Diet Quality Indices, All-Cause Mortality, Cardiovascular Disease, and Dementia-Outcomes from the Australian Longitudinal Study on Women's Health.

Abstract

Background: Cardiovascular disease (CVD) and dementia are the leading causes of death for Australian women. Diet is a modifiable risk factor; however, extent of risk reduction by type of diet is unclear.

Objectives: This study aimed to evaluate the relationship between indices of diet quality: Australian Recommended Food Score (ARFS), Mediterranean diet food score (MDFS), and cluster analysis, with all-cause mortality, CVD, and dementia in women. A secondary aim was to investigate the influence of socioeconomic status (SES) on the relationship.

Methods: In total, 9584 participants from the Australian Longitudinal Study on Women's Health (ALSWH) 1946-1951 cohort, with diet information from Food Frequency Questionnaires in 2001 and outcomes assessed at 2020. Five food clusters were identified using the K-means approach. Cox models were used to obtain hazard ratios (HRs) and 95% CIs for all-cause mortality, CVD and dementia according to quarters of the ARFS and MDFS and by food group clusters, with final models adjusted for health status, behaviors and SES.

Results: There were 656 deaths, 1585 incidents of CVD and 165 dementia diagnoses during 17.2 years of follow-up. For all-cause mortality, HRs comparing the highest (best) to lowest quarter of diet quality were 0.60 (95% CI: 0.46, 0.78; P < 0.001) for the ARFS, 0.64 (95% CI: 0.47, 0.87; P = 0.005) for the MDFS, and 0.67 (95% CI: 0.47, 0.95; P = 0.02) when comparing a diet higher in protein intake and lower milk/yogurt intake to diets higher in discretionary foods and lower in fruit and vegetables. There were no associations between diet indices with CVD and dementia outcomes or influence of SES on findings.

Conclusions: Better quality diets were associated with a lower risk of all-cause mortality, and there were no associations identified between diet and CVD or dementia outcomes. These findings provide insights into the potential benefits of improving diet quality of Australian women to improve longevity.