The role of vitamin D in multisystem sarcoidosis

Abstract

Recently published data indicate that vitamin D abnormalities are common in sarcoidosis patients. The purpose of this study was to compare serum vitamin 25(OH)D levels among sarcoidosis patients with different clinical courses of the disease. The study also included the first observations on cognitive functions (i.e. depression and fatigue syndrome) in relation to vitamin D deficiency in sarcoidosis patients. At the Biochemical Laboratory of the Clinical Center of Serbia, Belgrade, vitamin D25(OH)D was measured using the Elecsys® Vitamin D total test. A total of 226 patients with biopsy-positive sarcoidosis were analyzed. The average median value of serum vitamin D was 9.47 mg/L, suggesting severe deficiency. Statistically significant correlation was found in patients with chronic disease and low levels of serum vitamin 25(OH)D (Chi-Square=6.044; df=2; p=0.014). The patient group with vitamin D serum levels higher than 20 mg/L showed higher levels of the mean forced vital capacity (FVC) by 380 mL, and forced expiratory volume in one second (FEV1) by 220 mL, when compared to the patient group with lower serum vitamin D. A statistically significant role was established for serum vitamin 25(OH)D levels as the predictor of fatigue (R2=0.878; p=0.038 (b=0.216)) and depression in patients with sarcoidosis (R2=0.80; p=0.000 (b=0.391)). The insufficiency of 25(OH)D seems to be an important factor in predicting the course of chronic disease, significant lung function impairments and cognitive failures such as fatigue and depression. The fact that the majority of the analyzed sarcoidosis patients had totally deficient serum 25(OH)D levels made this finding even more notable.

Keywords

• vitamin d
• deficiency
• sarcoidosis