Table 4. Multivariate relative risks (RR) and 95% confidence intervals (95% CI) of colorectal cancer according to carotenoid intake and smoking status in the Multiethnic Cohort Study, 1993–2002.
| Never smokers | Former smokers | Current smokers | P for interaction | |
| RR (95% CI)* | RR (95% CI)* | RR (95% CI)* | ||
| Men | ||||
| No. of cases | 293 | 664 | 208 | |
| Total β-carotene† | 0.90 (0.59–1.39) | 0.93 (0.70–1.23) | 0.49 (0.25–0.94) | 0.20 |
| β-carotene‡ | 0.82 (0.54–1.25) | 0.93 (0.70–1.23) | 0.57 (0.30–1.06) | 0.48 |
| β-carotene supplement use‡ | 1.12 (0.61–2.05) | 1.12 (0.75–1.68) | 0.81 (0.32–2.02) | 0.87 |
| α-carotene | 0.75 (0.50–1.12) | 1.11 (0.84–1.45) | 0.87 (0.49–1.57) | 0.63 |
| Lycopene | 1.18 (0.79–1.76) | 1.14 (0.89–1.47) | 1.25 (0.79–1.95) | 0.75 |
| β-cryptoxanthin | 0.70 (0.46–1.08) | 1.01 (0.77–1.34) | 0.89 (0.53–1.49) | 0.77 |
| Lutein | 0.80 (0.54–1.18) | 1.11 (0.84–1.46) | 0.78 (0.46–1.31) | 0.41 |
| Total carotenoids§ | 1.00 (0.66–1.52) | 1.17 (0.89–1.56) | 0.85 (0.49–1.48) | 0.51 |
| Women | ||||
| No. of cases | 491 | 304 | 125 | |
| Total β-carotene† | 0.90 (0.64–1.26) | 0.89 (0.58–1.37) | 1.76 (0.89–3.50) | 0.39 |
| β-carotene‡ | 0.93 (0.67–1.31) | 0.93 (0.60–1.43) | 1.75 (0.87–3.51) | 0.42 |
| β-carotene supplement use‡ | 1.11 (0.70–1.77) | 1.12 (0.64–1.96) | 0.76 (0.24–2.48) | 0.74 |
| α-carotene | 0.95 (0.69–1.30) | 1.16 (0.77–1.75) | 1.48 (0.80–2.70) | 0.31 |
| Lycopene | 0.92 (0.69–1.24) | 1.13 (0.80–1.61) | 0.94 (0.52–1.69) | 0.38 |
| β-cryptoxanthin | 0.95 (0.69–1.30) | 0.86 (0.56–1.31) | 1.00 (0.51–1.96) | 0.39 |
| Lutein | 1.24 (0.90–1.72) | 0.99 (0.65–1.52) | 1.10 (0.59–2.03) | 0.77 |
| Total carotenoids§ | 1.00 (0.71–1.40) | 1.12 (0.73–1.72) | 1.64 (0.85–3.18) | 0.58 |
*RR of the highest vs. the lowest quintile; for β-carotene supplement use, yes vs. no. Adjusted for ethnicity and time since cohort entry as strata variables and the following variables as covariates: age at cohort entry, family history of colorectal cancer, history of intestinal polyps, pack-years of cigarette smoking (for former and current smokers only), body mass index, hours of vigorous activity, use of nonsteroidal anti-inflammatory drugs, multivitamin use, total energy intake, alcohol intake, red meat intake, dietary fiber intake, total calcium intake (foods and supplements), total vitamin D intake (foods and supplements), total folate intake (foods and supplements), and use of hormone replacement therapy (in women only).
†Intake from foods and β-carotene supplements.
‡Intakes from foods and supplement use were included in the same model so that results for each were adjusted for the other.
§Sum of β-carotene, α-carotene, lycopene, β-cryptoxanthin, and lutein intake from foods.