Association between gender, smoking, atopy, asthma and fraction of exhaled nitric oxide (FeNO)
| Variable | FeNO (ppb), geometric mean (SD) | p Value* | |
| Gender | Male (n=376) | 22 (2) | <0.001 |
| Female (n=423) | 15 (2) | ||
| Current smoking | Yes (n=198) | 14 (2) | <0.001 |
| No (n=601) | 19 (2) | ||
| Atopy | Yes (n=324) | 28 (2) | <0.001 |
| No (n=475) | 13 (2) | ||
| Asthma | Yes (n=155) | 29 (3) | <0.001 |
| No (n=644) | 16 (2) | ||
| Rhinitis | Yes (n=310) | 25 (2) | <0.001 |
| No (n=489) | 15 (2) | ||
| Current inhaled corticosteroid use in patients with asthma (n=155) | Yes (n=65) | 30 (3) | 0.65 |
| No (n=90) | 28 (3) |
↵* Two-sided t test comparing logarithmically-transformed FeNO for each variable.