Table 3 Adjusteda odds ratio (OR) and 95% confidence interval (CI) for breast cancer overall, triple negative breast cancer, and luminal-like subtype associated with BMI in premenopausal white women and premenopausal African-American women
All cases | Triple negative (ER–/PR–/HER2–) | Luminal-like (ER+ and/or PR+) | ||||
|---|---|---|---|---|---|---|
Number | OR (95% CI) | Number | OR (95% CI) | Number | OR (95% CI) | |
Premenopausal white women | ||||||
BMI at age 18 years, kg/m2 | ||||||
< 20.0 | 946 | Referent | 108 | Referent | 553 | Referent |
20.0–24.9 | 793 | 1.01 (0.84–1.22) | 91 | 0.92 (0.66–1.30) | 470 | 1.03 (0.83–1.28) |
≥ 25.0 | 121 | 0.76 (0.53–1.10) | 12 | 0.53 (0.26–1.09) | 64 | 0.73 (0.47–1.13) |
Per 5 kg/m2 increase | 0.86 (0.73–1.02) | 0.61 (0.44–0.86) | 0.87 (0.71–1.06) | |||
P value | 0.08 | 0.004 | 0.16 | |||
P value for homogeneity of slope coefficients between two subtypes = 0.04 | ||||||
Recent BMI, kg/m2 | ||||||
< 25.0 | 1274 | Referent | 136 | Referent | 754 | Referent |
25.0–29.9 | 373 | 0.87 (0.69–1.10) | 51 | 1.30 (0.87–1.93) | 205 | 0.78 (0.59–1.02) |
≥ 30.0 | 213 | 0.72 (0.53–0.97) | 24 | 1.00 (0.57–1.75) | 128 | 0.71 (0.50–1.01) |
Per 5 kg/m2 increase | 0.95 (0.86–1.05) | 1.12 (0.94–1.34) | 0.94 (0.83–1.06) | |||
P value | 0.32 | 0.19 | 0.28 | |||
P value for homogeneity of slope coefficients between two subtypes = 0.04 | ||||||
Premenopausal African-American women | ||||||
BMI at age 18 years, kg/m2 | ||||||
< 20.0 | 241 | Referent | 52 | Referent | 103 | Referent |
20.0–24.9 | 274 | 0.98 (0.72–1.33) | 53 | 0.92 (0.56–1.50) | 107 | 0.90 (0.61–1.35) |
≥ 25.0 | 52 | 0.66 (0.40–1.13) | 13 | 0.71 (0.31–1.65) | 19 | 0.60 (0.29–1.24) |
Per 5 kg/m2 increase | 0.79 (0.62–1.00) | 0.78 (0.54–1.15) | 0.74 (0.54–1.03) | |||
P value | 0.05 | 0.21 | 0.07 | |||
P value for homogeneity of slope coefficients between two subtypes = 0.80 | ||||||
Recent BMI, kg/m2 | ||||||
< 25.0 | 271 | Referent | 58 | Referent | 114 | Referent |
25.0–29.9 | 160 | 0.92 (0.66–1.29) | 29 | 0.79 (0.45–1.37) | 64 | 0.93 (0.60–1.44) |
≥ 30.0 | 136 | 1.02 (0.68–1.53) | 31 | 1.09 (0.58– 2.05) | 51 | 0.94 (0.55–1.59) |
Per 5 kg/m2 increase | 1.08 (0.92–1.25) | 1.13 (0.90–1.43) | 1.04 (0.85–1.28) | |||
P value | 0.35 | 0.30 | 0.69 | |||
P value for homogeneity of slope coefficients between two subtypes = 0.53 | ||||||