Table 4.

Odds ratios (OR) and 95% confidence intervals (CI) for jointly-classified histologic category of BBD/lobule type and breast cancer risk among participants in the Nurses’ Health Study (1988–1994) and Nurses’ Health Study II (1991–1995)

	Cases	Controls	OR (95% CI)*
Nonproliferative, no type 1 or mixed lobule types	31	199	1.0 (REF)
Nonproliferative, predominant type 1 and no type 3 lobules	16	132	0.80 (0.41–1.54)
Proliferative without atypia, no type 1 or mixed lobule types	73	334	1.43 (0.90–2.28)
Proliferative without atypia, predominant type 1 and no type 3 lobules	24	150	1.09 (0.59–1.99)
Atypical hyperplasia, no type 1 or mixed lobule types	42	61	4.76 (2.67–8.48)
Atypical hyperplasia, predominant type 1 and no type 3 lobules	14	39	2.53 (1.17–5.47)

^*Adjusted for age, year of BBD, and time since benign biopsy.