Table 3.

Multivariate RRs and 95% CIs of prostate cancer, according to categories of calcium intakes in the PLCO study

Calcium intake (mg/day)Ptrend*
Total calcium≤750751-1,0001,001-1,5001,501-2,000≥2,001
    Total cases24051379228085
        RR (95% CI)1.00 (referent)0.85 (0.72-1.01)0.95 (0.79-1.15)1.04 (0.83-1.30)0.89 (0.66-1.19)0.51
        RR (95% CI) + total dairy1.00 (referent)0.83 (0.70-0.99)0.89 (0.73-1.08)0.96 (0.76-1.22)0.82 (0.61-1.11)0.98
    Nonaggressive cases13428544516560
        RR (95% CI)1.00 (referent)0.87 (0.69-1.09)0.95 (0.74-1.22)1.06 (0.78-1.42)1.08 (0.75-1.56)0.24
        RR (95% CI) + total dairy1.00 (referent)0.84 (0.67-1.05)0.87 (0.67-1.13)0.95 (0.70-1.31)0.98 (0.67-1.43)0.58
    Aggressive cases10221833411423
        RR (95% CI)1.00 (referent)0.83 (0.64-1.07)0.97 (0.73-1.30)1.07 (0.76-1.51)0.61 (0.37-1.02)0.89
        RR (95% CI) + total dairy1.00 (referent)0.81 (0.62-1.05)0.92 (0.68-1.25)1.02 (0.71-1.47)0.58 (0.34-1.02)0.71
Dietary calcium≤750751-1,0001,001-1,5001,501-2,000≥2,001
    Total cases33266272615337
        RR (95% CI)1.00 (referent)0.89 (0.76-1.03)1.07 (0.89-1.28)1.17 (0.90-1.52)1.22 (0.83-1.79)0.05
    RR (95% CI) + total dairy1.00 (referent)0.86 (0.73-1.00)0.97 (0.78-1.19)1.07 (0.79-1.44)1.12 (0.75-1.69)0.32
    Nonaggressive cases18336341610225
        RR (95% CI)1.00 (referent)0.91 (0.75-1.12)1.13 (0.88-1.45)1.45 (1.03-2.03)1.52 (0.94-2.47)0.006
    RR (95% CI) + total dairy1.00 (referent)0.88 (0.72-1.09)1.02 (0.77-1.35)1.31 (0.89-1.94)1.40 (0.84-2.34)0.05
    Aggressive cases1432882995011
        RR (95% CI)1.00 (referent)0.86 (0.68-1.09)1.01 (0.76-1.34)0.89 (0.58-1.35)0.83 (0.42-1.64)0.88
        RR (95% CI) + total dairy1.00 (referent)0.83 (0.65-1.05)0.92 (0.67-1.27)0.81 (0.50-1.30)0.77 (0.38-1.55)0.54
Supplement calciumNo supplement≤400401-800≥801
    Total cases1,14551620940
        RR (95% CI)1.00 (referent)0.97 (0.87-1.08)0.95 (0.82-1.11)0.94 (0.68-1.29)0.46
        RR (95% CI) + total dairy1.00 (referent)0.99 (0.89-1.10)0.96 (0.83-1.12)0.96 (0.70-1.31)0.59
    Nonaggressive cases64030911921
        RR (95% CI)1.00 (referent)1.03 (0.90-1.18)0.96 (0.79-1.17)0.88 (0.57-1.36)0.58
        RR (95% CI) + total dairy1.00 (referent)1.05 (0.92-1.21)0.98 (0.80-1.19)0.90 (0.58-1.39)0.72
    Aggressive cases4851998918
        RR (95% CI)1.00 (referent)0.90 (0.76-1.07)0.97 (0.77-1.22)1.02 (0.63-1.63)0.77
        RR (95% CI) + total dairy1.00 (referent)0.91 (0.77-1.08)0.98 (0.78-1.23)1.03 (0.64-1.65)0.84
  • * P trend was based on the medians of the categories.

  • RRs adjusted for age, race, study center, family history of prostate cancer, body mass index, smoking status, physical activity, history of diabetes, red meat intake, total energy intake, education, number of screening examinations during the follow-up period, and total phosphorus intake.

  • Nonaggressive cases were defined as Gleason score <7 and stage I/II. Thirty cases were deleted due to missing data on Gleason sum or tumor stage. Aggressive cases were defined as Gleason score ≥7 or stage ≥ III.