Table 3.

Predominant type 1/no type 3 lobules according to batch-specific quartiles of plasma IGF-1:IGFBP-3 ratios

	IGF-1:IGFBP-3 ratio
	Quartile 1	Quartile 2	Quartile 3	Quartile 4	P value
Predominant type 1, no type 3/other lobule type (n)	(27/90)	(20/98)	(18/100)	(9/110)
Age and batch-adjusteda	1 (reference)	0.68 (0.33 to 1.39)	0.60 (0.29 to 1.26)	0.26 (0.11 to 0.64)	0.01
Multivariate model 1b	1 (reference)	0.80 (0.38 to 1.67)	0.75 (0.34 to 1.66)	0.34 (0.13 to 0.86)	0.10
Multivariate model 2c	1 (reference)	0.83 (0.39 to 1.76)	0.75 (0.33 to 1.71)	0.32 (0.12 to 0.83)	0.09

Data from the Nurses' Health Study II presented as odds ratio (95% confidence interval) unless stated otherwise. ^aAge at biopsy (continuous), insulin-like growth factor 1 (IGF-1):insulin-like growth factor binding protein-3 (IGFBP-3) batch. ^bAge at biopsy (continuous), IGF-1:IGFBP-3 batch, body mass index (continuous), menopausal status (premenopausal/dubious; postmenopausal, no postmenopausal hormone use; postmenopausal, postmenopausal hormone use), histological category of benign breast disease (proliferative without atypia, proliferative with atypia). ^cMultivariate model 1 plus parity (nulliparous, parous), alcohol (none, < 1.5, 1.5 to 4.5, 4.5+ g/day).