The Department of Health (DH) asked NICE to produce public health guidance on the prevention of type 2 diabetes mellitus among high-risk groups.

The referral was divided into two separate pieces of guidance. The first (this guidance) originally set out to address the prevention of 'pre-diabetes' among adults aged 18 to 74 in communities at high risk of developing type 2 diabetes. The second set out to focus on preventing the progression from 'pre-diabetes' to type 2 diabetes.

However, in January 2011 the World Health Organization (WHO) recommended that glycated haemoglobin (HbA1c) could be used as an alternative to standard glucose measures to diagnose type 2 diabetes among non-pregnant adults. HbA1c levels of 6.5% (48 mmol/mol) or above indicate that someone has type 2 diabetes – but there is no fixed point to indicate when someone has 'pre-diabetes'. (Increasing levels of HbA1c, up to the 6.5% (48 mmol/mol) cut-off point, mean someone is at increasing risk of type 2 diabetes.)

The title of this guidance has been changed since it went out for consultation to reflect this move away from recognising 'pre-diabetes' as a separate condition. However, the overall range and scope of the content remains the same. The second piece of guidance will consider the effectiveness and cost effectiveness of interventions to prevent type 2 diabetes among individuals at high-risk.

Factors which influence someone's risk of type 2 diabetes include: weight, waist circumference, age, physical activity and whether or not they have a previous history of gestational diabetes or a family history of type 2 diabetes.

In addition to these individual risk factors, people from certain communities and population groups are particularly at risk. This includes people of South Asian, African-Caribbean, black African and Chinese descent and those from lower socioeconomic groups.

The guidance is for commissioners, managers and practitioners with public health as part of their remit working within the NHS, local authorities, the national and local public health service and the wider public, private, voluntary and community sectors. It is also for national policy makers, caterers, food manufacturers and retailers.

The guidance is particularly aimed at: directors of public health, public health commissioners and all those working in national and local public health services. This includes: GPs, practice nurses, dietitians, public health nutritionists and other health professionals, as well as those involved in delivering physical activity interventions, community engagement teams and community leaders. It may also be of interest to members of the public.

The guidance complements, but does not replace, NICE guidance on: behaviour change, cardiovascular disease, community engagement, diabetes in pregnancy, management of type 2 diabetes, maternal and child nutrition, obesity, physical activity and weight management before, during and after pregnancy.

The Programme Development Group (PDG) developed these recommendations on the basis of reviews of the evidence, economic modelling, expert advice, stakeholder comments and fieldwork.

Members of the PDG are listed in appendix A. The methods used to develop the guidance are summarised in appendix B. Supporting documents used to prepare this document are listed in appendix E.