Problem of determining vitamin D status

Abstract

   Background. Recently, the demand for the measurement of vitamin D has been growing at a rate outrunning other types of laboratory tests. However, estimates of the prevalence of this nutrient status among population groups vary widely, based on target levels considered adequate or optimal for maintaining good health. The lack of a unified approach to stratifying the values of vitamin D in a patient’s blood creates difficulties in assessing the status of this nutrient.   Objective. Stratification of vitamin D results in pediatric and adult patients examined between 2017 and 2022 at the St. Petersburg Consultative and Diagnostic Centre for Children, using criteria of different research groups and professional societies.   Materials and methods. Vitamin D measurements were carried out using an immunochemical analyzer from January 2017 to December 2022 in 15,946 samples from children and 9,163 from adults.   Results. Using stratification criteria proposed by various research groups and professional societies, the range of vitamin D deficiency in 2017–2019 ranged from 3.0 % to 63.9 % in children and from 2.4 % to 81.7 % in adults. In 2020–2022 deficient status was less common for all criteria: from 0.2 % to 51.2 % in children and from 0.1 % to 42.5 % in adults. An inverse relationship was noted for vitamin D levels associated with risk of harm. In 2017–2019 such values were detected in 1.0 %, in 2020–2022 in 2.8 % of children. In adults, similar rates increased from 1.8 % in 2017–2019 up to 3.5 % in 2020–2022.   Conclusions. The wide variation in approaches reflects the uncertainty in research findings, recommendations, and guidelines involving vitamin D. Consensus on vitamin D thresholds will help arrive at the most likely conclusions from an evidence-based clinical perspective when establishing an association between a risk factor and an outcome.