biostudies-literatureUnknown10Flores R<h4>Background</h4>High systemic estrogen levels contribute to breast cancer risk for postmenopausal women, whereas low levels contribute to osteoporosis risk. Except for obesity, determinants of non-ovarian systemic estrogen levels are undefined. We sought to identify members and functions of the intestinal microbial community associated with estrogen levels via enterohepatic recirculation.<h4>Methods</h4>Fifty-one epidemiologists at the National Institutes of Health, including 25 men, 7 postmenopausal women, and 19 premenopausal women, provided urine and aliquots of feces, using methods proven to yield accurate and reproducible results. Estradiol, estrone, 13 estrogen metabolites (EM), and their sum (total estrogens) were quantified in urine and feces by liquid chromatography/tandem massJournal of translational medicine253https://www.ebi.ac.uk/biostudies/studies/S-EPMC3552825biostudies-literatureFecal microbial determinants of fecal and systemic estrogens and estrogen metabolites: a cross-sectional study.PMC3552825Goedert JJGail MHVeenstra TDGajer PFlores RRavel JShi JXu XFuhrman BfalseFecal microbial determinants of fecal and systemic estrogens and estrogen metabolites: a cross-sectional study.<h4>Background</h4>High systemic estrogen levels contribute to breast cancer risk for postmenopausal women, whereas low levels contribute to osteoporosis risk. Except for obesity, determinants of non-ovarian systemic estrogen levels are undefined. We sought to identify members and functions of the intestinal microbial community associated with estrogen levels via enterohepatic recirculation.<h4>Methods</h4>Fifty-one epidemiologists at the National Institutes of Health, including 25 men, 7 postmenopausal women, and 19 premenopausal women, provided urine and aliquots of feces, using methods proven to yield accurate and reproducible results. Estradiol, estrone, 13 estrogen metabolites (EM), and their sum (total estrogens) were quantified in urine and feces by liquid chromatography/tandem mass2012-01-01T00:00:00Z2012 Dec2025-04-22T21:31:25.794Z2019-03-27T01:03:40ZS-EPMC35528252325975810.1186/1479-5876-10-253