Introduction: Vitamin D is involved not only in the regulation of calciumphosphorus metabolism; it also plays an important role in maintaining the immune system, muscle strength and neuromuscular conduction. Lack of vitamin D is assumed as one of the mechanisms of autoimmune and infectious diseases. Chronic fatigue syndrome (CFS) is a syndrome manifesting with a severe chronic physical, mental weakness, psychological disturbances such as anxiety and depression, the development of which is associated with impaired immunity, chronic infectious diseases and brain dysfunction. There are published data on the high prevalence of low levels of vitamin D in the Finnish cohort of patients with CFS.
Aim: To assess the prevalence of vitamin D insufficiency, changers in anxiety and depression scores after treatment with 150 000 IU of cholecalciferol in patients with and without CFS.
Materials and methods: The study included 81 women aged 4060 years (median age 53±4 years), 29 of which were diagnosed with the CFS using CDC criteria (1994). Vitamin D levels were evaluated during the period from late June till September by LIASON 25OH total vitamin D assay (DiaSorin, Inc.). Beck depression and Zung anxiety scales we completed by patients before and after treatment.
Results: The prevalence of vitamin D deficiency, defined as a level <20 ng/ml was 54% in patients with CFS and 74% in the control group (P>0.05), the optimal level of vitamin D (30 ng/ml) was observed in 10 and 14% of patients, respectively (P>0.05). Medical therapy with cholecalciferol (25 000 IU a week orally during 6 weeks) resulted in decrease in depression scores from 35 to 13 in CFS+ group (P=0.00004) and insignificantly from 11 to 9.5 in CFS− group (P>0.05); decrease in anxiety scores from 38 to 35 in CFS+ group (P=0.00003) and from 28 to 22 in CFS− (P=0.0000000007); decrease in number of minor diagnostic criteria symptoms in patients with CFS from 5.4 to 4.9 (P=0.04). The studied parameters did not correlate with levels of vitamin D before and after treatment and with the net change in levels.
Conclusions: There is a high prevalence of vitamin D deficiency in perimenopausal women during period of sufficient insolation irrespective of CFS presence. Vitamin D treatment seems to improve psychological functioning but the mechanisms might not be direct.