Table 1.

Description of the study population, n (%)

Controls (n = 554)Cases (n = 519)
Sex, women264 (48)232 (45)
Age, mean (SD)57.0 (16.2)58.9 (15.6)
Reported asthma53 (10)35 (7)
Social class
    Unclassified197 (36)166 (32)
    Professionals15 (3)23 (4)
    Skilled manual and nonmanual79 (14)87 (17)
    Unskilled manual263 (48)243 (47)
Occupational exposures*
    Exposure to high molecular weight (IgE-mediated acting) agents87 (16)82 (16)
    Exposure to low molecular weight agents184 (34)157 (30)
    Exposure to bioaerosols145 (26)158 (31)
    Mixed exposures235 (43)251 (48)
    Exposure to other possible asthmagens287 (52)280 (54)
Lymphoma cell lineage
    B-cell416 (80)
    Hodgkin's59 (11)
    T-cell44 (9)
  • * Subjects could be classified in more than one category. Five controls and one case could not be assigned to any occupational category.