Table 3.

Risk of a pituitary tumor in relation to age at menarche, menopausal status, parity, and breastfeeding in a case-control study, United Kingdom, 2001 to 2005

FactorCases (n = 157)
Controls (n = 336)
OR (95% CI)*P
n%n%
Age at menarche (y)
    <123723.67722.91.0
    12-149258.621263.10.7 (0.4-1.2)0.25
    ≥152817.84714.00.9 (0.4-1.8)0.74
Ptrend = 0.5
Menopause
    Menopausal status
        Premenopausal9560.520962.21.0
        Postmenopausal5434.410029.83.2 (1.6-6.2)0.001
        Not known due to hysterectomy85.1236.91.6 (0.6-4.3)0.38
        Not known for other reasons41.2
    Type of menopause
        Natural4327.48625.62.3 (1.2-4.7)0.02
        Surgical95.7123.66.7 (2.2-19.9)0.001
        Not known21.320.6
    Age at menopause (if postmenopausal, y)
        <401610.792.97.5 (2.6-21.4)<0.001
        40-492516.84414.22.7 (1.2-6.1)0.02
        ≥50138.74514.61.3 (0.5-3.6)0.62
        Not known20.7Trend (postmenopausal only) P = 0.6
Live births
    Any
        No4126.18324.71.0
        Yes11673.925375.31.2 (0.7-2.1)0.48
    Age at first live birth (y)
        <202012.7164.83.4 (1.4-8.4)0.008
        20-244226.88525.31.2 (0.6-2.3)0.62
        25-293019.19227.40.9 (0.4-1.8)0.69
        30-34117.04112.20.7 (0.3-1.8)0.52
        ≥3595.7144.22.1 (0.7-6.1)0.20
        Not known42.651.5Trend (parous only) P = 0.1
    No of children
        12717.24814.31.4 (0.7-2.9)0.32
        24729.912938.41.0 (0.5-1.9)0.96
        32616.64914.61.6 (0.8-3.4)0.22
        ≥41610.2278.01.2 (0.5-2.9)0.67
Trend (all subjects) P = 0.4
Trend (parous only) P = 0.6
Breastfeeding (parous only)
    Ever
        No3522.29428.01.0
        Yes7950.315044.61.5 (0.8-2.7)0.17
        Not known21.392.7
    Lifetime months breastfeeding
        1-62817.84011.92.1 (1.0-4.5)0.06
        7-111912.15616.71.2 (0.6-2.8)0.60
        12-17117.0216.31.6 (0.6-4.2)0.39
        ≥182113.4308.91.3 (0.6-3.2)0.51
        Not known30.9Trend (all subjects) P = 0.9
Trend (ever breastfed only) P = 0.2
  • * ORs obtained from unconditional logistic regression model adjusted for sex, age at reference date, region, interview year, and Townsend deprivation score.

  • Menopausal status could not be assessed because women had a premenopausal hysterectomy without bilateral oophorectomy.