Turkish researchers at the Ankara Physical Medicine and Rehabilitation Training and Research Hospital recently published a paper detailing the connection between 25(OH)D levels and the risk of developing osteoarthritis:
Osteoarthritis (OA) is the most common form of arthritis worldwide. In people with OA, 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 OA 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 OA of the knee. A lower intake of the fat soluble vitamins (A, D, E, and K) has also been linked to an increased risk of developing OA.
For these reasons, the researchers decided to further explore this connection between vitamin D levels and OA. They recruited 80 women between the ages of 20 and 45 that did not have pain or problems with their knee joints. The women were divided into three groups based on their vitamin D levels:
- <10 ng/mL
- >10 ng/mL but < 20 ng/mL
- >20 ng/mL
The researchers then measured the thickness of the cartilage in the knees of the women by ultrasound. In the <10 ng/mL group, the cartilage in the knees was thinner in all places measured when compared with the other groups of women. However, only the measurements of the left medial condyle were statistically significantly thinner. The researchers concluded that being severely deficient in vitamin D increases the risk of developing OA.
This study is interesting because it is the first to measure the thickness of knee cartilage with ultrasound and compare it to vitamin D levels. The results are more reliable because only younger women without any knee problems were included, and women that may have had other health problems that could affect their knee joints were excluded. Some weaknesses include a low amount of study participants, including only women, and vitamin D was measured only one time during the study.
Still, a growing body of research indicates that having a low vitamin D level may put you at risk for developing OA. Furthermore, a study last year suggested that vitamin D supplementation may be able to help with OA-associated pain. This gives reason that if you have or are worried about getting OA, making sure you’re sufficient in vitamin D is one of many measures you can take to better your prognosis.