Insufficient Vitamin D Could Boost Arthritis Risk

0

Vitamin Ds important role in bone health, already linked to protection against osteoporosis, may extend to joints and prevention of the most common form of arthritis. A new study reports that men with insufficient vitamin D levels were twice as likely to have hip osteoarthritis as those with normal vitamin D.R. Krishna Chaganti, MD, of the University of California at San Francisco, and colleagues analyzed data on 1,104 older men in the Osteoporotic Fractures in Men Study. Participants, who averaged almost 78 years old, had their blood levels of vitamin D measured and then, about 4.5 years later, underwent pelvic radiography to look for signs of arthritis in the hips.Just as low vitamin D levels (15.1- 30 ng/mL) were associated with greater likelihood of arthritis, men with higher vitamin D levels (above 30 ng/mL) were less likely to have arthritis in the hips. The results were adjusted for age, season of the year and site of the clinic where testing was done.The association of low vitamin D levels with hip osteoarthritis underscores the potentially important role of vitamin D in the origins of arthritis, Dr. Chaganti and colleagues concluded. Although the study wasnt designed to determine the mechanism by which vitamin D might help prevent arthritis, the researchers noted that substances formed in vitamin D metabolism are associated with regulating the development and maintenance of bone and cartilage.They added, Vitamin D influences the mineralization of bone matrix, and low serum levels of vitamin D may result in poorly mineralized bone that might alter forces across the joint.Results of previous studies on vitamin D and arthritis have been mixed. One study failed to find a link between vitamin D levels and worsening of knee osteoarthritis, while a second study did find an association, especially in patients with decreased bone mineral density in the spine.More definitive answers may come from a randomized clinical trial led by Timothy E. McAlindon, MD, MPH, of Tufts School of Medicine, thats now wrapping up.The Daily Value (DV) of vitamin D for ages 51-70 is 400 IU and for ages 71-plus is 600 IU, although many experts believe these amounts are too low. An Institute of Medicine panel is currently reviewing vitamin D recommendations.TO LEARN MORE: Arthritis & Rheumatism, February 2010; abstract at www3.interscience.wiley.com/ journal/123266995/abstract.

Vitamin D Signals Immune System to Fight Infections
Got the sniffles? Maybe a few minutes in the sun will help. Vitamin D, the sunshine vitamin, is also apparently essential to fighting off infections. Danish scientists have discovered that T cells, the killer cells the bodys immune system enlists to combat infections, require vitamin D to activate. When a T cell is exposed to a foreign pathogen, it extends a signaling device or antenna known as a vitamin D receptor, with which it searches for vitamin D, explained Carsten Geisler, MD, PhD, DSc, of Copenhagen University. This means the T cell must have vitamin D or activation of the cell will cease. If the T cells cannot find enough vitamin D in the blood, they wont even begin to mobilize. The finding could have significant implications in the Third World and the fight against global epidemics: Nearly half the worlds population has sub-optimal levels of vitamin D, a problem thats getting worse as people spend more time indoors.TO LEARN MORE: Nature Immunology, online before print, dx.doi.org/10.1038/ni.1851.

LEAVE A REPLY

Please enter your comment!
Please enter your name here