Sleep disorders in systemic lupus erythematosus. Does vitamin D play a role?

Abstract

Objectives

Sleep disorders are common among patients with systemic lupus erythematosus (SLE) with unclear underlying mechanisms. We assessed the role of vitamin D in sleep quality of patients with SLE.

Methods

A retrospective study was conducted on women with SLE for whom the following data were available at the same time; sleep quality (Pittsburgh Sleep Quality Index (PSQI)), disease activity, cumulative disease damage, psychological state (Hospital Anxiety and Depression Scale (HADS)), and serum vitamin D level. Bivariate and regression analyses were computed to find contributors of sleep quality.

Results

In total, 63 women were studied. Serum vitamin D level was correlated with physical activity (r = 0.310, p = 0.015), season of assessment (r = −0.302, p = 0.016), the PSQI global score (r = −0.262, p = 0.043), anxiety score (r = −0.298, p = 0.021), and non-significantly with depression score (r = −0.218, p = 0.094). Including all variables into a linear regression model, vitamin D level was independently associated with the global PSQI score (beta = −0.364, p = 0.042). Association of vitamin D level with psychological state disappeared after controlling for season of assessment (beta = −0.248, p = 0.154).

Conclusions

We found a role for vitamin D in sleep quality of SLE patients. Further studies are warranted to confirm these results and to find possible mechanisms of action.