Association of Legume Intake with Incident Hyperuricemia: A Prospective Cohort Study in Shanghai Adult Residents

Objective: To evaluate the relationship between legume intake and incident hyperuricemia among Chinese adults using large-scale prospective cohort data. Methods: Baseline and follow-up information from the Shanghai Suburban Adult Cohort and Biobank (SSACB) were used to assess diet and hyperuricemia incidence [serum uric acid (SUA) ≥ 420 μmol/L in males and ≥ 360 μmol/L in females]. A Food Frequency Questionnaire (FFQ) covering 29 food categories quantified food consumption during the previous 12 months. Legume intake was calculated by multiplying the reported consumption of each item by (1 - water content), and participants were classified into tertiles with the lowest third (Q1) as the reference. Cox proportional-hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs), and restricted cubic splines (RCSs) with three knots (10th, 50th, and 90th percentiles) visualized the dose-response relation. Results: Among 43,371 participants, 1456 new cases of hyperuricemia were documented over 225,002.40 person-years (incidence density 6.47/1000 person-years; 95% CI 6.14-6.80). Incidence density decreased with higher legume intake: each 1 g/day increment was associated with a 2% lower risk (HR 0.98; 95% CI 0.97-0.99; p < 0.05). Compared with Q1, the highest tertile (Q3) showed a 26% risk reduction in the fully adjusted model (HR 0.74; 95% CI 0.64-0.86; p < 0.05). RCS revealed a significant nonlinear relationship (p-overall < 0.001, p-nonlinear = 0.0013), with the significant benefit in risk observed at 6-28 g/day. Conclusions: Legume intake is nonlinearly and inversely associated with hyperuricemia risk among Shanghai suburban adults. Given that the current low median intake, comprehensive strategies are needed to rationally adjust the dietary structure, improve legume intake, and provide sustainable development strategies for effective prevention and control of hyperuricemia.