Association of waist circumference trajectories with incident chronic kidney disease

Background: Chronic kidney disease (CKD) is a major public health burden. Waist circumference (WC) is associated with CKD risk, but the prognostic significance of longitudinal WC change remains uncertain. We examined the association between WC trajectories and incident CKD in Korean adults. Methods: This retrospective cohort study included 5,429 adults aged 40-69 years from the Korean Genome and Epidemiology Study Ansan-Ansung cohort who were free of CKD at baseline and during the 6-year exposure period. WC trajectories were classified as stable, increasing, or decreasing using Gaussian finite mixture modeling. Incident CKD during the subsequent 12-year event accrual period was defined as new-onset reduced estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 or urine dipstick albumin ≥1+ on two consecutive measurements. Multivariable Cox models estimated hazard ratios (HRs) and 95% confidence intervals (CIs). Results: Over a median follow-up of 11.8 years, 576 participants (10.6%) developed CKD. Compared with the stable WC trajectory, the increasing WC trajectory was associated with a higher risk of incident CKD (adjusted HR, 1.41; 95% CI, 1.17-1.71), whereas the decreasing trajectory was not (adjusted HR, 0.83; 95% CI, 0.56-1.23). Secondary analyses showed higher risks of incident reduced eGFR and new-onset dipstick albuminuria in the increasing WC group, and time-varying Cox analysis supported the primary finding. Restricted cubic spline analysis demonstrated a significant linear dose-response relationship. Conclusion: Serial WC increase may serve as a simple, clinically accessible marker of cumulative metabolic burden and future CKD risk.