Table 4.

Sensitivity analysis to examine alcohol intake (drinks per week) among ever drinkers during different age periods before diagnosis in relation to invasive breast cancer for CBCS and WCHS

ControlsCasesBasic modelaControlsCasesMV modelb
N (%)N (%)OR (95% CI)N (%)N (%)OR (95% CI)
Young age drinks per week (<30 years old)c
Number of alcoholic drinks per week
 01,287 (64.3)1,295 (64.7)1.05 (0.90–1.23)1,156 (64.7)1,159 (64.6)1.04 (0.88–1.23)
 >0–<4463 (23.1)439 (21.9)Ref.410 (22.9)396 (22.1)Ref.
 ≥4–<795 (4.8)96 (4.8)1.06 (0.78–1.45)82 (4.6)88 (4.9)1.09 (0.78–1.52)
 ≥7157 (7.8)173 (8.6)1.16 (0.90–1.49)139 (7.8)150 (8.4)1.07 (0.81–1.41)
  Ptrend0.250.64
Middle age drinks per week (30–<50 years old)d
Number of alcoholic drinks per week
 01,265 (63.3)1,227 (62.1)1.01 (0.86–1.19)1,140 (64.4)1,102 (62.4)0.97 (0.81–1.16)
 >0–<4442 (22.3)420 (21.3)Ref.383 (21.6)369 (20.9)Ref.
 ≥4–<7109 (5.5)132 (6.7)1.26 (0.95–1.68)92 (5.2)124 (7.0)1.38 (1.01–1.88)
 ≥7176 (8.9)197 (10.0)1.17 (0.92–1.49)155 (8.7)171 (9.7)1.14 (0.87–1.49)
  Ptrend0.120.25
Older age drinks per week (50+ years old)
Number of alcoholic drinks per week
 0879 (78.8)906 (80.3)1.04 (0.81–1.34)770 (78.7)786 (79.9)1.00 (0.75–1.32)
 >0–<4145 (13.0)141 (12.5)Ref.132 (13.4)125 (12.6)Ref.
 ≥4–<745 (4.0)30 (2.7)0.70 (0.41–1.17)36 (3.7)27 (2.7)0.76 (0.43–1.34)
 ≥746 (4.1)51 (4.5)1.08 (0.68–1.72)42 (4.3)47 (4.7)1.07 (0.65–1.76)
   Ptrend0.980.94
Restricted to women 50+ with data for all age periods
Number of alcoholic drinks per week
 0875 (78.9)893 (80.2)1.25 (0.92–1.69)767 (78.7)774 (79.6)1.22 (0.87–1.71)
 >0–<4145 (13.1)140 (12.6)Ref.132 (13.5)124 (12.8)Ref.
 ≥4–<744 (4.0)30 (2.7)0.63 (0.36–1.11)35 (3.6)27 (2.8)0.68 (0.37–1.26)
 ≥745 (4.1)51 (4.6)1.14 (0.68–1.89)41 (4.2)47 (4.8)1.14 (0.66–1.97)
  Ptrend0.690.65

Abbreviation: CI, confidence interval.

  • aBasic model adjusted for age, study, time period, and geographic region.

  • bMultivariable model adjusted for age, study, time period, geographic region, education, age at menarche, BMI, menopausal status (pre-/post-), HT use (ever/never), parity, smoking status, and duration of oral contraceptive use.

  • c<25 years old for CBCS.

  • d25–<50 years old for CBCS.