Effect of smoking on serum vitamin D levels and inflammatory markers

Aim: Vitamin D deficiency is emphasized in the pathophysiology of various inflammatory diseases and low-grade inflammation. The aim of this study was to investigate the effect of smoking on serum vitamin D and inflammation markers. Material and Method: The study was done in Ministry of Health, Giresun University Prof. Dr. A. Ilhan Ozdemir Education and Research Hospital. A questionnaire about smoking was obtained by consent of the individuals who applied to the blood collection unit and who were asked for serum 25(OH)D, C-reactive protein and complete blood count in the Hospital Information Management System. 110 volunteers who did not have any systemic diseases, did not take vitamin D supplements, were not pregnant and were aged 18 and over were included in the study. The study was completed in one month period (09.08.2017-08.09.2017). The 25(OH)D and C-reactive protein levels of the smokers and non-smokers were compared with the values of leukocytes and subgroups. Results: In the smoker group, leukocyte (p=0.001) and neutrophil (p=0.001) numbers were significantly higher than nonsmokers; the number and percentage of neutrophils in women (N=76) were significantly higher in the smoker group than the nonsmoker group (p=0.011; p=0.005); the percentage of lymphocytes was significantly lower in the smoker group (p=0.031). In males (N=34); the number of leukocytes (p=0.013), neutrophils (p=0.031) and lymphocytes (p=0.022) were significantly higher in the smoker group than the non-smoker group. The percentage of neutrophils, neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) were significantly higher in smoker women compared to smoker men (p=0.004; p=0.011; p=0.005, respectively); the number of lymphocytes and percentage of lymphocytes were significantly lower in smoker women compared to smoker men (p=0.030; p=0.028); the mean age of non-smoker men was significantly higher than non-smoker women (p=0.001). In the non-smokers group, there was a positive, weak-moderate correlation between 25(OH) vitamin D levels and the duration of outdoors (rs=0,249; p=0,038);there was a negative-moderate correlation between 25(OH)D levels and leukocyte counts (rs=-0.564; p=0.015) in the smoking men group; whole group of smokers, 25(OH) vitamin D levels and lymphocyte percent values were positively correlated with a weak-to-moderate correlation (rs=0.332; p=0.043). Conclusion: Chronic smoking increases the number of leukocytes and neutrophils in the blood. We think the reason of increase is that the immunomodulatory chemicals and gases contained in cigarette smoke cause an inflammatory reaction and the resulting cellular defense mechanism. Although there was a significant positive correlation between the duration of outdoors and vitamin D levels in the non-smoker group, it was not found in the smoker group. Smoking has been shown to adversely affect cutaneous vitamin D synthesis. Key words: Smoking, vitamin D, C-reactive protein, leukocyte, inflammation