Table 2.

Age-adjusted relative risk of colorectal cancer by quintile of dietary calcium, category of calcium from supplements, and quintile of total calcium (dietary calcium plus calcium from supplements)

Quintile or category (for supplements) of calcium intake
Q1Q2Q3Q4Q5Ptrend
Dietary calcium*
    Median intake (range), mg337 (<412)473 (412-528)588 (529-655)733 (656-830)985 (>830)
    Cases11393929591
    RR (95% CI)1.00 (reference)0.79 (0.60-1.04)0.77 (0.59-1.02)0.78 (0.60-1.03)0.74 (0.56-0.98)0.05
Calcium from supplements
    Median intake (range), mg0 (0)130 (1-400)540 (401-800)1,130 (>800)
    n25,4419,4524,1766,285
    Cases2731154452
RR (95% CI)1.00 (reference)1.08 (0.87-1.34)0.96 (0.70-1.32)0.76 (0.56-0.98)0.09
Total calcium
    Median intake (range), mg377 (<472)551 (472-635)728 (636-844)1,003 (845-1,270)1,676 (>1,270)
    Cases1021108610680
RR (95% CI)1.00 (reference)1.03 (0.79-1.35)0.80 (0.60-1.06)0.96 (0.73-1.26)0.74 (0.55-0.99)0.02
  • * Based on residual method for energy adjustment of dietary calcium intake.