The overall aim of the project is to evaluate the (cost-)effectiveness of the SLIMMER diabetes prevention intervention in Dutch primary health care.

This is a randomised controlled trial, conducted in a real-life setting (Dutch primary health care).

Inclusion Criteria:

• Age 40-70 years

• Impaired fasting glucose (IFG; i.e. venous plasma glucose concentration ≥6.1 and

  ≤6.9 mmol/l) during the past 5 years, according to the GP registration database OR diabetes risk score ≥7 as calculated from the Diabetes Risk Test

• Willing and able to participate in the intervention for at least 1.5 years

• Dutch speaking

Exclusion Criteria:

• Known diabetes mellitus

• Any chronic illness that makes 1.5-years survival improbable, interferes with glucose tolerance, or makes participation in a lifestyle intervention impossible

• Patients with any severe cardiovascular disease (this also includes history of cardiac dysrhythmia), unless GP gives agreement

• Medication known to interfere with glucose tolerance

• Any mental or physical disability that will hinder participation in the lifestyle intervention

• Severe psychiatric disease

• Patients who showed bad compliance in the past

• Participation in another regular vigorous exercise and/or diet programme, i.e.:

  • Intensive exercise programme: any exercise programme offered by a physiotherapist and/or patients sporting at least 3 times a week at their own initiative.
  • Intensive diet programme: patients who visited a dietician at least 3 times during the last year.