Table 3.

Recency of breast cancer according to breast-feeding and pregnancy weight gain: Collaborative Breast Cancer Study (1996–2001)

	Any Breast-feeding				No Breast-feeding
Recency of last birth	Cases	Controls	OR*	95% CI	Cases	Controls	OR*	95% CI
Nulliparous	274	255	1.00	Ref	-	-	-	-
>10 years	472	515	1.11	0.82–1.50	480	538	1.11	0.84–1.48
>5–10 years	170	175	1.18	0.80–1.74	105	97	1.25	0.83–1.90
≤5 years	141	133	1.24	0.80–1.91	64	43	1.64	0.97–2.78
p trend			0.32				0.12
Interaction term p-value†				0.30
	< 24% increase in weight‡				≥ 24% increase in weight‡
Recency of last birth	Cases	Controls	OR*	95% CI	Cases	Controls	OR*	95% CI
Nulliparous	274	255	1.00	Ref	-	-	-	-
>10 years	431	484	1.09	0.81–1.47	452	494	1.10	0.82–1.48
>5–10 years	133	111	1.40	0.93–2.12	124	150	0.91	0.61–1.36
≤5 years	92	77	1.39	0.86–2.24	97	91	1.10	0.69–1.74
p trend			0.18				0.62
Interaction term p-value†				0.09

^*Adjusted for age, state, parity, age at first birth, education, mammogram in last 5 years, family history, body-mass index, benign breast disease.

^†Breastfeeding and weight gain according to years since most recent birth among parous women.

^‡197 women with missing data for weight change.