Associations of LRP5 and MTHFR Gene Variants with Osteoarthritis Prevalence in Elderly Women: A Japanese Cohort Survey Randomly Sampled from a Basic Resident Registry.

OBJECTIVE: Osteoarthritis (OA) is a common and degenerative joint disorder in the elderly. A greater importance of understanding the relationship between genetic factors and OA prevalence has emerged with population aging. We therefore investigated the associations of several bone disease-related genetic variants with the prevalence of OA and osteoporosis in Japanese elderly women from the Obuse study cohort, which was randomly sampled from a basic town resident registry. METHODS AND RESULTS: In total, 206 female participants (mean ± standard deviation age: 69.7 ± 11.0 years) who completed OA, bone mineral density, and genotype assessments were included. The number of patients diagnosed as having knee/hip OA and osteoporosis was 59 (28.6%) and 30 (14.6%), respectively. Fisher's exact testing revealed significant relationships between the minor T allele of LDL receptor related protein 5 (LRP5) rs3736228 and the prevalence of knee/hip OA and osteoporosis. The respective odds ratios (ORs) of the TT genotype for knee/hip OA and osteoporosis were 7.28 (95% confidence interval [CI] 2.22-28.08) and 5.24 (95% CI 0.95-26.98). An additional subgroup analysis for knee OA revealed that the frequency of the common C allele of methylenetetrahydrofolate reductase (MTHFR) rs1801133 had a statistically significant protective association with the prevalence of knee OA (OR 0.58, 95% CI 0.35-0.97). CONCLUSION: In sum, the present study demonstrated significant associations of LRP5 rs3736228 and MTHFR rs1801133 with knee/hip OA and osteoporosis prevalences and knee OA prevalence, respectively, in Japanese elderly women. These results will help further the understanding of OA pathogenesis and related genetic risk factors.