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Table 4 Workplace asbestos exposure and bladder cancer in men from the NECSS, 1994–1997

From: Silica and asbestos exposure at work and the risk of bladder cancer in Canadian men: a population-based case-control study

Asbestos exposure groupsCasesControlsMinimal aFull b
N%N%OR (95% CI)OR (95% CI)
Ever exposed to asbestos
 Never53826.7120959.91.001.00
 Ever1206.01517.51.58 (1.20–2.08)1.32 (0.98–1.77)
  ≥ 20 years ago44 36 2.51 (1.57–4.03)2.04 (1.25–3.34)
  ≥ 40 years ago84 105 1.64 (1.19–2.25)1.26 (0.90–1.78)
Highest attained concentration of exposure to asbestos
 Unexposed53826.7120959.91.001.00
 Low1065.31346.61.55 (1.17–2.07)1.29 (0.95–1.76)
 Medium/ High140.7170.81.80 (0.85–3.81)1.56 (0.73–3.32)
 p-trend    < 0.0010.07
Highest attained frequency of exposure to asbestos
 Unexposed53826.7120959.91.001.00
  < 5%40.2100.50.79 (0.24–2.63)0.63 (0.18–2.15)
 5–30%1075.31226.11.75 (1.31–2.35)1.45 (1.06–1.98)
  ≥ 30%90.5190.90.92 (0.40–2.10)0.90 (0.39–2.08)
 p-trend    < 0.0010.08
Duration of exposure to asbestos (years)
 Unexposed53826.7120959.91.001.00
  < 9452.2462.31.90 (1.22–2.95)1.69 (1.08–2.66)
 9 - < 25391.9512.51.57 (0.99–2.47)1.26 (0.78–2.02)
  ≥ 25331.6512.51.27 (0.79–2.03)1.04 (0.64–1.69)
 Unknown30.230.2  
 p-trend    < 0.0010.07
Duration of exposure at low concentrations of asbestos (years)
 Unexposed54727.1122160.51.001.00
  < 10442.2432.11.98 (1.26–3.11)1.75 (1.10–2.77)
 10 - < 24331.6442.21.43 (0.88–2.33)1.13 (0.68–1.87)
  ≥ 24311.5492.41.30 (0.80–2.10)1.05 (0.63–1.73)
 Unknown30.230.2  
 p-trend    < 0.0010.11
Duration of exposure at medium/high concentrations of asbestos (years)
 Unexposed64431.9134366.61.001.00
  < 750.380.41.61 (0.50–5.19)1.39 (0.43–4.46)
  ≥ 790.590.51.75 (0.66–4.64)1.54 (0.58–4.14)
 p-trend    0.140.36
Cumulative exposure to asbestos
 Unexposed53826.7120959.91.001.00
 Lowest tertile452.2472.31.92 (1.24–2.99)1.69 (1.07–2.65)
 Middle tertile371.8482.41.47 (0.93–2.34)1.22 (0.76–1.97)
 Highest tertile351.7532.61.35 (0.85–2.14)1.13 (0.70–1.82)
 Unknown30.230.20.010.23
 p-trend      
  1. a Adjusted for province of residence, age at interview, proxy respondent and cigarette pack-years
  2. b Adjusted for province of residence, age at interview, proxy respondent, cigarette pack-years, highest attained concentration of diesel exposure, ever exposed to mineral/lube oil at work