Table 2.

ORs and 95% CIs for colon and rectal cancer, combined and stratified, according to OC use

CharacteristicControls
Colorectal cancer
Colon cancer
Rectal cancer
n = 4,297* (%)n = 1,488* (%)OR (95% CI)n = 1,122* (%)OR (95% CI)§n = 366* (%)OR (95% CI)
OC use
    Never2,257 (53.4)1,032 (56.4)1778 (55.9)1254 (58.1)1
    Ever1,968 (46.6)426 (43.6)0.89 (0.75-1.06)326 (44.1)0.87 (0.72-1.06)100 (41.9)0.87 (0.65-1.17)
Duration of OC use (mos)
    1-23472 (24.0)101 (22.1)0.88 (0.67-1.15)78 (21.1)0.88 (0.65-1.19)23 (23.4)0.82 (0.51-1.32)
    24-53507 (25.8)112 (28.9)0.96 (0.74-1.25)82 (27.8)0.90 (0.66-1.22)30 (31.9)1.03 (0.67-1.61)
    54-107477 (24.2)103 (24.7)0.90 (0.69-1.17)82 (26.1)0.90 (0.66-1.22)21 (21.4)0.79 (0.48-1.29)
    >108512 (26.0)110 (24.3)0.84 (0.64-1.09)84 (24.9)0.83 (0.61-1.13)26 (23.4)0.85 (0.54-1.35)
    Ptrend0.10.80.2
Age started OC use
    19 or younger356 (18.4)41 (16.5)0.72 (0.46-1.12)29 (15.8)0.72 (0.42-1.21)12 (18.0)0.78 (0.37-1.61)
    20-23621 (32.0)96 (34.0)0.80 (0.58-1.09)73 (34.1)0.79 (0.55-1.14)23 (32.9)0.89 (0.50-1.57)
    24-28442 (22.8)97 (23.4)1.06 (0.79-1.41)74 (23.8)1.02 (0.73-1.41)23 (22.8)1.19 (0.71-2.00)
    >29519 (26.8)171 (26.2)0.89 (0.72-1.11)132 (26.3)0.87 (0.68-1.13)39 (26.4)0.82 (0.56-1.19)
    Ptrend0.90.80.7
Recency of OC use (y)
    <14518 (26.5)69 (24.9)0.82 (0.58-1.17)53 (26.2)0.93 (0.61-1.41)16 (21.7)0.53 (0.28-1.00)
    14-18392 (20.1)68 (19.7)0.89 (0.64-1.23)49 (18.7)0.96 (0.65-1.42)19 (22.3)0.92 (0.54-1.58)
    19-23478 (24.5)108 (26.1)1.00 (0.77-1.29)83 (25.9)0.93 (0.69-1.26)25 (26.2)0.88 (0.56-1.40)
    >24566 (29.0)175 (29.3)0.86 (0.69-1.08)136 (29.2)0.81 (0.63-1.05)39 (29.8)1.01 (0.68-1.52)
    Ptrend0.30.60.4
  • * Variable sums that do not equal the total n are due to missing data.

  • Percentages are age-adjusted to the distribution of controls.

  • Conditional on age and study of enrollment; adjusted for family history of colorectal cancer, BMI, education, screening, smoking, hormone replacement therapy, and age at first birth.

  • § Conditional on age and study of enrollment; adjusted for family history of colorectal cancer, BMI, education, screening, smoking, hormone replacement therapy, alcohol consumption, age at first birth, and menopausal status.

  • Conditional on age and study of enrollment; adjusted for family history of colorectal cancer, physical activity, education, screening, smoking, and hormone replacement therapy.

  • Compared with never-users of OCs.