Table 3.

Association of endometrial cancer with oral contraceptive use, stratified by obesity status 1995–2013

Non-obese (BMI < 30 kg/m2)Obese (BMI ≥ 30 kg/m2)
CasesRateaIRRb95% CICasesRateaIRRb95% CI
OC use
 Never2349.41.00Referent33103.51.00Referent
 Ever9625.20.680.41–1.1314564.81.050.69–1.58
  Former8829.70.700.42–1.1613169.51.050.69–1.59
   Years since last use
    1–91513.30.470.23–0.972541.60.960.54–1.72
    10–191822.20.710.36–1.412038.30.970.53–1.78
    20–292846.30.940.51–1.723068.81.030.61–1.76
    ≥302367.90.640.34–1.1852189.11.120.70–1.78
  Current89.50.440.18–1.071439.80.980.48–2.01
 Duration (years)
  1–46834.50.860.51–1.439576.31.110.73–1.70
  5–91718.70.550.28–1.072549.60.950.55–1.65
  ≥1067.50.190.07–0.471843.70.770.42–1.41
  • aCrude rate per 100,000 person-years.

  • bMultivariable model stratified by age and study period and adjusted for age at menarche, parity, menopausal status, estrogen-only FMH use, estrogen plus progestin FMH use, smoking, body mass index, (continuous), and vigorous physical activity.