Assessment of the vitamin D, calcium and phosphorus sufficiency in individuals deployed in Arctic

Abstract

Inadequate ultraviolet insolation is one of the the key prerequisites for the pathogenesis of body's vitamin D insufficiency in the North. The study was aimed to assess the body's vitamin D, calcium and phosphorus sufficiency in the contract servicemen deployed in Arctic. The contract servicemen deployed on the Cape Chelyuskin and Dixon Island were surveyed (n = 51). The serum levels of 25(OH)D, the intermediate of the vitamin D conversion, along with the ionized calcium, total calcium, and inorganic phosphorus levels, were determined in June. Three degrees of the vitamin D sufficiency were revealed in the military, who had been deployed in Arctic for 5.9 ± 0.4 years: deficiency (in 29.4%), insufficiency (in 52.9%), and optimal levels (in 17.7%). However, the optimal levels revealed were close to the lower limit of normal range. Low ionized calcium levels were found in 29.4% of blood samples (15.5 ± 0.6 ng/mL). A total of 70.6% of samples that were within normal range were close to the lower limit of normal range based on Q25 (1.16 mmol/L) and were within the lower half of normal range (1.15–1.35 ng/mL) based on Q75 (1.22 mmol/L). The measured total calcium and inorganic phosphorus levels were close to the lower limits of reference ranges (2.29 ± 0.009 and 0.83 ± 0.006 mmol/L, respectively). In general, the reduced ionized calcium levels associated with vitamin D insufficiency were revealed, which were indicative of impaired calcium metabolism. The vitamin D deficiency results from the total calcium and inorganic phosphorus concentrations that are close to lower limits of reference ranges. Further negative changes in the body's vitamin D, phosphorus and calcium sufficiency should be expected during polar night. The study actualizes the year-round replenishement of the vitamin D and mineral deficiency in the military.