Table 4.

Timing of Breastfeeding and Epithelial Ovarian Cancer, the HOPE Study 2003–2008

	Controls	Cases	Odds Ratio	95% Confidence Interval	Adjusted Odds Ratio*	95% Confidence Interval
	N (%)	N (%)
Factor
Age at First Breastfeeding Episode (years)
Never Breastfed	684 (43.5)	386 (56.0)	1		1
<25	415 (26.4)	141 (20.5)	0.60	0.48–0.76	0.63	0.50–0.80
25–29	295 (18.8)	91 (13.2)	0.55	0.42–0.71	0.71	0.54–0.95
30+	178 (11.3)	71 (10.3)	0.71	0.52–0.96	0.92	0.67–1.27
					trend
					p=0.001
Age at Last Breastfeeding Episode (years)
Never Breastfed	684 (43.5)	386 (56.0)	1		1
<25	199 (12.7)	75 (10.9)	0.67	0.50–0.90	0.66	0.49–0.89
25–29	246 (15.7)	90 (13.1)	0.65	0.49–0.85	0.76	0.57–1.00
30+	443 (28.2)	138 (20.0)	0.55	0.44–0.69	0.70	0.55–0.90
Time Since First Breastfeeding Episode (years)
Never Breastfed	684 (43.5)	386 (56.0)	1		1
<10	71 (4.5)	12 (1.7)	0.30	0.16–0.56	0.56	0.28–1.10
10–19	150(9.5)	41(5.9)	0.48	0.34–0.70	0.76	0.50–1.14
20–29	253(16.1)	92(13.4)	0.64	0.49–0.84	0.85	0.63–1.14
30+	414(26.3)	158 (22.9)	0.68	0.54–0.84	0.64	0.51–0.80
Time Since Last Breastfeeding Episode (years)
Never Breastfed	684(43.5)	386 (56.0)	1		1
<10	114(7.3)	21(3.1)	0.33	0.20–0.53	0.56	0.32–0.95
10–19	209(13.3)	58(8.4)	0.49	0.36–0.67	0.70	0.49–0.99
20–29	224(14.3)	82(11.9)	0.65	0.49–0.86	0.80	0.59–1.07
30+	341 (21.7)	142 (20.6)	0.74	0.59–0.93	0.69	0.53–0.88

^*Separate models and analyses for each factor. Each model adjusted for age, race, education, duration of oral contraceptive use, and number of pregnancies.