Table 2.
Risk of premenopausal breast cancer in relation to weight change between various ages, by oestrogen‐receptor status of breast cancer
| Ages at weight change | Median weight change, kg (25–75th percentile) | ER status | No. of cases | Weight gain category, kg | Trend per 5 kg gain1 | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Loss ≥5.0 kg | Stable ±4.9 kg | Gain 5.0–9.9 kg | Gain 10.0–14.9 kg | Gain 15.0–19.9 kg | Gain ≥20.0 kg | |||||||
| HR (95% CI)2 | HR2 | HR (95% CI)2 | HR (95% CI)2 | HR (95% CI)2 | HR (95% CI)2 | p‐int | HR (95% CI)2 | p int‐trend | ||||
| Ages 18–24 to 25–34 | 4.5 (0.4–9.6) | ER+ | 1834 | 1.00 (0.80–1.25) | 1.00 (ref) | 0.89 (0.79–1.01) | 0.96 (0.83–1.12) | 0.87 (0.71–1.07) | 0.85 (0.70–1.02) | 0.98 (0.95–1.01) | ||
| ER− | 591 | 1.24 (0.86–1.79) | 1.00 (ref) | 1.10 (0.90–1.36) | 1.06 (0.82–1.38) | 0.85 (0.59–1.24) | 1.12 (0.83–1.50) | 0.39 | 1.01 (0.96–1.07) | 0.24 | ||
| Ages 18–24 to 35–44 | 6.9 (2.3–13.6) | ER+ | 3,976 | 0.92 (0.78–1.09) | 1.00 (ref) | 1.00 (0.92–1.08) | 0.96 (0.87–1.05) | 0.88 (0.78–0.99) | 0.77 (0.69–0.86) | 0.95 (0.93–0.97) | ||
| ER− | 1,268 | 0.85 (0.62–1.18) | 1.00 (ref) | 1.07 (0.93–1.24) | 1.11 (0.94–1.31) | 1.11 (0.90–1.35) | 1.01 (0.85–1.21) | 0.07 | 1.01 (0.98–1.04) | 0.0009 | ||
| Ages 18–24 to 45–54 | 10.0 (4.5–18.2) | ER+ | 2,249 | 0.80 (0.60–1.05) | 1.00 (ref) | 0.98 (0.87–1.11) | 1.02 (0.90–1.15) | 0.89 (0.77–1.03) | 0.79 (0.70–0.90) | 0.96 (0.94–0.98) | ||
| ER− | 625 | 1.27 (0.81–2.00) | 1.00 (ref) | 1.26 (1.00–1.58) | 1.18 (0.93–1.52) | 0.97 (0.73–1.31) | 1.02 (0.80–1.30) | 0.27 | 0.99 (0.95–1.02) | 0.16 | ||
| Age 25–34 to 35–44 | 3.2 (0–7.3) | ER+ | 1,547 | 0.99 (0.77–1.28) | 1.00 (ref) | 0.99 (0.86–1.13) | 0.99 (0.81–1.20) | 0.71 (0.50–0.99) | 0.72 (0.50–1.03) | 0.94 (0.89–0.99) | ||
| ER− | 466 | 0.74 (0.44–1.24) | 1.00 (ref) | 1.04 (0.82–1.33) | 1.13 (0.81–1.57) | 0.85 (0.49–1.49) | 1.08 (0.64–1.83) | 0.61 | 1.03 (0.96–1.10) | 0.03 | ||
| Age 25–34 to 45–54 | 7.3 (3.1–13.6) | ER+ | 726 | 1.45 (0.94–2.26) | 1.00 (ref) | 1.10 (0.92–1.32) | 0.91 (0.73–1.15) | 0.86 (0.64–1.16) | 0.90 (0.68–1.19) | 0.95 (0.90–1.00) | ||
| ER− | 169 | 0.25 (0.03–1.80) | 1.00 (ref) | 1.07 (0.74–1.54) | 0.91 (0.58–1.43) | 0.98 (0.56–1.71) | 0.69 (0.37–1.28) | 0.58 | 0.95 (0.86–1.04) | 1.00 | ||
| Age 35–44 to 45–54 | 3.2 (0–7.7) | ER+ | 2,575 | 1.15 (0.94–1.41) | 1.00 (ref) | 0.95 (0.86–1.05) | 1.08 (0.94–1.24) | 1.16 (0.96–1.42) | 0.89 (0.71–1.12) | 1.00 (0.96–1.03) | ||
| ER− | 670 | 0.77 (0.48–1.22) | 1.00 (ref) | 1.04 (0.86–1.26) | 1.03 (0.79–1.35) | 0.71 (0.44–1.14) | 0.89 (0.58–1.37) | 0.19 | 0.98 (0.91–1.05) | 0.61 | ||
1
Including subjects with weight gain only.
2
HRs are adjusted for attained age, cohort, year of birth, adult height, weight at start of age range, age at menarche, age at first birth, number of births, time since last birth and family history of breast cancer.
Abbreviations: CI, confidence interval; ER, oestrogen‐receptor; HR, hazard ratio; p‐int, p‐value for interaction test.