How do we identify people at high risk of Type 2 diabetes and help prevent the condition from developing?

AIMS: To review the evidence regarding the identification of those at high risk of Type 2 diabetes and the conceptual and clinical criteria defining high risk, the prevention or delay of onset of Type 2 diabetes through lifestyle interventions, and the evolution of evidence from efficacy trials, through effectiveness trials in real‐world settings, to implementation programmes at scale. METHOD: The wide scope of this review precluded a systematic approach, therefore, we present a narrative review that highlights key themes and contemporary developments, drawing on landmark studies, previous systematic and expert reviews, and previous meta‐analyses. RESULTS: While the diagnostic thresholds for Type 2 diabetes are accepted, international consensus on whether, and how, to classify those at high risk of Type 2 diabetes has not been achieved. There is ongoing debate about which laboratory test to use and each test's corresponding inclusion threshold, about where the balance of clinical benefits and harms sit when defining thresholds, and about how affordability of subsequent preventative interventions might influence the derivation of such thresholds within any particular population. A remarkable international effort has seen the evolution of interventions for those at high risk move from efficacy trials, through effectiveness trials, to implementation at scale, and the evidence supporting each stage is reviewed. CONCLUSIONS: To achieve healthcare system sustainability, many countries are now focusing on disease prevention. To complement population‐level interventions that address the obesogenic environment, lifestyle interventions that empower individuals at high risk of Type 2 diabetes to modify this risk beneficially are now being implemented at scale.