Influence of longitudinal trajectories of body mass index on new-onset gallstone disease

Objective To investigate the effect of longitudinal trajectories of body mass index( BMI) on new-onset gallstone disease.Methods A prospective cohort study was conducted for 44168 employees who underwent physical examination in Kailuan General Hospital in 2006,2008,and 2010,and related data,including BMI,were collected. Physical examination was performed once every two years,and the employees were followed up to observe the onset of gallstone disease. According to the longitudinal trajectories of BMI,the employees were divided into low-stable group with 14888 employees,medium-stable group with 22334 employees,and high-stable group with 6948 employees. A one-way analysis of variance was used for comparison of normally distributed continuous data between multiple groups,and the Kruskal-Wallis H test was used for comparison of continuous data with skewed distribution between multiple groups; the chi-square test was used for comparison of categorical data between groups. The Kaplan-Meier method was used to calculate the cumulative incidence rate of gallstone disease in each group,and the log-rank test was used for comparison between groups. The Cox proportional-hazards regression model was used to analyze the influence of longitudinal trajectories of BMI on the onset of gallstone disease. Results the mean follow-up of 5. 41 years,a total of 902 patients with gallstone disease were observed,and the cumulative incidence rates of gallstone disease in the low-stable group,the medium-stable group,and the high-stable group were 4. 80%,5. 25%,and 9. 45%,respectively,with a significant difference between groups based on the log-rank test( χ2= 81. 86,P < 0. 01). After adjustment for confounding factors in the Cox proportional hazards model,compared with the low-stable group,the medium-stable group and the high-stable group had a risk of gallstone disease increased by 1. 55 times( 95% confidence interval[CI]: 1. 31-1. 84) and 2. 29 times( 95% CI: 1. 86-2. 80),respectively. Conclusion The ncreased longitudinal trajectory of BMI is an independent risk factor for the onset of gallstone disease.