Boosting levels of vitamin D, through supplements or sun exposure, may help ease knee pain for people with osteoarthritis.
That’s the upshort of a new study, published in the journal Arthritis & Rheumatism, that found black Americans with lower levels of vitamin D had greater pain sensitivity, compared to white Americans who have higher levels of the “sunshine vitamin.”
The findings, by University of Florida researchers, at the latest to suggest that vitamin D not only aids in calcium absorption, but also is a powerfully beneficial agent that acts on numerous functions throughout the body — including the body’s immune system — and may help reduce the risks of such diseases as cancer and diabetes.
"People associate vitamin D with good bone health," said lead researcher Toni Glover, a research nurse practitioner who specializes in the study of pain in older adults. "Yet, not everyone is aware of what factors decrease vitamin D and how low levels could contribute to health issues, including chronic pain."
With funding from the National Institute on Aging and the John A. Hartford Foundation and the Mayday Fund, Glover and colleagues from UF and the University of Alabama at Birmingham recruited 94 participants — 45 black and 49 white patients with knee osteoarthritis — to complete questionnaires regarding their symptoms and undergo testing that included sensitivity to heat and pain.
The results showed 84 percent of the black study participants had low vitamin D levels, compared to 51% of white subjects. They also reported greater overall knee pain and sensitivity to heat.
"Our data demonstrate that differences in experimental pain sensitivity between the two races are mediated at least in part by variations in vitamin D levels," said Glover. "It may be warranted that older black Americans with chronic widespread pain be screened for vitamin D deficiency to reduce disparities in pain."
Experts estimate 27 million Americans over 25 years of age have osteoarthritis. Most vitamin D in humans comes from exposure to the sun.