Table 1 Selected characteristics according to asthma status of 5876 study participants aged ⩾20 years (NHANES III, 1988–1994).
| Characteristic | Asthma status | p value | |
|---|---|---|---|
| Current (n = 290) | Never (n = 5586) | ||
| Mean or % (SE) | Mean or % (SE) | ||
| Age (years) | 43.6 (1.2) | 44.4 (0.7) | 0.61 |
| Male (%) | 39.9 (4.2) | 48.5 (1.0) | 0.07 |
| White (%) | 79.7 (3.5) | 77.0 (1.6) | 0.44 |
| Education (years) | 12.3 (0.2) | 12.4 (0.1) | 0.53 |
| Current smoker (%) | 34.1 (3.6) | 27.2 (1.1) | 0.09 |
| Serum cotinine (ng/ml) | 78.6 (10.3) | 73.5 (2.8) | 0.62 |
| Body mass index (kg/m2) | 27.8 (0.6) | 26.4 (0.2) | 0.03 |
| Triceps skinfold thickness (mm) | 20.2 (0.7) | 18.7 (0.2) | 0.04 |
| Physical activity (MET frequency) | 110.0 (16.1) | 112.2 (4.4) | 0.89 |
| History of diabetes (%) | 5.7 (1.6) | 3.7 (0.3) | 0.23 |
| Presence of domestic pets (%) | 49.9 (3.8) | 41.5 (1.3) | 0.04 |
| History of atopy (%) | 40.0 (4.2) | 9.9 (0.7) | <0.01 |
| Leptin concentration (μg/l, unadjusted) | 13.7 (0.9) | 11.1 (0.3) | <0.01 |
MET, metabolic equivalent (a unit of expended energy).