Persistent status of metabolic syndrome and risk of cholangiocarcinoma: A Korean nationwide population-based cohort study

It is unknown whether persistent metabolic syndrome (MetS) is associated with an increased risk of cholangiocarcinoma (CCA). Therefore, we investigated the risk of CCA according to changes in MetS status.This nationwide cohort study included 8,581,407 adults who underwent anthropometric measurements and laboratory tests in two consecutive national health screenings during 2009-2012 and observed the subjects until 2017. Individuals with cancer, or follow-up duration1 year were excluded (n = 377,915). Subjects were classified into the MetS-free, MetS-developed, MetS-improved, and MetS-persistent groups. The outcome was the incidence of CCA, identified using the claims database. Multivariable Cox proportional hazards regression models were used.Among the 8,203,492 subjects (mean age 48.9 ± 12.8 years; 56.7% male), 7506 CCA patients were newly identified during a median follow-up of 5.1 years. The probability of CCA was consistently higher in the MetS-persistent group than in the MetS-free group (P 0.001). MetS-persistent status was significantly associated with an increased risk of CCA compared with the MetS-free status (unadjusted hazard ratio [HR] 2.8, 95% confidence interval [CI] 2.66-2.95), even after adjusting for multiple covariates (adjusted HR 1.07, 95% CI 1.01-1.13). Improved or newly developed MetS was not associated with CCA risk in the fully adjusted model (aHR 1.02, 95% CI 0.94-1.10 and aHR 0.99, 95% CI 0.92-1.06, respectively).MetS was associated with an increased risk of CCA if it persisted for ≥2 years. Our finding suggests that MetS may be a potentially modifiable risk factor for CCA.