Table 2.

Cox proportional hazards regression measured hazard ratio of breast cancer.

	Event	Crude		Adjusted
	(n = 111)	HR (95% CI)	p-value	HR (95% CI)	p-value
Non-lactational mastitis
No	74	Ref.		Ref.
Yes	37	1.94 (1.31–2.87)	0.001	1.94 (1.30–2.90)	0.001
Age at baseline
<40	42	Ref.		Ref.
40–49	42	2.96 (1.93–4.54)	<0.001	2.60 (1.63–4.14)	<0.001
50–59	18	3.04 (1.75–5.28)	<0.001	2.67 (1.43–4.96)	0.002
≥60	9	2.92 (1.42–6.01)	0.004	2.66 (1.14–6.21)	0.023
Monthly income (NT$)
0–15840	38	Ref.		Ref.
15841–28800	52	2.01 (1.32–3.05)	0.001	1.42 (0.91–2.22)	0.127
28801–45800	14	2.02 (1.09–3.72)	0.025	1.34 (0.71–2.55)	0.370
>45800	7	3.41 (1.52–7.63)	0.003	2.41 (1.05–5.53)	0.038
Baseline comorbidity
Schizophrenia	6	2.46 (1.08–5.6)	0.032	2.66 (1.16–6.09)	0.021
Hypertension	18	1.68 (1.02–2.79)	0.044	0.91 (0.5–1.67)	0.773
Chronic obstructive pulmonary disease	16	1.54 (0.91–2.63)	0.108	1.15 (0.66–2.00)	0.611
Thyroid disease	6	0.71 (0.31–1.62)	0.416	0.58 (0.25–1.32)	0.194
Diabetes	13	1.75 (0.98–3.12)	0.059	1.19 (0.61–2.32)	0.611
Hyperlipidemia	19	1.64 (1–2.68)	0.051	0.98 (0.54–1.77)	0.939
Obesity	0	—	—
Medication
Hormonal medication	56	1.06 (0.73–1.55)	0.745	1.00 (0.68–1.48)	0.982

*Abbreviation: HR, hazard ratio; CI, confidence interval.

*Adjusted HR: adjusted for age, income, comorbidities and medication in Cox proportional hazards regression.