D-laying arthritis.

It's only one study, so don't get your hopes up. But it looks like vitamin D may show osteoarthritis, say researchers at Boston University Medical Center and elsewhere.

Between 1987 and 1989, David Felson and co-workers measured vitamin D intakes and blood levels in 556 participants in the ongoing Framingham Study. Each volunteer had his or her knees X-rayed once between 1983 and 1985 and again between 1992 and 1993.

Vitamin D wasn't related to the risk of getting arthritis in the 394 people who started out with healthy knees. But among the 162 people whose knees were already arthritic on the first X-ray, those with low levels of vitamin D in their blood or their diets were three times more likely to D get worse than those with higher levels.

"A vitamin D deficiency could impair the body's ability to repair the damage that arthritis causes in both bone and cartilage," says Felson. "It's smart to get the recommended, levels of vitamin D whether our findings are corroborated by future studies or not." The Daily Value for vitamin D is 400 International Units (IU).

In a previously study, Felson found that arthritis progressed more slowly in people who consumed 150 to 180 mg or more of vitamin C a day. One explanation: "Vitamin C is known to be important in the synthesis of collagen, which makes up much of the cartilage in the knee," he says.

Annals of Internal Medicine 125:353, 1996.