Table 2. Association between benign breast disease histology and breast cancer risk.

Histologic category	No. of cases	No. of controls	OR (95% CI)
No lesion or non-proliferative lesiona	101	98	1b
Epithelial hyperplasia without atypia	236	238	0.96 (0.69,1.34)
Atypical hyperplasia	14	2	6.79 (1.50, 30.67)

^a14 cases, 13 controls had no breast lesion.

^b Reference category.