Table 3

Incidence RR of bladder cancer according to toenail selenium levels and smoking status; Netherlands Cohort Study (1986–1992)

Smoking status and cessationaNo. of casesQuintile of toenail selenium (boundaries in μg/g)P trend
1 (≤0.483)2 (≤0.530)3 (≤0.573)4 (≤0.630)5 (>0.630)
Neverb511.00 (reference)2.69 (1.02–7.09)1.37 (0.50–3.79)1.09 (0.38–3.14)1.36 (0.50–3.69)0.62
Exc1861.00 (reference)0.74 (0.46–1.19)0.48 (0.28–0.81)0.49 (0.29–0.83)0.44 (0.26–0.75)<0.01
 ≤10 yrs891.00 (reference)0.42 (0.19–0.94)0.47 (0.21–1.08)0.45 (0.20–1.01)0.30 (0.12–0.75)<0.01
 >10 yrs961.00 (reference)1.06 (0.55–2.06)0.48 (0.22–1.01)0.47 (0.20–1.09)0.58 (0.29–1.18)<0.01
Currentc1701.00 (reference)1.36 (0.86–2.14)0.45 (0.24–0.86)0.76 (0.39–1.47)1.13 (0.56–2.27)0.25
  • a P for interaction was 0.19.

  • b Adjusted for age (years) and sex.

  • c Adjusted for age (years), sex, number of cigarettes/day, and years of cigarette smoking.