Table 2.

HRs and 95% CIs for associations of total, caffeinated, and decaffeinated coffee consumption with risk of breast cancer overall and by hormone receptor subtype, CPS-II NC 1999–2015 (N = 57,075).

Coffee consumption (cups/day)
Nondrinker<11–<2≥2
(n = 9,831)(n = 11,787)(n = 12,849)(n = 22,608)PtrendaPer 1 cup/dayP
All breast cancers (N = 2,980)
Total coffee
n, cases4945736851,228
Age-adjusted HRs (95% CIs)1.00 (ref)0.97 (0.86–1.10)1.06 (0.95–1.19)1.06 (0.95–1.17)0.151.02 (0.99–1.04)0.23
Multivariable-adjusted HRs (95% CIs)b1.00 (ref)0.94 (0.83–1.06)1.01 (0.90–1.14)0.99 (0.89–1.11)0.681.01 (0.98–1.03)0.61
Caffeinated coffee
n, cases1,284436493767
Age-adjusted HRs (95% CIs)c1.00 (ref)0.94 (0.84–1.05)1.10 (0.99–1.22)1.00 (0.91–1.09)0.831.00 (0.97–1.03)0.93
Multivariable-adjusted HRs (95% CIs)b,c1.00 (ref)0.92 (0.83–1.03)1.08 (0.97–1.20)0.96 (0.87–1.06)0.610.99 (0.96–1.02)0.58
Decaffeinated coffee
n, cases1,419780338443
Age-adjusted HRs (95% CIs)c1.00 (ref)0.97 (0.89–1.06)0.94 (0.84–1.06)1.12 (1.00–1.25)0.051.04 (1.01–1.08)0.02
Multivariable-adjusted HRs (95% CIs)b,c1.00 (ref)0.96 (0.88–1.05)0.91 (0.80–1.03)1.06 (0.95–1.19)0.301.03 (0.99–1.07)0.15
ER or PR positive (n = 2,392)
Total coffee
n, cases401469537985
Multivariable-adjusted HRs (95% CIs)b1.00 (ref)0.94 (0.82–1.08)0.97 (0.85–1.10)0.96 (0.85–1.09)0.881.01 (0.98–1.04)0.75
Caffeinated coffee
n, cases1,050349381612
Multivariable-adjusted HRs (95% CIs)b,c1.00 (ref)0.90 (0.79–1.01)1.01 (0.89–1.14)0.93 (0.83–1.03)0.280.98 (0.95–1.02)0.38
Decaffeinated coffee
n, cases1,124632272364
Multivariable-adjusted HRs (95% CIs)b,c1.00 (ref)0.97 (0.88–1.07)0.91 (0.80–1.05)1.08 (0.95–1.22)0.291.03 (0.99–1.08)0.16
ER and PR negative (n = 302)
Total coffee
n, cases465978119
Multivariable-adjusted HRs (95% CIs)b1.00 (ref)1.07 (0.72–1.57)1.30 (0.90–1.88)1.11 (0.78–1.57)0.801.00 (0.92–1.08)0.89
Caffeinated coffee
n, cases122525969
Multivariable-adjusted HRs (95% CIs)b,c1.00 (ref)1.16 (0.84–1.62)1.41 (1.03–1.93)0.97 (0.71–1.32)0.800.99 (0.90–1.09)0.95
Decaffeinated coffee
n, cases137843843
Multivariable-adjusted HRs (95% CIs)b,c1.00 (ref)1.06 (0.81–1.40)1.05 (0.73–1.52)1.10 (0.78–1.56)0.641.03 (0.92–1.15)0.99
  • Abbreviation: MET, metabolic equivalent.

  • aPtrend was calculated using a continuous variable created from the medians within each category of consumption.

  • bMultivariable models included body mass index (15–<18.5, 18.5–<25, 25–<30, 30+ kg/m2, and missing), race (white, black, and other/missing), physical activity (<8.75, 8.75–17.5, >17.5 MET-hours/week, and unknown), parity (no live births, 1–2, 3+ live births, and unknown), personal history of benign breast disease (no and yes), family history of breast cancer (no and yes), cigarette smoking history [never smoker, former (<10, 10–<20, 20–<30, 30+, and missing years since quit), and current (<20, 20–<40, 40+, and missing cigarettes per day)], age at menopause (<45, 45–<50, 50–53, 54+ years, and unknown), menopausal hormone use (never, former, current, and unknown), mammography screening in 1999 (none, routine screening, symptomatic screening, both routine and symptomatic, and unknown), and alcohol consumption (nondrinker, <1 drink/week, 1–<7 drinks/week, 1–<2 drinks/day, 2+ drinks/day, and unknown).

  • cCaffeinated and decaffeinated coffee consumption were mutually adjusted.