Table 1

 Selected characteristics according to asthma status of 5876 study participants aged ⩾20 years (NHANES III, 1988–1994)

CharacteristicAsthma statusp value
Current (n = 290)Never (n = 5586)
Mean or % (SE)Mean or % (SE)
MET, metabolic equivalent (a unit of expended energy).
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