Table 1. Descriptive characteristics of studies participating in meta-analysis.* .
| Study | Description | N | Female, % | Age, years | Caffeine, mg/day | Current smokers, % | Platform |
| ARIC | Cohort | 8,945 | 52.8 | 54.3 (5.7) | 332.9 (311.1) | 24.4 | Affymetrix 6.0 |
| PLCO | Cohort: nested case-control** | 4,942 | 23.5 | 67.7 (5.4) | 491.1 (494.1) | 22.1 | Illumina 240KIllumina 310KIllumina 550kIllumina 610Q |
| NHS T2D | Cohort: nested T2D case-control | 3,135 | 100 | 51.1 (10.5) | 284.5 (206.3) | 14.8 | Affymetrix 6.0 |
| NHS CHD | Cohort: nested CHD case-control | 1,102 | 100 | 53.5(10.6) | 316.7 (218.0) | 30.0 | Affymetrix 6.0 |
| NHS KS | Cohort: nested KS case-control | 488 | 100 | 47.7 (11.7) | 264.4 (203.6) | 15.3 | Illumina 610Q |
| NHS BrC | Cohort: nested BrC case-control | 2,049 | 100 | 52.3 (9.6) | 286.5 (204.0) | 15.6 | Illumina 550k |
| HPFS T2D | Cohort: nested T2D case-control | 2,381 | 0 | 55.5 (8.4) | 250.9 (227.6) | 7.6 | Affymetrix 6.0 |
| HPFS CHD | Cohort: nested CHD case-control | 1,099 | 0 | 56.7 (8.7) | 243.2 (230.7) | 9.9 | Affymetrix 6.0 |
| HPFS KS | Cohort: nested KS case-control | 543 | 0 | 48.8 (6.8) | 230.5 (241.6) | 6.4 | Illumina 610Q |
| WGHS | Cohort | 22,658 | 100 | 54.7 (7.1) | 298.5 (232.9) | 11.5 | Illumina HumanHap300 Duo+ |
| Total | 47,341 |
*Values are mean (standard deviation) for age and caffeine; percent for female and current smokers.
**Includes samples from prostate cancer case-control (n = 1885), bladder cancer case-control (n = 572), glioma case-control (n = 3), lung cancer case-control (n = 1758), pancreatic cancer case-control (n = 299), renal cancer case-control study (n = 271).