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
    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
    20-24.9327/47,0021.0 (reference)1.0 (reference)1.0 (reference)
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
    20-24.9466/61,0081.0 (reference)1.0 (reference)1.0 (reference)
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)
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.