Table 2.
Overlap of genes identified by EWAS and GWAS
| Trait | n EWAS genes | n GWAS genes | Gene overlap | obs OR | exp overlap | exp OR | p diff |
|---|---|---|---|---|---|---|---|
| Body mass index | 232 | 3228 | 23 | 2.0 | 39 | 3.04 | 5.2e−02 |
| Current versus never smoking | 1933 | 312 | 27 | 2.9 | 39 | 3.42 | 3.2e−01 |
| Former versus never smoking | 282 | 323 | 9 | 6.4 | 7 | 3.43 | 2.2e−02 |
| Alcohol consumption per day | 361 | 190 | 3 | 2.6 | 3 | 2.44 | 9.1e−01 |
| C-reactive protein | 189 | 302 | 3 | 3.2 | 1 | 0.91 | 1.2e−01 |
| Educational attainment | 25 | 1594 | 1 | 1.5 | 3 | 3.00 | 4.3e−01 |
| Fasting glucose | 15 | 50 | 0 | 0.0 | 0 | 0.00 | 1.0e+00 |
| Fasting insulin | 36 | 5 | 0 | 0.0 | 0 | 0.00 | 1.0e+00 |
| Systolic blood pressure | 99 | 3210 | 18 | 4.0 | 12 | 2.13 | 9.4e−03 |
| Diastolic blood pressure | 56 | 3586 | 15 | 5.8 | 6 | 1.87 | 5.2e−06 |
| Birthweight | 894 | 162 | 6 | 2.6 | 7 | 2.64 | 9.1e−01 |
| Cognitive abilities: digit test | 26 | 875 | 0 | 0.0 | 1 | 2.44 | 4.2e−01 |
| FEV1 | 51 | 1664 | 4 | 3.0 | 3 | 1.92 | 3.9e−01 |
| eGFR | 256 | 2611 | 44 | 4.7 | 20 | 1.81 | 2.1e−10 |
| Urate | 251 | 666 | 16 | 6.3 | 4 | 1.28 | 3.5e−11 |
exp = expected, obs = observed, fev1 = forced expiratory volume in 1 s.
odds ratios (ORs) can be interpreted as the odds of an gene being identified by EWAS and a GWAS over the odds of a gene being identified by an EWAS but not by a GWAS.
exp OR = the mean OR after repeating the analysis 1000 times, randomly sampling EWAS genes equal to the number identified in the empirical analysis.
p diff = P value from a two-sided Z-test assessing the difference between the observed and expected OR.