title: Physical activity and the incidence of type 2 diabetes in the Shanghai women's health study.
abstract: BACKGROUND
  Leisure-time physical activity (LPA) has been associated with a reduced risk of type 2 diabetes. However, the potential effect of other types of physical activity on type 2 diabetes is still uncertain. The aim of this study was to examine the effect of occupational, commuting, daily living, and LPA on the incidence of type 2 diabetes in a cohort of middle-aged women.
  
  
  METHODS
  We prospectively followed 70,658 women who had no prior history of diabetes at study recruitment for 4.6 years. Participants completed in-person interviews at baseline that collected information on diabetes risk factors including physical activity habits. Anthropometric measurements were taken by trained interviewers. Multivariate-adjusted hazard ratios were estimated by levels of occupational, commuting, daily living, and LPA.
  
  
  RESULTS
  We documented 1973 incident cases of diabetes during 326,625 person-years of follow-up. LPA and daily living physical activity (DPA) were associated with a moderately reduced risk of type 2 diabetes. The relative risk for type 2 diabetes associated with LPA and DPA categories were 1.00, 0.89, 1.05, and 0.83, (P trend = 0.12) and 1.00, 0.98, 0.95, and 0.88, (P trend = 0.06) respectively. LPA was associated with lower risk of type 2 diabetes in employed participants (P trend = 0.09) while DPA was mainly associated with a reduction in risk in non-employed participants (P trend <0.01). While occupational physical activity was not associated with type 2 diabetes risk in this population, commuting to work was associated with a reduction in risk. A combination of DPA and LPA was associated with a reduced risk of type 2 diabetes.
  
  
  CONCLUSIONS
  This study suggests that physical activity, either from leisure-time exercise or daily activity reduces the risk of type 2 diabetes in women, supporting the current health promotion efforts encouraging both exercise and non-exercise activity levels.
authors.affiliation: Department of Medicine, Vanderbilt Epidemiology Center Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
authors.forename: Raquel
authors.initials: R
authors.lastname: Villegas
authors.forename: Xiao-Ou
authors.initials: XO
authors.lastname: Shu
authors.forename: Honglan
authors.initials: H
authors.lastname: Li
authors.forename: Gong
authors.initials: G
authors.lastname: Yang
authors.forename: Charles E
authors.initials: CE
authors.lastname: Matthews
authors.forename: Michael
authors.initials: M
authors.lastname: Leitzmann
authors.forename: Qi
authors.initials: Q
authors.lastname: Li
authors.forename: Hui
authors.initials: H
authors.lastname: Cai
authors.forename: Yu-Tang
authors.initials: YT
authors.lastname: Gao
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D015992:Body Mass Index; D002681:China / Q000453:epidemiology; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology* / Q000503:physiopathology; D004032:Diet; D004651:Employment; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D015994:Incidence; D007899:Leisure Activities; D008875:Middle Aged; D005082:Physical Exertion / Q000502:physiology*; D011446:Prospective Studies; D012307:Risk Factors; D049629:Waist-Hip Ratio