Table 5.
Relationship between measures of body size at baseline and risk of ER+ and triple-negative breast cancer among non-users of hormone therapy at baseline
| Non-cases | Cases* |
|||||
|---|---|---|---|---|---|---|
| ER+ | Triple-negative | |||||
| n (%) | n (%) | HR (95% CI)† | n (%) | HR (95% CI)† | p-value‡ | |
| BMI(kg/m2) | ||||||
| Quartiles | ||||||
| <23.75 | 17,070 (23) | 209 (19) | 1.0 (ref) | 28 (18) | 1.0 (ref) | 0.71 |
| 23.75 – 26.89 | 18,038 (24) | 247 (22) | 1.27 (1.03–1.56) | 37 (24) | 1.18 (0.66–2.12) | |
| 26.90 – 31.04 | 19,439 (26) | 291 (26) | 1.37 (1.11–1.68) | 46 (30) | 1.59 (0.91–2.76) | |
| ≥31.05 | 21,256 (28) | 369 (33) | 1.71 (1.39–2.10) | 44 (28) | 1.50 (0.85–2.67) | |
| Missing | 722 | 9 | 0 | |||
| ptrend | <0.01 | 0.11 | ||||
| pinteraction | 0.01 | 0.98 | ||||
| Standard Cutpoints | ||||||
| <25.0 | 24,154 (32) | 303 (27) | 1.0 (ref) | 45 (29) | 1.0 (ref) | 0.74 |
| 25.0 – 29.9 | 26,220 (35) | 372 (33) | 1.21 (1.02–1.44) | 54 (35) | 1.22 (0.76–1.96) | |
| ≥30.0 | 25,429 (34) | 441 (39) | 1.59 (1.33–1.89) | 56 (36) | 1.47 (0.91–2.38) | |
| Missing | 772 | 9 | 0 | |||
| ptrend | <0.01 | 0.12 | ||||
| pinteraction | 0.04 | 0.97 | ||||
| Waist circumference (cm)§ | ||||||
| <76 | 16,861 (22) | 188 (17) | 1.0 (ref) | 35 (23) | 1.0 (ref) | 0.68 |
| 76 – 84.4 | 18,224 (24) | 254 (23) | 1.20 (0.94–1.52) | 27 (17) | 0.63 (0.32–1.21) | |
| 84.5 – 94.5 | 20,335 (27) | 317 (28) | 1.32 (1.00–1.74) | 46 (30) | 0.85 (0.42–1.75) | |
| ≥95 | 20,834 (27) | 366 (33) | 1.46 (1.06–2.00) | 47 (30) | 1.07 (0.47–2.45) | |
| Missing | 321 | 0 | 0 | |||
| ptrend | 0.02 | 0.63 | ||||
| pinteraction | 0.03 | 0.36 | ||||
| Hip circumference (cm)§ | ||||||
| <98 | 18,757 (25) | 213 (19) | 1.0 (ref) | 38 (25) | 1.0 (ref) | 0.63 |
| 98 – 104.4 | 18,138 (24) | 247 (22) | 1.13 (0.90–1.43) | 34 (22) | 0.72 (0.39–1.32) | |
| 104.5 – 112.9 | 19,447 (26) | 323 (29) | 1.33 (1.02–1.74) | 38 (25) | 0.61 (0.30–1.23) | |
| ≥113 | 19,867 (26) | 341 (30) | 1.28 (0.93–1.76) | 45 (29) | 0.77 (0.34–1.77) | |
| Missing | 366 | 1 | 0 | |||
| ptrend | 0.10 | 0.50 | ||||
| pinteraction | 0.04 | 0.83 | ||||
*
ER+ = estrogen receptor-positive cases with known HER2 expression status; triple-negative = ER−/PR−/HER2−
†
Adjusted for age, education, income, family history of breast cancer, race, and recreational physical activity level, history of mammography (at baseline), and mammography during follow-up.
‡
Analysis of the partial likelihoods for equality between subtype-specific estimates.
§
Additionally adjusted for BMI at baseline.