Table 1.

Summary of results from the seven eligible studies on selenium and bladder cancer risk

First author, yearCountryMatrixSexCasesControlsSelenium concentrationOR (95% CI)PtrendSmokerAdjustment
Case-control
Helzlsouer, 1989 (17)United StatesSerumCombined sexes1423<110 μg/L1.000.03UndefinedAge, sex, race, blood collection, previous meal
1423110-119 μg/L0.51 (0.15-1.75)
724>119 μg/L0.49 (0.16-1.49)
Kellen, 2006 (18)BelgiumSerumCombined sexes1091201.60-82.39 μg/L1.00<0.001UndefinedAge, sex, smoking, occupation, polycyclic aromatic hydrocarbons or aromatic amines
4112082.40-95.99 μg/L0.48 (0.29-0.79)
28122≥96.00 μg/L0.30 (0.17-0.51)
Wallace, 2009 (22)United StatesToenailsCombined sexes245280<0.77 μg/g1.000.15UndefinedAge, sex, smoking
2172750.77-0.86 μg/g1.04 (0.79-1.35)
1382760.87-0.95 μg/g0.73 (0.55-0.98)
167277>0.95 μg/g0.90 (0.68-1.19)
MenN.a.N.a.<0.77 μg/g1.000.35UndefinedAge, smoking
N.a.N.a.0.77-0.86 μg/g1.27 (0.93-1.71)
N.a.N.a.0.87-0.95 μg/g0.83 (0.59-1.16)
N.a.N.a.>0.95 μg/g0.97 (0.70-1.36)
WomenN.a.N.a.<0.77 μg/g1.000.11UndefinedAge, smoking
N.a.N.a.0.77-0.86 μg/g0.53 (0.30-0.93)
N.a.N.a.0.87-0.95 μg/g0.50 (0.29-0.84)
N.a.N.a.>0.95 μg/g0.66 (0.40-1.10)
Combined sexesN.a.N.a.<0.77 μg/g1.000.12NeverAge, sex
N.a.N.a.0.77-0.86 μg/g1.05 (0.59-1.88)
N.a.N.a.0.87-0.95 μg/g0.53 (0.29-1.00)
N.a.N.a.>0.95 μg/g0.78 (0.44-1.37)
N.a.N.a.<0.77 μg/g1.000ModerateAge, sex
N.a.N.a.0.77-0.86 μg/g0.85 (0.56-1.31)
N.a.N.a.0.87-0.95 μg/g0.45 (0.28-0.72)
N.a.N.a.>0.95 μg/g0.61 (0.39-0.96)
N.a.N.a.<0.77 μg/g1.000.01HeavyAge, sex
N.a.N.a.0.77-0.86 μg/g1.09 (0.73-1.64)
N.a.N.a.0.87-0.95 μg/g1.30 (0.83-2.01)
N.a.N.a.>0.95 μg/g1.44 (0.91-2.27)
Nested case-control
Nomura, 1987 (16)United StatesSerumMen626<103.1 μg/L1.000.12UndefinedAge, smoking
650103.1-112.0 μg/L0.53 (0.15-1.81)
576112.1-123.0 μg/L0.91 (0.26-3.24)
759123.1-133.0 μg/L0.53 (0.16-1.73)
582≥133.1 μg/L0.31 (0.09-1.10)
Michaud, 2002 (20)FinlandToenailsMen44431st tertile1.000.79EverAge, nail collection, intervention group
47432nd tertile0.88 (0.47-1.68)
42473rd tertile0.90 (0.45-1.78)
Michaud, 2005 (19)United StatesToenailsMen52550.660 μg/g1.000.61UndefinedAge, sex, smoking, nail collection
54570.765 μg/g1.09 (0.59-2.01)
53550.863 μg/g1.09 (0.59-2.00)
62560.990 μg/g1.17 (0.66-2.07)
Women37280.626 μg/g1.000.02UndefinedAge, sex, smoking, nail collection
35310.716 μg/g0.73 (0.35-1.55)
23290.800 μg/g0.49 (0.21-1.16)
21290.933 μg/g0.36 (0.14-0.91)
Case-cohort
Zeegers, 2002 (21)The NetherlandsToenailsCombined sexes1142,986≤0.483 μg/g1.00<0.01UndefinedAge, sex, smoking
1163,0220.483-0.530 μg/g1.09 (0.80-1.48)
783,0310.531-0.573 μg/g0.55 (0.38-0.79)
622,9930.574-0.630 μg/g0.63 (0.43-0.91)
613,001>0.630 μg/g0.67 (0.46-0.97)
N.a.N.a.≤0.483 μg/g1.000.62NeverAge, sex, smoking
N.a.N.a.0.483-0.530 μg/g2.69 (1.02-7.09)
N.a.N.a.0.531-0.573 μg/g1.37 (0.50-3.79)
N.a.N.a.0.574-0.630 μg/g1.09 (0.38-3.14)
N.a.N.a.>0.630 μg/g1.36 (0.50-3.69)
N.a.N.a.≤0.483 μg/g1.00<0.01FormerAge, sex, smoking
N.a.N.a.0.483-0.530 μg/g0.74 (0.46-1.19)
N.a.N.a.0.531-0.573 μg/g0.48 (0.28-0.81)
N.a.N.a.0.574-0.630 μg/g0.49 (0.29-0.83)
N.a.N.a.>0.630 μg/g0.44 (0.26-0.75)
N.a.N.a.≤0.483 μg/g1.000.25CurrentAge, sex, smoking
N.a.N.a.0.483-0.530 μg/g1.36 (0.86-2.14)
N.a.N.a.0.531-0.573 μg/g0.45 (0.24-0.86)
N.a.N.a.0.574-0.630 μg/g0.76 (0.39-1.47)
N.a.N.a.>0.630 μg/g1.13 (0.56-2.27)

Abbreviation: N.a., not available.