Table 2.

Multivariate-adjusted RRs of postmenopausal breast cancer by relative weight at age 12 y, overall and stratified by first-degree family history of breast or ovarian cancer, and by breast cancer subtype based on ER and PR status

Type of breast cancerRelative weight at age 12All
No family history
Family history
CasesRR (95% CI)P trendCasesRR (95% CI)P trendCasesRR (95% CI)P trend
AllBelow5961.02 (0.92-1.13)0.084650.99 (0.88-1.11)0.021121.10 (0.87-1.38)0.05
Average16351.00 (reference)13091.00 (reference)2821.00 (reference)
Above2720.85 (0.74-0.98)2200.86 (0.73-1.01)430.84 (0.60-1.17)
P interaction (family history and weight 12) = 0.44
ER+Below3831.01 (0.89-1.16)0.082960.95 (0.82-1.11)0.06721.25 (0.94-1.67)0.03
Average10551.00 (reference)8591.00 (reference)1651.00 (reference)
Above1660.80 (0.67-0.96)1370.82 (0.68-1.00)240.77 (0.49-1.22)
P interaction (family history and weight 12) = 0.21
ER−Below761.10 (0.81-1.48)0.20621.17 (0.84-1.63)0.11120.78 (0.38-1.60)0.71
Average1901.00 (reference)1471.00 (reference)351.00 (reference)
Above310.77 (0.50-1.19)260.81 (0.50-1.30)50.81 (0.31-2.09)
P interaction (family history and weight 12) = 0.73
PR+Below3151.00 (0.86-1.16)0.482400.94 (0.80-1.11)0.31631.27 (0.93-1.74)0.06
Average8681.00 (reference)7011.00 (reference)1391.00 (reference)
Above1490.90 (0.74-1.09)1220.91 (0.73-1.12)230.94 (0.59-1.48)
P interaction (family history and weight 12) = 0.19
PR−Below1231.08 (0.85-1.37)0.241001.08 (0.83-1.40)0.02180.91 (0.52-1.59)0.45
Average3281.00 (reference)2641.00 (reference)541.00 (reference)
Above420.62 (0.43-0.89)360.69 (0.47-1.01)60.53 (0.21-1.34)
P interaction (family history and weight 12) = 0.81
  • NOTE: Cox proportional hazards regression analysis was used, accounting for age, education status, age at menopause, age at menarche, parity, age at first birth BMI at age 18 y, BMI in 1986, oral contraceptive use, hormone replacement therapy, smoking status, alcohol use, and physical activity level.