Insufficient vitamin D supply may increase osteoarthritis risk

According to a new study from Turkey women with low levels of vitamin D seem to have thinner femoral cartilage, increasing their risk of developing osteoarthritis of the knee.

The observational study measured blood vitamin D concentrations and thickness of cartilage in the knees of 80 women between the ages of 20 and 45 who did not have pain or problems with their knee joints (1). The study results showed that women with very low vitamin D values (below 10 ng/mL) had significantly thinner femoral cartilage.

The researchers concluded that being severely deficient in vitamin D seems to increase the risk of develo- ping osteoarthritis. These findings are supported by earlier research indicating that vitamin D supplementa- tion may be able to help with osteoarthritis associated pain (2).

Osteoarthritis is the most common form of arthritis worldwide. In people with osteoarthritis, the cartilage in the joints wears down over time, causing pain. It is commonly referred to as “wear and tear” arthritis, to differentiate it from the autoimmune disorder rheumatoid arthritis. Risk factors for osteoarthritis include age, obesity, previous injury, and being female. An adequate vitamin D intake is necessary for normal bone and cartilage turnover, and previous epidemiologic research has shown a connection between low vitamin D levels and having osteoarthritis of the knee. Lower concentrations of antioxidant vitamins (C and E in parti- cular) in joint fluid has also been linked to an increased osteoarthritis risk (3).

1. Malas F. U. et al. Does vitamin D affect femoral cartilage thickness? An ultrasonographic study. Clin Rheumatol. Published online 2013.
   
2. Sanghi D. et al. Does vitamin D improve osteoarthritis of the knee: a randomized controlled pilot trial. Clin Orthop Relat Res. 2013; 471(11):3556-3562.
   
3. Regan E. A. et al. Joint fluid antioxidants are decreased in osteoarthritic joints compared to joints with macroscopically intact cartilage and subacute injury. Osteoarthritis Cartilage. 2008; 16(4):515–521.