Dietary patterns in rural and metropolitan Australia: a cross-sectional study exploring dietary patterns, inflammation and association with cardiovascular disease risk factors

OBJECTIVES: This study sought first to empirically define dietary patterns and to apply the novel Dietary Inflammation Score (DIS) in data from rural and metropolitan populations in Australia, and second to investigate associations with cardiovascular disease (CVD) risk factors. DESIGN: Cross-sectional study. SETTING: Rural and metropolitan Australia. PARTICIPANTS: Adults over the age of 18 years living in rural or metropolitan Australia who participated in the Australian Health survey. PRIMARY OUTCOMES: A posteriori dietary patterns for participants separated into rural and metropolitan populations using principal component analysis. Secondary outcomes: association of each dietary pattern and DIS with CVD risk factors was explored using logistic regression. RESULTS: The sample included 713 rural and 1185 metropolitan participants. The rural sample was significantly older (mean age 52.7 compared with 48.6 years) and had a higher prevalence of CVD risk factors. Two primary dietary patterns were derived from each population (four in total), and dietary patterns were different between the rural and metropolitan areas. None of the identified patterns were associated with CVD risk factors in metropolitan or rural areas, aside diet pattern 2 being strongly associated with from self-reported ischaemic heart disease (OR 13.90 95% CI 2.29 to 84.3) in rural areas. There were no significant differences between the DIS and CVD risk factors across the two populations, except for a higher DIS being associated with overweight/obesity in rural areas. CONCLUSION: Exploration of dietary patterns between rural and metropolitan Australia shows differences between the two populations, possibly reflective of distinct cultures, socioeconomic factors, geography, food access and/or food environments in the different areas. Our study provides evidence that action targeting healthier dietary intakes needs to be tailored to rurality in the Australian context.