Preventive interventions also exist for type 2 diabetes, which motivated the recent evaluation of risk scores (including those studied here) for the prediction of type 2 diabetes. The Cambridge risk score and the Framingham offspring risk score are based on a combination of demographic, family history, anthropometric, and biochemical data, but neither includes genetic information.7 8 Although these phenotype based risk models seem to perform well, an important question is whether typing a panel of validated genetic risk factors might improve their ability to predict type 2 diabetes. Some studies in this area have used case-control datasets.37 38 39 Although efficient for gene discovery, these are a suboptimal design for evaluating the predictive performance of a marker, as risk information is available only in relative terms and the range of metrics that can be derived to assess predictive performance is more limited than for prospective studies with incident cases of disease. Those prospective studies that have previously evaluated the performance of genetic markers have been set outside the UK, typed fewer type 2 diabetes risk alleles, or reported only some
