Diabetes and large-scale prevention programs

July 2015

Diabetes is a crucial health issue for Australia. More than 10% of Australians have diabetes or are at high risk.
The burden of diabetes is compounded because many complications of diabetes can be debilitating or life threatening, such as cardiovascular disease, end-stage kidney disease, loss of vision, amputations and mental health issues.
This review collates the evidence on diabetes prevention, highlights the key modifiable risk factors to target, and analyses what system-level changes are needed to successfully implement a population-wide diabetes prevention program.

There is substantial evidence that type 2 diabetes can be prevented and delayed, particularly in certain high-risk groups, and this has been successfully demonstrated in prevention programs in a range of settings.
There is also evidence of type 2 diabetes prevention interventions being successfully scaled up and implemented population-wide.
The system-level factors needed to successfully scale up an intervention are known and should be considered when planning large-scale diabetes prevention programs.
However, while it is clear that large-scale prevention interventions can be effective, further research is needed to determine which characteristics are needed to maximise the efficacy of an intervention.

July 2015

Progression to diabetes can be prevented or delayed. Modifiable risk/protective factors for diabetes include body mass index, physical activity, smoking status and early life factors such as birthweight.
Many lifestyle interventions for diabetes prevention help to prevent other chronic diseases such as cardiovascular disease.
Delaying the onset and severity of diabetes is important because it can prevent diabetes-related complications.
This review aimed to:
- Summarise the evidence regarding type 2 diabetes prevention interventions, focusing on lifestyle interventions
- Assess the effect size of different lifestyle interventions, and to consider the potential for scalability
- Identify research gaps and areas of most potential to inform future research investment.

While not lifestyle interventions, bariatric surgery and medications were included as comparators in many studies assessing lifestyle interventions so were included in this review.
Bariatric surgery was the only intervention with a large effect size, but the studies only assessed participants who were obese and at high risk. Bariatric surgery is likely to be inapplicable and unfeasible at the general population level.
Interventions with a medium effect size were: diet and/or exercise; diet and exercise and an additional component such as education; and exercise and/or education.
Not all existing lifestyle intervention studies were included in this review as they did not meet the inclusion criteria. Many population-level interventions measured weight loss or other clinical indicators as a proxy for impact on diabetes risk.
Many study participants had successful and sustained weight loss, suggesting reduced diabetes risk. However, this information was inadequate to confidently calculate effect size.