Associations of dietary inflammatory index with incident cardiovascular outcomes and all-cause mortality in patients with prediabetes and type 2 diabetes mellitus: A prospective study of data from the UK Biobank

Background While the dietary inflammatory index (DII) is linked to cardiovascular disease (CVD) and mortality in the general population, its role in individuals with prediabetes and type 2 diabetes (T2D) remains understudied. Given the elevated inflammatory burden in this high-risk group, we aimed to examine the association between energy-adjusted DII (E-DII) and incident cardiovascular outcomes and all-cause mortality using a prospective cohort from the UK Biobank. Methods We conducted a prospective cohort study using UK Biobank data, including 18,193 individuals with prediabetes and 6,469 with T2D, all free of cardiovascular disease and cancer at baseline. The E-DII was derived from 24-hour dietary recall data, incident CVD and all-cause mortality were ascertained through linked hospital and death records. Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs), with a median duration of 12.2 years (IQR: 11.5–13.0). Results Among participants with T2D, an energy-adjusted DII > 1 (vs. ≥−1 to ≤1) was associated with a higher risk of cardiovascular events (HR 1.24, 95% CI 1.00–1.53) and all-cause mortality (HR 1.36, 95% CI 1.01–1.84). The association with cardiovascular mortality was not statistically significant (HR 1.50, 95% CI 0.76–2.94). No significant associations were observed among participants with prediabetes. Conclusions A more pro-inflammatory dietary pattern, as measured by the E-DII, is independently associated with increased risks of incident cardiovascular events and all-cause mortality in individuals with T2D. These findings support the integration of DII into nutritional risk assessment for diabetic populations and highlight the potential of dietary modification to improve long-term outcomes.