To investigate the effect of the Lifestyle Inflammation Score (LIS) on the risk of developing inflammatory bowel disease.

Utilizing data from the prospective cohort study of the UK Biobank (UKB), the Lifestyle Inflammation Score was calculated, and participants were categorized into three groups based on their tertiles: LIS1 (<-0.18), LIS2 (-0.18 to 0.50), and LIS3 (>0.50). The cumulative incidence of IBD and its subtypes was calculated using the Kaplan-Meier method, and inter-group comparisons were conducted using the Log-rank test. Cox regression models were employed to analyze the hazard ratios (HR) and 95% confidence intervals (95%CI) for the occurrence of IBD, ulcerative colitis (UC), and Crohn’s disease (CD) across different LIS groups.

A total of 365 343 participants were included in the study, with a median follow-up period of 12.62 years. The incidence counts for IBD, UC, and CD were 2 784, 1 969, and 993, respectively. The Log-rank test revealed a statistically significant difference in the cumulative incidence of IBD among the three groups (χ²=7.973, P<0.05). Using the occurrence of IBD as the dependent variable and LIS grouping as the independent variable, after adjusting for confounding factors such as age, gender, history of breastfeeding, and appendectomy, the risk of developing IBD was found to increase in the LIS3 group compared to LIS1 group (HR=1.155, 95%CI: 1.041-1.281). In subgroup analyses, the risk of developing UC was also elevated in the LIS3 group compared to LIS1 (HR=1.150, 95%CI:1.015-1.304), while no significant trend was observed in the CD subgroup.

The Lifestyle Inflammation Score is positively correlated with the risk of IBD and UC, but does not significantly increase the risk of CD.