Rheumatoid arthritis (RA) is an autoimmune, inflammatory condition in which the body’s immune system mistakenly attacks the joints. The tissue that lines the joints, called the synovium, becomes inflamed and swells, causing discomfort, pain and if left untreated, cartilage and bone damage.
RA is the most common form of autoimmune arthritis, affecting about 1% of the world’s population. Additionally, research reports a moderate to high prevalence of anxiety and depression in individuals with RA; between 13-20% of individuals may experience depression and between 21-70% of RA patients may experience anxiety. This is likely associated with the pain, fatigue and disability commonly seen in RA patients.
However, the pathology of depression and anxiety in RA patients is not yet understood. Due to the evidence that suggests vitamin D status is associated with mood disorders, including depression and anxiety, researchers recently hypothesized that vitamin D status may play a role in the prevalence of mood irregularities in RA patients.
A total of 161 RA patients were included in this cross-sectional study. Researchers selected patients from the Department of Rheumatology and Immunology of the First Afflicted Hospital of Xian Jiaotong University from November 2016 through the end of February 2017. Additionally, all participants included in the study supplemented with approximately 800 IU of vitamin D per day.
Researchers measured the patient’s serum 25(OH)D status. RA severity was measured by a health assessment questionnaire (HAQ) and the European League Against Rheumatism Disease Activity Score. Pain was measured by the visual analogue score (VAS), with higher scores indicating increased pain. Depression was evaluated by the Hamilton Depression Scale (HAMD), with higher scores indicating increased feelings of depression. Last, anxiety was measured using the Hamilton Anxiety Scale (HAMA), with higher scores indicating increased anxiety.
This is what the researchers found:
- 47.2% of the RA patients were considered vitamin D deficient (<20 ng/ml; 50 nmol/l).
- Approximately 62% and 60% of the participant experienced some degree of depression or anxiety, respectively, while 57% experienced both.
- There was an inverse correlation between vitamin D levels and HAMD (p < 0.001) and HAMA (p < 0.001).
- Of those experiencing anxiety, depression or both, vitamin D levels were lower in those who had moderate and severe depression/anxiety than those with mild depression/anxiety (p = 0.046 and p < 0.001, respectively).
The researchers concluded,
“Depression and anxiety are common in patients with RA in Northern China. Serum levels of 25-OH-D3 are negatively associated with depression or anxiety.
“If vitamin D can be identified as a risk factor for depression or anxiety in RA patients, keeping sufficient level of vitamin D may reduce the incidence of depression or anxiety among those patients who are at a higher risk of developing depression or anxiety due to their low levels of vitamin D.”
There were some limitations of this study that should be addressed. First, because all of the participants were selected from a single hospital in Northern China, the results may not necessarily represent the entire RA population. Also, there were some confounding factors, such as use of medication, which could have been attributed to the low vitamin D levels found in RA patients. Further studies are required in order to determine the effect vitamin D sufficiency has in RA patients experiencing depression and/or anxiety.
Individuals looking to increase their vitamin D status should spend time outside when their shadow is shorter than they are tall or supplement with at least 5,000 IU (125 mcg) daily. If you have any questions about vitamin D supplementation, sun exposure or the relationship between vitamin D and RA or mood disorders, please contact us at firstname.lastname@example.org.
Peterson, R. & Cannell, JJ. Recent study discovers low vitamin D status in rheumatoid arthritis patients experiencing anxiety and depression. The Vitamin D Council Blog & Newsletter, 2017.