Is Vitamin D Deficiency Associated with Fatigue and Depression in Iranian MS Patients?
Higher levels of depression and fatigue are not significantly correlated with vitamin D deficiency in Iran, says a new study.
In an area of the world where modesty in public is required and skin exposure to sunlight is limited, the prevalence of multiple sclerosis has been on the rise in recent years. In one of the first population studies conducted in 2005 by the Isfahan MS Society (IMSS) in Iran, the prevalence of MS in the Isfahan region was 43.8/100,000 between April 2003 and July 2006 with an incidence rate of 3.64/100,000 for the year 2005. A later study was conducted in 2010, reporting an increased prevalence of 73.3/100,000 between April 2003 and July 2010 with an incidence rate of 9.1/100,000 in 2009 (Etemadifar, 2012). The IMSS witnessed an increase in the reported incidence of new MS cases of 150% in only a few years.
In previous studies conducted in Europe and the United States, low serum levels of 25-hydroxy vitamin D is associated with increased risk of developing MS, and in some studies, increased levels of disease activity. The definition of vitamin D deficiency can vary in studies due to differences in unit of measurements. In the US, many experts believe that blood levels of vitamin D above 30 ng/mL are adequate for healthy individuals (Solomon, 2011). In other areas of the world, the unit of measurement for vitamin D is nmol/L. A vitamin D level of 30 ng/mL is approximately equivalent to 75 nmol/L.
In a case-control study conducted in Isfahan, Iran in 2010, the rate of vitamin D deficiency was significantly increased in patients diagnosed with MS (n=50) as compared to healthy controls (n=50). The mean level of 25-hydroxy vitamin D in case and control groups were 48 and 62 nmol/L, respectively (P=0.036). There was not any significant relationship between age and serum level of vitamin D in both groups (P=0.83).
Subjects were divided into three groups based on their 25-hydroxy vitamin D serum level: vitamin D deficient patients (serum level below 25 nmol/L), vitamin D insufficient cases (serum level between 25 and 75 nmol/L) and subjects with normal or higher than normal vitamin D level (serum level higher than 75 nmol/L). The number of MS patients with vitamin D deficiency, insufficiency and normal range were 15 (30%), 28 (56%) and 7 (14%), respectively. These numbers for control group were 9 (18%), 22 (44%), 19 (38%), respectively.
In the present study, researchers from the Department of Neurology at Isfahan University investigated whether lower levels of vitamin D were associated with depression or fatigue in MS patients in Iran. In 200 MS patients [154 female (77%) and 46 (23%) male], the relationship, if any, between FSS scale (measuring fatigue), BDI-PC score (measuring depression), EDSS (measuring disability) and low Vitamin D status (<75 nmol/L) were determined (Ashtari, 2013).
The prevalence of low vitamin D status was 48.5% (97/200). Researchers found that low vitamin D status was associated with depressive symptoms in MS patients. However, results did not reach statistical significance. There was also no significant correlation between vitamin D status and fatigue symptoms.
What researchers found
Researchers did, however, find a significant correlation between MS disability (evaluated by EDSS) and fatigue and depression. Unraveling the connection between increased disability and fatigue and depression in MS is difficult for researchers and patients alike. Each affects a patient’s quality of life in an interconnected way.
Although this study does not provide any solutions to addressing fatigue or depression through vitamin D supplementation, it does suggest that vitamin D deficiency is not to be blamed for increased fatigue in MS patients.
More on fatigue and depression
If you are experiencing fatigue or depression, talk to your neurologist about possible causes and available treatments. If you do not know your vitamin D level, ask your neurologist to order a simple blood test to determine whether you are deficient in vitamin D and may need to take daily supplements. Although 25-hydroxy vitamin D serum levels above 30 ng/mL are considered adequate for healthy individuals, your neurologist may want to raise your levels to the 50-80 ng/mL range (as mine does). Talk to your doctor to determine what is right for you.
Ashtari F, Ajalli M, et al. The relation between Vitamin D status with fatigue and depressive symptoms of multiple sclerosis. J Res Med Sci. 2013 March; 18(3): 193–197. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3732898/
Etemadifar M, Abtahi SH. Multiple sclerosis in Isfahan, Iran: Past, Present, and Future. Int J Prev Med. 2012 May; 3(5): 301–302. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3372071/
Shaygannejad V, Golabchi K, et al. A Comparative Study of 25 (OH) Vitamin D Serum Levels in Patients with Multiple Sclerosis and Control Group in Isfahan, Iran. Int J Prev Med. 2010 Summer; 1(3): 195–201. http://www.ncbi.nlm.nih.gov/pubmed/21566791
Solomon AJ. Multiple sclerosis and vitamin D. Neurology 2011 Oct 25;77(17):e99-100. doi: 10.1212/WNL.0b013e318237c282. http://www.neurology.org/content/77/17/e99.full.pdf