Osteoarthritis and obesity: vitamin D helps movement and counteracts pain

Adequate levels of vitamin D can improve movement and reduce joint pain in obese and arthritis-affected individuals. The benefits of the vitamin could be due to both its ability to protect bone and to reduce inflammation.

This is explained by the results of a study conducted by researchers at the University of Florida (USA) and published in The Clinical Journal of Pain.

Osteoarthritis: a very common condition

Arthritis is a collection of different conditions that share the common characteristic of causing joint inflammation, swelling, stiffening, and pain leading to a loss of joint function. The prevalence of knee arthritis is increasing as the population ages and is exacerbated by the growing number of obese and elderly people. Several studies in recent years have suggested that vitamin D deficiency in adults may exacerbate osteopenia, osteoporosis, muscle weakness, fractures, autoimmune diseases, infectious diseases, and cardiovascular diseases. Low levels of vitamin D measured in serum as 25-hydroxyvitamin D (25(OH)D), in the elderly and obese, correlate with several health conditions including chronic pain.

Relationship found between vitamin D and osteoarthritis pain? 

Dr. Glover, who directed the study, and his colleagues collected and analyzed data from 256 people with an 'average age of 57 years. Participants provided a report regarding knee osteoarthritis pain and were tested for lower extremity functional performance. Vitamin D levels were obtained by analyzing blood samples from each subject. The results showed that in people who were obese but had adequate vitamin D levels, knee pain was less than in obese and vitamin deficient people. In addition, some motor performances, such as standing up from a sitting position, also seemed significantly better in those with higher concentrations of vitamin D in their blood.

A relationship yet to be explained

According to the authors, the study shows a relationship, but the potential mechanism to explain the association between vitamin D levels and improved function is not fully known. It could be due to the vitamin's anti-inflammatory action and ability to maintain proper calcium and phosphate levels in bones. Dr. Glover also pointed out that the pain caused by 'osteoarthritis could limit physical activity, including outdoor activity promoting a 'further deficiency in vitamin D levels (sunlight stimulates its synthesis ) and increased obesity.   

Source: T.L. Glover, B.R. Goodin, C.D. King, et al. "A Cross-Sectional Examination of Vitamin D, Ob esity, and Measures of Pain and Function in Middle-Aged and Older Adults with Knee Osteoarthritis" The Clinical Journal of Pain. doi: 10.1097/AJP.0000000000000210