INTRODUCTION: The aim of this study was to investigate the serum concentration of vitamin D in patients with obstructive sleep apnea syndrome (OSAS) alone and with coexisting fibromyalgia syndrome (FMS) and to assess the relationship to pain.
METHODS: A total of 60 patients diagnosed with OSAS and 40 healthy individuals whose age and sex were analogous to the patient group were included in this study. The OSAS patients were examined for FMS according to the American College of Rheumatology criteria, and 27 cases were identified. Group 1 consisted of patients with OSAS alone (n=33) and Group 2 comprised patients with FMS+OSAS (n=27). Serum samples were analyzed using an ultra-performance liquid chromatography analyzer (Thermo Dionex Ultimate 3000; Thermo Fisher Scientific, Inc., Waltham, MA, USA).
RESULTS: A comparison of the OSAS and FMS+OSAS groups with the healthy individuals revealed that the vitamin D level was significantly lower in the patient groups (Group 1: p=0.001, Group 2: p=0.038). No statistically significant difference was found in the vitamin D level between the subgroups of OSAS and FMS+OSAS. A weak negative correlation was determined between the number of the tender points (r=-0.428) and the vitamin D level in the subjects with FMS (p=0.013). In addition, the oxygen desaturation values of the FMS+OSAS and OSAS patient groups were significantly different (p=0.001).
DISCUSSION AND CONCLUSION: Patients with OSAS and FMS+OSAS had a low vitamin D level, which should be considered when planning treatment strategies.