Bone Mineral Density and Radiographic Knee Osteoarthritis in Elderly Hakka Women: Ethnic-Specific Insights from an Aged Population

Purpose Osteoporosis and knee osteoarthritis are prevalent and often coexisting musculoskeletal conditions in elderly women, but their interrelationship remains controversial. Recent studies suggest this association may vary by disease severity and ethnicity. Ethnic-specific data on bone health are especially scarce among the Hakka, a major Han Chinese subgroup. Methods We conducted a retrospective study of community-dwelling Hakka women aged ≥ 65 years in a super-aged region. Anthropometric data (age, height, weight, BMI) and bone mineral density (BMD) of the lumbar spine and hips were obtained using dual-energy X-ray absorptiometry (DXA). Radiographic knee osteoarthritis was defined by Kellgren–Lawrence grade ≥ 3. Pearson correlation and multivariable regression analyses were used to evaluate the associations among anthropometric variables, osteoarthritis status, and BMD. Results Among 607 women, age was negatively correlated with BMD, while weight and BMI were positively associated. Women with radiographic knee osteoarthritis had significantly higher BMD at the lumbar spine and both hips. In multivariable models, age, weight, and BMI were independent predictors of lumbar BMD, jointly explaining 31% of its variance. Higher age, body weight, and BMI were also associated with increased odds of having knee osteoarthritis. Conclusions In this ethnic-specific cohort of elderly Hakka women, knee osteoarthritis was associated with greater BMD, supporting a possible protective effect via mechanical loading. These findings align with prior evidence of a nonlinear osteoarthritis–BMD relationship and suggest that higher bone mass in osteoarthritis may not necessarily indicate lower fracture risk. Our results underscore the need for culturally tailored osteoporosis assessment strategies and consideration of joint health in bone health evaluations.