Author
NEOGI, TUHINA - BOSTON UNIV SCH OF MED | |
BOOTH, SARAH - TUFTS/HNRCA | |
ZHANG, YU QING - BOSTON UNIV SCH OF MED | |
JACQUES, PAUL - TUFTS/HNRCA | |
TERKELTAUB, ROBERT - UNIV CALIF AT SAN DIEGO | |
ALIABADI, PIRAN - BRIGHAM & WOMENS HOSPITAL | |
FELSON, DAVID - BOSTON UNIV SCH OF MED |
Submitted to: Journal of the American Medical Association
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/30/2005 Publication Date: 3/29/2006 Citation: Neogi, T., Booth, S.L., Zhang, Y., Jacques, P.F., Terkeltaub, R., Aliabadi, P., Felson, D.T. 2006. Low vitamin k status is associated with osteoarthritis in the hand and knee. Journal of the American Medical Association. 54(4):1255-1261. Interpretive Summary: Poor functioning of vitamin K-dependent compounds in the body is associated with abnormal cartilage and bone mineralization. Further, osteophytes (abnormal bony outgrowths in the joints) occur during low vitamin K status. Our objective was to determine the association of vitamin K status with osteoarthritis. Participants of the Framingham Osteoarthritis Study who had X-rays of both hands and knees, and who completed a food frequency questionnaire (FFQ) (dietary study) or who had plasma vitamin K measures (biochemical study) were included. Each hand and knee joint was scored for the presence of osteoarthritis. We determined the presence of osteoarthritis relative to vitamin K measure for each joint. All analyses were adjusted for age, sex, body mass index, hip bone mineral density, plasma or dietary vitamin D, and total energy intake. In the dietary study (511 men and 765 women with an average age of 76 years), we found no significant association of vitamin K intake with any of the hand or knee osteoarthritis measures - except that with increasing intake of vitamin K, there was a decrease in the mean number of hand joints having osteophytes. In the biochemical study (314 men and 358 women with an average age of 65 years), there was a decrease in the number of joints in the hand with osteoarthritis with increased plasma vitamin K levels. For the knee, there was a decrease in the number of knee joints with osteophytes with increased vitamin K levels. Low vitamin K status, especially when assessed using biochemical measures, is associated cross-sectionally with more osteoarthritis, including the number of osteophytes, in the hand and knee. These observational data support a relationship between low vitamin K status and possibly overall hand osteoarthritis. Technical Abstract: Subnormal functioning of vitamin K (VK)-dependent proteins is associated with abnormal cartilage and bone mineralization. Further, osteophyte (OST) growth recapitulates the process of growth plate mineralization, which depends on VK proteins. Our objective was to determine the association of VK status with radiographic features of osteoarthritis (OA). Participants of the Framingham Osteoarthritis Study who had bilateral hand and knee radiographs and who completed a food frequency questionnaire (FFQ) (dietary study) or had plasma VK measures (biochemical study) were included. Each hand and knee joint was scored for presence of OA (Kellgren and Lawrence grade >/= 2), OST (0-3), and joint space narrowing (JSN) (0-3). We cross-sectionally determined the prevalence ratios (PR) of OA per quartile of VK measure for each joint, adjusting for correlated joints using GEE, and the adjusted mean number of joints with OA per quartile of VK measure. We repeated these analyses for OST and JSN. All analyses were adjusted for age, sex, BMI, hip BMD, plasma or dietary vitamin D, and total energy intake. In the dietary study (1276 subjects; mean age: 76.0 years, 765 female), we found no significant association of VK intake with any of the hand or knee OA phenotypes except that with increasing intake of VK, there was a decrease in the mean number of hand joints with OST (3.0 to 2.5, p=0.04). In the biochemical study (672 subjects; mean age: 65.6 years, 358 female), the PR and adjusted mean number of joints for all three outcomes in the hand significantly decreased with increasing VK levels (p=0.01 for all). For example, PR for hand OA decreased from 1.0 to 0.7 (p=0.005), and adjusted mean number of hand joints with OA decreased from 4.4 to 3.0 (p=0.007). For the knee, only PR for OST and adjusted mean number of knee joints with OST decreased significantly with increasing VK levels (PR=1.0 to 0.6, p=0.01; adjusted mean number of knee joints with OST: 0.2 to 0.1, p=0.007). Low VK status, especially when assessed using biochemical measures, is associated cross-sectionally with more OA, including OST and JSN, in the hand, and with OST in the knee. These observational data support a relationship between low VK status and large OST in the hand and knee, and possibly overall hand OA. |