Vitamin D status in chronic fatigue syndrome/myalgic encephalomyelitis: a cohort study from the North-West of England

Objective: Severe vitamin D deficiency is a recognised cause of skeletal muscle fatigue and myopathy. The aim of this study was to examine whether Chronic Fatigue Syndrome / Myalgic Encephalomyelitis (CFS/ME) is associated with altered circulating vitamin D metabolites. Design: Cohort study. Setting: UK university hospital, recruiting from April 2014 to April 2015. Participants: 92 patients with CFS/ME and 94 age-matched healthy controls. Main outcome measures: The presence of a significant association between CFS/ME, fatigue and vitamin D measures. Results: No evidence of a deficiency in serum total 25[OH] vitamin D (25[OH]D2 and 25[OH]D3 metabolites) was evident in individuals with CFS/ME. Liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis revealed that total 25[OH]D was significantly higher (p = 0.001) in serum of CFS/ME patients compared with healthy controls (60.2 and 47.3nmol/L respectively). Analysis of food/supplement diaries with WinDiets revealed that the higher total 25[OH] vitamin D concentrations observed in the CFS/ME group were associated with increased vitamin D intake through use of supplements compared with the control group. Analysis of Chalder Fatigue Questionnaire data revealed no association between perceived fatigue and vitamin D levels. Conclusions: Low serum concentrations of total 25 [OH]D do not appear to be a contributing factor to the level of fatigue of CFS/ME