BackgroundTriglyceride-glucose (TyG) index is an emerging surrogate indicator of insulin resistance, which has been demonstrated as a risk factor for various cardiovascular diseases including coronary syndrome, in-stent restenosis, and heart failure. However, association of TyG index with incident aortic dissection (AD) and aortic aneurysm (AA) remains to be investigated.MethodsThis study included 420,292 participants without baseline AD/AA from the large-scale prospective UK Biobank cohort. The primary outcome was incident AD/AA, comprising AD and AA. Multivariable-adjusted Cox proportional hazards regression models and restricted cubic spline (RCS) analyses were applied to assess the relationship between TyG index and the onset of AD/AA. In addition, the association between TyG index and incident AD/AA was examined within subgroups defined by age, gender, smoking status, drinking status, diabetes, hypertension, and BMI.ResultsOver a median follow-up period of 14.8 (14.1, 15.5) years, 3,481 AD/AA cases occurred. The incidence of AD/AA rose along with elevated TyG index. RCS curves showed a linear trend of TyG index with risk of incident AD/AA. TyG index was positively associated with risk of incident AD/AA after adjusting for age, gender, smoking status, drinking status, BMI, hypertension, LDL-c, and HbA1c, with adjusted HRs of 1.0 (reference), 1.20 (95% CI 1.08–1.35), 1.21 (95% CI 1.08–1.35), and 1.30 (95% CI 1.16–1.45) for TyG index quartiles 2, 3, and 4, respectively. Especially, participants in the highest TyG index quartile had highest risk of developing AA, with an adjusted HR of 1.35 (95% CI 1.20–1.52).ConclusionsTyG index is independently associated with a higher risk of incident AD/AA, indicating the importance of using TyG index for risk assessment of AD/AA, especially for AA.