title: Serum enterolactone concentration is not associated with breast cancer risk in a nested case-control study.
abstract: The lignan enterolactone produced by the intestinal microflora from dietary precursors has been hypothesized to protect against hormone-dependent cancers. We conducted a nested case-control study to examine the relationship between serum enterolactone concentration and risk of breast cancer. Enterolactone concentrations were measured by time-resolved fluoroimmunoassay in serum collected at 4 independent cross-sectional population surveys from 206 women with breast cancer diagnosed during follow-up (mean 8.0 years) and from 215 controls frequency-matched to cases by study cohort, 5-year age group and study area. Mean serum enterolactone concentration (nmol/l) did not significantly differ between case and control subjects [25.2 (SD 22.2) vs. 24.0 (SD 21.3), respectively]. Odds ratios for breast cancer risk estimated by conditional logistic regression for increasing concentration of enterolactone in quartiles were 1.00 (referent), 1.67 (95% CI 0.95-2.95), 1.71 (95% CI 0.96-3.06) and 1.30 (95% CI 0.73-2.31), and p for trend was 0.48. Our findings do not support the hypothesis that high serum enterolactone concentration is associated with reduced risk of breast cancer.
authors.affiliation: Department of Epidemiology and Health Promotion, National Public Health Institute, Helsinki, Finland. annamari.kilkkinen@ktl.fi
authors.forename: Annamari
authors.initials: A
authors.lastname: Kilkkinen
authors.forename: Jarmo
authors.initials: J
authors.lastname: Virtamo
authors.forename: Erkki
authors.initials: E
authors.lastname: Vartiainen
authors.forename: Risto
authors.initials: R
authors.lastname: Sankila
authors.forename: Mikko J
authors.initials: MJ
authors.lastname: Virtanen
authors.forename: Herman
authors.initials: H
authors.lastname: Adlercreutz
authors.forename: Pirjo
authors.initials: P
authors.lastname: Pietinen
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000097:blood*; D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000097:blood / Q000453:epidemiology* / Q000473:pathology; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D004967:Estrogens / Q000097:blood; D005260:Female; D005387:Finland / Q000453:epidemiology; D015200:Fluoroimmunoassay; D006801:Humans; D017705:Lignans / Q000097:blood*; D008875:Middle Aged; D016017:Odds Ratio; D017698:Postmenopause; D017697:Premenopause; D011446:Prospective Studies; D012307:Risk Factors
chemical_list: D004967:Estrogens; D017705:Lignans; D015107:4-Butyrolactone; C029497:2,3-bis(3'-hydroxybenzyl)butyrolactone