Table 3.

Odds ratios (ORs) and 95% confidence intervals (CI) for breast cancer risk according to histologic subtype of benign breast disease and type and extent of atypia among participants in the Nurses’ Health Study (1976-1998) and Nurses’ Health Study II (1991-1997)

BBD Histologic Subtype and type and extent of atypia	Cases	Percent Ipsilateral*	Controls	OR (95% CI)
Non-proliferative	108	51.3	680	1.0 (ref)
Proliferative without atypia	256	54.9	1035	1.6 (1.3-2.1)
ADH, 1-2 foci	37	61.3	75	3.5 (2.2-5.6)
ADH, ≥3 foci	15	69.2	41	2.7 (1.4-5.1)
ALH, 1-2 foci	19	52.6	25	5.2 (2.7-10.0)
ALH, ≥3 foci	32	57.7	26	8.0 (4.5-14.2)

^*Among cases with available laterality data (N=387).

** Adjusted for matching factors (age at breast cancer diagnosis, year of benign breast biopsy, and time since BBD biopsy) and family history of breast cancer, age at menarche, parity/age at first birth, body mass index, menopausal status/type of menopause, and duration of postmenopausal hormone use.

Age-adjusted p-value for difference in laterality: ADH 1-2 vs. ≥3 foci, p=0.58; ALH 1-2 vs. ≥3 foci, p=0.66

p-het for breast cancer risk (not laterality):

p-het (age-adjusted), ADH 1-2 vs. ≥3 foci=0.41; p-het (age-adjusted), ALH 1-2 vs. ≥3 foci=0.19

p-trend (age-adjusted), number of AH foci among those with ADH = 0.54; p-trend (age-adjusted), number of AH foci among those with ALH = 0.24