Table 1.
Basic characteristics of female participants from NHS and NHS II*
| Variable | Control group | Conventional adenoma | Serrated polyp |
|---|---|---|---|
| No. of participants | 9172 | 1234 | 914 |
| Caucasian, % | 96 | 97 | 97 |
| Age at blood draw, y | 53.9 (8.0) | 54.9 (7.9) | 52.9 (7.8) |
| Blood fasting, % | 76 | 79 | 79 |
| No. of endoscopies over follow-up | 2.8 (1.8) | 2.0 (1.4) | 2.1 (1.4) |
| Time since most recent endoscopy, y | 2.6 (2.9) | 2.1 (3.2) | 2.6 (3.5) |
| Height, cm | 164.3 (6.1) | 164.6 (6.0) | 164.6 (5.6) |
| BMI, kg/m2 | 25.4 (4.8) | 25.6 (4.4) | 25.8 (4.7) |
| Family history of colorectal cancer, % | 24 | 31 | 26 |
| Pack-year of smoking | 9.1 (15.4) | 11.4 (16.5) | 12.7 (17.3) |
| Never, % | 51 | 47 | 41 |
| Past, % | 40 | 40 | 40 |
| Current, % | 9 | 13 | 18 |
| Alcohol intake, g/d | 5.7 (9.0) | 6.3 (9.3) | 7.1 (10.2) |
| Physical activity, MET-hours/wk† | 18.7 (19.9) | 17.7 (18.1) | 19.1 (17.9) |
| AHEI dietary score | 53.1 (10.2) | 52.5 (9.6) | 52.1 (9.4) |
| Regular aspirin use, %‡ | 48 | 44 | 44 |
| Postmenopause, % | 57 | 59 | 56 |
| Current postmenopausal hormone use, % | 50 | 44 | 42 |
| Biomarker§ | |||
| C-peptide, ng/mL | 1.52 (1.11–2.22) | 1.58 (1.13–2.28) | 1.56 (1.19–2.21) |
| IGF1, ng/mL | 159.6 (125.0–200.0) | 155.4 (120.0–195.1) | 165.8 (128.1–206.5) |
| IGFBP1, ng/mL | 30.1 (15.5–48.5) | 26.1 (14.8–44.1) | 23.6 (13.2–37.3) |
| IGFBP3, ng/mL | 4317 (3786–4934) | 4334 (3821–4926) | 4375 (3885–4967) |
| IGF1 to IGFBP3 molar ratio‖ | 0.14 (0.11–0.16) | 0.13 (0.10–0.16) | 0.14 (0.11–0.16) |
All variables are adjusted for age except for age itself. Mean (SD) is presented for continuous variables and percentage for categorical variables, unless otherwise specified. AHEI, Alternative Healthy Eating Index; BMI = body mass index; IGF1, insulin-like growth factor 1; IGFBP1, insulin-like growth factor binding protein 1; IGFBP3, insulin-like growth factor binding protein 3; MET, metabolic equivalent task; NHS = Nurses’ Health Study.
Physical activity is represented by the product sum of the METs of each specific recreational activity and hours spent on that activity per week.
A standard tablet contains 325 mg aspirin, and regular users were defined as those who used at least two tablets per week.
The natural-log transformed biomarker concentrations were back transformed and presented as median values (quartiles).
(IGF1 [ng/mL] × 0.13)/(IGFBP3 [ng/mL] × 0.036).