Sleep status in multiple sclerosis: Role of vitamin D and body mass index

Background: Sleep disorders are major but neglected symptoms in patients with multiple sclerosis (MS). This study aimed to describe the sleep status in patients with MS. Methods: We selected mildly-disabled [Expanded Disability Status Scale (EDSS) score < 4] patients with relapsing-remitting MS (RRMS). After determining the level of vitamin D in a blood sample of the patients, the validated Persian versions of Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), and snoring, tiredness, observed apnea, high blood pressure, body mass index (BMI), age, neck circumference, and gender (STOP-Bang) questionnaires were filled and the sleep condition was described. Besides, the impact of age, sex, disease duration, and EDSS on sleep status was determined. Results: 37.87% of 103 included patients with MS had poor sleep quality. 21.35% rate of subthreshold, 10.67% rate of moderate, and 1.94% rate of severe insomnia were also observed. Only 1.94% of patients had a high risk of obstructive sleep apnea (OSA). There was a significant relation between Beck Depression Inventory (BDI) score with ISI (r = 0.45, P < 0.01), PSQI (r = 0.53, P < 0.01), and STOP (r = 0.20, P = 0.03). A significant correlation between STOP with BMI (r = 0.24, P = 0.01) and age (r = 0.21, P = 0.03) was also observed. Sleep status was not significantly different in groups of the patients based on vitamin D, overweight, or sex. Conclusion: Poor sleep quality is a common finding among mildly-disabled patients with MS. There is also a 33.99% rate of subthreshold or clinical insomnia in different severities. Quality of sleep and insomnia is not significantly correlated to BMI, level of vitamin D, and sex in patients with MS.