Plant-Based Dietary Patterns Associated With Reduced Risk of All-Cause Mortality in Diabetes Subgroups: A Prospective Cohort Study From the UK Biobank

Abstract

OBJECTIVE To investigate the association between adherence to a plant-based dietary index (PDI), healthy PDI, and unhealthy PDI with all-cause mortality in people with type 2 diabetes and to assess whether associations varied by diabetes subgroups. RESEARCH DESIGN AND METHODS We included 4,829 UK Biobank participants with type 2 diabetes and at least two 24-h dietary recalls. We generated overall, healthy, and unhealthy scores. Multi-variable Cox regression estimated hazard ratios (HRs) and 95% CIs for all-cause mortality, comparing the highest tertile (T3) with the lowest T1 of adherence to PDI, a healthy PDI, and an unhealthy PDI. Interactions between PDI adherence and diabetes subgroups (HbA1c, waist circumference, age at diagnosis, diabetes duration) were assessed by two-dimensional B-splines and by including product terms into the model. RESULTS During a mean follow-up of 11.3 years, 679 deaths occurred. Individuals with the highest PDI adherence, compared with those with lowest, were at lower risk of all-cause mortality (T3 vs. T1: HR 0.79 [95% CI 0.63; 0.99]), and a similar direction was observed for those with a healthy PDI (0.82 [0.67; 1.02]) but the 95% CI included the null value. Unhealthy PDI was associated with increased mortality risk (1.24 [1.00; 1.54]). The associations of PDI, healthy PDI, and unhealthy PDI with all-cause mortality risk were more pronounced for those with poorer glycemic control, higher waist circumference, diagnosis earlier in life, and longer diabetes duration. CONCLUSIONS Higher PDI adherence was associated with decreased mortality risk and higher unhealthy PDI adherence with an increased mortality risk. There was an indication for differences in these association depending on diabetes subgroups.