Serum vitamin D level is associated with obstructive sleep apnea state and severity

Background Growing reports have argued about the possible association between vitamin D (VD) insufficiency and obstructive sleep apnea (OSA) prevalence and severity but with inconsistent results. This study aimed at investigating the association between VD level and OSA state and severity in Egyptian patients. Patients and methods A case-control study was conducted from January 2016 to January 2017 that recruited 50 patients with OSA and 50 matched healthy controls. OSA was diagnosed by a full night sleep study using a computerized polysomnogram system. All participants were subjected to evaluation of symptoms of excessive sleepiness using Epworth sleepiness scale and serum VD level measurement. Results A total of 50 cases with OSA and 50 age-matched, sex-matched, and BMI-matched healthy controls were enrolled. Cases with sleep apneas had a higher Epworth sleepiness score (9.23 +/- 2.34, P<0.001) and a lower VD level (21.37 +/- 4.97, P<0.001) than controls. VD deficiency is associated with OSA, whereas adequate VD level is associated with normal controls. There was a significant negative correlation between OSA severity (assessed by apnea-hypopnea index) and VD level (P<0.001). Conclusion OSA had lower VD levels in comparison with healthy matched controls. This lower level of VD was correlated with OSA severity.