Vitamin D level and endogenous DNA damage in patients with cancers in Duhok city, KRG-Iraq

INTRODUCTION: Many clinical and pre-clinical studies suggested the protective effect of vitamin D against cancer development and cancer progression. Vitamin D deficiency is highly prevalent worldwide, and its link to DNA damage is worthy to study. It has been shown that vitamin D supplementation can reduce the risk of cancer with a favorable prognosis. Studies on DNA damage in different types of cancer and its link to plasma vitamin D has not been found in literature. PATIENTS AND METHODS: In this study we included 45 patients with different types of cancers and 35 healthy individuals as controls. The plasma vitamin D levels were measured in all participants. DNA damage levels of peripheral blood (mononuclear) cells in 45 newly diagnosed and untreated cancer patients and in 35 healthy individuals were measured using Alkaline Comet Assay technique. RESULTS: The DNA damage observed in cancer patients was significantly higher than in healthy individuals. Interestingly, we have found a significant inverse correlation between the plasma levels of vitamin D and DNA damage in cancer patients (p < 0.0001) and in healthy individuals (p < 0.001). CONCLUSION: There is an inverse association between endogenous DNA damage and plasma vitamin D levels. Patients with vitamin D deficiency show highest levels of DNA damage suggesting that deficiency of vitamin D is probably one of the factors which increases the risk of cancer.