Table 2.

RR (95% CI) of BCC by group of serum concentration of antioxidants at baseline, person-based analyses in 485 participants of the Nambour Skin Cancer Study, 1996-2004

Serum biomarkerBiomarker concentration
Ptrend
Group 1Group 2Group 3
α-Carotene
    Median (μmol/L; min-max)0.05 (0.01-0.07)0.11 (0.08-0.15)0.22 (0.16-1.04)
    No. tumors/participants18/15335/17124/161
    Basic RR (95% CI)*1.001.87 (1.05-3.30)1.33 (0.72-2.46)0.91
    Multivariate RR (95% CI)1.001.70 (0.95-3.03)1.28 (0.68-2.41)0.69
β-Carotene
    Median (μmol/L; min-max)0.30 (0.02-0.44)0.59 (0.45-0.79)1.10 (0.80-5.10)
    No. tumors/participants23/16330/15924/163
    Basic RR (95% CI)*1.001.33 (0.77-2.30)1.06 (0.59-1.90)0.99
    Multivariate RR (95% CI)1.001.30 (0.74-2.30)1.07 (0.59-1.96)0.95
β-Cryptoxanthin
    Median (μmol/L; min-max)0.10 (0.02-0.16)0.29 (0.18-0.42)0.73 (0.43- 3.20)
    No. tumors/participants23/15930/16824/158
    Basic RR (95% CI)*1.001.10 (0.64-1.90)0.90 (0.50-1.63)0.63
    Multivariate RR (95% CI)1.001.07 (0.61-1.87)0.91 (0.50-1.67)0.68
Lutein and zeaxanthin
    Median (μmol/L; min-max)0.20 (0.04-0.28)0.37 (0.29-0.47)0.64 (0.48-1.60)
    No. tumors/participants26/16221/15830/165
    Basic RR (95% CI)*1.000.85 (0.48-1.51)1.05 (0.62-1.77)0.78
    Multivariate RR (95% CI)1.000.81 (0.45-1.46)1.06 (0.62-1.83)0.71
α-Tocopherol
    Median (μmol/L; min-max)24.0 (9.0-27.0)30.0 (28.0-33.0)38.5 (34.0-130.0)
    No. tumors/participants22/16329/15826/164
    Basic RR (95% CI)*1.001.12 (0.63 1.98)0.90 (0.50-1.65)0.65
    Multivariate RR (95% CI)1.000.88 (0.49-1.56)0.95 (0.51-1.75)0.92
  • * Adjusted for age, sex, and allocation of a β-carotene supplement during the Nambour trial. All RRs from multivariate Poisson regression.

  • Adjusted for age, sex, pack-years of smoking, β-carotene supplement allocation during the trial, alcohol intake (continuous), time spent outdoors on weekdays, and history of skin cancer before 1996.