Table 3.

ORs and 95% CIs of breast cancer by quartile of total 12-h overnight aMT6s output [aMT6s concentration (ng/mL) multiplied with 12-h volume in mL]

Group and parameterQuartile
1234Ptrend*
Urinary aMT6s output/12 h (μg)<10.110.1-14.614.7-20.5≥20.6
No. of case patients/no. of control subjects39/17034/17155/17252/170
Invasive and in situ breast cancer cases
    Simple OR*1.00 (Reference)0.91 (0.54-1.53)1.50 (0.92-2.45)1.53 (0.91-2.56)0.01
    Multivariate OR1.00 (Reference)0.88 (0.51-1.50)1.43 (0.85-2.42)1.43 (0.83-2.45)0.03
Excluding current smokers
No. of case patients/no. of control subjects32/9627/10744/10641/114
    Simple OR1.00 (Reference)0.75 (0.41-1.36)1.24 (0.70-2.20)1.16 (0.63-2.15)0.19
    Multivariate OR1.00 (Reference)0.72 (0.38-1.38)1.11 (0.59-2.08)1.00 (0.52-1.94)0.29
Multivariate lagtime analyses among nonsmokers
No. of case patients/no. of control subjects5/354/298/3311/35
    Multivariate OR among women diagnosed within 3 y from urine collection1.00 (Reference)0.90 (0.09-8.75)1.88 (0.23-15.3)14.8 (1.39-157)0.03
No. of case patients/no. of control subjects30/7324/8241/8135/89
    Multivariate OR 1 y lag time1.00 (Reference)0.61 (0.30-1.23)1.07 (0.54-2.12)0.90 (0.45-1.82)0.40
No. of case patients/no. of control subjects28/6524/7938/7530/83
    Multivariate OR 2 y lagtime1.00 (Reference)0.58 (0.28-1.19)0.95 (0.47-1.94)0.68 (0.32-1.44)0.63
No. of case patients/no. of control subjects27/6123/7836/7330/79
    Multivariate OR 3 y lagtime1.00 (Reference)0.51 (0.24-1.08)0.87 (0.42-1.82)0.69 (0.32-1.48)0.52
No. of case patients/no. of control subjects24/5319/7333/6728/68
    Multivariate OR 4 y lag time1.00 (Reference)0.41 (0.18-0.92)0.76 (0.34-1.66)0.61 (0.26-1.39)0.80
No. of case patients/no. of control subjects23/5219/6428/6527/62
    Multivariate OR 5 y lag time1.00 (Reference)0.47 (0.20-1.09)0.66 (0.29-1.48)0.66 (0.28-1.54)0.93
No. of case patients/no. of control subjects20/4417/5725/5723/51
    Multivariate OR 6 y lag time1.00 (Reference)0.46 (0.18-1.14)0.68 (0.28-1.64)0.75 (0.29-1.92)0.79
No. of case patients/no. of control subjects19/4016/5122/4716/46
    Multivariate OR 7 y lag time1.00 (Reference)0.43 (0.16-1.17)0.53 (0.19-1.47)0.38 (0.13-1.11)0.13
No. of case patients/no. of control subjects18/3115/4618/3912/36
    Multivariate OR 8 y lag time1.00 (Reference)0.25 (0.07-0.90)0.29 (0.07-1.10)0.17 (0.04-0.71)0.01
  • *We tested for trends by modeling aMT6s concentrations continuously and calculating the Wald statistic.

  • Simple conditional logistic regression model adjusting for the matching variables [year of birth, month and year of urine collection, and laboratory batch].

  • Multivariate conditional logistic regression models; relative risks were adjusted for the following breast cancer risk factors: BMI in six categories (≤21, 21.1-23, 23.1-25, 25.1-27, 27.1-30, >30), history of benign breast disease (yes/no), family history (mother or sister) of breast cancer (yes/no), smoking history (never, past, current), age at menarche in four categories (≤12, 13, 14, 15+), alcohol consumption per day in grams, three categories (none, ≤12, >12), years of oral contraceptive use (never, ≤1 y, >1 y), parity in three categories (nulliparous, 1-2, 3+ children), age at first birth in three categories (<20, 20-24, ≥25), and participant's educational status in years of schooling, three categories [≤5 y (elementary school), 8 y (superior education), >8 y].