Objective: The risk of gallstones among metabolically healthy obesity (MHO) individuals is largely unexplored. Therefore, the present study investigated the association between MHO and gallstones in a health check-up cohort of Chinese adults.
Design: A prospective cohort study.
Methods: Participants included 58 862 individuals from the MJ health check-up cohort aged ≥ 18 years without a history of gallstones at baseline. Gallstones were diagnosed using abdominal B-type ultrasound. Metabolically healthy was defined as not having any one of the components of metabolic syndrome. Obesity was identified by BMI and waist circumference (WC). Participants were cross-classified at baseline by metabolic health and obesity. Adjusted hazard ratios (HRs) and 95% CIs of gallstones across BMI or WC categories were estimated with Cox proportional hazard regression models.
Results: During a median follow-up of 3.0 years (interquartile range, 1.6-6.1), 1269 participants developed gallstones. Individuals with MHO (HR: 1.95, 95% CI: 1.23, 3.09 for BMI criteria; HR: 1.74, 95% CI: 1.37, 2.21 for WC criteria) had a significantly higher risk of gallstones than those with metabolically healthy normal weight. In metabolically healthy individuals, BMI and WC both displayed linear dose-response relationships with gallstones (P for non-linearity >0.05). The association between MHO and gallstones remained unchanged when using different criteria for metabolic health and obesity.
Conclusions: MHO was significantly associated with gallstones, suggesting that obesity can independently contribute to gallstones development, even among metabolically healthy individuals. These findings emphasize that metabolically healthy individuals may still benefit from maintaining normal body weight to prevent gallstones.