Table 4.
Description of GWAS consortiums used for each phenotype. Table reproduced with permission from Wootton et al, 201839
| Variable | First author (year) | Consortium | Sample size | Population* | Sex* |
|---|---|---|---|---|---|
| Subjective wellbeing | Okbay25 (2016) | SSGAC | 298 420 | 100% European | Mixed† |
| Body mass index | Locke26 (2015) | GIANT | 339 224 | 95% European | 53% female |
| Waist to hip ratio | Shungin27 (2015) | GIANT | 210 088 | 100% European | 56% female |
| Waist circumference | Shungin27 (2015) | GIANT | 232 101 | 100% European | 55% female |
| Body fat percentage | Lu28 (2016) | Not available | 100 716 | 89% European | 48% female |
| HDL cholesterol | Willer29 (2013) | GLGC | 92 860 | 100% European | Mixed† |
| LDL cholesterol | Willer29 (2013) | GLGC | 83 198 | 100% European | Mixed† |
| Total cholesterol | Willer29 (2013) | GLGC | 92 260 | 100% European | Mixed† |
| Coronary artery disease | Nikpay30 (2015) | CARDIoGRAMplusC4D | Cases=60 801; controls=123 504 | 77% European | Mixed† |
| Myocardial infarction | Nikpay30 (2015) | CARDIoGRAMplusC4D | Cases=43 676; controls=128 199 | Mixed† | Mixed† |
| Diastolic blood pressure | Wain31 (2017) | Not available | 150 134 | 100% European | 60% female |
| Systolic blood pressure | Wain31 (2017) | Not available | 150 134 | 100% European | 60% female |
SSGAC=Social Science Genetics Association Consortium; GLGC=Global Lipids Genetics Consortium; GIANT=Genetic Investigation of Anthropometric Traits consortium; HDL=high density lipoprotein; LDL=low density lipoprotein; GWAS=genome wide association study.
If not reported, percentage sex and European ancestry were calculated from contributing cohort data in the supplementary materials. All GWAS had similar sex ratios and ancestries included. The largest difference was between the consortiums for coronary artery disease and subjective wellbeing, which used 77% and 100% individuals of European ancestry, respectively. If two populations differ, two sample mendelian randomisation can still be used to test for a causal effect, but the magnitude of the effect might not be as precise.32
Information on the sex ratios and ancestry proportions for the whole sample were not reported or not possible to calculate in the CARDIoGRAMplusC4D, GLGC, and SSGAC consortiums.