Table 1. Characteristics of the Study Population.
| Variable | No. (%) |
|---|---|
| Age, median (IQR), y | 59 (50-69) |
| Year of breast cancer diagnosis | |
| July-December 2006 | 21 841 (5.0) |
| 2007-2009 | 138 482 (31.5) |
| 2010-2012 | 139 592 (31.7) |
| 2013-2015 | 139 789 (31.8) |
| Affiliation with complementary universal health insurancea | 19 376 (7.2) |
| Comorbidities | |
| Measurable history of smoking | 24 923 (5.7) |
| Alcohol use disorder | 7113 (1.6) |
| Obesity | 56 174 (12.8) |
| Medical contraceptionb | |
| IUD | 24 260 (22.7) |
| Birth control pill (reimbursed by health insurance) | 12 153 (11.4) |
| Birth control implant | 1676 (1.6) |
| Hormone replacement therapyc | 47 674 (12.7) |
| Breast cancer type | |
| Invasive | 409 523 (93.1) |
| In situ | 30 181 (6.9) |
| Breast cancer diagnosisd | |
| Mammography | 89 427 (95.5) |
| Biopsy | 87 182 (93.1) |
| Ultrasonography | 87 075 (93.0) |
| MRI | 29 506 (31.5) |
| PET scan | 1332 (1.4) |
| Breast cancer treatmente | |
| Surgical procedure | 365 318 (83.1) |
| Radiation therapy | 334 678 (76.1) |
| Chemotherapy | 186 142 (42.3) |
| Hormone therapy | 291 007 (66.2) |
| Anti–HER2 | 41 363 (9.4) |
| Growth factors (antianemic/hematopoietic) | 118 692 (27.0) |
Abbreviations: IQR, interquartile range; IUD, intrauterine device; MRI, magnetic resonance imaging; PET, positron emission tomography.
a
Free access to health care for people with an annual income less than 50% of the poverty threshold and younger than 65 years (n = 169 031).
b
For patients younger than 50 years (n = 107 004).
c
For patients aged 45 years or older (n = 374 208).
d
For patients included in 2014-2015 (n = 93 615).
e
For any corresponding reimbursement registered within 1 year of cohort entry.