Study selection
Eligible for inclusion in the review were interventions that were either replications or modifications of all or some components of the US Diabetes Prevention Program (DPP), Finnish Diabetes Prevention Study (DPS) or any other reference trial, or those including the reduction of diabetes risk or diabetes incidence explicitly. Eligible study designs were RCTs, before-and-after studies, cohort studies with or without a control group, and interrupted-time-series analyses. Eligible studies had to last least three months, with three months follow-up of single (either nutrition or physical activity programmes with or without medication) or combined (nutrition and physical activity) programmes, with or without medication. Eligible participants were adults with impaired glucose regulation at risk of diabetes. Comparators included no intervention or alternative intervention (single or combined).