title: Adherence to healthy lifestyle and risk of gestational diabetes mellitus: prospective cohort study.
abstract: OBJECTIVE
  To quantify the association between a combination of healthy lifestyle factors before pregnancy (healthy body weight, healthy diet, regular exercise, and not smoking) and the risk of gestational diabetes.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Nurses' Health Study II, United States.
  
  
  METHODS
  20,136 singleton live births in 14,437 women without chronic disease.
  
  
  METHODS
  Self reported incident gestational diabetes diagnosed by a physician, validated by medical records in a previous study.
  
  
  RESULTS
  Incident first time gestational diabetes was reported in 823 pregnancies. Each lifestyle factor measured was independently and significantly associated with risk of gestational diabetes. The combination of three low risk factors (non-smoker, ≥ 150 minutes a week of moderate to vigorous physical activity, and healthy eating (top two fifths of Alternate Healthy Eating Index-2010 adherence score)) was associated with a 41% lower risk of gestational diabetes compared with all other pregnancies (relative risk 0.59, 95% confidence interval 0.48 to 0.71). Addition of body mass index (BMI) <25 before pregnancy (giving a combination of four low risk factors) was associated with a 52% lower risk of gestational diabetes compared with all other pregnancies (relative risk 0.48, 0.38 to 0.61). Compared with pregnancies in women who did not meet any of the low risk lifestyle factors, those meeting all four criteria had an 83% lower risk of gestational diabetes (relative risk 0.17, 0.12 to 0.25). The population attributable risk percentage of the four risk factors in combination (smoking, inactivity, overweight, and poor diet) was 47.5% (95% confidence interval 35.6% to 56.6%). A similar population attributable risk percentage (49.2%) was observed when the distributions of the four low risk factors from the US National Health and Nutrition Examination Survey (2007-10) data were applied to the calculation.
  
  
  CONCLUSIONS
  Adherence to a low risk lifestyle before pregnancy is associated with a low risk of gestational diabetes and could be an effective strategy for the prevention of gestational diabetes.
authors.affiliation: Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20852, USA zhangcu@mail.nih.gov.
authors.forename: Cuilin
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Departments of Nutrition and Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA.
authors.forename: Deirdre K
authors.initials: DK
authors.lastname: Tobias
authors.affiliation: Departments of Nutrition and Epidemiology, Harvard 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: Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20852, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Bao
authors.affiliation: Departments of Nutrition and Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA.
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.affiliation: Departments of Nutrition and Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA.
authors.forename: Sylvia H
authors.initials: SH
authors.lastname: Ley
authors.affiliation: Departments of Nutrition and Epidemiology, Harvard 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
mesh_terms: D000328:Adult; D015331:Cohort Studies; D016640:Diabetes, Gestational / Q000453:epidemiology* / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008019:Life Style; D010349:Patient Compliance / Q000706:statistics & numerical data*; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors; D055815:Young Adult