Long-term risk of irritable bowel syndrome associated with triglyceride-glucose related indices: a large-scale prospective cohort study

Background: Insulin resistance (IR) may play a crucial role in irritable bowel syndrome (IBS) pathogenesis. However, it remains unclear whether triglyceride-glucose (TyG)-related indices, useful biomarkers for assessing IR, are associated with IBS development. Objectives: To investigated the link between baseline TyG-related indices and incident IBS. Design: A prospective, population-based cohort study. Methods: Participants free of IBS with available TyG-related indices (TyG-waist circumference (TyG-WC), TyG-waist-to-height ratio (TyG-WHtR), and TyG-body mass index (TyG-BMI)) at enrollment were included ( N = 356,904). Primary endpoint was incident IBS. Cox regression was used to evaluate the association between TyG-related indices and IBS. Results: During a median 14.6 years of follow-up (5,023,899 person-years), 7381 (2.1%) participants developed IBS. The mean (standard deviation) level of baseline TyG index was 8.7(0.6), with 8.0 (0.2), 8.5 (0.1), 8.9 (0.1), and 9.5 (0.3) in quartile 1–4. Compared with the lowest quartile, the highest quartile of all TyG-related indices was significantly associated with greater risk of incident IBS (TyG hazard ratio (HR) = 1.24, 95% confidence interval (CI): 1.16–1.33, <0.001; TyG-WC HR = 1.25, 95% CI: 1.16–1.34, <0.001; TyG-WHtR HR = 1.24, 95% CI: 1.16–1.33, <0.001; TyG-BMI HR = 1.15, 95% CI: 1.07–1.23, <0.001). Meanwhile, per standardized deviation increment of TyG-related indices were also associated with 6%–9% greater risk of IBS (TyG HR = 1.09, 95% CI: 1.07–1.12; TyG-WC HR = 1.09, 95% CI: 1.07–1.12; TyG-WHtR HR = 1.09, 95% CI: 1.06–1.11; TyG-BMI HR = 1.06, 95% CI: 1.03–1.08). Similar results were observed in various sensitivity analyses and subgroup analysis. Conclusion: Higher TyG-related indices are linked to higher risk of incident IBS, highlighting the importance of IR in IBS pathogenesis.