Relationship Between the Vitamin D Status and the Season, Place of Living, Age, Gender, and Chronic Disease

Objective: The aim of the present study was to investigate the variations in 25-OH Vitamin D levels considering age, gender, the place of living, season, and presence of chronic disease. Materials and Methods: Individuals whose 25-OH Vitamin D levels were measured in seven state hospitals in the Tokat Province, Turkey, between September 2016 and August 2017 were selected using the hospital information system and included in this retrospective study. Results: The study included a total of 22,044 individuals aged ≥18 years. Vitamin D deficiency and insufficiency were observed in 89.4% of the individuals surveyed. Of all participants, 78.7% (n=17.328) were female, and 74.3% (n=16.377) were living in urban areas. An average 25-OH Vitamin D level was significantly low in people living in urban areas (15+-12.4 ng/ml) compared to those living in rural areas (15.4+-11.5 ng/ml; p=0.03). An average seasonal 25-OH Vitamin D level was the lowest in the winter (13.4+-11.5 ng/ml) and the highest in the summer season (17+-12.1 ng/ml; p