title: Pre-pregnancy potato consumption and risk of gestational diabetes mellitus: prospective cohort study.
abstract: OBJECTIVE
  What is the association between potato consumption before pregnancy and the risk of gestational diabetes mellitus (GDM)?
  
  
  METHODS
  This prospective cohort study included 15,632 women from the Nurses' Health Study II (1991-2001). They had no previous GDM or chronic diseases before pregnancy. Consumption of potatoes and other foods was assessed every four years. Incident first time GDM was ascertained from self reports of a physician diagnosis of GDM, which was previously validated by medical records.
  
  
  CONCLUSIONS
  Over the 10 year follow-up there were 854 incident cases of GDM among 21,693 singleton pregnancies. After adjustment for age, parity, and dietary and non-dietary factors, women who consumed more potatoes before pregnancy had higher rates of developing GDM. Substitution of two servings a week of total potatoes with other vegetables, legumes, and whole grain foods was significantly associated with a 9-12% lower risk of GDM. Consumption and diabetes were self reported, and severity of diabetes was unknown. More than 90% of women were white. A causal association cannot be assumed.
  
  
  CONCLUSIONS
  Higher levels of potato consumption before pregnancy are associated with greater risk of GDM, and substitution of potatoes with other vegetables, legumes, or whole grain foods might lower the risk.
  
  
  BACKGROUND
  Funding was received from the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the National Institutes of Health, and the American Diabetes Association (No 7-12-MN-34). The authors have no competing interests or additional data to share.
authors.affiliation: Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD 20852, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Bao
authors.affiliation: Division of Preventive Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02215, USA Department of Nutrition, Harvard T H Chan School of Public Health, Boston, MA 02115, USA.
authors.forename: Deirdre K
authors.initials: DK
authors.lastname: Tobias
authors.affiliation: Department of Nutrition, Harvard T H Chan School of Public Health, Boston, MA 02115, USA Department of Epidemiology, Harvard T H Chan School of Public Health, Boston, MA 02115, USA Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Frank B
authors.initials: FB
authors.lastname: Hu
authors.affiliation: Department of Nutrition, Harvard T H Chan School of Public Health, Boston, MA 02115, USA Department of Epidemiology, Harvard T H Chan School of Public Health, Boston, MA 02115, USA Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Chavarro
authors.affiliation: Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD 20852, USA zhangcu@mail.nih.gov.
authors.forename: Cuilin
authors.initials: C
authors.lastname: Zhang
mesh_terms: D000328:Adult; D016640:Diabetes, Gestational / Q000209:etiology* / Q000517:prevention & control; D005247:Feeding Behavior; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016742:Preconception Care; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors; D011198:Solanum tuberosum / Q000009:adverse effects*