Table 2

Pooled relative risks (95% confidence intervals) of lung cancer for quintiles of dietary carotenoids

CarotenoidQuintile 1Quintile 2Quintile 3Quintile 4Quintile 5P
Test for trendTest for between study heterogeneity for quintile 5Test for between study heterogeneity due to sex for quintile 5
α-Carotene
 Age-adjusted1.000.78 (0.70–0.88)0.73 (0.65–0.82)0.70 (0.61–0.80)0.61 (0.53–0.71)<0.0010.150.06
 Multivariatea1.000.91 (0.80–1.05)0.94 (0.84–1.06)0.95 (0.84–1.07)0.93 (0.82–1.06)0.470.390.74
β-Carotene
 Age-adjusted1.000.81 (0.70–0.94)0.77 (0.67–0.90)0.69 (0.59–0.80)0.65 (0.58–0.73)<0.0010.680.73
 Multivariatea1.000.97 (0.82–1.16)1.00 (0.84–1.20)0.94 (0.82–1.08)0.98 (0.87–1.11)0.470.850.47
β-Cryptoxanthin
 Age-adjusted1.000.71 (0.64–0.80)0.59 (0.51–0.69)0.56 (0.48–0.64)0.50 (0.43–0.57)<0.0010.270.26
 Multivariatea1.000.90 (0.80–1.00)0.83 (0.71–0.96)0.86 (0.76–0.97)0.76 (0.67–0.86)<0.0010.950.60
Lutein/Zeaxanthin
 Age-adjusted1.000.86 (0.77–0.96)0.76 (0.67–0.88)0.78 (0.69–0.87)0.74 (0.66–0.83)0.0010.570.16
 Multivariatea1.000.98 (0.87–1.10)0.92 (0.79–1.06)0.97 (0.86–1.10)0.91 (0.81–1.03)0.150.810.25
Lycopene
 Age-adjusted1.000.78 (0.69–0.87)0.74 (0.66–0.83)0.74 (0.66–0.83)0.77 (0.68–0.88)0.030.250.55
 Multivariatea1.000.86 (0.75–0.97)0.85 (0.74–0.99)0.88 (0.77–1.01)0.91 (0.78–1.07)0.420.110.92
  • a Adjusted for education (<high school graduate, high school graduate, and >high school graduate), body mass index (<23, 23 to <25, 25 to <30, and ≥30 kg/m2), alcohol consumption (0, >0 to <5, 5 to <15, 15 to <30, and ≥30 g/day), energy (continuous), smoking status (current, past, and never smokers), smoking duration for current smokers (continuous), smoking duration for past smokers (continuous), and amount smoked for current smokers (continuous). Because the α-Tocopherol, β-Carotene Cancer Prevention Study only includes current smokers, in this study we adjusted for smoking as smoking duration (continuous) and amount smoked (continuous).