Association between healthiness of community food environments and diet-related health outcomes in regional Australia: an ecological study

Background: The community food environment influences access to healthy and affordable foods and is considered a risk factor for diet-related health outcomes. An ecological approach helps identify links between food environments and health outcomes by generating hypotheses. Evidence is limited and inconsistent, particularly in regional Australia. This study examined the association between community food environment metrics and diet-related health outcomes in a large regional area of Australia. Methods: An ecological analysis was conducted using secondary data from the 2021 census at the Statistical Area Level 2 (SA2) and from the Public Health Information Development Unit (PHIDU), according to Population Health Area (PHA) levels. Health outcomes included the age-standardised prevalence of diet-related health outcomes (e.g., diabetes, kidney disease, overweight) and self-rated health. Food environment metrics, calculated at both SA2 and PHA levels included: (1) the ratio of unhealthy to healthy/less healthy food outlets; (2) the Modified Retail Food Environment Index (mRFEI) - the proportion of healthy food outlets among all available outlets; (3) the Relative Healthy Food Availability (RHFA) - the proportion of supermarkets and greengrocers relative to fast-food outlets; and (4) the Relative Fast Food Availability (RFFA) - the proportion of fast-food outlets among all available outlets. Spearman’s correlation was used to examine associations. Results: A higher ratio of unhealthy to healthy/less healthy food outlets was positively associated with diabetes (ρ = 0.48, P = 0.001), kidney disease (ρ = 0.42, P = 0.006), stroke (ρ = 0.32, P = 0.042), and poor/fair self-rated health (ρ = 0.41, P = 0.029). A higher RFFA was positively associated with diabetes (ρ = 0.6, P < 0.001) and stroke (ρ = 0.43, P = 0.005). The RHFA was negatively associated with diabetes (ρ = -0.38, P = 0.012) and overweight (ρ = -0.51, P = 0.005), while the mRFEI was negatively associated with overweight (ρ = -0.46, P = 0.013). Conclusion: Community food environment metrics are significantly associated with population-level diet-related health outcomes in regional Australia. These ecological findings identify key metrics for future individual-level research and inform local and state policies aimed at reducing unhealthy food outlets and increasing healthy options.