ROC curves and the corresponding AUC estimates indicated statistical discriminative ability to predict obesity (BMI > 30 kg/m2, AUC = 0.588, 95% CI = [0.567, 0.610]). AUC estimates were similar to those found in previous studies. For example, Renstrom et al. (2009) used a genetic score of 9 SNPs and reported an AUC estimate of 0.575 in a sample of 353 obese and 1,370 normal weight diabetic and non-diabetic northern Swedes. Additionally, a study by Cheung et al. (2010) estimated an AUC of 0.582 with a genetic score including 13 SNPs in a Chinese sample of 470 obese cases and 700 normal weight controls. Although these AUC estimates were statistically significant, they were below 0.8, the threshold used in clinical practice for screening. In the MGS-C sample, however, the ability to predict morbid obesity (class III) was notably better and approached clinical criteria for a screening test (AUC = 0.697, 95% CI = [0.663, 0.731]).
