title: Effect of long-term storage on hormone measurements in samples from pregnant women: the experience of the Finnish Maternity Cohort.
abstract: Validity of biobank studies on hormone associated cancers depend on the extent the sample preservation is affecting the hormone measurements. We investigated the effect of long-term storage (up to 22 years) on immunoassay measurements of three groups of hormones and associated proteins: sex-steroids [estradiol, progesterone, testosterone, dihydroepiandrosterone sulphate (DHEAS), sex hormone-binding globulin (SHBG)], pregnancy-specific hormones [human chorionic gonadotropin (hCG), placental growth hormone (pGH), alpha-fetoprotein (AFP)], and insulin-like growth factor (IGF) family hormones exploiting the world largest serum bank, the Finnish Maternity Cohort (FMC). Hormones of interest were analyzed in a random sample of 154 Finnish women in the median age (29.5 years, range 25 to 34 years) of their first pregnancy with serum samples drawn during the first trimester. All hormone measurements were performed using commercial enzyme-linked- or radio-immunoassays. Storage time did not correlate with serum levels of testosterone, DHEAS, hCG, pGH and total IGFBP-1. It had a weak or moderate negative correlation with serum levels of progesterone (Spearman's ranked correlation coefficient (r(s))=- 0.36), IGF-I (r(s)=-0.23) and IGF binding protein (BP)-3 (r(s)=-0.38), and weak positive correlation with estradiol (r(s)=0.23), SHBG (r(s)=0.16), AFP (r(s)=0.20) and non-phosphorylated IGF binding protein (BP)-1 (r(s)=0.27). The variation of all hormone levels studied followed the kinetics reported for early pregnancy. Bench-lag time (the time between sample collection and freezing for storage) did not materially affect the serum hormone levels. In conclusion, the stored FMC serum samples can be used to study hormone-disease associations, but close matching for storage time and gestational day are necessary design components of all related biobank studies.
authors: Department of Child and Adolescent Health, National Public Health Institute, Oulu, Finland. katsiaryna.holl@ktl.fi
authors: Katsiaryna
authors: K
authors: Holl
authors: Eva
authors: E
authors: Lundin
authors: Marjo
authors: M
authors: Kaasila
authors: Kjell
authors: K
authors: Grankvist
authors: Yelena
authors: Y
authors: Afanasyeva
authors: Göran
authors: G
authors: Hallmans
authors: Matti
authors: M
authors: Lehtinen
authors: Eero
authors: E
authors: Pukkala
authors: Helja-Marja
authors: HM
authors: Surcel
authors: Paolo
authors: P
authors: Toniolo
authors: Anne
authors: A
authors: Zeleniuch-Jacquotte
authors: Pentti
authors: P
authors: Koskela
authors: Annekatrin
authors: A
authors: Lukanova
mesh_terms: D000328:Adult; D016477:Artifacts; D001793:Blood Preservation; D001798:Blood Proteins / Q000032:analysis / Q000737:chemistry; D015331:Cohort Studies; D005260:Female; D005387:Finland; D006728:Hormones / Q000097:blood* / Q000737:chemistry; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods* / Q000706:statistics & numerical data; D008403:Mass Screening; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000097:blood*; D011295:Prenatal Care; D012034:Refrigeration; D012494:Sampling Studies; D044967:Serum / Q000737:chemistry; D013997:Time Factors
chemical_list: D001798:Blood Proteins; D006728:Hormones