An Estrogen Model: The Relationship between Body Mass Index, Menopausal Status, Estrogen Replacement Therapy, and Breast Cancer Risk

Table 1

Studies used to validate the model.

Study	Type of study	Baseline cohort size		Mean years of followup	Use for model validation
Pooling Project [16]	Pooled reanalysis of 7 cohort studies	Total*	337,819	3–8	Premenopausal and postmenopausal models
EPIC [17]	Prospective cohort study	Premenopausal	73,542	4.7	Premenopausal and postmenopausal models
		Postmenopausal
		non-HRT users	79,030
Million Women Study [14, 18]	Prospective cohort study	Premenopausal	63,153	5.4	Premenopausal, postmenopausal, and ERT models
		Postmenopausal
		never users of HRT	392,757
		current users of HRT	285,987
CPS-II [19]	Prospective cohort study	Postmenopausal		8	Postmenopausal model
		non-HRT users	41,159
WHI Observational Study [20]	Prospective cohort study	Postmenopausal		2.9	Postmenopausal model
		never users of HRT	32,547
WHI Estrogen-Alone Trial [21]	Randomized controlled trial	Postmenopausal		7.1	ERT model
		non-HRT users	5,429
		ERT users	5,310

*Separate numbers of postmenopausal and premenopausal women included in the Pooling Project were unavailable.