Table 2.

Age and age-adjusted baseline characteristics of 683 controls by quartiles of urinary aMT6s level

All control womenQuartiles of 12-h overnight urinary aMT6s output (μg)
Q1 (n = 170)Q2 (n = 171)Q3 (n = 172)Q4 (n = 170)
Range of urinary aMT6s output/12 h (μg)<10.110.1-14.614.7-20.5≥20.6
Age, y43.843.042.443.3
Age at menarche, y12.812.612.612.5
Parity (no. of children, among parous women only)2.12.01.91.9
Age at first birth (among parous women only)25.424.926.126.1
Family history of breast cancer (%)8.87.05.88.8
OC use (%)38.945.937.747.7
BMI, kg/m224.624.424.524.2
Alcohol consumption, g/d8.07.811.77.7
History of benign breast disease (%)29.429.825.624.1
Education beyond 8 y of elementary school (%)31.928.630.235.9
Smoking history
    Current smoker (%)27.124.024.422.4
    Past smoker (%)6.514.014.015.3
    Never smoker (%)66.562.061.662.4
    Pack-years among ever smokers12.99.87.57.9
Sex hormone levels
    SHBG (nmol/L)64.768.668.267.8
    Testosterone (ng/mL)0.300.290.290.25
    Free testosterone (pg/mL)0.720.680.700.65
    Estradiol (pg/mL)98.197.795.490.1
    FSH (μg/mL)4.14.14.03.7
    LH (μg/mL)2.83.02.82.3

NOTE: Mean of age and other baseline characteristics are shown.