Nineteen-Year Associations between Three Diet Quality Indices and All-Cause and Cardiovascular Disease Mortality: The Australian Diabetes, Obesity, and Lifestyle Study

ABSTRACT Background Examining a variety of diet quality methodologies will inform best practice use of diet quality indices for assessing all-cause and cardiovascular disease (CVD) mortality. Objectives To examine the association between 3 diet quality indices (Australian Dietary Guideline Index, DGI; Dietary Inflammatory Index, DII; Mediterranean-DASH (Dietary Approaches to Stop Hypertension) Intervention for Neurodegenerative Delay, MIND) and risk of all-cause mortality, CVD mortality, and nonfatal CVD events ≤19 y later. Methods Data on 10,009 adults (mean age 51.8 y; 52% female) from the Australian Diabetes, Obesity, and Lifestyle study were used. An FFQ was used to calculate DGI, DII, and MIND at baseline. Cox proportional hazard models were used to estimate HRs and 95% CI of all-cause mortality, CVD mortality, and nonfatal CVD events (stroke; myocardial infarction) according to 1 SD increase in diet quality, adjusted for age, sex, education, smoking, physical activity, energy intake, history of stroke or heart attack, and diabetes and hypertension status. Results Deaths due to all-cause (n = 1955) and CVD (n = 520), and nonfatal CVD events (n = 264) were identified during mean follow-ups of 17.7, 17.4, and 9.6 y, respectively. For all-cause mortality, HRs associated with higher DGI, DII, and MIND were 0.94 (95% CI: 0.89, 0.99), 1.08 (95% CI: 1.02, 1.15), and 0.93 (95% CI: 0.89, 0.98), respectively. For CVD mortality, HRs associated with higher DGI, DII, and MIND were 0.93 (95% CI: 0.85, 0.99), 1.10 (95% CI: 1.00, 1.24), and 0.90 (95% CI: 0.82, 0.98), respectively. There was limited evidence of associations between diet quality and nonfatal CVD events. Conclusions A better quality diet predicted lower risk of all-cause and CVD mortality in Australian adults, whereas a more inflammatory diet predicted higher mortality risk. These findings highlight the applicability of following Australian dietary guidelines, a Mediterranean-style diet, and a low-inflammatory diet for the reduction of all-cause and CVD mortality risk.