Table 3.

Risk of breast cancer after a diagnosis of benign breast disease

	Person-years at risk	No. of breast cancers	Rate/1,000 person-years	Unadjusted RR (95 % CI)	Age-adjusted* RR (95 % CI)
No benign breast disease	3,549,268	6,513	1.84	1.00 (Referent)	1.00 (Referent)
Nonproliferative disease	27,703	114	4.12	2.24 (1.86–2.70)	2.23 (1.86–2.68)
Proliferative disease without atypia	5,731	38	6.63	3.61 (2.63–4.96)	3.58 (2.61–4.91)
Proliferative disease with atypia	711	6	8.44	4.60 (2.08–10.15)	4.56 (2.06–10.07)
Total benign breast disease	34,145	158	4.63	2.52 (2.16–2.95)	2.51 (2.14–2.93)

RR rate ratio, 95 % CI 95 % confidence interval

* Adjusted by continuous age