Table 5.

HR and 95% CI for the association between dietary magnesium and colorectal cancer risk, by sex and racea (ARIC 1993–2012)

Dietary magnesium quintiles (mEq/L)58.68–185.35185.36–226.07226.08–265.62265.64–318.73318.79–792.01Ptrend
Sex (Pinteraction: 0.04)
 Males
  Number of cases1631163038
  Person-years9,63912,05613,87215,51616,809
  HR (95% CI)b1 (ref)1.67 (0.87–3.20)0.65 (0.30–1.41)1.11 (0.52–2.39)1.10 (0.43–2.87)0.88
 Females
  Number of cases3026312315
  Person-years23,15420,61019,06817,47614,930
  HR (95% CI)b1.00 (ref.)0.88 (0.50–1.55)1.09 (0.58–2.04)0.79 (0.36–1.72)0.51 (0.17–1.54)0.43
Race (Pinteraction: 0.13)
 White participants
  Number of cases3047313645
  Person-years23,54825,15726,16626,36525,864
  HR (95% CI)c1 (ref)1.31 (0.81–2.13)0.79 (0.45–1.39)0.87 (0.47–1.60)0.91 (0.42–2.00)0.79
 Black participants
  Number of cases161016178
  Person-years9,2447,5096,7746,6275,876
  HR (95% CI)c1 (ref)0.63 (0.27–1.49)0.96 (0.39–2.35)0.95 (0.34–2.65)0.36 (0.07–1.82)0.40
  • aFollow-up beginning at visit 3 (1993–1995). Dietary magnesium assessed as the average of visits 1 (1987–1989) and 3 (1993–1995).

  • bAdjusted for age, race, study center, total calories, dietary calcium, dietary fiber, BMI, physical activity, alcohol intake, smoking status, pack-years of smoking, aspirin use, HRT use, and diabetes.

  • cAdjusted for age, sex, study center, total calories, dietary calcium, dietary fiber, BMI, physical activity, alcohol intake, smoking status, pack-years of smoking, aspirin use, HRT use, and diabetes.