Table 2.
Effect of weight change over past 4 years on incidence of breast cancer, Nurses’ Health Study, 1980–2006, 4196 cases, 1,445,578 person-years
| Model | Group | Mean (sd)c
(10–90 %)d |
Number of cases | 4-year weight change (lbs) | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Loss of >5 lbs | No changea(ref) | Gain of 5.1–9.9 lbs | Gain of 10.0–14.9 lbs | Gain of ≥15.0 lbs | RR (per25 lbs wt gain) | P_trend | ||||
| 1 | Overall |
2.56 (11.89) (−10, 15) |
4196 | 0.97 (0.89–1.07) | 1.0 | 1.05 (0.94–1.16) | 1.09 (0.98–1.20) | 1.20 (1.09–1.33) | 1.13 (1.06–1.21) | <0.001 |
| 2 | Pre-menopausalb |
4.59 (11.60) (−6, 17) |
736 | 1.02 (0.79–1.32) | 1.0 | 0.98 (0.77–1.25) | 1.10 (0.88–1.38) | 1.38 (1.13–1.69) | 1.26 (1.08–1.48) | 0.004 |
| 3 | Post-menopausalb |
1.41 (11.83) (−10, 14) |
3009 | 0.98 (0.88–1.08) | 1.0 | 1.05 (0.93–1.19) | 1.06 (0.94–1.20) | 1.10 (0.97–1.25) | 1.08 (1.00–1.16) | 0.063 |
| 4 | Current pmhb |
2.24 (10.76) (−9, 14) |
1068 | 0.99 (0.83–1.18) | 1.0 | 1.18 (0.98–1.43) | 0.94 (0.75–1.17) | 1.16 (0.94–1.43) | 1.10 (0.95–1.28) | 0.18 |
| 5 | No pmhb |
1.13 (12.23) (−11, 14) |
1475 | 0.96 (0.83–1.10) | 1.0 | 0.99 (0.82–1.19) | 1.16 (0.98–1.38) | 1.04 (0.87–1.25) | 1.07 (0.97–1.19) | 0.19 |
Using proc phreg of SAS
pmh postmenopausal hormones
aWeight change of ≤5 lbs
bAt both time t and time t − 4
cMean (sd) 4-year weight change
d10–90 percentile of 4-year weight change