Variable | Q1 | Q2 | Q3 | Q4 | P_{trend} |
---|---|---|---|---|---|
Dietary variables | |||||
Red meat (g/1,000 kcal) | |||||
Quartile median, quartile cutoff points | 13.8 (≤20.1) | 26.2 (>20.1–31.3) | 37.5 (>31.3–46.8) | 59.8 (>46.8) | |
Cases/controls | 72/96 | 70/96 | 96/96 | 104/96 | |
OR^{a} (95% CI) | Ref | 0.97 (0.63–1.50) | 1.33 (0.88–2.02) | 1.45 (0.96–2.20) | 0.04 |
OR^{b} (95% CI) | Ref | 1.08 (0.69–1.71) | 1.42 (0.91–2.21) | 1.59 (1.02–2.49) | 0.03 |
Total dietary iron, mg/1,000 kcal | |||||
Quartile median (quartile cutoff points) | 6.6 (≤7.4) | 8.1 (>7.4–8.7) | 9.4 (>8.7–10.3) | 11.6 (>10.3) | |
Cases/controls | 74/96 | 108/96 | 87/96 | 73/96 | |
OR^{a} (95% CI) | Ref | 1.46 (0.97–2.20) | 1.18 (0.77–1.79) | 0.99 (0.64–1.52) | 0.54 |
OR^{b} (95% CI) | Ref | 1.49 (0.97–2.28) | 1.24 (0.80–1.92) | 0.98 (0.62–1.55) | 0.98 |
Heme iron, mg/1,000 kcal | |||||
Quartile median (quartile cutoff points) | 76.3 (≤108.0) | 141.4 (>108.0–170.1) | 211.0 (>170.1–259.5) | 355.7 (>259.5) | |
Cases/controls | 74/95 | 77/96 | 83/96 | 105/96 | |
OR^{a} (95% CI) | Ref | 1.03 (0.67–1.58) | 1.11 (0.72–1.69) | 1.41 (0.93–2.14) | 0.07 |
OR^{b} (95% CI) | Ref | 1.08 (0.69–1.69) | 1.09 (0.69–1.71) | 1.46 (0.94–2.29) | 0.08 |
Serologic indices | |||||
Ferritin (ng/mL) | |||||
Quartile median (quartile cutoff points) | 54 (≤83) | 119 (>83–161) | 209 (>161–276) | 419 (>276) | |
Cases/controls | 80/98 | 125/100 | 77/99 | 74/99 | |
OR^{a} (95% CI) | Ref | 1.53 (1.03–2.29) | 0.96 (0.63–1.46) | 0.92 (0.60–1.41) | 0.15 |
OR^{b} (95% CI) | Ref | 1.60 (1.05–2.43) | 0.93 (0.59–1.47) | 0.86 (0.53–1.38) | 0.08 |
Iron, μg/dL | |||||
Quartile median (quartile cutoff points) | 74 (≤86) | 96 (>86–105) | 118 (>105–130) | 154 (>130) | |
Cases/controls | 95/101 | 77/95 | 88/100 | 96/100 | |
OR^{a} (95% CI) | Ref | 0.86 (0.57–1.30) | 0.94 (0.63–1.40) | 1.02 (0.69–1.52) | 0.77 |
OR^{b} (95% CI) | Ref | 0.85 (0.55–1.30) | 0.95 (0.63–1.45) | 1.02 (0.66–1.55) | 0.78 |
Transferrin saturation, % | |||||
Quartile median (quartile cutoff points) | 20 (≤24) | 27 (>24–29) | 33 (>29–37) | 43 (>37) | |
Cases/controls | 82/98 | 73/95 | 102/107 | 99/96 | |
OR^{a} (95% CI) | Ref | 0.92 (0.60–1.40) | 1.14 (0.76–1.70) | 1.23 (0.82–1.85) | 0.20 |
OR^{b} (95% CI) | Ref | 0.92 (0.59–1.43) | 1.18 (0.78–1.79) | 1.28 (0.83–1.98) | 0.16 |
TIBC, μg/dL | |||||
Quartile median (quartile cutoff points) | 300 (≤323) | 338 (>323–351) | 369 (>351–389) | 421 (>389) | |
Cases/controls | 119/97 | 72/102 | 82/97 | 83/100 | |
OR^{a} (95% CI) | Ref | 0.58 (0.38–0.86) | 0.69 (0.46–1.03) | 0.68 (0.45–1.01) | 0.10 |
OR^{b} (95% CI) | Ref | 0.51 (0.34–0.78) | 0.62 (0.41–0.95) | 0.57 (0.37–0.88) | 0.03 |
UIBC, μg/dL | |||||
Quartile median (quartile cutoff points) | 185 (≤209) | 228 (>209–243) | 263 (>243–280) | 314 (>280) | |
Cases/controls | 118/98 | 77/101 | 80/99 | 81/98 | |
OR^{a} (95% CI) | Ref | 0.63 (0.42–0.95) | 0.67 (0.45–1.00) | 0.69 (0.46–1.02) | 0.08 |
OR^{b} (95% CI) | Ref | 0.59 (0.39–0.90) | 0.60 (0.39–0.91) | 0.62 (0.40–0.95) | 0.04 |
^{a}OR adjusted for age only.
^{b}Multivariate OR adjusted for age (≤59, 60–64, 65–69, ≥70 years), gender, season of blood draw (May–Sep, Oct–Apr), sigmoidoscopy interval (3 or 5 years), race (non-Hispanic white, other), study center, year of entry to study, education (≤12 years or completed high school, post–high school training other than college/some college, college graduate or postgraduate), smoking (never, former, current, cigar/pipe), regular NSAID use (yes/no), and family history of colorectal cancer (yes/no).