Table 3.

Association between puerperal mastitis and histologic type of ovarian cancer.

	All cases and controls				Restricted to those who breast fed
	No mastitis N (%)	Mastitis N (%)	Adjusted* OR (95% CI)	p-value	No mastitis N (%)	Mastitis N (%)	Adjusted* OR (95% CI)	p-value
Controls	1440 (91.2)	138 (8.8)	1.00		692 (83.5)	137 (16.5)	1.00
Serous borderline	158 (96.3)	6 (3.7)	0.60 (0.25, 1.45)	0.25	57 (90.5)	6 (9.5)	0.64 (0.26, 1.58)	0.34
Serous invasive	660 (95.8)	29 (4.2)	0.64 (0.42, 1.00)	0.05	235 (89.7)	27 (10.3)	0.61 (0.38, 0.97)	0.04
Mucinous	147 (93.0)	11 (7.0)	1.05 (0.52, 2.16)	0.88	48 (81.4)	11 (18.6)	1.10 (0.52, 2.32)	0.81
Endometrioid	251 (96.5)	9 (3.5)	0.65 (0.31, 1.36)	0.25	68 (88.3)	9 (11.7)	0.59 (0.27, 1.28)	0.18
Clear cell	86 (97.7)	2 (2.3)	0.54 (0.12, 2.45)	0.42	17 (89.5)	2 (10.5)	0.48 (0.10, 2.27)	0.36
Other/undifferentiated	121 (97.6)	3 (2.4)	0.44 (0.13, 1.48)	0.18	36 (92.3)	3 (7.7)	0.39 (0.11, 1.36)	0.14

^*Adjusted for study, center and period, reference age, menopausal status, oral contraceptive use (never, <1 year, 1–5 years, >5 years), endometriosis, bladder infection, colitis, parity (0, 1, 2, 3, >3), duration of breastfeeding (never, <4 months, 4–9 months, 10–16 months, >16 months), and pack years (never smoked, <9, ≥9).