Table 2

Population characteristics for participants reporting a job change because the work affected their breathing (125 cases), and matched controls

ControlsCases specifying job in year prior to change
Variable (% of valid)*Females (n=4592)Males (n=3760)Females (n=47)Males (n=78)
Mean age in years38.439.439.640.4
Smoking
 Never smoked2268 (50.6)1814 (49.2)19 (40)31 (40)
 Ex-smoker1087 (24.2)903 (24.5)12 (26)21 (27)
 Current smoker1130 (25.2)967 (26.2)16 (34)25 (32)
Asthma symptoms in past 12 months:
 Wheezing955 (21.2)754 (20.3)27 (60)42 (56)
 Chest tightness698 (15.6)448 (12.2)25 (56)38 (51)
 Dyspnoea307 (6.9)261 (7.2)17 (38)29 (38)
 Physician-diagnosed asthma490 (11.0)395 (10.8)28 (64)34 (45)
 Symptoms prior to age 16307 (66.5)243 (64.3)12 (44)19 (56)
 Nasal allergy1387 (30.9)1154 (31.4)30 (67)43 (55)
  • *Each categorical variable had missing values; these did not exceed 9% of the column total.