Changes of Vitamin [25 (OH) D3] Levels According to Age and Gender Groups in the Period of Summer and Winter.

Objective: Vitamin D has important implications for human health. The aim of this research was to investigate retrospectively how the laboratory data of vitamin D level changes according to sex and age groups during winter and summer months. Materials and Methods: Study groups composed of woman and men were formed according to age groups of 0-4 years, 5-12 years, 13-18 years, 19-49 years, 50-90 years. For this purpose, between July and October, the data of 354 male and 1105 female patients, of a total of 1459 subjects were taken. Between November and March, data of 544 men and of 1579 women, of total 2123 persons were analyzed. In total, data of 3582 personswere screened retrospectively from laboratory automation data. Blood samples (Containing EDTA) were analyzed by Thermo uHPLC (Ultra High Performance Liquid Chromatography) after preliminary processing the results of calibration and control are found appropriate. Results: Vitamin D levels of automation data were scanned in different age and gender groups in summer months where sunny days were long and numerous and in winter days where sunny days were short and fewer. The cut-off value in the scan was accepted as 20 ng/dL (limit value). Accordingly, when all age groups were considered,there was a decrease of 36.4% for men and 38.2% for women in Vitamin D levels in winter months compared to that in summer months. Conclusion: In this research, it has been observed that vitamin D levels in winter months decrease by a rate of 1/3. Accordingly, when vitamin D levels are below 20 ng/ml due to inadequate exposure to sunlight, it may be recommended that people be exposed to sunlight in sunny days or take D vitamin preparations