Table 2.

Incidence rates (IRs), HRs, and 95% CI for testicular cancer (n = 119 cases) by exposure to “ever” cannabis use in 45,250 conscripts with data available on all study covariates

Cases/noncasesCrude incidence rate per 10,000 PYCrude modelModel 1aModel 2bModel 3c
Study covariatesNIR (95% CI)HR (95% CI)HR (95% CI)HR (95% CI)HR (95% CI)
Ever use of cannabis
 Never use of any drugs102/39,9750.64 (0.53–0.77)1.001.001.001.00
 Ever use of cannabisd17/5,1560.85 (0.53–1.37)1.32 (0.79–2.21)1.32 (0.79–2.21)1.44 (0.83–2.47)1.42 (0.83–2.45)
Birth year
 194910/2,4271.06 (0.57–1.97)1.001.001.001.00
 195016/7,8360.52 (0.32–0.85)0.49 (0.22–1.08)0.49 (0.22–1.09)0.49 (0.22–1.08)0.50 (0.22–1.09)
 195193/34,8680.67 (0.54–0.82)0.63 (0.33–1.22)0.65 (0.34–1.24)0.64 (0.33–1.23)0.64 (0.34–1.24)
Cryptorchidism
 No115/44,8970.64 (0.54–0.77)1.001.001.00
 Yes4/2344.23 (1.59–11.27)6.59 (2.43–17.86)e6.42 (2.37–17.42)6.26 (2.30–17.01)
Parental testicular cancer
 No118/45,0630.66 (0.55–0.79)1.001.001.00
 Yes1/683.58 (0.50–25.40)5.46 (0.76–39.05)4.95 (0.69–35.57)4.82 (0.67–34.72)
Tobacco smoking
 Never46/18,7760.61 (0.46–0.82)1.001.001.00
 1–5 cigarettes/day16/5,0040.80 (0.49–1.30)1.31 (0.74–2.31)1.37 (0.77–2.44)1.38 (0.77–2.46)
 6–10 cigarettes/day18/9,3490.48 (0.30–0.77)0.79 (0.46–1.36)0.83 (0.47–1.45)0.83 (0.47–1.45)
 11–20 cigarettes/day33/10,4200.80 (0.57–1.13)1.30 (0.83–2.04)1.41 (0.88–2.28)1.41 (0.88–2.28)
 More than 20 cigarettes/day6/1,5820.98 (0.44–2.18)1.58 (0.68–3.71)1.95 (0.80–4.71)1.90 (0.79–4.60)
Alcohol consumption (g of 100% alcohol/week)
 Abstainers (0 g)10/2,7700.90 (0.48–1.67)1.001.001.00
 Light (1–100 g)91/33,7310.67 (0.55–0.83)0.75 (0.39–1.44)0.67 (0.34–1.32)0.67 (0.34–1.32)
 Moderate (101–250 g)17/7,3110.59 (0.37–0.95)0.65 (0.30–1.42)0.49 (0.21–1.14)0.49 (0.21–1.14)
 Heavy (more than 250 g)1/1,3190.20 (0.03–1.41)0.22 (0.03–1.70)0.13 (0.02–1.09)0.14 (0.02–1.11)
  • aModel 1 adjusted for conscript's birth year, conscript's cryptorchidism, and paternal history of testicular cancer.

  • bModel 2 adjusted for conscript's birth year, conscript's frequency of tobacco smoking and conscript's alcohol consumption.

  • cModel 3 adjusted for all covariates in the table.

  • dExposure to ever use of cannabis before conscription (with or without use of any other illicit drugs).

  • eBolded estimates represent statistically significant values generated from the statistical modeling.