Table 3.

RR (95% CI) of SCC 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/participants19/15326/17114/161
    Basic RR (95% CI)*1.001.28 (0.71-2.32)0.74 (0.37-1.49)0.59
    Multivariate RR (95% CI)1.001.30 (0.70-2.39)0.71 (0.35-1.45)0.49
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/participants20/16322/15917/163
    Basic RR (95% CI)*1.001.09 (0.59-2.01)0.88 (0.45-1.69)0.64
    Multivariate RR (95% CI)1.001.08 (0.57-2.03)0.92 (0.47-1.81)0.78
β-Cryptoxanthin
    Median (μmol/L; min-max)0.10 (0.01-0.17)0.29 (0.18-0.42)0.73 (0.43- 3.20)
    No. tumors/participants16/15922/16821/158
    Basic RR (95% CI)*1.001.18 (0.62-2.25)1.11 (0.56-2.16)0.87
    Multivariate RR (95% CI)1.001.16 (0.60-2.241.17 (0.59-2.33)0.70
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/participants17/16221/15821/165
    Basic RR (95% CI)*1.001.34 (0.71-2.55)1.04 (0.55-1.98)0.96
    Multivariate RR (95% CI)1.001.26 (0.66-2.42)1.01 (0.53-1.93)0.91
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/participants19/16320/15820/164
    Basic RR (95% CI)*1.000.84 (0.44-1.60)0.76 (0.39-1.47)0.44
    Multivariate RR (95% CI)1.000.78 (0.41-1.50)0.85 (0.43-1.65)0.68
  • * Adjusted for age and sex. All RRs from multivariate Poisson regression.

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