Tabriz University of Medical Sciences Journal of Research in Clinical Medicine 2717-0616 8 1 2020 02 15 Serum level of melatonin in patients with osteoarthritis and its relation with 8-hydroxy-2-deoxyguanosine and vitamin D 34 34 10.34172/jrcm.2020.034 EN Misagh Asanjani Oskoii https://orcid.org/0000-0002-7547-8354 Nasrin Khatami Maryam Majidinia Mohammad-Amin Rezazadeh Seyed Mostafa Mir Alireza Sadeghpour https://orcid.org/0000-0001-9828-6876 Bahman Yousefi https://orcid.org/0000-0002-4220-1527 Journal Article 10.34172/jrcm.2020.034 2020 04 30 2020 07 06 Introduction: This study aimed to evaluate the relationship between the serum level of melatonin, 8-hydroxy-2-deoxy guanosine, and vitamin-D in patients with osteoarthritis (OA). Methods: This study enrolled 47 patients with OA and 40 healthy controls. Serum levels of melatonin and 8-hydroxy-2-deoxy guanosine (8-OH-dG) were assessed. Also, serum levels of bone turnover biomarkers such as calcium, phosphorus, vitamin D, and alkaline phosphatase (ALP) were measured in OA patients and controls. Results: The serum level of melatonin was significantly lower in OA patients than the controls (6.18±2.25 vs. 11.57±3.87 pg/mL, P<0.05). In contrast, the serum level of 8-OH-dG was significantly increased in OA patients compared to controls (65.21±16.12 vs. 22.51±5.3 ng/dL, P<0.001). There was a negative correlation between serum melatonin and 8-OHdG levels in OA patients (P<0.05). There was a positive correlation between serum melatonin and vitamin D levels in OA patients (P<0.05). We found decreased calcium and vitamin D levels, and increased phosphorus and ALP levels in OA patients compared to controls (P<0.05). Conclusion: Decreased levels of melatonin and elevated levels of 8-OH-dG might play a role in the pathogenesis of OA. Therefore, melatonin might be involved in decreasing DNA damage and exerting a preventive function in OA.