Table 2

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

Quintiles of toenail selenium (boundaries in μg/g)All years of follow-upFirst year excluded
Cases in cohortPerson years in subcohortRR (95% CI)aRR (95% CI)bRR (95% CI)b
1 (≤0.483)11429861.00 (reference)1.00 (reference)1.00 (reference)
2 (0.483 to ≤0.530)11630221.05 (0.79–1.40)1.09 (0.80–1.48)1.19 (0.86–1.64)
3 (0.530 to ≤0.573)7830310.51 (0.36–0.73)0.55 (0.38–0.79)0.61 (0.42–0.89)
4 (0.573 to ≤0.630)6229930.53 (0.37–0.76)0.63 (0.43–0.91)0.63 (0.42–0.94)
5 (>0.630)6130010.54 (0.38–0.76)0.67 (0.46–0.97)0.78 (0.54–1.14)
P for linear trend<0.01<0.01<0.01
Increment in standard unitsc0.86 (0.77–0.96)0.94 (0.83–1.05)0.89 (0.79–1.00)
  • a Adjusted for age (years) and sex.

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

  • c z-scores based on In-transformed toenail selenium levels (increment of 0.202 μg/g).