Do antioxidant micronutrients protect against the development and progression of knee osteoarthritis?

Abstract

Objective. Cumulative damage to tissues, mediated by reactive oxygen species, has been implicated as a pathway that leads to many of the degenerative changes associated with aging. We hypothesized that increased intake of antioxidant micronutrients might be associated with decreased rates of osteoarthritis (OA) in the knees, a common age-related disorder.Methods. (range 0-3). The association of vitamin C, beta carotene, and vitamin E intake, ranked in sex-specific tertiles, with incidence and progression of OA was compared with that of a panel of nonantioxidant vitamins, B,, B,, niacin, and folate, using logistic regression and generalized estimation equations to adjust for correlation between fellow knees. The lowest tertile for each dietary exposure was used as the referent category. Odds ratios (OR) were adjusted for age, sex, body mass index, weight change, knee injury, physical activity, energy intake, and health status.Results. Six hundred forty participants received complete assessments. Incident and progressive OA occurred in 81 and 68 knees, respectively. We found no significant association of incident OA with any nutrient. A 3-fold reduction in risk of OA progression was found for both the middle tertile (adjusted OR = 0.3, 95% confidence interval [95% CI] 0.14.8) and highest tertile (adjusted OR = 0.3, 95% CI 0.1-0.6) of vitamin C intake. This related predominantly to a reduced risk of cartilage loss (adjusted OR = 0.3, 95% CI 0.1-0.8). Those with high vitamin C intake also had a reduced risk of developing knee pain (adjusted OR = 0.3, 95% CI 0.14.8). A reduction in risk of OA progression was seen for beta carotene (adjusted OR = 0.4, 95% CI 0.20.9) and vitamin E intake (adjusted OR = 0.7,95% CI 0.3-1.6), but was less consistent. No significant associations were observed for the nonantioxidant nutrients.Conclusion. High intake of antioxidant micronutrients, especially vitamin C, may reduce the risk of cartilage loss and disease progression in people with OA. We found no effect of antioxidant nutrients on incident OA. These preliminary findings warrant confirmation.Oxidative damage to DNA, proteins, and other macromolecules accumulates with time and is postu-

Prognostic factors of progression of osteoarthritis of the knee: A systematic review of observational studies

“…McAlindon et al (13,35) investigated the relationship between nutrition variables and progression of OA. For vitamin D, a low dietary intake and low serum level were statistically and significantly associated with progression of knee OA (OR 4.05, 95% CI 1.40 -11.6 and OR 2.89, 95% CI 1.01-8.25 for lowest versus highest tertile of dietary intake and serum levels, respectively).…”

Dietary manipulation in musculoskeletal conditions

“…McAlindon and colleagues [68] conducted a prospective observational study of the effect of dietary antioxidant nutrients (vitamin C, E and β-carotene) on OA of the knee as part of the Framingham Osteoarthritis Cohort Study. A significant three-fold reduction in risk of OA progression, which related predominantly to a reduced risk of cartilage loss, was found for both the middle and the highest tertile of vitamin C intake.…”

Ascorbic acid increases the severity of spontaneous knee osteoarthritis in a guinea pig model

“…Based upon results of short-term studies in the guinea pig (1,2) and an epidemiologic study in humans (3), it has been suggested that ascorbic acid might be protective against osteoarthritis (OA). The antioxidant properties of ascorbic acid have been posited as one explanation for these results.…”