title: Cross-national comparison of socioeconomic inequalities in obesity in the United States and Canada.
abstract: BACKGROUND
  Prior cross-national studies of socioeconomic inequalities in obesity have only compared summary indices of inequality but not specific, policy-relevant dimensions of inequality: (a) shape of the socioeconomic gradient in obesity, (b) magnitude of differentials in obesity across socioeconomic levels and, (c) level of obesity at any given socioeconomic level. We use unique data on two highly comparable societies - U.S. and Canada - to contrast each of these inequality dimensions.
  
  
  METHODS
  Data came from the 2002/2003 Joint Canada/U.S. Survey of Health. We calculated adjusted prevalence ratios (APRs) for obesity (compared to normal weight) by income quintile and education group separately for both nations and, between Canadians and Americans in the same income or education group.
  
  
  RESULTS
  In the U.S., every socioeconomic group except the college educated had significant excess prevalence of obesity. By contrast in Canada, only those with less than high school were worse off, suggesting that the shape of the socioeconomic gradient differs in the two countries. U.S. differentials between socioeconomic levels were also larger than in Canada (e.g., PR quintile 1 compared to quintile 5 was 1.82 in the U.S. [95 % CI: 1.52-2.19] but 1.45 in Canada [95 % CI: 1.10-1.91]). At the lower end of the socioeconomic gradient, obesity was more prevalent in the U.S. than in Canada.
  
  
  CONCLUSIONS
  Our results suggest there is variation between U.S. and Canada in different dimensions of socioeconomic inequalities in obesity. Future research should examine a broader set of nations and test whether specific policies or environmental exposures can explain these differences.
authors.affiliation: Dalla Lana School of Public Health, University of Toronto, 155 College Street, Room 566, Toronto, ON, M5T 3M7, Canada. aa.siddiqi@utoronto.ca.|Department of Health Behavior, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, Chapel Hill, NC, US. aa.siddiqi@utoronto.ca.
authors.forename: Arjumand
authors.initials: A
authors.lastname: Siddiqi
authors.affiliation: Division of Epidemiology, School of Public Health, University of California, Berkeley, 101 Haviland Hall, Berkeley, CA, 94720-7358, US. rashida.brown@berkeley.edu.
authors.forename: Rashida
authors.initials: R
authors.lastname: Brown
authors.affiliation: Department of Health Promotion and Education, College of Health, University of Utah, 1901 E. So. Campus Drive, #2120, Salt Lake City, UT, 84112, US. quynh.nguyen@health.utah.edu.
authors.forename: Quynh C
authors.initials: QC
authors.lastname: Nguyen
authors.affiliation: Department of Sociology, University of Oxford, Manor Road Building, Manor Road, Oxford, OX1 3UQ, UK. Rachel.loopstra@sociology.ox.ac.uk.
authors.forename: Rachel
authors.initials: R
authors.lastname: Loopstra
authors.affiliation: Department of Society, Human Development, and Health, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Kresge Building 7th Floor, Boston, MA, 02115, US. i.kawachi@hsph.harvard.edu.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kawachi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002170:Canada / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D054625:Healthcare Disparities / Q000706:statistics & numerical data*; D006801:Humans; D007182:Income / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology*; D015995:Prevalence; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology