title: Childbearing recency and modifiers of premenopausal breast cancer risk.
abstract: The purpose of this study was to examine the risk of premenopausal breast cancer for women in relation to childbearing recency and whether this association differs by breast-feeding history and/or the amount of weight gained during pregnancy. This analysis was based on data from a population-based case-control study composed of 1,706 incident cases of invasive breast cancer and 1,756 population controls from Wisconsin, New Hampshire, and Massachusetts. In a telephone interview conducted from 1996 to 2001, information was gathered on established breast cancer risk factors, as well as reproductive history, including amount of weight gained during the last full-term pregnancy and whether the child was breast-fed. Unconditional logistic regression was used to estimate odds ratios and Wald 95% confidence intervals for the risk of breast cancer. When compared with nulliparous women, women that had given birth within the past 5 years before breast cancer diagnosis in the cases or a comparable period in controls had a nonsignificant 35% increased risk of invasive breast cancer (odds ratio, 1.35; 95% confidence interval, 0.90-2.04), adjusting for age and known breast cancer risk factors (Ptrend = 0.14). We did not find a significant interaction with breast-feeding (Pinteraction = 0.30) or pregnancy weight gain (Pinteraction = 0.09).
authors.affiliation: Division of General Internal Medicine and Public Health, Department of Medicine, Vanderbilt University Medical Center, Suite 6108, Medical Center East, North Tower, Nashville, TN 37232-8300, USA. neeraja.peterson@vanderbilt.edu
authors.forename: Neeraja B
authors.initials: NB
authors.lastname: Peterson
authors.forename: Yifan
authors.initials: Y
authors.lastname: Huang
authors.forename: Polly A
authors.initials: PA
authors.lastname: Newcomb
authors.forename: Linda
authors.initials: L
authors.lastname: Titus-Ernstoff
authors.forename: Amy
authors.initials: A
authors.lastname: Trentham-Dietz
authors.forename: Gabriella
authors.initials: G
authors.lastname: Anic
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Egan
mesh_terms: D001942:Breast Feeding; D001943:Breast Neoplasms / Q000453:epidemiology*; D016022:Case-Control Studies; D005260:Female; D020073:Gravidity; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008404:Massachusetts / Q000453:epidemiology; D009513:New Hampshire / Q000453:epidemiology; D011247:Pregnancy; D017697:Premenopause; D012306:Risk; D013997:Time Factors; D015430:Weight Gain; D014922:Wisconsin / Q000453:epidemiology