Table 2.
Characteristics of cases and controls
| Variable | Asthma | Chronic rhino-sinusitis | Asthma and chronic rhino-sinusitis | Controls |
|---|---|---|---|---|
| Age (mean; SD) | 46.37 (14.50) | 48.60 (14.22) | 47.44 (13.58) | 49.48 (14.61) |
| Sex (% male) | 40.80 | 46.60 | 37.45 | 44.93 |
| Height (mean; SD) | 170.12 (9.64) | 170.37 (10.33) | 168.56 (10.33) | 170.23 (9.65) |
| Smoking (Men) | ||||
| Never (%) | 44.48 | 42.70 | 42.86 | 43.29 |
| Former (%) | 41.01 | 35.14 | 45.05 | 34.42 |
| Current (%) | 14.51 | 22.16 | 12.09 | 22.29 |
| Smoking (Women) | ||||
| Never (%) | 53.81 | 49.53 | 50.00 | 56.33 |
| Former (%) | 30.72 | 25.94 | 28.29 | 28.35 |
| Current (%) | 15.47 | 24.53 | 21.71 | 15.32 |
| Pack years in ever smokers (men) | 10.82 | 14.41 | 15.58 | 12.96 |
| Pack years in ever smokers (women) | 6.88 | 9.75 | 9.76 | 7.03 |
| Atopy (%) | 73.11 | 45.68 | 64.16 | 44.73 |
| Atopy (%) aged<40 | 84.48 | 55.05 | 82.05 | 56.16 |
| Atopy (%) aged ≥ 40 | 66.08 | 41.54 | 54.42 | 39.77 |
| Nasal discharge (%) | 5.02 | 54.39 | 65.16 | 4.13 |
| Blocked nose (%) | 15.94 | 90.73 | 92.62 | 11.61 |
| Nasal discharge or blocked nose (%) | 20.98 | 100 | 100 | 15.74 |
| Facial pain/pressure or reduced sense of smell (%) | 9.41 | 86.96 | 79.92 | 9.67 |
| Steroid use | ||||
| None/limited (%) | 65.59 | 96.73 | 60.53 | 96.31 |
| Regular (%) | 34.37 | 3.32 | 39.47 | 3.73 |
| Postbronchodilator FEV1 (Men) L | 3.53 | 3.80 | 3.36 | 3.69 |
| Postbronchodilator FEV1 (Men)% predicted | 88.23 | 95.72 | 84.23 | 95.38 |
| Postbronchodilator FVC (Men) L | 4.79 | 4.84 | 4.53 | 4.74 |
| Postbronchodilator FVC (Men)% predicted | 94.42 | 96.06 | 89.78 | 95.09 |
| Postbronchodilator FEV1/FVC (Men)% | 73.66 | 78.13 | 73.01 | 77.71 |
| Postbronchodilator FEV1/FVC (Men)% of% predicted | 93.96 | 99.91 | 93.16 | 100.08 |
| Postbronchodilator FEV1 (Women) L | 2.73 | 2.76 | 2.67 | 2.82 |
| Postbronchodilator FEV1 (Women)% predicted | 91.10 | 96.66 | 91.58 | 97.14 |
| Postbronchodilator FVC (Women) L | 3.52 | 3.48 | 3.37 | 3.52 |
| Postbronchodilator FVC (Women)% predicted | 95.42 | 97.82 | 93.64 | 97.28 |
| Postbronchodilator FEV1/FVC (Women)% | 77.19 | 79.19 | 78.76 | 80.33 |
| Postbronchodilator FEV1/FVC (Women)% of% predicted | 94.80 | 98.42 | 97.11 | 99.53 |
Asthma cases had both a self-reported diagnosis of asthma and a history of either wheezing, shortness of breath or waking at night with breathlessness within the previous 12 months.
Chronic rhino-sinusitis cases were participants reporting at least two of these symptoms; 1) nasal blockage, 2) nasal discharge, 3) facial pain or pressure, or 4) reduced sense of smell, at least one of which had to be either blockage or discharge and symptoms had to have been present at least for 12 weeks without remission.
The controls lived in the same area but met neither of the criteria for diagnosis of asthma or sinusitis as above.
Use of inhaled corticosteroids was classified as regular if a participant reported using it for at least two and half years in the last five years and limited if otherwise. FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; Atopy was considered positive if ≥3 mm reaction size to any of the allergens.
FEV1 and FVC percent predicted are based on the NHANES prediction equations.