Evaluation of osteopenia and osteoporosis in younger breast cancer survivors compared with cancer-free women: a prospective cohort study

Table 3 Risk of incident osteopenia and osteoporosis among breast cancer survivors compared with cancer-free women, stratified by characteristics at diagnosis

	Events/person-years	Age-adjusted HR (95% CI)	MV-adjusted HR^a (95% CI)^a
Age at diagnosis
Cancer-free	67/3509	1.00 (reference)	1.00 (reference)
≤ 50 years	27/651	2.34 (1.46–3.75)	1.98 (1.21–3.24)
> 50 years	18/375	1.64 (0.93–2.88)	1.34 (0.75–2.40)
Menopausal status at diagnosis
Cancer-free	67/3509	1.00 (reference)	1.00 (reference)
Premenopausal at diagnosis	27/728	1.97 (1.24–3.12)	1.76 (1.09–2.84)
Postmenopausal at diagnosis	18/298	2.05 (1.15–3.64)	1.58 (0.86–2.89)
ER status^b
Cancer-free	67/3509	1.00 (reference)	1.00 (reference)
ER-negative	7/200	1.68 (0.76–3.72)	1.26 (0.54–2.94)
ER-positive	32/611	2.32 (1.52–3.55)	2.10 (1.34–3.29)

Abbreviations: ER Estrogen receptor, MV Multivariable
^aAdjusted for age (years), menopausal status (premenopausal, postmenopausal), bilateral oophorectomy at age < 45 years (yes, no), body mass index (kg/m²), physical activity (MET-h/wk), smoking status (never, ever), alcohol intake (g/d), and hormone replacement therapy (never, ever)
^bBreast cancer survivors were restricted to stages I–III