Associations of homocysteine metabolism with the risk of spinal osteoarthritis progression in postmenopausal women.

Purpose Although homocysteine accumulation is a reported risk factor for several age-related disorders, little is known on its relationship with osteoarthritis (OA). We therefore investigated for associations of homocysteine and C677T polymorphism in methylenetetrahydrofolate reductase (MTHFR), which is involved in homocysteine clearance, with the development and progression of spinal OA, through a combined cross-sectional and longitudinal cohort study. Methods A total of 1306 Japanese postmenopausal outpatients participating in the Nagano Cohort Study were followed for a 9.7-year mean period. Cross-sectional multiple logistic regression for spinal OA prevalence at registration by serum homocysteine level was performed with adjustment for confounders. In addition to Kaplan-Meier analysis, multivariate Cox regression was employed to examine the independent risk of MTHFR C677T variant for spinal OA progression. Results Multivariate regression analysis revealed a significant association between homocysteine and spinal OA prevalence (odds ratio 1.38; 95% confidence interval [CI] 1.14-1.68). Kaplan-Meier curves showed a gene dosage effect of the T allele in MTHFR C677T polymorphism on the accelerated progression of spinal OA severity (P = 0.003). A statistically significant independent risk of the T allele for spinal OA advancement was validated by Cox regression analysis. Respective adjusted hazard ratios for the CT/TT and TT genotypes were 1.68 (95% CI 1.16-2.42) and 1.67 (95% CI 1.23-2.28). Conclusions Circulating homocysteine and C677T variant in MTHFR are associated with the prevalence rate and ensuing progression, respectively, of spinal OA. These factors may represent potential interventional targets to prevent OA development and improve clinical outcomes.