Short-term improvements in diet quality in people newly diagnosed with type 2 diabetes are associated with smoking status, physical activity and body mass index: the 3D case series study

Background: Dietary intake impacts glycaemic control through its effect on weight and glucose–insulin homeostasis. Early glycaemic control is associated with improved outcomes and reduced mortality for people with type 2 diabetes (T2D). To date, the diet quality of people with T2D has only been studied cross-sectionally. The objective of this paper is to quantify short-term improvements in diet quality and to identify factors associated with improvements after T2D diagnosis among participants in the 3D study. Methods: Data from 225 Australian adults newly diagnosed with T2D in the 3D study were used. Telephone interviews collected demographic, diet, physical and health data at baseline and 3 months. Diet quality was assessed using the Dietary Approaches to Stop Hypertension (DASH) tool. Participants were categorized as ‘improvers’ (increase in DASH score ≥3) or ‘maintainers’ (<3-point increase, no change or decrease). Factors associated with change in DASH scores were clinically and statistically evaluated. Results: The 3D cohort was comparable to Australian cohorts with diabetes by gender and BMI but differed by age, remoteness and socioeconomic status. Mean (SD) baseline DASH score was 24.4 (4.7). One third improved their DASH score by 3 months. Improvers had lower baseline diet quality (p<0.001), lower BMI (p=0.045; effect in males p=0.048), higher physical activity (p=0.028) and were less likely to smoke (p=0.018). Conclusions: Diet quality changes after diagnosis were associated with lifestyle behaviours (smoking status, physical activity, BMI) rather than demographics. Targeted strategies are needed to support smokers, those with low physical activity and higher BMI. Future research should investigate links between early diet quality changes and long-term outcomes.