Despite numerous studies, the status of vitamin D remains the subject of debate among scientists around the world. Deficiency in the level of 25-hydroxyvitamin D (25(OH)D) in the blood serum contributes to the development of a number of skeletal and non-skeletal pathological effects. An important condition for maintaining human health is the level of 25(OH)D in the blood serum of at least 75 nmol/l.
OBJECTIVE
To study the frequency of detection of the generally accepted established standards for the level of 25(OH)D in the blood serum of healthy indigenous people of Kyrgyzstan.
MATERIAL AND METHODS
A pilot multicenter cross-sectional study of the level of 25(OH)D in the blood serum of the indigenous people of Kyrgyzstan was carried out. The geographical location of the republic is characterized by the annual amount of solar radiation from 5547 MJ/m2 in the Chui valley (Bishkek weather station, 756 m above sea level) to 6660 MJ/m2 (Tien Shan weather station, 3610 m above sea level). In accordance with the exclusion criteria, a group of healthy individuals was selected for data verification according to the purpose of the study. Statistical analysis was performed using PASW Statistics 21.0 (SPSS Inc., IBM, USA).
RESULTS
The sample is represented by 293 healthy indigenous people from various regions of Kyrgyzstan. 129 (44.0%) men and 164 (56.0%) women were examined. The mean age of the representative sample was 38.7±0.9 (95% CI 36.0-40.5) years. The age range is from 17 to 77 years, represented by five age groups. The exclusion group included 62 (17.2%) people. The average level of 25(OH)D in the blood serum of the examined was 38.7±1.0 (95% CI 36.6-40.7) nmol/l, there were no statistically significant gender differences (p=0.066). Seasonal fluctuations were revealed — from 30.2±1.9 (95% CI 26.3-34.1) nmol/l in winter to 46.6±1.9 (95% CI 42.8-50.3) nmol/l l in autumn (p=0.0001). The level is less than 50 nmol/l in 71.3±2.6 (95% CI 66.1-76.5)% of cases, 50-75 nmol/l in 24.6±2.5 (95% CI 19.7-24.5)% of cases; more than 75 nmol/l — in 4.1±1.2 (95% CI 1.8-6.4)% of cases.
CONCLUSIONS
The study showed a deficiency in the level of 25-hydroxyvitamin D in the blood serum of more than 70% of healthy native residents of Kyrgyzstan. The findings provide the basis for an expanded study to identify the determinants of vitamin D deficiency.
