Table 3.

Risk of premenopausal breast cancer according to body size and shape

CharacteristicsNo. of Cases/Non-casesAge-Adjusted RR95% CIMultivariate RR*95% CIMultivariate RR95% CI
Perceived body shape at age 7
    Very thin92/11,1801.130.90-1.411.130.90-1.431.080.85-1.38
    Thin164/22,8780.940.79-1.130.940.78-1.130.900.74-1.09
    Average411/54,3641.0 (reference)1.0 (reference)1.0 (reference)
    Fat/very fat46/8,9510.690.51-0.930.690.50-0.930.730.53-1.01
P for linear trend0.100.110.49
BMI (kg/m2) at age 18
    <20330/40,7611.070.92-1.251.060.90-1.241.030.87-1.21
    20-24.9327/47,0021.0 (reference)1.0 (reference)1.0 (reference)
    ≥2532/4,4990.750.61-0.920.740.59-0.910.900.66-1.24
P for linear trend0.0040.0040.60
BMI at age 18 per unit increase0.960.93-0.990.960.93-0.990.980.95-1.02
BMI (kg/m2) at cohort enrolment
    <20123/13,3711.221.00-1.491.200.98-1.471.160.94-1.44
    20-24.9466/61,0081.0 (reference)1.0 (reference)1.0 (reference)
    25-29.9104/17,3070.800.65-0.990.790.63-0.990.820.65-1.04
    ≥3023/4,5840.680.45-1.040.620.40-0.970.660.40-1.07
P for linear trend0.00030.00030.007
BMI at cohort enrolment per unit increase0.960.94-0.980.960.94-0.980.960.94-0.99
Adult height (cm)
    <16054/10,2580.670.50-0.900.700.50-0.930.720.54-0.97
    160-164186/26,6470.890.73-1.070.880.72-1.060.890.73-1.08
    165-169251/31,6941.0Reference1.0Reference1.0Reference
    170-174180/21,18601.050.86-1.270.990.81-1.201.000.82-1.22
    ≥17557/7,2581.010.76-1.350.900.67-1.210.910.67-1.23
P for trend0.0030.020.03
  • * Multivariate adjustment for age at enrolment, parity, age at first birth, oral contraceptive use, age at menarche, family history of breast cancer, total duration of breast-feeding, and country of residence.

  • Same model as above, with additional covariates: (a) adult BMI in the analysis of perceived body shape at age 7, BMI at age 18, and height and (b) body shape at age 7 and BMI at age 18 in the analysis of adult BMI.