Table 3.
Hazard ratio (HR) with 95% confidence interval (CI) for obesity-related cancer risk by weight change category between the enrolment (Q1) and follow-up questionnaire (Q2)
| Model 1 age-adjusted | Model 2 Multivariable | |||||||
|---|---|---|---|---|---|---|---|---|
| N | Cancer cases | HR | 95% CI | N | Cancer cases | HR | 95% CI | |
| Overall obesity-related cancer a | ||||||||
| Weight loss (< −2kg) | 7876 | 478 | 1.15 | 1.04–1.28 | 6886 | 406 | 1.09 | 0.97–1.22 |
| Stable weight (−2– < 2 kg) | 23,711 | 1315 | 1.00 | Reference | 20,950 | 1 142 | 1.00 | Reference |
| Low weight gain (2– < 5 kg) | 22,362 | 1356 | 1.10 | 1.02–1.19 | 19,844 | 1 209 | 1.14 | 1.05–1.23 |
| Moderate weight gain (5– < 10 kg) | 19,495 | 1218 | 1.14 | 1.06–1.24 | 17,202 | 1 069 | 1.14 | 1.05–1.25 |
| High weight gain (≥ 10 kg) | 7486 | 464 | 1.19 | 1.06–1.32 | 6558 | 406 | 1.16 | 1.04–1.31 |
| 5 kg increment | 80,930 | 4831 | 1.02 | 1.00–1.05 | 71,440 | 4 232 | 1.03 | 1.00–1.07 |
| Postmenopausal breast cancer b | ||||||||
| Weight loss (< −2kg) | 5456 | 128 | 1.00 | 0.82–1.22 | 4040 | 97 | 1.16 | 0.92–1.47 |
| Stable weight (−2– < 2 kg) | 14,997 | 388 | 1.00 | Reference | 11,605 | 277 | 1.00 | Reference |
| Low weight gain (2– < 5 kg) | 12,462 | 383 | 1.11 | 0.97–1.28 | 9858 | 293 | 1.16 | 0.98–1.36 |
| Moderate weight gain (5– < 10 kg) | 10,103 | 312 | 1.08 | 0.93–1.25 | 8025 | 254 | 1.20 | 1.01–1.43 |
| High weight gain (≥ 10 kg) | 3690 | 121 | 1.15 | 0.93–1.41 | 2924 | 102 | 1.36 | 1.08–1.71 |
| 5 kg increment | 46,708 | 1 332 | 1.04 | 0.98–1.09 | 36,452 | 1023 | 1.08 | 1.02–1.14 |
| Colorectal cancer c | ||||||||
| Weight loss (< −2kg) | 7876 | 120 | 1.28 | 1.03–1.58 | 7874 | 120 | 1.25 | 1.01–1.55 |
| Stable weight (−2– < 2 kg) | 23,711 | 286 | 1.00 | Reference | 23,705 | 286 | 1.00 | Reference |
| Low weight gain (2– < 5 kg) | 22,362 | 273 | 1.11 | 0.94–1.31 | 22,361 | 273 | 1.11 | 0.94–1.32 |
| Moderate weight gain (5– < 10 kg) | 19,495 | 253 | 1.24 | 1.05–1.48 | 19,492 | 252 | 1.24 | 1.05–1.48 |
| High weight gain (≥ 10 kg) | 7486 | 75 | 1.04 | 0.8–1.34 | 7486 | 75 | 1.02 | 0.79–1.33 |
| 5 kg increment | 80,930 | 1007 | 0.99 | 0.94–1.06 | 80,918 | 1006 | 1.00 | 0.94–1.06 |
| Colon cancer d | ||||||||
| Weight loss (< −2kg) | 7876 | 91 | 1.30 | 1.01–1.66 | 7872 | 91 | 1.26 | 0.98–1.61 |
| Stable weight (−2– < 2 kg) | 23,711 | 212 | 1.00 | Reference | 23,695 | 210 | 1.00 | Reference |
| Low weight gain (2– < 5 kg) | 22,362 | 181 | 1.01 | 0.83–1.24 | 22,355 | 181 | 1.03 | 0.84–1.26 |
| Moderate weight gain (5– < 10 kg) | 19,495 | 174 | 1.19 | 0.97–1.47 | 19,487 | 173 | 1.19 | 0.97–1.46 |
| High weight gain (≥ 10 kg) | 7486 | 52 | 1.01 | 0.74–1.38 | 7483 | 52 | 0.98 | 0.72–1.34 |
| 5 kg increment | 80,930 | 710 | 0.98 | 0.91–1.05 | 80,892 | 707 | 0.98 | 0.91–1.05 |
| Rectal cancer e | ||||||||
| Weight loss ( < −2kg) | 7876 | 29 | 1.22 | 0.80–1.88 | 7876 | 29 | 1.22 | 0.80–1.88 |
| Stable weight (−2 to < 2 kg) | 23,711 | 74 | 1.00 | Reference | 23,711 | 74 | 1.00 | Reference |
| Low weight gain (2 to < 5 kg) | 22,362 | 92 | 1.37 | 1.00–1.86 | 22,362 | 92 | 1.37 | 1.00–1.86 |
| Moderate weight gain (5 to < 10 kg) | 19,495 | 79 | 1.38 | 1.00–1.91 | 19,495 | 79 | 1.38 | 1.00–1.91 |
| High weight gain ( ≥ 10 kg) | 7486 | 23 | 1.11 | 0.69–1.78 | 7486 | 23 | 1.11 | 0.69–1.78 |
| 5 kg increment | 80,930 | 297 | 1.03 | 0.92–1.15 | 80,930 | 297 | 1.03 | 0.92–1.15 |
| Endometrial cancer f | ||||||||
| Weight loss (< −2kg) | 7281 | 59 | 1.24 | 0.92–1.68 | 6813 | 55 | 1.03 | 0.75–1.41 |
| Stable weight (−2– < 2 kg) | 22,238 | 153 | 1.00 | Reference | 20,899 | 139 | 1.00 | Reference |
| Low weight gain (2– < 5 kg) | 20,998 | 136 | 0.94 | 0.75–1.19 | 19,798 | 127 | 0.99 | 0.78–1.26 |
| Moderate weight gain (5– < 10 kg) | 18,389 | 154 | 1.23 | 0.98–1.54 | 17,413 | 150 | 1.27 | 1.01–1.61 |
| High weight gain (≥ 10 kg) | 6989 | 69 | 1.51 | 1.13–2.01 | 6674 | 68 | 1.40 | 1.04–1.88 |
| 5 kg increment | 75,895 | 571 | 1.10 | 1.02–1.19 | 71,597 | 539 | 1.12 | 1.04–1.20 |
| Ovarian cancer g | ||||||||
| Weight loss (< −2kg) | 7614 | 37 | 1.62 | 1.09–2.41 | 6650 | 30 | 1.52 | 0.99–2.34 |
| Stable weight (−2– < 2 kg) | 23,041 | 74 | 1.00 | Reference | 20,409 | 66 | 1.00 | Reference |
| Low weight gain (2– < 5 kg) | 21,890 | 90 | 1.25 | 0.92–1.71 | 19,497 | 84 | 1.29 | 0.93–1.79 |
| Moderate weight gain (5– < 10 kg) | 19,133 | 84 | 1.32 | 0.96–1.81 | 16,955 | 75 | 1.30 | 0.93–1.82 |
| High weight gain (≥ 10 kg) | 7345 | 25 | 1.05 | 0.66–1.66 | 6511 | 23 | 1.08 | 0.67–1.74 |
| 5 kg increment | 79,023 | 310 | 0.96 | 0.86–1.06 | 70,022 | 278 | 0.98 | 0.87–1.10 |
| Pancreatic cancer h | ||||||||
| Weight loss (< −2kg) | 7876 | 25 | 1.84 | 1.12–3.02 | 7176 | 21 | 1.58 | 0.93–2.69 |
| Stable weight (−2– < 2 kg) | 23,711 | 42 | 1.00 | Reference | 21,697 | 39 | 1.00 | Reference |
| Low weight gain (2– < 5 kg) | 22,362 | 50 | 1.37 | 0.91–2.07 | 20,641 | 43 | 1.28 | 0.83–1.98 |
| Moderate weight gain (5– < 10 kg) | 19,495 | 48 | 1.59 | 1.04–2.43 | 18,124 | 46 | 1.60 | 1.03–2.47 |
| High weight gain (≥ 10 kg) | 7486 | 21 | 1.95 | 1.14–3.32 | 6971 | 21 | 1.91 | 1.11–3.30 |
| 5 kg increment | 80,930 | 186 | 1.09 | 0.95–1.26 | 74,609 | 170 | 1.12 | 0.97–1.29 |
| Kidney cancer i | ||||||||
| Weight loss (< −2kg) | 7876 | 17 | 1.29 | 0.73–2.28 | 5750 | 10 | 1.08 | 0.52–2.27 |
| Stable weight (−2– < 2 kg) | 23,711 | 41 | 1.00 | Reference | 18,350 | 26 | 1.00 | Reference |
| Low weight gain (2– < 5 kg) | 22,362 | 40 | 1.07 | 0.69–1.66 | 17,697 | 27 | 1.14 | 0.66–1.96 |
| Moderate weight gain (5– < 10 kg) | 19,495 | 35 | 1.10 | 0.70–1.74 | 15,223 | 23 | 1.14 | 0.64–2.01 |
| High weight gain (≥ 10 kg) | 7486 | 15 | 1.31 | 0.72–2.38 | 5634 | 8 | 1.10 | 0.49–2.45 |
| 5 kg increment | 80,930 | 148 | 1.05 | 0.90–1.23 | 62,654 | 94 | 1.09 | 0.90–1.31 |
The Norwegian Women and Cancer study, 1991–2014 (n = 80,930)
aModel 2 for obesity-related cancer was adjusted for age, BMI (Q1), physical activity (Q1), smoking status and smoking transition
bOnly in women who were postmenopausal at Q2, model 2 for postmenopausal breast cancer was adjusted for age, education, parity/age at first full-term pregnancy, hormone therapy use and history of breast cancer in the mother
cModel 2 for colorectal cancer was adjusted for age and smoking status
dModel 2 for colon cancer was adjusted for age, BMI (Q1) and smoking status
eModel 2 for rectal cancer did not significantly differ from model 1 and was only adjusted for age
fModel 2 for endometrial cancer was adjusted for age, BMI (Q1), age at menarche, parity/age at first full-term pregnancy, oral contraceptive use and menopausal status
gModel 2 for ovarian cancer was adjusted for age, physical activity (Q1) and parity/age at first full-term pregnancy
hModel 2 for pancreatic cancer was adjusted for age, education and smoking status
iModel 2 for kidney cancer was adjusted for age, alcohol intake and diabetes