Table 1. Population characteristics of the discovery cohort.
| Cases, n (%) | Controls, n (%) | P-valuea | |
|---|---|---|---|
| Male | 626 (39.3) | 3029 (55.2) | <0.001 |
| Female | 969 (60.7) | 2456 (44.8) | |
| Genetic ancestry | |||
| European ancestry | 1346 (84.3) | 4661 (85.0) | <0.001 |
| African ancestry | 178 (11.2) | 701 (12.8) | |
| Other | 71 (4.5) | 123 (2.2) | |
| Birth decade (IQR) | 1930–1950 | 1920–1940 | <0.001 |
| Ever smoked | 515 (32.9) | 2403 (43.8) | <0.001b |
| History of | |||
| Asthma | 262 (16.4) | 882 (16.1) | 0.74 |
| GERD | 668 (41.9) | 2035 (37.1) | <0.001 |
| PND | 530 (33.2) | 1507 (27.5) | <0.001 |
| Other lung disease | 331 (20.8) | 1626 (29.7) | <0.001 |
Abbreviations: GERD, gastroesophageal reflux disease; IQR, interqquartile range; PND, postnasal drip.
a
P-value obtained from chi-square analysis.
b
Calculation excludes 776 subjects (184 cases, 592 controls) with an unknown smoking history.