Table 5.

Multivariable HR (95% CI) of colorectal adenomas by quartiles of heme iron intake according to dietary antioxidant intake

Colorectal adenomas (n = 1,409)
FRAP <12.7 mmol/dayFRAP ≥12.7 mmol/day
CasesHRa (95% CI)CasesHRa (95% CI)Pinteraction
Total heme iron (mg/day)
 <0.751801.001291.000.25
 0.75–<1.071861.15 (0.93–1.42)1651.18 (0.93–1.49)
 1.07–<1.451841.35 (1.08–1.70)1981.26 (0.99–1.61)
 ≥1.451611.56 (1.19–2.05)2061.23 (0.93–1.61)
Ptrend0.00090.20
Nonnitrosylated heme iron (mg/day)
 <0.631801.001241.000.50
 0.63–<0.921791.06 (0.86–1.31)1781.31 (1.04–1.66)
 0.92–<1.241911.25 (1.00–1.57)1941.31 (1.02–1.67)
 ≥1.241591.31 (1.00–1.72)2021.26 (0.96–1.66)
Ptrend0.030.23
Nitrosylated heme iron (mg/day)
 <0.061931.001441.000.15
 0.06–<0.131720.96 (0.78–1.18)1661.08 (0.86–1.35)
 0.13–<0.231721.09 (0.88–1.34)1901.13 (0.90–1.42)
 ≥0.231741.29 (1.02–1.62)1981.09 (0.85–1.39)
Ptrend0.010.82
  • aCox proportional hazards model with the ages of individuals as the time scale and adjusted by colorectal cancer in first-degree relatives, educational level, smoking status, menopausal status, physical activity, BMI, total energy, energy-adjusted intake alcohol, fibers, dietary and supplemental calcium, and dietary zinc. Nitrosylated and non-nitrosylated heme iron were simultaneously included in the model.