title: Steroid hormone measurements from different types of assays in relation to body mass index and breast cancer risk in postmenopausal women: Reanalysis of eighteen prospective studies.
abstract: Epidemiological studies have examined breast cancer risk in relation to sex hormone concentrations measured by different methods: "extraction" immunoassays (with prior purification by organic solvent extraction, with or without column chromatography), "direct" immunoassays (no prior extraction or column chromatography), and more recently with mass spectrometry-based assays. We describe the associations of estradiol, estrone and testosterone with both body mass index and breast cancer risk in postmenopausal women according to assay method, using data from a collaborative pooled analysis of 18 prospective studies. In general, hormone concentrations were highest in studies that used direct assays and lowest in studies that used mass spectrometry-based assays. Estradiol and estrone were strongly positively associated with body mass index, regardless of the assay method; testosterone was positively associated with body mass index for direct assays, but less clearly for extraction assays, and there were few data for mass spectrometry assays. The correlations of estradiol with body mass index, estrone and testosterone were lower for direct assays than for extraction and mass spectrometry assays, suggesting that the estimates from the direct assays were less precise. For breast cancer risk, all three hormones were strongly positively associated with risk regardless of assay method (except for testosterone by mass spectrometry where there were few data), with no statistically significant differences in the trends, but differences may emerge as new data accumulate. Future epidemiological and clinical research studies should continue to use the most accurate assays that are feasible within the design characteristics of each study.
authors.forename: T J
authors.initials: TJ
authors.lastname: Key
authors.forename: P N
authors.initials: PN
authors.lastname: Appleby
authors.forename: G K
authors.initials: GK
authors.lastname: Reeves
authors.forename: R C
authors.initials: RC
authors.lastname: Travis
authors.forename: L A
authors.initials: LA
authors.lastname: Brinton
authors.forename: K J
authors.initials: KJ
authors.lastname: Helzlsouer
authors.forename: J F
authors.initials: JF
authors.lastname: Dorgan
authors.forename: S M
authors.initials: SM
authors.lastname: Gapstur
authors.forename: M M
authors.initials: MM
authors.lastname: Gaudet
authors.forename: R
authors.initials: R
authors.lastname: Kaaks
authors.forename: E
authors.initials: E
authors.lastname: Riboli
authors.forename: S
authors.initials: S
authors.lastname: Rinaldi
authors.forename: J
authors.initials: J
authors.lastname: Manjer
authors.forename: G
authors.initials: G
authors.lastname: Hallmans
authors.forename: G G
authors.initials: GG
authors.lastname: Giles
authors.forename: L
authors.initials: L
authors.lastname: Le Marchand
authors.forename: L N
authors.initials: LN
authors.lastname: Kolonel
authors.forename: B E
authors.initials: BE
authors.lastname: Henderson
authors.forename: S S
authors.initials: SS
authors.lastname: Tworoger
authors.forename: S E
authors.initials: SE
authors.lastname: Hankinson
authors.forename: A
authors.initials: A
authors.lastname: Zeleniuch-Jacquotte
authors.forename: K
authors.initials: K
authors.lastname: Koenig
authors.forename: V
authors.initials: V
authors.lastname: Krogh
authors.forename: S
authors.initials: S
authors.lastname: Sieri
authors.forename: P
authors.initials: P
authors.lastname: Muti
authors.forename: R G
authors.initials: RG
authors.lastname: Ziegler
authors.forename: C
authors.initials: C
authors.lastname: Schairer
authors.forename: B J
authors.initials: BJ
authors.lastname: Fuhrman
authors.forename: E
authors.initials: E
authors.lastname: Barrett-Connor
authors.forename: G A
authors.initials: GA
authors.lastname: Laughlin
authors.forename: E J
authors.initials: EJ
authors.lastname: Grant
authors.forename: J
authors.initials: J
authors.lastname: Cologne
authors.forename: W
authors.initials: W
authors.lastname: Ohishi
authors.forename: A
authors.initials: A
authors.lastname: Hida
authors.forename: J A
authors.initials: JA
authors.lastname: Cauley
authors.forename: E O
authors.initials: EO
authors.lastname: Fourkala
authors.forename: U
authors.initials: U
authors.lastname: Menon
authors.forename: T E
authors.initials: TE
authors.lastname: Rohan
authors.forename: H D
authors.initials: HD
authors.lastname: Strickler
authors.forename: M J
authors.initials: MJ
authors.lastname: Gunter
mesh_terms: D015992:Body Mass Index; D001943:Breast Neoplasms / Q000209:etiology*; D004958:Estradiol / Q000097:blood*; D004970:Estrone / Q000097:blood*; D005260:Female; D006801:Humans; D017698:Postmenopause / Q000097:blood*; D011446:Prospective Studies; D012307:Risk Factors; D013739:Testosterone / Q000097:blood*
chemical_list: D004970:Estrone; D013739:Testosterone; D004958:Estradiol
keywords: Body mass index; Breast cancer; Direct immunoassay; Estradiol; Extraction immunoassay; Mass spectrometry