Study of the dynamics of the vitamin D level increase and the development of a method for calculating the required duration of cholecalciferol intake
Authors:   High Technology Park, Khanty-Mansiysk, Russia, Krivosheev V. V. , Kozlovsky I. V. ,   BU «District Clinical Hospital», Khanty- Mansiysk, Russia, Nikitina L. Yu. ,   National Medical Research Center, specializing in pulmonology, Moscow, Russia, Fedorov A. V. ,   High Technology Park, Khanty-Mansiysk, Russia
Published: September 2023

Pandemic D-avitaminosis swept the planet. Among the inhabitants of the northern hemisphere, about 45 % are deficient, and 32 % have insufficient vitamin D serum levels. In Russia, the situation is even more tense: the level of deficiency was registered in 56.4 % of the population, and insufficiency in 27.87 % of our fellow citizens. Maintaining an optimal concentration of vitamin D in the blood serum reduces the risk and severity of autoimmune, cardiovascular diseases, many types of cancer, dementia, type 1 and 2 diabetes, respiratory tract infections, improves dental and oral health, and increases physical performance. The problem of the increased prevalence of vitamin D deficiency during pregnancy, which has serious consequences not only for the mother, but also for the child throughout later life, requires special attention. A review of the documents regulating the intake of vitamin D supplements suggests that there is some uncertainty in the instructions, which leads to a wide variability in medical recommendations to patients on the choice of the type of drug, its dosage and the duration of vitamin D intake. Recommendations on the required duration of vitamin D supplementation, in our opinion, look the most vulnerable and insufficiently substantiated, therefore, in this work, on the basis of international clinical practice, studies of the dynamics of the increment in the level of vitamin D were carried out and a method was developed for calculating the required duration of taking the most common vitamin D3 preparations at present. The analysis of domestic and foreign practice of increasing the level of vitamin D in the blood serum, as well as the conducted statistical studies, allow, with some caution, to draw the following conclusions. When taking vitamin D3 preparations, the increase in the level of 25(OH)D over time is quite correctly described by an exponential equation. As the duration of taking vitamin D3 preparations increases, the rate of increase in the level of 25(OH)D in the blood serum decreases. The current calcifediol level when taking in vitamin D3 preparations in asymptotical persons, is associated with a power-law dependence on the daily drug dose and increases as it increases. As shown by numerous results of clinical trials, the main increase in the level of 25(OH)D occurs within 30–90 days under different conditions. The multiple regression equation we obtained indicates that the time of blood serum saturation with vitamin D3 is inversely related to the daily dose of the drug, the patient’s age, and the initial level of 25(OH)D in the blood serum. The method developed by the authors makes it possible to estimate the dynamics of the increase in the level of 25(OH)D in the patient’s blood serum as vitamin D3 preparations are taken and to determine the required duration of the drug intake.