Vitamin D levels and rheumatoid arthritis

This study explored the relationship between vitamin D levels and rheumatoid arthritis (RA). The study concluded that RA patients frequently had lower vitamin D levels than healthy patients. 

RA is a chronic autoimmune disease (when the immune system attacks healthy tissue) that is thought to be caused by both genetic and environmental factors. A lack of Vitamin D may be one of those factors. RA patients can often also have osteoporosis (brittle and fragile bones). Osteoporosis can be caused by a lack of vitamin D. Vitamin D is an important nutrient that is anti-inflammatory and is known to help regulate the immune system. The relationship between vitamin D levels and RA is unclear. 

This study aimed to establish whether there was a strong relationship between vitamin D levels and RA. This study analyzed the results of 24 studies including 3,489 patients.

RA patients had consistently lower vitamin D levels than healthy patients (average difference was 16.52 nmol/L). Lower vitamin D levels were correlated with higher RA disease activity (number of joints affected by pain and swelling). 

The study concluded that there may be a relationship between vitamin D levels and RA disease activity.