Table 2.
Univariate associations of demographic and clinical factors with fracture risk in breast cancer patients on aromatase inhibitors (AI).
| Variable | # Fracture/total | HR (95% CI) | P-value |
|---|---|---|---|
| Age at breast cancer diagnosis, years | <0.001 | ||
| <50 | 6/79 | 1.00 | – |
| 50–59 | 58/639 | 1.28 (0.55–2.98) | – |
| 60–69 | 107/890 | 1.78 (0.78–4.06) | – |
| ≥70 | 141/544 | 4.81 (2.12–10.89) | – |
| Age at breast cancer diagnosis, per year | NA | 1.07 (1.06, 1.08) | <0.001 |
| Menopausal status at breast cancer diagnosis | 0.01 | ||
| Premenopausal | 11/142 | 1.00 | – |
| Postmenopausal | 301/2010 | 2.17 (1.19–3.97) | – |
| Race/ethnicity | 0.007 | ||
| White | 248/1565 | 1.00 | – |
| Black | 10/122 | 0.53 (0.28–1.00) | – |
| Asian | 20/224 | 0.52 (0.33–0.83) | – |
| Hispanic | 30/199 | 0.95 (0.65–1.39) | – |
| Other | 4/42 | 0.58 (0.22–1.56) | – |
| Body mass index at breast cancer diagnosis, kg/m2 | 0.15 | ||
| <25.0 | 94/580 | 1.00 | – |
| 25.0–29.9 | 108/699 | 0.94 (0.71–1.24) | – |
| ≥30.0 | 110/873 | 0.77 (0.59–1.02) | – |
| Body mass index at breast cancer diagnosis, kg/m2, per unit increase | NA | 0.99 (0.97, 1.01) | 0.25 |
| AJCC stage | 0.71 | ||
| I | 170/1166 | 1.00 | – |
| II | 110/746 | 1.09 (0.86–1.39) | – |
| III | 29/205 | 1.20 (0.81–1.78) | – |
| IV | 3/35 | 1.45 (0.46–4.56) | – |
| Breast cancer treatment | 0.001 | ||
| Chemotherapy | 29/254 | 1.00 | – |
| Radiation therapy | 119/869 | 1.11 (0.74–1.66) | – |
| Both | 73/572 | 1.08 (0.70–1.66) | – |
| None | 91/457 | 1.80 (1.18–2.73) | – |
| AI treatment length - time-dependent model | 0.62 | ||
| ≤2.0 years | NA | 1.00 | – |
| 2.1–4.0 years | NA | 1.14 (0.78, 1.65) | – |
| 4.1–5.0 years | NA | 1.11 (0.77, 1.61) | – |
| >5.0 years | NA | 1.30 (0.88, 1.91) | – |
| AI treatment length, per year - time-dependent model | NA | 1.03 (0.97, 1.11) | 0.34 |
| Osteoporosis prior to breast cancer diagnosis | <0.001 | ||
| No | 263/1986 | 1.00 | – |
| Yes | 49/165 | 2.69 (1.98, 3.65) | – |
| Bisphosphonate use after AI initiation - time-dependent model | |||
| No | 1511 | 1.00 | – |
| Yes | 641 | 2.36 (1.87, 2.99) | <0.001 |
| Bisphosphonate use after AI initiation, per year - time-dependent model | 1.15 (1.07, 1.24) | <0.001 | |
| Major osteoporotic fracture prior to breast cancer diagnosis | <0.001 | ||
| No | 284/2052 | 1.00 | – |
| Yes | 28/99 | 2.63 (1.78, 3.88) | – |
| BMD at the time close to initiation of AI treatment, 0.1 increment | |||
| Spine | NA | 0.88 (0.80–0.96) | 0.006 |
| Hip | NA | 0.70 (0.62–0.79) | <0.001 |
| Femoral neck | NA | 0.74 (0.62–0.89) | <0.001 |
| Polygenic score of gSOS | <0.001 | ||
| Tertile 1 | 124/636 | 1.00 | – |
| Tertile 2 | 83/635 | 0.63 (0.48, 0.83) | – |
| Tertile 3 | 74/656 | 0.54 (0.41, 0.73) | – |
| Polygenic score of gSOS, per unit increase | NA | 0.52 (0.40, 0.67) | <0.001 |