Table 2

 Self-reported and interview-based occupational quartz exposure in those with and without respiratory symptoms in a Norwegian general population study, 1987–8

SymptomQuartz exposure
Self-reportedInterview basedSensitivitySpecificity
Source: Bakke et al.15
Morning cough
    Yes (n = 180)9.4%12.2%59.1%98.6%
    No (n = 534)2.1%7.5%21.0%99.4%
Chronic cough
    Yes (n = 92)10.9%12.0%63.6%97.4%
    No (n = 622)2.9%8.2%27.5%99.5%
Phlegm when coughing
    Yes (n = 179)8.4%12.3%45.5%96.4%
    No (n = 535)2.4%7.0%27.5%98.3%
Breathlessness grade 2
    Yes (n = 94)9.6%14.9%50.0%95.5%
    No (n = 620)3.1%7.7%29.2%98.3%
Wheezing
    Yes (n = 196)8.2%13.3%50.0%96.0%
    No (n = 518)2.3%6.9%22.2%99.6%
Asthma
    Yes (n = 88)8.1%18.0%62.9%98.0%
    No (n = 626)2.2%7.2%21.0%100.0%