RESUMEN
INTRODUCTION: Cholelithiasis is increasingly encountered in childhood and adolescence due to the rise in obesity. As in adults, weight loss is presumed to be an important risk factor for cholelithiasis in children, but this has not been studied. METHODS: In a prospective observational cohort study we evaluated the presence of gallstones in 288 severely obese children and adolescents (mean age 14.1±2.4 years, body mass index (BMI) z-score 3.39±0.37) before and after participating in a 6-month lifestyle intervention program. RESULTS: During the lifestyle intervention, 17/288 children (5.9%) developed gallstones. Gallstones were only observed in those losing >10% of initial body weight and the prevalence was highest in those losing >25% of weight. In multivariate analysis change in BMI z-score (odds ratio (OR) 3.26 (per 0.5 s.d. decrease); 95% CI:1.60-6.65) and baseline BMI z-score (OR 2.32 (per 0.5 s.d.); 95% CI: 1.16-4.70) were independently correlated with the development of gallstones. Sex, family history, OAC use, puberty and biochemistry were not predictive in this cohort. During post-treatment follow-up (range 0.4-7.8 years) cholecystectomy was performed in 22% of those with cholelithiasis. No serious complications due to gallstones occurred. CONCLUSION: The risk of developing gallstones in obese children and adolescents during a lifestyle intervention is limited and mainly related to the degree of weight loss and initial body weight.