Table 5

Crude prevalence of irregular and rounded opacities (median scores) among construction workers by duration of exposure, age, and smoking category

Irregular opacitiesRounded opacities
nProfusion category 
 ⩾1/0, n=121 (9.4%)Profusion category 
 ⩾1/1, n=31 (2.4%)Profusion category ⩾1/0, n=10 (0.77%)
*Exposure index × duration of exposure.
Cumulative exposure index*
    0–3.9925819 (7.4%)2 (0.8%)1 (0.39%)
    4–7.9941729 (7.0%)5 (1.2%)2 (0.48%)
    8–14.9933531 (9.3%)9 (2.7%)1 (0.30%)
    ⩾1528142 (15%)15 (5.3%)6 (2.1%)
Age at survey
    27–3533016 (5%)3 (0.9%)1 (0.29%)
    36–4135028 (8%)6 (1.7%)3 (0.86%)
    42–4831534 (11%)10 (3.2%)3 (0.95%)
    ⩾4929643 (15%)12 (4.1%)3 (1.0%)
Pack-years smoked
    0–1.935515 (4.2%)3 (0.85%)4 (1.1 %)
    2–11.943635 (2.7%)8 (1.8%)3 (0.69 %)
    12–19.924828 (11%)9 (3.6%)2 (0.81%)
    ⩾2025243 (17%)11 (4.4%)1 (0.40 %)