OBJECTIVES: Most previous research on plant-based diets and hypertension primarily focused on the general population, with limited data available among adults with type 2 diabetes (T2DM). Therefore, the present study was designed to investigate the association between plant-based dietary patterns and hypertension among adults with T2DM. DESIGN: Cross-sectional study. SETTING: The AZAR cohort is part of the Persian Cohort, an Iranian screening programme, and includes participants who were residing in Shabestar county, East Azerbaijan Province, Iran for a minimum of 9 months PARTICIPANTS: A total of 1947 participants with T2DM were included in the current analysis. OUTCOME MEASURES: Hypertension was the outcome measure. This was defined as blood pressure ≥140/90 mm Hg, self-reported physician-diagnosed hypertension (supported by medical records) or use of antihypertensive medications. RESULTS: The mean age of the participants was 54.90±8.25 years, with 61% being female. The prevalence of hypertension among the participants was 48.6% (n=946). Adherence to plant-based diet index (PDI) showed a significant inverse association with hypertension in the crude model (OR: 0.60, 95% CI: 0.46 to 0.80, P-trend<
0.001), but this association became non-significant after adjusting for confounders (OR: 0.88, 95% CI: 0.63 to 1.24, P-trend: 0.54). Moreover, healthful plant-based diet index displayed a significant positive association with hypertension in unadjusted analysis (OR: 2.03, 95% CI: 1.52 to 2.70, P-trend<
0.001), which also disappeared after controlling for potential confounders (OR: 0.86, 95% CI: 0.61 to 1.21, P-trend: 0.35). However, no significant relationship was found between adherence to unhealthful plant-based diet index and hypertension in crude or fully adjusted models. Findings remained consistent across different subgroups, as well as sensitivity analyses. CONCLUSIONS: The present study did not find a significant association between adherence to PDIs and hypertension in T2DM patients. Future studies are needed to investigate this association and to explore potential mechanisms linking plant-based dietary pattern with hypertension in diverse populations.