Background Vitamin D deficiency is a global health problem, it is assessed by measuring serum 25-hydroxivitamin D (25(OH) D), nevertheless epidemiological data for many countries remains underreported. Objectives To study the prevalence of vitamin D deficiency throughout the calendar year in a large cohort recruited ina multiethnic Transcarpathian region of Ukraine. Methods In this retrospective study 25(OH) D serum concentration was measured during all 12 months of the year 2019 by electrochemoluminescent assay on the automatic analyzer Cobas e411 in 1823 subjects, including both children and adults (1551 females (85.03%) and 273 males (14.97%)). Results The mean 25(OH) D concentration in adults demonstrates significantly lower levels compared to children (22.67 ± 8.63 ng/ml vs. 26.00 ± 10.72 ng/ml respectively, p < 0.001). Adult women expressed significantly lower mean annual serum 25 (OH) D concentrations in comparison to men (22.29 ± 8.46 ng/ml vs. 25.75 ± 9.38 ng/ml respectively, p < 0.001). In contrast, children did not show a significant difference between sexes (girls 24.98 ± 10.38 ng/ml vs. boys 27.01 ± 11.01 ng/ml, p = 0.2003). In the winter months, 25(OH) D levels fell below 20 ng/ml in 51,74% of adult population of Thranscarpathia, and in 12.91%, − below 12 ng/ml. Conclusions The results of this study contradict the previously reported evaluations of the vitamin D levels in Ukraine which were assessed by measuring serum 25(OH) D. Specifically, only approximately half of the studied population is vitamin D deficient during winter season. This study features the most representative sample size in Ukraine to date.

Background The main goal of this collaborative effort is to provide genome-wide data for the previously underrepresented population in Eastern Europe, and to provide cross-validation of the data from genome sequences and genotypes of the same individuals acquired by different technologies. We collected 97 genome-grade DNA samples from consented individuals representing major regions of Ukraine that were consented for public data release. BGISEQ-500 sequence data and genotypes by an Illumina GWAS chip were cross-validated on multiple samples and additionally referenced to 1 sample that has been resequenced by Illumina NovaSeq6000 S4 at high coverage. Results The genome data have been searched for genomic variation represented in this population, and a number of variants have been reported: large structural variants, indels, copy number variations, single-nucletide polymorphisms, and microsatellites. To our knowledge, this study provides the largest to-date survey of genetic variation in Ukraine, creating a public reference resource aiming to provide data for medical research in a large understudied population. Conclusions Our results indicate that the genetic diversity of the Ukrainian population is uniquely shaped by evolutionary and demographic forces and cannot be ignored in future genetic and biomedical studies. These data will contribute a wealth of new information bringing forth a wealth of novel, endemic and medically related alleles.