Abstract
BACKGROUND: Diet is a modifiable risk factor for gallstone formation and influence the risk of gallstone disease (GSD). The present study was designed with the aim of investigating the association between different dietary protein and the risk of GSD. METHODS: This case-control study was conducted on 189 patients diagnosed with GSD and 342 controls. Intake of total protein and its subgroups was measured based on food frequency questionnaire. Using multiple logistic regression models, crude and multivariable adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated. RESULTS: Total protein intake can have protective effects against GSD and its beneficial effect was more in moderate consumption (OR(T2 vs.T1) = 0.2, 95% CI 0.1-0.4) than high consumption (OR(T3 vs.T1) = 0.39, 95% CI 0.23-0.66) (p for trend < 0.001). The relationship between dairy protein intake and the risk of GSD was U-shaped, so that moderate intake was associated with a reduced risk (OR(T2 vs.T1) = 0.76) and higher intake was associated with an increased risk of the disease (OR(T3 vs.T1) = 1.5) (p for trend = 0.027). Vegetable protein as a protective factor and animal protein as a risk factor showed a significant relationship with the risk of GSD. CONCLUSION: Dietary protein intake, especially vegetable protein, may protect against GSD, while animal protein may be a predisposing factor. Dairy protein protects against GSD when consumed in moderation, but higher intakes may increase the risk of GSD.