Calcium2026-06

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

Suleiman Aminu, Lotfaliany Mojtaba, Williams Lana J, Stuart Amanda L et al. — Arthroplasty (London, England)

Summary

This long-term study investigated factors that might reduce the need for hip or knee joint replacement surgery. Researchers found that a lower body mass index (BMI) was linked to a lower risk. Interestingly, while lower dietary calcium intake initially appeared to reduce risk, this connection became less clear when calcium supplement use was considered, suggesting a more complex relationship than a simple cause-and-effect.

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Key points

A lower body mass index (BMI) was associated with a reduced risk of needing joint replacement surgery.
The study initially found that lower dietary calcium intake seemed linked to a lower risk of joint replacement.
However, this link between dietary calcium and joint replacement risk was complicated by calcium supplement use.
Other factors like lower spine bone density and not experiencing falls also showed associations with reduced risk.

What the study looked at

What question did this study ask? This research aimed to identify factors that might reduce a person's risk of needing hip or knee joint replacement surgery, which is performed to alleviate pain and restore function in severely damaged joints. How was it studied? Researchers followed nearly 3,000 Australian men and women, aged 20 to 96, for an average of over 16 years. They collected extensive data on participants' body measurements, lifestyle, medical history, and blood markers, then tracked who eventually underwent joint replacement surgery. What did it find? The study found that a lower body mass index (BMI) was consistently linked to a reduced risk of joint replacement. Interestingly, while a lower intake of calcium from food initially appeared to reduce this risk, this connection became less clear once calcium supplement use was taken into account. The authors suggest this complex finding might be due to people with existing joint issues changing their diet or supplement habits. Other factors like lower spine bone density and not experiencing falls were also associated with a lower risk.

Dietary takeaway

This study suggests that maintaining a healthy weight, indicated by a lower BMI, may be beneficial for long-term joint health. While the role of dietary calcium in preventing joint replacement is not straightforward in this research, it's important to ensure adequate calcium intake for overall bone health through foods like dairy, leafy greens, and fortified products. Remember, this is one study, and more research is needed to fully understand the complex interplay of diet, calcium, and joint health.

Abstract

BACKGROUND: Hip and knee replacement (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 20-96 years). A time-dependent Cox regression model with age as the primary time scale and sex as a stratification variable was fitted. Forward stepwise and the least absolute shrinkage and selection operator (LASSO) 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. Factors with the reduced risk of JR included lower body mass index (HR 0.96, 95% CI, 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). Lower dietary calcium intake (0.74, 0.52-1.04) was associated with the reduced risk of JR in the main models, but this association was attenuated after accounting for supplement use. Compared with low socioeconomic status (SES), participants with medium and high SES had higher 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: Age-related spine degeneration may explain the link between higher spine BMD and JR. The association between lower dietary calcium intake and reduced JR risk is likely driven by confounding by indication or reverse causality. Lower BMI and lower P1NP levels emerged as potentially modifiable pathways. The absence of falls and no history of cancer were associated with reduced JR risk; however, the cancer association was attenuated in the Fine-Gray analysis when competing mortality was accounted for, and the fall association should be interpreted as observational rather than as evidence of a modifiable pathway. Socioeconomic disparities also highlight potential avenues for reducing JR risk. Overall, these findings suggest that biological, lifestyle, and social determinants may play important roles in shaping long-term JR outcomes.

View on PubMed →DOI: 10.1186/s42836-026-00403-9