RT Journal Article SR Electronic T1 Relationship between Serum Magnesium Concentration and Radiographic Knee Osteoarthritis JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP jrheum.141414 DO 10.3899/jrheum.141414 A1 Chao Zeng A1 Jie Wei A1 Hui Li A1 Tuo Yang A1 Fang-Jie Zhang A1 Ding Pan A1 Yong-Bing Xiao A1 Tu-Bao Yang A1 Guang-Hua Lei YR 2015 UL http://www.jrheum.org/content/early/2015/05/25/jrheum.141414.abstract AB Objective To establish whether there is a relationship between serum magnesium (Mg) concentration and radiographic knee osteoarthritis (OA). Methods There were 2855 subjects in this cross-sectional study. Serum Mg concentration was measured using the chemiluminescence method. Radiographic OA of the knee was defined as changes consistent with Kellgren-Lawrence (K-L) grade 2 on at least 1 side. Mg concentration was classified into 1 of 4 quartiles: ≤ 0.87, 0.88–0.91, 0.92–0.96, or ≥ 0.97 mmol/l. Multivariable logistic analysis was used to test the association between serum Mg and radiographic knee OA after adjustment for potentially confounding factors. The OR with 95% CI for the association between radiographic knee OA and serum Mg concentration were calculated for each quartile. The quartile with the lowest value was regarded as the reference category. Results Significant association between serum Mg concentration and radiographic knee OA was observed in the model after adjustment for age, sex, and body mass index, as well as in the multivariable model. The multivariable-adjusted OR (95% CI) for radiographic knee OA in the second, third, and fourth serum Mg concentration quartiles were 0.90 (95% CI 0.71–1.13), 0.92 (95% CI 0.73–1.16), and 0.72 (95% CI 0.57–0.92), respectively, compared with the lowest (first) quartile. A clear trend (p for trend was 0.01) was observed. The relative odds of radiographic knee OA was decreased by 0.72 times in the fourth serum Mg quartile compared with the lowest quartile. Conclusion Serum Mg concentration may have an inverse relationship with radiographic OA of the knee.