Gallstones - Genetics versus environment

Objective The aim of this study was to determine if a significant genetic component contributes to the pathogenesis of symptomatic gallstones. Summary Background Data Gallstones represent a polygenic disorder that affects more than 30,000,000 Americans and results in more than 750,000 cholecystectomies in the United States annually. Risk factors include age, gender, race, parity, obesity, and diabetes, A family history of gallstones also has been identified as a risk factor suggesting that genetics play a role in gallstone formation, However, the role of genetics in the pathogenesis of gallstone formation has not been determined. Methods A gallbladder disease-specific questionnaire was administered to 904 healthy unrelated adult volunteers (association study). The questionnaire ascertained a history of cholecystectomy and gallstone disease in first-degree relatives, as well as medical history, demographic, and anthropometric data. A logistic regression model was used to identify risk factors for symptomatic gallstone disease in a multivariate analysis. A maximum likelihood based variance decomposition approach was then used in 1,038 individuals from 358 families (family study) to estimate the additive genetic heritability of symptomatic gallstone disease. Results In the association study significant risk factors for symptomatic gallstone disease were female gender (relative risk 8.8, P < .003), obesity (BMI > 30, relative risk 3.7, P < .001), age > 50 (relative risk 2.5, P <.001), and a positive family history of previous cholecystectomy in a first-degree family member (relative risk 2.2, P < .01). In the family study the additive genetic heritability of symptomatic gallstones was 29% (P < .02), age and gender were significant covariates and explained 9.3% of the phenotypic variation in gallbladder disease. Conclusions These data suggest that genetic factors are responsible for at least 30% of symptomatic gallstone disease. However, the true role of heredity in gallstone pathogenesis is probably higher because data based on symptomatic gallbladder disease underestimates the true prevalence in the population.