Association of serum carotenoids, retinol, and tocopherols with radiographic knee osteoarthritis: possible risk factors in rural Japanese inhabitants.
BACKGROUND
The consumption of antioxidant nutrients may influence the development and progression of osteoarthritis (OA). To determine the association between serum antioxidants and radiographic knee osteoarthritis, we undertook a cross-sectional investigation in a community-based study in Japan.


METHODS
A total of 562 subjects (224 male, 338 female) > or = 40 years of age were enrolled in the Comprehensive Health Examination Program (CHEP, Yakumo Study) from 2003 to 2005. Subjects were categorized to the OA group (n = 140) if either knee was graded as Kellgren-Lawrence (K-L) grade > or = 2. The no-OA group was defined as showing radiographic findings of K-L 0 or 1 in either knee (n = 422). The serum levels of retinol, beta-/gamma-tocopherols, alpha-tocopherol, zeaxanthin/lutein, canthaxanthin, cryptoxanthin, lycopene, alpha-carotene, and beta-carotene were measured by high-performance liquid chromatography. The values of these antioxidants were divided into tertiles, and a logistic regression analysis was performed to analyze the association between them and radiographic knee OA, adjusting for potential confounders.


RESULTS
Logistic regression analysis showed that compared to the lowest tertile of beta-/gamma-tocopherols the adjusted odds ratio (OR) was 0.52 [95% confidence interval (CI) 0.29-0.93] in the highest tertile; it also indicated a linear trend across tertiles. Furthermore, the adjusted OR was significantly decreased only in the middle tertile of alpha-tocopherol (OR 0.51, 95% CI 0.29-0.90). We reevaluated any independent association for these tocopherols after adjustment by entering them into the model simultaneously. The significance of beta-/gamma-tocopherols was maintained. In contrast, no associations were found with any carotenoids or retinol.


CONCLUSIONS
High serum values of beta-/gamma-tocopherols were found to be significantly associated with a low OR for radiographic knee osteoarthritis. The decreasing risk with a high serum value of beta-/gamma-tocopherols may support the possible protective effects against knee OA.
Seki
Taisuke
T
Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
Hasegawa
Yukiharu
Y
Yamaguchi
Jin
J
Kanoh
Toshiya
T
Ishiguro
Naoki
N
Tsuboi
Masaki
M
Ito
Yoshinori
Y
Hamajima
Nobuyuki
N
Suzuki
Koji
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000975:Antioxidants / Q000032:analysis; D002338:Carotenoids / Q000097:blood*; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D020370:Osteoarthritis, Knee / Q000097:blood* / Q000000981:diagnostic imaging; D011859:Radiography; D012307:Risk Factors; D012424:Rural Population; D024505:Tocopherols / Q000097:blood*; D014801:Vitamin A / Q000097:blood*
D000975:Antioxidants; D014801:Vitamin A; D002338:Carotenoids; D024505:Tocopherols