Circulating serum xenoestrogens and mammographic breast density

Breast Cancer Research

Table 4 The association of serum phthalates, parabens, and phenols with mammographic breast density (N = 264), Wisconsin Breast Density Study, 2008 to 2009

	Mean percentage density (95% confidence interval)^a,b
Chemical	Nondetected	Below median^d	Above median^d	P _trend ^c
	n = 225	n = 19	n = 18
Mono-ethyl phthalate	13.1 (11.9, 14.3)	13.0 (9.1, 17.7)	18.2 (13.4, 23.7)	0.07
	n = 88	n = 88	n = 87
Propyl paraben	12.7 (10.9, 14.8)	13.3 (11.4, 15.4)	13.9 (12.0, 16.1)	0.41
	n = 121	n = 72	n = 71
Butyl paraben	14.4 (12.7, 16.3)	12.4 (10.4, 14.7)	12.4 (10.4, 14.7)	0.13
	n = 228	n = 19	n = 16
Octylphenol	13.5 (12.3, 14.7)	11.3 (7.6, 15.6)	14.5 (9.9, 19.9)	0.93
	n = 155	n = 55	n = 54
Nonylphenol	14.1 (12.6, 15.6)	12.1 (9.8, 14.7)	12.5 (10.1, 15.1)	0.21
	n = 193	n = 35	n = 34
Bisphenol A	12.6 (11.4, 14.0)	13.7 (10.7, 17.1)	17.6 (14.1, 21.5)	0.01

SE, standard error. ^aAdjusted for age, body mass index, parity, family history of breast cancer, vigorous physical activity, and smoking. ^bMean percentage density displayed is reverse transformed from model of square root density. ^cP_trend refers to the test for the ordinal variable representing nondetected, below median detected value, and above median detected value in a separate model. ^dRefers to the median of detected serum levels (that is, excluding nondetectable samples).

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