Table 2. Incidence and hazard ratio for the osteonecrosis cohort compared to the comparison cohort.

	Osteoporosis		Comparison		HR (95% CI)
	Case no.	IR †	Case no.	IR	Crude	Adjusted a
Overall	121	11.72	110	5.32	2.20 (1.70–2.85)**	2.05 (1.58–2.65)**
Age, year
20–64	40	7.30	56	5.12	1.43 (0.95–2.14)	1.32 (0.88–2.00)
≥ 65	81	16.72	54	5.53	3.02 (2.14–4.26)**	2.95 (2.09–4.17)**
Gender
Women	98	11.13	96	5.47	2.03 (1.54–270)**	1.89 (1.42–2.51)**
Men	23	15.15	14	4.44	3.42 (1.76–6.64)**	3.19 (1.63–6.24)**
Comorbidity
No	29	7.47	45	4.41	1.70 (1.06–2.71)*	1.62 (1.01–2.58)*
Yes	92	14.29	65	6.19	2.31 (1.68–3.17)**	2.28 (1.66–3.14)**
Diabetes
No	84	10.26	80	4.64	2.21 (1.63–3.00)***	2.09 (1.53–2.84)***
Yes	37	17.36	30	8.73	1.99 (1.23–3.22)**	1.95 (1.20–3.16)**
Hypertension
No	40	8.78	53	4.69	1.88 (1.25–2.83)**	1.74 (1.15–2.63)**
Yes	81	14.05	57	6.07	2.31 (1.65–3.25)***	2.28 (1.62–3.20)***
Cancer
No	111	11.22	107	5.33	2.10 (1.61–2.74)***	1.95 (1.50–2.55)***
Yes	10	23.51	3	4.90	4.78 (1.32–17.4)*	4.90 (1.35–17.8)*

CI, confidence interval.

^aAdjusted model, adjusted for age, gender, hypertension, diabetes, and cancer.

^†IR, incidence ratio, per 10,000 person-years.

*P<0.05;

**P<0.01.