title: Birth weight and later life adherence to unhealthy lifestyles in predicting type 2 diabetes: prospective cohort study.
abstract: OBJECTIVE
  To prospectively assess the joint association of birth weight and established lifestyle risk factors in adulthood with incident type 2 diabetes and to quantitatively decompose the attributing effects to birth weight only, to adulthood lifestyle only, and to their interaction.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Health Professionals Follow-up Study (1986-2010), Nurses' Health Study (1980-2010), and Nurses' Health Study II (1991-2011).
  
  
  METHODS
  149,794 men and women without diabetes, cardiovascular disease, or cancer at baseline.
  
  
  METHODS
  Incident cases of type 2 diabetes, identified through self report and validated by a supplementary questionnaire. Unhealthy lifestyle was defined on the basis of body mass index, smoking, physical activity, alcohol consumption, and the alternate healthy eating index.
  
  
  RESULTS
  During 20-30 years of follow-up, 11,709 new cases of type 2 diabetes were documented. The multivariate adjusted relative risk of type 2 diabetes was 1.45 (95% confidence interval 1.32 to 1.59) per kg lower birth weight and 2.10 (1.71 to 2.58) per unhealthy lifestyle factor. The relative risk of type 2 diabetes associated with a combination of per kg lower birth weight and per unhealthy lifestyle factor was 2.86 (2.26 to 3.63), which was more than the addition of the risk associated with each individual factor, indicating a significant interaction on an additive scale (P for interaction < 0.001). The attributable proportions of joint effect were 22% (95% confidence interval 18.3% to 26.4%) to lower birth weight alone, 59% (57.1% to 61.5%) to unhealthy lifestyle alone, and 18% (13.9% to 21.3%) to their interaction.
  
  
  CONCLUSIONS
  Most cases of type 2 diabetes could be prevented by the adoption of a healthier lifestyle, but simultaneous improvement of both prenatal and postnatal factors could further prevent additional cases.
authors.affiliation: Department of Nutrition, Harvard T H Chan School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA yanping@hsph.harvard.edu.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Nutrition, Harvard T H Chan School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA.
authors.forename: Sylvia H
authors.initials: SH
authors.lastname: Ley
authors.affiliation: Department of Nutrition, Harvard T H Chan School of Public Health, 665 Huntington Avenue, 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, 665 Huntington Avenue, Boston, MA 02115, USA Division of Preventive Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston.
authors.forename: Stephanie E
authors.initials: SE
authors.lastname: Chiuve
authors.affiliation: Department of Epidemiology, Harvard T H Chan School of Public Health, Boston Department of Biostatistics, Harvard T H Chan School of Public Health, Boston.
authors.forename: Tyler J
authors.initials: TJ
authors.lastname: VanderWeele
authors.affiliation: Department of Epidemiology, Harvard T H Chan School of Public Health, Boston Connors Center for Women's Health and Gender Biology, Brigham and Women's Hospital, Harvard Medical School, Boston.
authors.forename: Janet W
authors.initials: JW
authors.lastname: Rich-Edwards
authors.affiliation: Department of Epidemiology, Harvard T H Chan School of Public Health, Boston Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston Renal Division, Department of Medicine, Brigham and Women's Hospital, Boston.
authors.forename: Gary C
authors.initials: GC
authors.lastname: Curhan
authors.affiliation: Department of Nutrition, Harvard T H Chan School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA Department of Epidemiology, Harvard T H Chan School of Public Health, Boston Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston.
authors.forename: Walter C
authors.initials: WC
authors.lastname: Willett
authors.affiliation: Division of Preventive Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston Department of Epidemiology, Harvard T H Chan School of Public Health, Boston.
authors.forename: JoAnn E
authors.initials: JE
authors.lastname: Manson
authors.affiliation: Department of Nutrition, Harvard T H Chan School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA Department of Epidemiology, Harvard T H Chan School of Public Health, Boston Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston.
authors.forename: Frank B
authors.initials: FB
authors.lastname: Hu
authors.affiliation: Department of Nutrition, Harvard T H Chan School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA Department of Epidemiology, Harvard T H Chan School of Public Health, Boston Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston yanping@hsph.harvard.edu.
authors.forename: Lu
authors.initials: L
authors.lastname: Qi
mesh_terms: D000328:Adult; D000368:Aged; D000428:Alcohol Drinking; D001724:Birth Weight; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000209:etiology*; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D008019:Life Style; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking; D014481:United States / Q000453:epidemiology