its levels are not easy to standardizeas factors such as cloud cover, altitude, ethnicity, or air pollution in each region can affect its synthesis and therefore these population levels. They even differ between summer and winter, as we do not get the same amount of sun and wear more clothing.

«It would be desirable to conduct more studies with representative populations. and a standardized methodology to establish optimal levels of vitamin D and the impact of its intake in each situation. Meanwhile, in clinical practice, we must adapt to the recommendations of national and international scientific societies,” conclude the experts at Puerta de Hierro.