Background Examining a variety of diet quality methodologies will inform best practice use of diet quality indices for assessing all-cause and CVD mortality. Objective To examine the association between three diet quality indices (Australian Dietary Guideline Index, DGI; Dietary Inflammatory Index, DII; Mediterranean-DASH Intervention for Neurodegenerative Delay, MIND) and risk of all-cause mortality, CVD mortality and non-fatal CVD events up to 19 years later. Design Data on 10,009 adults (51.8 years; 52% female) from the Australian Diabetes, Obesity and Lifestyle study were used. A food frequency questionnaire was used to calculate DGI, DII and MIND at baseline. Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% CI of all-cause mortality, CVD mortality and non-fatal 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 = 1,955) and CVD (n = 520), and non-fatal CVD events (n = 264) were identified during mean follow-ups of 17.7, 17.4 and 9.6 years, 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 non-fatal CVD events. Conclusions Better quality diet predicted lower risk of all-cause and CVD mortality in Australian adults, while 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.

Background Mounting evidence highlights the importance of combined modifiable lifestyle factors in reducing risk of cognitive decline and dementia. Several a priori additive scoring approaches have been established; however, limited research has employed advanced data-driven approaches to explore this association. This study aimed to examine the association between data-driven lifestyle profiles and cognitive function in community-dwelling Australian adults. Methods A cross-sectional study of 4561 Australian adults (55.3% female, mean age 60.9 ± 11.3 years) was conducted. Questionnaires were used to collect self-reported data on diet, physical activity, sedentary time, smoking status, and alcohol consumption. Cognitive testing was undertaken to assess memory, processing speed, and vocabulary and verbal knowledge. Latent Profile Analysis (LPA) was conducted to identify subgroups characterised by similar patterns of lifestyle behaviours. The resultant subgroups, or profiles, were then used to further explore associations with cognitive function using linear regression models and an automatic Bolck, Croon & Hagenaars (BCH) approach. Results Three profiles were identified: (1) “Inactive, poor diet” (76.3%); (2) “Moderate activity, non-smokers” (18.7%); and (3) “Highly active, unhealthy drinkers” (5.0%). Profile 2 “Moderate activity, non-smokers” exhibited better processing speed than Profile 1 “Inactive, poor diet”. There was also some evidence to suggest Profile 3 “Highly active, unhealthy drinkers” exhibited poorer vocabulary and verbal knowledge compared to Profile 1 and poorer processing speed and memory scores compared to Profile 2. Conclusion In this population of community-dwelling Australian adults, a sub-group characterised by moderate activity levels and higher rates of non-smoking had better cognitive function compared to two other identified sub-groups. This study demonstrates how LPA can be used to highlight sub-groups of a population that may be at increased risk of dementia and benefit most from lifestyle-based multidomain intervention strategies.

Background: Dementia prevention is a global health priority, and there is emerging evidence to support associations between individual modifiable health behaviors and cognitive function and dementia risk. However, a key property of these behaviors is they often co-occur or cluster, highlighting the importance of examining them in combination. Objective: To identify and characterize the statistical approaches used to aggregate multiple health-related behaviors/modifiable risk factors and assess associations with cognitive outcomes in adults. Methods: Eight electronic databases were searched to identify observational studies exploring the association between two or more aggregated health-related behaviors and cognitive outcomes in adults. Results: Sixty-two articles were included in this review. Fifty articles employed co-occurrence approaches alone to aggregate health behaviors/other modifiable risk factors, eight studies used solely clustering-based approaches, and four studies used a combination of both. Co-occurrence methods include additive index-based approaches and presenting specific health combinations, and whilst simple to construct and interpret, do not consider the underlying associations between co-occurring behaviors/risk factors. Clustering-based approaches do focus on underlying associations, and further work in this area may aid in identifying at-risk subgroups and understanding specific combinations of health-related behaviors/risk factors of particular importance in the scope of cognitive function and neurocognitive decline. Conclusion: A co-occurrence approach to aggregating health-related behaviors/risk factors and exploring associations with adult cognitive outcomes has been the predominant statistic approach used to date, with a lack of research employing more advanced statistical methods to explore clustering-based approaches.

Changes between diet quality and health-related quality of life (HR-QoL) over 12 years were examined in men and women. In 2844 adults (46% males; mean age 47.3 (SD 9.7) years) from the Australian Diabetes, Obesity and Lifestyle study with data at baseline, 5 and 12 years. Dietary intake was assessed with a 74-item FFQ. Diet quality was estimated with the Dietary Guideline Index (DGI); Mediterranean-Dietary Approaches to Stop Hypertension Diet Intervention for Neurological Delay Index (MIND); and Dietary Inflammatory Index (DII). HR-QoL in terms of global, physical component summary (PCS), mental component summary (MCS) was assessed with the Short Form Health Survey 36. Fixed effects regression models adjusted for confounders were performed. Mean MCS increased from baseline (49.0, SD 9.3) to year 12 (50.7, SD 9.1), whereas mean PCS decreased from baseline (51.7, SD 7.4) to year 12 (49.5, SD 8.6). For the total sample, an improvement in MIND was associated with an improvement in global QoL (β=0.28, 95% CI:0.007, 0.55). In men, an improvement in MIND was associated with an improvement in global QoL (β=0.28, 95% CI:0.0004, 0.55). In women, improvement in MIND was associated with improvements in global QoL (β=0.62 95% CI:0.38, 0.85), MCS (β=0.75, 95% CI:0.29,1.22), and PCS (β=0.75, 95% CI:0.29,1.22). Positive changes in diet quality were associated with broad improvements in HR-QoL, and most benefits were observed in women when compared to men. These findings support the need for strategies to assist the population in consuming healthy dietary patterns to lead to improvements in HR-QoL.

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