Association between phosphorus intake and wrist fracture: the mediating role of bone mineral density.

BACKGROUND: Phosphorus correlates with bone mineral density (BMD), a key factor in fracture risk. Thus, BMD may mediate phosphorus-fractures association, which has not yet been elucidated. OBJECTIVE: This study aimed to trace phosphorus intake-wrist fracture association, and analyze the mediating role of BMD. METHODS: Data were derived from the National Health and Nutrition Examination Survey (NHANES) database. Logistic regression and restricted cubic spline (RCS) analyses were utilized to assess phosphorus intake-wrist fracture association. Subgroup analyses examined differences across populations with varying characteristics. Mediation analysis explored the potential mediating role of BMD in the phosphorus-wrist fracture association. RESULTS: A total of 7,952 participants were included. In the fully adjusted model, compared with the Q1 group, the Q4 group had a remarkably reduced wrist fracture risk (odds ratio [OR] = 0.58, 95% confidence interval [CI]: 0.38-0.88, P = 0.011). RCS revealed a non-linear association between phosphorus intake and wrist fracture (P-non-linear = 0.026). When phosphorus intake was <1,086.5 mg/day, higher intake correlated with lower wrist fracture risk; no significant negative association was observed beyond the threshold. In addition, no subgroups with interactions were identified (P-interaction > 0.05). Mediation analysis indicated that BMD mediated 12.1% of the association between phosphorus intake and wrist fracture. CONCLUSION: When phosphorus intake is <1,086.5 mg/day, higher intake is associated with reduced wrist fracture risk, with BMD as a key mediator. These findings provided crucial scientific evidence for developing targeted nutritional strategies to prevent wrist fractures.