Lower Bone Mineral Density Can Be a Risk for an Enlarging Bone Marrow Lesion: A Longitudinal Cohort Study of Japanese Women Without Radiographic Knee Osteoarthritis.

OBJECTIVES To elucidate the longitudinal relationship between bone mineral density (BMD) at baseline and the change of bone marrow lesion (BML) during a two-year follow-up period (2YFU). METHODS Seventy-eight female participants (Mean age: 54.9 ± 9.6) without radiographic knee osteoarthritis were eligible. Based on right-knee MRI, maximum BML area (BMLa) was calculated by tracing BML border. The change in BMLa was defined using the following formula: [2YFU] - [Baseline] = ΔBMLa. Positive ΔBMLa was defined as enlarged; negative ΔBMLa was defined as regressed. Dual-energy X-ray absorptiometry was performed to measure the BMD of distal radius. Young adult mean [YAM (%)] of the BMD was used for statistical analysis. Linear regression analysis was conducted with ΔBMLa as the dependent variable and YAM as the independent variable. ROC curve and logistic regression analysis were conducted for YAM to predict the prevalence of BML enlargement or regression. RESULTS Twenty-six (33.3%) patients had enlarged BMLa, 12 (15.4%) participants showed regressing BMLa, and 40 (51.3%) patients remained stable. YAM was negatively associated with ΔBMLa (β: - 0.375, P=0.046). The best predictor of BML enlargement risk was 85% YAM; this cut-off could predict the prevalence of BML enlargement (Odds ratio: 8.383, P=0.025). CONCLUSIONS Lower BMD could predict BML enlargement during a two-year follow-up period.