Characteristics of postmenopausal breast cancer survivors in a nested case–control analysis of IGFI receptor status, carbohydrate intake, and breast cancer recurrence
| Case status | IGFI receptor status of breast tumor tissue | |||||
|---|---|---|---|---|---|---|
| Overall | Control | Case | Negative | Positive | ||
| Characteristic | N = 265 | N = 174 (65.7%) | N = 91 (34.3%) | N = 132 (49.8%) | N = 133 (50.2%) | |
| Age at diagnosis, y (mean, SD)b | ||||||
| Non-Hispanic White | 221 (83.4%) | 144 (82.8%) | 77 (84.6%) | 116 (87.9%) | 105 (79.0%) | |
| College graduates | 115 (43.4%) | 76 (43.7%) | 39 (42.9%) | 62 (47.0%) | 53 (39.9%) | |
| BMI, kg/m2 (mean, SD) | 28.7 (6.2) | 28.7 (6.2) | 28.6 (6.2) | 28.4 (6.5) | 29.0 (5.9) | |
| Physical activity, METs (mean, SD) | 12.3 (12.2) | 12.2 (11.9) | 12.4 (12.9) | 13.0 (13.0) | 11.6 (11.4) | |
| Carbohydrate intake, g (mean, SD) | ||||||
| Baseline | 243 (60.4) | a | a | 246 (58.6) | 240 (62.2) | |
| Change (year 1 – baseline) | −32 (59.0) | a | a | −31.4 (59.2) | −31.7 (58.9) | |
| Years from diagnosis to study enrollment (mean, SD)b | 1.9 (1.0) | 2.0 (1.0) | 1.9 (1.0) | 1.9 (0.9) | 2.0 (1.0) | |
| Stage of primary cancerb | ||||||
| I | 66 (24.9%) | 43 (24.7%) | 23 (25.3%) | 28 (21.2%) | 38 (28.6%) | |
| II | 175 (66.0%) | 115 (66.1%) | 60 (65.9%) | 90 (68.2%) | 85 (63.9%) | |
| IIIA | 24 (9.1%) | 16 (9.2%) | 8 (8.8%) | 14 (10.6%) | 10 (7.5%) | |
| Number of positive nodes | ||||||
| 0 | 122 (46.0%) | 86 (49.4%) | 36 (39.6%) | 55 (41.7%) | 67 (50.4%) | |
| 1—3 | 76 (28.7%) | 53 (30.5%) | 23 (25.3%) | 40 (30.3%) | 36 (27.1%) | |
| >3 | 67 (25.3%) | 35 (20.1%) | 32 (35.2%) | 37 (28.0%) | 30 (22.6%) | |
| Estrogen receptor positive | 190 (72.8%) | 121 (70.8%) | 69 (76.7%) | 67 (51.2%) | 88 (69.3%) | |
| Progesterone receptor positive | 155 (60.1%) | 97 (57.7%) | 58 (64.4%) | 103 (78.0%) | 82 (62.1%) | |
| Chemotherapy | 185 (70.1%) | 121 (70.8%) | 69 (76.7%) | 103 (78.0%) | 82 (62.1%) | |
| Radiation therapy | 168 (63.4%) | 97 (57.7%) | 58 (64.4%) | 88 (66.7%) | 80 (60.2%) | |
| Ever tamoxifen use | 199 (75.1%) | 121 (70.8%) | 69 (76.7%) | 93 (70.5%) | 106 (79.7%) | |
NOTE: P < 0.05 for differences in number of positive nodes by case–control status and for differences in progesterone receptor status and chemotherapy by IGFI receptor status.
Abbreviation: METs, metabolic equivalent hours per week.
↵aAs detailed in the Materials and Methods, cases were counter matched on decreased versus stable/increased carbohydrate intake to increase power to detect an interaction. Therefore, baseline intake for cases [254 (56.4)] versus controls [222 (62.3)] and change in intake among cases [−46.1 (54.3)] versus controls [−3.7 (57.8)] are a function of the study design.
↵bMatching factor.