Evidence Update: Preventing type 2 diabetes at the population and community level

With the rate at which new evidence is published, it’s impossible for guidelines or even systematic reviews to keep pace. That’s why NICE Evidence Updates are so, err, nice! They summarise what’s new in relation to existing NICE guidelines since they were published.

The NICE guidance

This Evidence Update relates to NICE guideline 35 on Preventing type 2 diabetes: population and community-level interventions.

Download the 2014 Evidence Update for this guideline (PDF)

Methods

A comprehensive literature search was conducted across numerous databases and expert groups, spanning the period 7/7/2010 to 14/2/2014.

Search results were sifted to identify systematic reviews that are relevant to the remit of the guideline.

The evidence

12 new studies were found for inclusion in the Evidence Update.

Unsurprisingly, increasing the price of junk food reduces consumption. Though maybe 99 bucks is a bit steep!

In terms of impact on current guidance, the most important findings were that raising the price of unhealthy foods reduces their consumption, and that subsidies for healthy foods increase their consumption.

Furthermore:

Fiscal and regulatory measures are cost-effective in the long term for preventing obesity

So that’s one in the eye for the self styled anti-“Nanny State” brigade. Nanny knows best it would seem!

The studies were:

Two economic models that were built on key assumptions about the effectiveness of prevention interventions. [Backholer 2013, Gregg 2013]
Systematic reviews of:
- qualitative studies about barriers to exercise in older South Asian adults [Horne 2012] and of dietary interventions amonst black people of African ancestry [Osey-Assibey 2011]
- mass media campaigns to promote physical activity [Leavy 2011]
- food taxes [Powell 2013], subsidies [An 2013] and cost-effectiveness studies of obesity prevention [Lehnert 2012]
- workplace health promotion programmes [Rongen 2013], community-wide exercise programmes [Baker 2011] and programmes for socioeconomically disadvantaged women [Cleland 2012].

There’s good news here for diabetes prevention strategies, working with high risk populations, mass media campaigns and workplace health promotion schemes.

Other findings, which don’t impact on the current guidance, were:

Diabetes prevention strategies may slow the rate of increase in the prevalence of diabetes
Carefully designed strategies can reduce risk factors amongst high risk populations, particularly older people from South Asian ethnic origin and people with black African ancestry
Mass media campaigns can increase physical activity
Workplace health promotion can reduce sickness absence and improve productivity
Health workers need training in how to promote healthy living.

Comments

The search was limited to populations including ethnic minority, economically disadvantaged or underserved communities. This may have led to some studies being missed that didn’t specify one of these populations in the abstract.
It is not clear what the inclusion criteria for the review were, exactly.
The systematic reviews generally reported substantial heterogeneity and many included both randomized and non-randomized studies.
The quality of the individual studies was variable, and in some of the reviews, not assessed at all.
Most of the outcomes reported in these studies were surrogates. In other words, they weren’t actually looking at progression to diabetes, but instead at behaviours that we assume will lead to a reduction in the risk of diabetes.
Given the foregoing, and whilst this is the best evidence currently available, we would expect to see new evidence in future that changes our conclusions.