Family history of later-onset breast cancer, breast healthy behavior and invasive breast cancer among postmenopausal women: a cohort study

Table 3 Hazard of invasive breast cancer according to each component cause, adjusting for potential confounders, in postmenopausal women (50-79 years old) enrolled in the Women's Health Initiative Observational Study (1993-2003)

	Component one	Component two
	FHLBC	Breast healthy behavior
	Crude HR (95% CI)	Crude HR (95% CI)
	1.50 (1.33, 1.68)	0.76 (0.60, 0.97)
Potential confounders	Adjusted HR (95% CI)	Adjusted HR (95% CI)
Age	1.48 (1.31, 1.66)	0.77 (0.61, 0.99)
Education	N/A	0.75 (0.59, 0.95)
Caucasian	1.47 (1.30, 1.65)	0.77 (0.61, 0.97)
Income of less than $35,000/year	N/A	0.77 (0.60, 0.98)
No mammogram in past 2 years	1.48 (1.31, 1.67)	0.74 (0.58, 0.94)
Breast biopsy ever	1.44 (1.28, 1.63)	N/A
Current hormone therapy use	1.52 (1.35, 1.71)	0.74 (0.58, 0.94)
Menarche at less than 12 years of age	N/A	0.77 (0.61, 0.98)
Never pregnant	N/A	N/A

CI, confidence interval; FHLBC, family history of later-onset breast cancer; HR, hazard ratio; N/A, not applicable, because these factors were not associated with the component cause and thus are not potential confounding variables for the interaction contrast.

ISSN: 1465-542X