Type 2 diabetes: prevention in people at high risk

Behaviour change

Evidence-based behaviour-change advice includes:

Brief advice

Typically, for diabetes prevention, brief advice might consist of a 5 to 15 minute consultation. The aim is to help someone make an informed choice about whether to make lifestyle changes to reduce their risk of diabetes. The discussion covers what that might involve and why it would be beneficial. Practitioners may provide written information in a range of formats and languages about the benefits and, if the person is interested in making changes, may discuss how these can be achieved and sustained in the long term.

Brief intervention

Brief interventions for diabetes prevention can be delivered by GPs, nurses, healthcare assistants and professionals in primary healthcare and the community. They may be delivered in groups or on a one-to-one basis. They aim to improve someone's diet and help them to be more physically active. A patient-centred or 'shared decision-making' communication style is adopted to encourage people to make choices and have a sense of 'ownership' of their lifestyle goals and individual action plans. Providers of brief interventions should be trained in the use of evidence-based behaviour-change techniques for supporting weight loss through lifestyle change.

Computer-based risk-assessment tools

These tools identify a set of risk characteristics in patient health records. They can be used to interrogate GP patient databases and provide a summary score to indicate someone's level of risk. Examples include the Cambridge diabetes risk score and the Leicester practice score.

Diabetes prevention programmes

Diabetes prevention programmes comprise two integrated components: first, risk identification services and second, intensive lifestyle-change programmes. Participants are acknowledged as the decision-makers throughout the process. Also see 'Intensive lifestyle-change programmes'.

High risk

High risk is defined as a fasting plasma glucose level of 5.5 to 6.9 mmol/l or an HbA1c level of 42 to 47 mmol/mol (6.0 to 6.4%). These terms are used instead of specific numerical scores because risk assessment tools have different scoring systems. Examples of risk assessment tools include: Diabetes risk score assessment tool, QDiabetes risk calculator and Leicester practice risk score. Risk can also be assessed using the NHS Health Check.

Glycated haemoglobin (HbA1c)

Glycated haemoglobin (HbA1c) forms when red cells are exposed to glucose in the plasma. The HbA1c test reflects average plasma glucose over the previous 8 to 12 weeks. Unlike the oral glucose tolerance test, an HbA1c test can be performed at any time of the day and does not require any special preparation, such as fasting.

HbA1c is a continuous risk factor for type 2 diabetes. This means there is no fixed point when people are (or are not) at risk. The World Health Organization recommends a level of 48 mmol/mol (6.5%) for HbA1c as the cut-off point for diagnosing type 2 diabetes in non-pregnant adults. For the purposes of this guidance, the range 42–47 mmol/mol (6.0 to 6.4%) is considered to be 'high risk'.

Impaired fasting glucose (IFG)

Impaired fasting glucose is defined as a fasting plasma glucose between 6.1 and 6.9 mmol/l.

Impaired glucose tolerance

This is a risk factor for future diabetes and/or other adverse outcomes. The current WHO diagnostic criteria for impaired glucose tolerance are: a fasting plasma glucose of less than 7.0 mmol/l and a 2-hour venous plasma glucose (after ingestion of 75 g oral glucose load) of 7.8 mmol/l or greater, and less than 11.1 mmol/l.

Impaired glucose regulation (IGR)

This is a risk factor for future diabetes and/or other adverse outcomes. The term covers blood glucose levels that are above the normal range but are not high enough for the diagnosis of type 2 diabetes. It is used to describe the presence of impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) as defined by the WHO.

IFG is defined as fasting plasma glucose 6.1 to 6.9 mmol/l. IGT is defined as a fasting plasma glucose (FPG) less than 7 mmol/l and 2-hour venous plasma glucose (after ingestion of 75 g oral glucose load) of 7.8 mmol/l or greater and less than 11.1 mmol/l.

Impaired fasting glucose and impaired glucose tolerance can occur as isolated, mutually exclusive conditions or together, that is, fasting plasma glucose between 6.1 and 6.9 mmol/l and 2-hour glucose of 7.8 mmol/l or greater and less than 11.1 mmol/l during the oral glucose tolerance test.

Intensive lifestyle-change programmes

A structured and coordinated range of interventions provided in different venues for people identified as being at high risk of developing type 2 diabetes (following a risk assessment and a blood test). The aim is to help people become more physically active and to improve their diet. If the person is overweight or obese, the programme should result in weight loss. Programmes may be delivered to individuals or groups (or involve a mix of both) depending on the resources available. They can be provided by primary care teams and public, private or community organisations with expertise in dietary advice, weight management and physical activity.

Level of risk

The terms 'high', 'intermediate' and 'low' risk are used to refer to the results from a risk assessment tool. Examples of validated risk assessment tools are available in the NHS Health Check best practice guidance. These terms are used instead of specific numerical scores because the tools have different scoring systems. The term 'moderate risk' is used to denote a high risk assessment score where a blood test did not confirm that risk (FPG less than 5.5 mmol/l or HbA1c less than 42 mmol/mol [6.0%]). A fasting plasma glucose of 5.5 to 6.9 mmol/l or an HbA1c level of 42 to 47 mmol/mol [6.0 to 6.4%] indicates high risk.

Moderate-intensity physical activity

The UK Chief Medical Officers' physical activity guidelines sets out physical activity recommendations. The definition of moderate physical activity is included in the glossary of the report (see the UK Chief Medical Officers' physical activity guidelines for more information).

Oral glucose tolerance test

An oral glucose tolerance test involves measuring the blood glucose level after fasting, and then 2 hours after drinking a standard 75 g glucose drink. Fasting is defined as no calorie intake for at least 8 hours. More than one test on separate days is required for diagnosis in the absence of hyperglycaemic symptoms.

Vigorous-intensity physical activity

Vigorous-intensity physical activity requires a large amount of effort, causes rapid breathing and a substantial increase in heart rate. Examples include running and climbing briskly up a hill. On an absolute scale, vigorous intensity is defined as physical activity that is above 6 metabolic equivalents (METs).

Vulnerable groups

Adults from vulnerable groups whose risk of type 2 diabetes may be increased by a medical condition, or who may not realise they are at risk or who are less likely to access healthcare services. This includes people with severe mental health problems, learning disabilities, physical disabilities or sensory disabilities; people who live in hostels, nursing or residential homes, residential mental health or psychiatric care units, secure hospitals, prisons or remand centres; and people who are part of a mobile population such as travellers, asylum seekers and refugees.

Weight-loss programmes

Effective weight-loss programmes are structured lifestyle-change programmes to help people lose weight in a sustainable way. They:

Weight management

In this guidance, the term weight management includes:

For other public health and social care terms see the Think Local, Act Personal Care and Support Jargon Buster.