Table 1

Characteristics of TESAOD participants with and without chronic bronchitis at enrolment

Participants with chronic bronchitis at enrolment (n = 97)Participants without chronic bronchitis at enrolment (n = 1315)p Value*
Sex: % male51.540.80.04
Age in years: mean (SD)50 (14)49 (18)0.54
Body mass index (n = 1363): mean (SD)25.0 (4.8)24.4 (3.7)0.13
Years of formal education: % with >12 years26.846.8<0.001
Pack-years (n = 1411):
    % <1 pack-year15.550.5<0.001
    % 1–19.9 pack-years27.827.4
    % 20–49.9 pack-years42.316.4
    % ⩾50 pack-years14.45.7
Allergy skin tests† (n = 1393): % positive31.235.70.38
Total IgE in IU/ml (n = 1284): geometric mean (95% CI)28 (20 to 38)23 (21 to 25)0.31
Eosinophilia‡ (n = 1067): % positive12.56.80.07
FEV1/FVC ratio: mean (SD)81.3 (6)83.0 (7)0.02
  • n is 1412 unless otherwise specified.

  • *p Value for the comparison between the two groups.

  • †Wheal at least 2 mm larger than the control wheal for at least one of five tested allergens (house dust, Bermuda grass, tree mix, weed mix and Dematiaceae mould mix).

  • ‡Eosinophils were measured as percentages from stained blood smears, and blood eosinophilia was defined as eosinophils >4%.

  • FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; IgE, immunoglobulin E; TESAOD, Tucson Epidemiological Study of Airway Obstructive Disease.