We assessed discrimination with the detection rate, which is equivalent to sensitivity and defined as the proportion of all cases detected for a pre-specified false positive rate, as well as the area under the receiver operating characteristics curve. We assessed the calibration of the Cambridge risk score and Framingham offspring risk score in the estimation of the absolute risk of type 2 diabetes by comparing the difference between observed and expected event rates in different categories of risk with the Hosmer-Lemeshow test, with Akaike’s information criterion and the likelihood ratio test as global measures of model fit.33 We used the net reclassification improvement measure to assess the extent to which adding the genetic variables reassigned people to risk categories that better reflected their final outcome.34
