title: Dynamic relations between fast-food restaurant and body weight status: a longitudinal and multilevel analysis of Chinese adults.
abstract: BACKGROUND
  Mixed findings have been reported on the association between Western fast-food restaurants and body weight status. Results vary across study contexts and are sensitive to the samples, measures and methods used. Most studies have failed to examine the temporally dynamic associations between community exposure to fast-food restaurants and weight changes.
  
  
  METHODS
  Bayesian hierarchical regressions are used to model changes in body mass index, waist-to-height ratio (WHtR) and waist-to-hip ratio (WHpR) as a function of changes in Western fast-food restaurants in 216 communities for more than 9000 Chinese adults followed up multiple times between 2000 and 2009.
  
  
  RESULTS
  Number of Western fast-food restaurants is positively associated with subsequent increases in WHtR and WHpR among rural population. More fast-food restaurants are positively associated with a future increase in WHpR for urban women. Increased availability of fast food between two waves is related to increased WHtR for urban men over the same period. A past increase in number of fast-food restaurants is associated with subsequent increases in WHtR and WHpR for rural population.
  
  
  CONCLUSIONS
  The associations between community exposure to Western fast food and weight changes are temporally dynamic rather than static. Improved measures of exposure to community environment are needed to achieve more precise estimates and better understanding of these relationships. In light of the findings in this study and China's rapid economic growth, further investigation and increased public health monitoring is warranted since Western fast food is likely to be more accessible and affordable in the near future.
authors.affiliation: Institute for Social Research, University of Michigan, Ann Arbor, MI 48106-1248, USA. xuhongw@umich.edu
authors.forename: Hongwei
authors.initials: H
authors.lastname: Xu
authors.forename: Susan E
authors.initials: SE
authors.lastname: Short
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
mesh_terms: D000328:Adult; D000368:Aged; D001499:Bayes Theorem; D015992:Body Mass Index; D002681:China / Q000453:epidemiology; D057140:Fast Foods; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D055361:Multilevel Analysis; D009765:Obesity / Q000208:ethnology*; D012111:Residence Characteristics; D012147:Restaurants / Q000706:statistics & numerical data*; D012959:Socioeconomic Factors; D014505:Urban Population; D055105:Waist Circumference; D049629:Waist-Hip Ratio; D015430:Weight Gain / Q000208:ethnology* / Q000502:physiology; D019366:Western World