Key determinants for lowering the risk of arthroplasty in weight-bearing joints: a population-based cohort study

Background Arthroplasty is used to treat advanced joint disease by reducing pain and restoring joint function. This study aimed to identify determinants associated with a lower risk of joint replacement (JR). Methods Longitudinal data from the Geelong Osteoporosis Study (GOS) were used. JR was identified via linkage with the Barwon Joint Registry, medical records, and self-report. Anthropometry, body composition, and blood biomarkers were obtained. Demographics, lifestyle, and comorbidities were self-reported. Fractures were identified from radiological reports. Participants with JR before baseline were excluded, leaving 2,882 eligible participants (1,436 men, 1,446 women; ages 20–96y). A time-dependent Cox regression model with age as the primary time scale and sex as a stratification variable was fitted. Forward stepwise regression identified relevant predictors. Results Over a median follow-up of 16.7 years (IQR: 9.7–23.2), 223 participants (7.7%) underwent JR. Protective factors included lower dietary calcium intake (HR:0.74, 95%CI: 0.52–1.04), lower body mass index (0.96, 0.94–0.99), lower spine bone mineral density (BMD) (0.84, 0.77–0.92), lower procollagen type 1 N-terminal propeptide (0.69, 0.50–0.96), non-fallers (0.74, 0.55–0.99) and no history of cancer (0.66, 0.48–0.90). Compared to low socioeconomic status (SES), participants with medium and high SES had an increased JR risk (1.91, 1.04–3.50; 1.88, 1.13–3.15), although the association was weaker in women (interaction: 0.48, 0.25–0.91). Conclusion While age-related spine degeneration may explain the link between higher spine BMD and JR, our findings highlight several factors that may contribute to reduced JR risk during ageing. Lower BMI, lower P1NP levels, lower dietary calcium intake, and fall prevention emerged as potentially modifiable pathways. The absence of cancer was also linked to a lower risk of JR. In addition, socioeconomic disparities offer potential pathways for reducing JR risk. These findings suggest that both biological, lifestyle and social determinants may play important roles in shaping long-term JR outcomes.