title: Physical activity, sedentary behaviors and risk of gestational diabetes mellitus: a population-based cross-sectional study in Tianjin, China.
abstract: OBJECTIVE
  Physical activity in a nonpregnant state or before pregnancy reduces the risk of type 2 diabetes and is also associated with reduced risk of gestational diabetes mellitus (GDM). However, it is uncertain whether physical activity during pregnancy reduces the risk of GDM.
  
  
  METHODS
  Using an established universal screening system in Tianjin, China, we prospectively recruited 11 450 pregnant women within the 12th gestational week from 2010 to 2012. These women underwent a 50-g 1-h glucose challenge test (GCT) at 24-28 weeks of gestation and a 75-g 2-h oral glucose tolerance test if GCT glucose ≥7.8mmol/L. GDM was defined according to the International Association of Diabetes and Pregnancy Study Group's criteria. Self-reported physical activity in the last month was collected at GCT time using a validated questionnaire.
  
  
  RESULTS
  GDM developed in 7.3% (n=840) of the women. Women with GDM were less likely to be engaged in moderate-to-high physical activity during pregnancy than those without (79.8% vs 81.6%, P=0.191). Moderate-to-high physical activity during pregnancy was associated with decreased risk of GDM (multivariable odds ratio (OR): 0.81, 95% confidence interval (CI): 0.67-0.97). Sitting at home for 2-4h per day and >4h per day were associated with significantly increased risk of GDM (multivariable OR of sitting time for 2-4h vs <2h: 1.59, 95% CI: 1.18-2.15; OR of sitting time for >4h vs <2h: 1.73, 95% CI: 1.22-2.43).
  
  
  CONCLUSIONS
  Increased physical activity during pregnancy was associated with reduced GDM risk, whereas sedentary lifestyle was associated with increased GDM risk among Chinese pregnant women.
authors.affiliation: Department of Epidemiology and BiostatisticsSchool of Public Health, Tianjin Medical University, Tianjin, China Tianjin Women and Children's Health CentreTianjin, China.
authors.forename: Junhong
authors.initials: J
authors.lastname: Leng
authors.affiliation: Tianjin Women and Children's Health CentreTianjin, China.
authors.forename: Gongshu
authors.initials: G
authors.lastname: Liu
authors.affiliation: Tianjin Women and Children's Health CentreTianjin, China.
authors.forename: Cuiping
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Tianjin Dong Li Women and Children's Health CentreTianjin, China.
authors.forename: Shijuan
authors.initials: S
authors.lastname: Xin
authors.affiliation: Tianjin Women and Children's Health CentreTianjin, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Chen
authors.affiliation: Tianjin Women and Children's Health CentreTianjin, China.
authors.forename: Baojuan
authors.initials: B
authors.lastname: Li
authors.affiliation: Tianjin Women and Children's Health CentreTianjin, China.
authors.forename: Huiguang
authors.initials: H
authors.lastname: Tian
authors.affiliation: Population Cancer Research Program and Department of PediatricsDalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Zhijie
authors.initials: Z
authors.lastname: Yu
authors.affiliation: Centre for Vascular PreventionDanube-University Krems, Krems, Austria Diabetes Prevention UnitNational Institute for Health and Welfare, Helsinki, Finland Instituto de Investigacion Sanitaria del Hospital Universario LaPaz (IdiPAZ)Madrid, Spain Diabetes Research GroupKing Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Jaakko
authors.initials: J
authors.lastname: Tuomilehto
authors.affiliation: Chronic Disease Epidemiology LaboratoryPennington Biomedical Research Center, Baton Rouge, Louisiana, USA.
authors.forename: Gang
authors.initials: G
authors.lastname: Hu
authors.affiliation: Department of Epidemiology and BiostatisticsSchool of Public Health, Tianjin Medical University, Tianjin, China yangxilin@tmu.edu.cn yxl@hotmail.com.
authors.forename: Xilin
authors.initials: X
authors.lastname: Yang
mesh_terms: D000328:Adult; D001786:Blood Glucose; D002681:China; D003430:Cross-Sectional Studies; D016640:Diabetes, Gestational / Q000175:diagnosis / Q000209:etiology*; D015444:Exercise; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors; D057185:Sedentary Behavior
chemical_list: D001786:Blood Glucose