Association of premenopausal and postmenopausal weight change with breast cancer
| Risk factor model . | Initial interval . | Subsequent interval . | Initial weight change* . | Subsequent weight change* . | No. cases . | Person-years . | Incidence† . | RR (95% CI)‡ . | RR (95% CI)§ . |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Age 30 y to menopause | Menopause to baseline | Gain | Gain | 710 | 132,929 | 530 | 1.00 (Reference) | 1.00 (Reference) |
| No change | 494 | 102,131 | 488 | 0.93 (0.83-1.04) | 0.93 (0.82-1.04) | ||||
| Loss | 148 | 36,683 | 404 | 0.77 (0.64-0.92) | 0.78 (0.65-0.94) | ||||
| No change/loss | Gain | 325 | 73,973 | 437 | 0.83 (0.72-0.94) | 0.82 (0.72-0.94) | |||
| No change | 266 | 79,989 | 334 | 0.63 (0.55-0.73) | 0.62 (0.54-0.72) | ||||
| Loss | 44 | 17,187 | 251 | 0.48 (0.35-0.65) | 0.46 (0.34-0.64) | ||||
| 2 | Age 18-30 y | Age 30 y to menopause | Gain | Gain | 879 | 171,216 | 513 | 1.00 (Reference) | 1.00 (Reference) |
| No change | 272 | 67,562 | 400 | 0.78 (0.68-0.89) | 0.76 (0.66-0.88) | ||||
| Loss | 55 | 17,737 | 310 | 0.61 (0.46-0.80) | 0.62 (0.47-0.82) | ||||
| No change/loss | Gain | 471 | 99,828 | 473 | 0.93 (0.83-1.03) | 0.91 (0.81-1.03) | |||
| No change | 289 | 76,825 | 376 | 0.73 (0.64-0.84) | 0.71 (0.61-0.82) | ||||
| Loss | 15 | 8,581 | 176 | 0.36 (0.22-0.60) | 0.35 (0.21-0.59) |
| Risk factor model . | Initial interval . | Subsequent interval . | Initial weight change* . | Subsequent weight change* . | No. cases . | Person-years . | Incidence† . | RR (95% CI)‡ . | RR (95% CI)§ . |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Age 30 y to menopause | Menopause to baseline | Gain | Gain | 710 | 132,929 | 530 | 1.00 (Reference) | 1.00 (Reference) |
| No change | 494 | 102,131 | 488 | 0.93 (0.83-1.04) | 0.93 (0.82-1.04) | ||||
| Loss | 148 | 36,683 | 404 | 0.77 (0.64-0.92) | 0.78 (0.65-0.94) | ||||
| No change/loss | Gain | 325 | 73,973 | 437 | 0.83 (0.72-0.94) | 0.82 (0.72-0.94) | |||
| No change | 266 | 79,989 | 334 | 0.63 (0.55-0.73) | 0.62 (0.54-0.72) | ||||
| Loss | 44 | 17,187 | 251 | 0.48 (0.35-0.65) | 0.46 (0.34-0.64) | ||||
| 2 | Age 18-30 y | Age 30 y to menopause | Gain | Gain | 879 | 171,216 | 513 | 1.00 (Reference) | 1.00 (Reference) |
| No change | 272 | 67,562 | 400 | 0.78 (0.68-0.89) | 0.76 (0.66-0.88) | ||||
| Loss | 55 | 17,737 | 310 | 0.61 (0.46-0.80) | 0.62 (0.47-0.82) | ||||
| No change/loss | Gain | 471 | 99,828 | 473 | 0.93 (0.83-1.03) | 0.91 (0.81-1.03) | |||
| No change | 289 | 76,825 | 376 | 0.73 (0.64-0.84) | 0.71 (0.61-0.82) | ||||
| Loss | 15 | 8,581 | 176 | 0.36 (0.22-0.60) | 0.35 (0.21-0.59) |
Weight gain (loss) defined as increase (decrease) of at least 5% of body weight from beginning to end of interval.
Age-adjusted incidence per 100,000 person-years.
Accounting for age at baseline.
Accounting for age at baseline, BMI at age 18 years, age at menopause, education, age at menarche, oral contraceptive use, HRT, number of live births, age at first live birth, smoking status, and alcohol consumption.