title: Effects of parity on pregnancy hormonal profiles across ethnic groups with a diverse incidence of breast cancer.
abstract: Epidemiologic evidence suggests that a full-term pregnancy may affect maternal risk of breast cancer later in life. The objective of this cross-sectional study was to compare circulating levels of maternal hormones affecting breast differentiation (human chorionic gonadotropin and prolactin) and proliferation [alpha-fetoprotein, insulin-like growth factor I (IGF-I), and estradiol] between women at a low to moderate risk (Asians and Hispanics), as compared with women at a high risk for breast cancer (Caucasians and African-Americans). Between May 2002 and December 2004, a total of 586 pregnant women were approached during a routine prenatal visit. Among them, 450 women (206 Caucasian, 126 Asian, 88 Hispanic, and 30 African-American) met the inclusion criteria and signed the informed consent. Only singleton pregnancies were considered. Blood samples were drawn during the second trimester of pregnancy. Laboratory analyses were done using the IMMULITE 2000 immunoassay system. Gestational age standardized mean levels of estradiol, IGF-I, and prolactin were significantly higher in Hispanic women compared with Caucasian women. Mean concentration of IGF-I was significantly higher in African-American women compared with Caucasian and Asian women. No significant differences in pregnancy hormone levels were observed between Caucasian and Asian (predominantly second-generation Chinese) women in this study. Irrespective of ethnicity, women who had their first pregnancy had substantially higher mean levels of alpha-fetoprotein, human chorionic gonadotropin, estradiol, and prolactin compared with women who previously had at least one full-term pregnancy. These data suggest that circulating pregnancy hormone levels may explain some of the ethnic differences in breast cancer risk.
authors.affiliation: Department of Obstetrics and Gynecology, New York University School of Medicine, 550 First Avenue, NBV-9E2, New York, NY 10016, USA. akhmea01@med.nyu.edu
authors.forename: Alan A
authors.initials: AA
authors.lastname: Arslan
authors.forename: Anne
authors.initials: A
authors.lastname: Zeleniuch-Jacquotte
authors.forename: Annekatrin
authors.initials: A
authors.lastname: Lukanova
authors.forename: Yelena
authors.initials: Y
authors.lastname: Afanasyeva
authors.forename: Joseph
authors.initials: J
authors.lastname: Katz
authors.forename: Mortimer
authors.initials: M
authors.lastname: Levitz
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Del Priore
authors.forename: Paolo
authors.initials: P
authors.lastname: Toniolo
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000097:blood* / Q000175:diagnosis* / Q000208:ethnology*; D006063:Chorionic Gonadotropin / Q000097:blood; D004958:Estradiol / Q000097:blood; D005006:Ethnicity; D005260:Female; D005865:Gestational Age; D006728:Hormones / Q000097:blood*; D006801:Humans; D007118:Immunoassay; D015994:Incidence; D010298:Parity; D011247:Pregnancy; D011388:Prolactin / Q000097:blood; D000509:alpha-Fetoproteins / Q000096:biosynthesis
chemical_list: D006063:Chorionic Gonadotropin; D006728:Hormones; D000509:alpha-Fetoproteins; D004958:Estradiol; D011388:Prolactin