title: Lactation and Progression to Type 2 Diabetes Mellitus After Gestational Diabetes Mellitus: A Prospective Cohort Study.
abstract: BACKGROUND
  Lactation improves glucose metabolism, but its role in preventing type 2 diabetes mellitus (DM) after gestational diabetes mellitus (GDM) remains uncertain.
  
  
  OBJECTIVE
  To evaluate lactation and the 2-year incidence of DM after GDM pregnancy.
  
  
  METHODS
  Prospective, observational cohort of women with recent GDM. (ClinicalTrials.gov: NCT01967030).
  
  
  METHODS
  Integrated health care system.
  
  
  METHODS
  1035 women diagnosed with GDM who delivered singletons at 35 weeks' gestation or later and enrolled in the Study of Women, Infant Feeding and Type 2 Diabetes After GDM Pregnancy from 2008 to 2011.
  
  
  METHODS
  Three in-person research examinations from 6 to 9 weeks after delivery (baseline) and annual follow-up for 2 years that included 2-hour, 75-g oral glucose tolerance testing; anthropometry; and interviews. Multivariable Weibull regression models evaluated independent associations of lactation measures with incident DM adjusted for potential confounders.
  
  
  RESULTS
  Of 1010 women without diabetes at baseline, 959 (95%) were evaluated up to 2 years later; 113 (11.8%) developed incident DM. There were graded inverse associations for lactation intensity at baseline with incident DM and adjusted hazard ratios of 0.64, 0.54, and 0.46 for mostly formula or mixed/inconsistent, mostly lactation, and exclusive lactation versus exclusive formula feeding, respectively (P trend = 0.016). Time-dependent lactation duration showed graded inverse associations with incident DM and adjusted hazard ratios of 0.55, 0.50, and 0.43 for greater than 2 to 5 months, greater than 5 to 10 months, and greater than 10 months, respectively, versus 0 to 2 months (P trend = 0.007). Weight change slightly attenuated hazard ratios.
  
  
  CONCLUSIONS
  Randomized design is not feasible or desirable for clinical studies of lactation.
  
  
  CONCLUSIONS
  Higher lactation intensity and longer duration were independently associated with lower 2-year incidences of DM after GDM pregnancy. Lactation may prevent DM after GDM delivery.
  
  
  BACKGROUND
  National Institute of Child Health and Human Development.
authors.forename: Erica P
authors.initials: EP
authors.lastname: Gunderson
authors.forename: Shanta R
authors.initials: SR
authors.lastname: Hurston
authors.forename: Xian
authors.initials: X
authors.lastname: Ning
authors.forename: Joan C
authors.initials: JC
authors.lastname: Lo
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Crites
authors.forename: David
authors.initials: D
authors.lastname: Walton
authors.forename: Kathryn G
authors.initials: KG
authors.lastname: Dewey
authors.forename: Robert A
authors.initials: RA
authors.lastname: Azevedo
authors.forename: Stephen
authors.initials: S
authors.lastname: Young
authors.forename: Gary
authors.initials: G
authors.lastname: Fox
authors.forename: Cathie C
authors.initials: CC
authors.lastname: Elmasian
authors.forename: Nora
authors.initials: N
authors.lastname: Salvador
authors.forename: Michael
authors.initials: M
authors.lastname: Lum
authors.forename: Barbara
authors.initials: B
authors.lastname: Sternfeld
authors.forename: Charles P
authors.initials: CP
authors.lastname: Quesenberry
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology* / Q000517:prevention & control; D016640:Diabetes, Gestational / Q000378:metabolism; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007223:Infant; D007774:Lactation / Q000502:physiology*; D050356:Lipid Metabolism; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors; D012959:Socioeconomic Factors; D013997:Time Factors
chemical_list: D001786:Blood Glucose