As shown in Supplementary Table 4, the results of only 27 (19%) meta-analyses used populations of mixed ancestry in the discovery stage or followed up the meta-analyses findings in populations of different ancestries than the discovery population. Loci and even more effect sizes may be difficult to generalize across different ancestries (75). For a total of 79 meta-analyses, investigators had performed further association analyses between SNPs discovered in the discovery GWA meta-analysis and traits or diseases other than those examined in the meta-analyses. Additionally, for 19 (14%) meta-analyses investigators had extended their association testing to diverse phenotypes. These diverse phenotypes resulted from using cut-offs in order to transform a continuous trait to binary disease outcome (ankle-brachial index and peripheral artery disease; systolic blood pressure and hypertension; diastolic blood pressure and hypertension; BMI and obese/overweight; urinary albumin excretion and microalbuminuria; common and internal carotid intima media thickness and plaque); from using different definitions of the indexed trait (waist circumference and waist to hip ratio to measure adiposity; forced expiratory volume in 1 second (FEV1) and FEV1/FVC (forced vital capacity) to measure
