. Author manuscript; available in PMC: 2016 Jan 28.

Published in final edited form as: Cancer Lett. 2014 Apr 28;356(2 0 0):231–243. doi: 10.1016/j.canlet.2014.04.018

Table 3.

Risk estimates for estrogens and their metabolites and breast cancer risk in premenopausal women: results from meta-analysis, systematic review, or individual studies of over 300 cases only.

First author, year, reference	Hormone	Cases/controls	Design/Biospecimen	Odds ratio (95% CI) for the top vs. bottom hormone category level	P_trend
Fortner, 2013^a [132]	Estradiol		Nested case-control/blood
	Follicular	462/909		1.0 (0.7 to 1.5)	0.76
	Luteal	479/959		0.9 (0.6 to 1.4)	0.65
	Free estradiol
	Follicular	447/886		0.8 (0.5 to 1.2)	0.48
	Luteal	469/944		1.0 (0.7 to 1.5)	0.99
	Estrone
	Follicular	469/920		1.0 (0.7 to 1.4)	0.62
	Luteal	500/1005		0.9 (0.7 to 1.3)	0.89
	SHBG	624/1246		1.2 (0.8 to 1.6)	0.23
Key, 2013^b,^c [136]	Total estradiol	600/1375	Pooled analysis/blood	1·19 (1·06–1·35)	0·0042
	Free estradiol	587/1341		1·17 (1·03–1·33)	0·014
	Estrone	477/933		1·27 (1·05–1·54)	0·014
	SHBG	767/1699		1·07 (0·94–1·23)	0.29
	Androstenedione	569/1177		1·30 (1·10–1·55)	0·0026
Walker, 2011^d [135]	Estradiol	693/1609	Meta-analysis/blood	1.10 (0.96–1.27)	N/A
Dallal, 2013^e [118]	2-OHE1/16α-OHE1 Ratio	183/543	Combined analysis/urine	0.74 (0.45–1.23)	0.25
Obi, 2011^f,^g [119]	2-OHE1/16α-OHE1 Ratio	682/1027	Systematic review/urine	0.5 (0.25–1.01) to 0.75 (0.35–1.62)	0.05, N/A
Arslan, 2009 ^h [138]	2-OHE1/16α-OHE1 Ratio	377/377	Nested case-control/blood	1.13 (0.68–1.87)	0.51

Abbreviations: N/A, not available; SHBG, sex hormone binding globulin; 2-OHE1, 2-hydroxyestrone; 16α-OHE1, 16-alpha-hydroxyestrone; OR, odds ratio; CI, confidence interval.

Reported odds ratio is based on quintile comparisons.

ORs for a doubling in concentrations of hormones.

From individual studies cited in references [124], [126], and [128–132].

From individual studies cited in references [123–128], and [130].

From individual studies cited in references [117], [137], and [143]. Reported odds ratio is based on tertile comparison.

Range of ORs with respective CIs. Reported odds ratios are based on tertile comparisons.

From individual studies cited in references [117], [137], and [146].

Reported odds ratios is based on quartile comparisons.

Note: All studies adjusted or matched for different covariates affecting breast cancer risk, but not necessarily for phase of menstrual cycle. Studies with less than 300 cases are part of meta-analysis or systematic review studies reported above.