Low levels of vitamin D are most likely not responsible for the fatigue, depression, and cognitive impairment experienced by patients with multiple sclerosis.
MONTREAL—Although patients with multiple sclerosis (MS) often have low serum levels of vitamin D, no significant correlation was found between this insufficiency and MS-associated fatigue, depression, or cognition, according to research presented at the 25th Annual Meeting of the Consortium of Multiple Sclerosis Centers.
Previous studies have reported a connection between cognitive decline and depression in the elderly, but this relationship has not been studied thoroughly in patients with MS, the investigators noted. “Fatigue, depression, and cognitive impairment are frequently present in MS, but their underlying etiologies are unclear,” they wrote. “[Our objective was] to investigate the relationship between vitamin D and fatigue, depression, and cognition in MS.”
Led by Sandra L. Cook, RN, from the Partners Multiple Sclerosis Center and Brigham and Women’s Hospital in Boston, the researchers analyzed testing results of 220 participants enrolled in the Comprehensive Longitudinal Investigation of Multiple Sclerosis at the Brigham and Women’s Hospital, Partners MS Center (CLIMB). Persons enrolled in this study underwent annual neurologic examinations and completed annual psychosocial and cognitive measures, including the Modified Fatigue Impact Scale (MFIS), Center for Epidemiologic Studies Depression Scale (CESD), and Symbol Digit Modalities Test (SDMT), which measures speed of information processing and working memory. Scores on the Expanded Disability Status Scale (EDSS) were also recorded.
The study population was mostly female (73.1%) and had a mean age of 47. The majority of patients had relapsing-remitting MS (77.4%), the median EDSS score was 1.5, and the mean disease duration from symptom onset was 13.3 years.
“The mean vitamin D level in our sample was 36.4 ng/mL,” Ms. Cook and colleagues reported. “Using 30 ng/mL as a cutoff, 27.4% of subjects were insufficient. Mean scores for outcome variables were 25.4 for MFIS, 28.5 for CESD, and 55.4 for SDMT.” When the investigators examined scores on the neurologic, psychosocial, and cognitive measures, they found no significant relationships between levels of vitamin D and fatigue, depression, cognition, or EDSS score, suggesting that vitamin D insufficiency is not the underlying mechanism for these symptoms.
—Ariel Jones