title: The association between obesity and back pain in nine countries: a cross-sectional study.
abstract: BACKGROUND
  The association between obesity and back pain has mainly been studied in high-income settings with inconclusive results, and data from older populations and developing countries are scarce. The aim of this study was to assess this association in nine countries in Asia, Africa, Europe, and Latin America among older adults using nationally-representative data.
  
  
  METHODS
  Data on 42116 individuals ≥50 years who participated in the Collaborative Research on Ageing in Europe (COURAGE) study conducted in Finland, Poland, and Spain in 2011-2012, and the World Health Organization's Study on Global Ageing and Adult Health (SAGE) conducted in China, Ghana, India, Mexico, Russia, and South Africa in 2007-2010 were analysed. Information on measured height and weight available in the two datasets was used to calculate Body Mass Index (BMI). Self-reported back pain occurring in the past 30 days was the outcome. Multivariable logistic regression analysis was used to assess the association between BMI and back pain.
  
  
  RESULTS
  The prevalence of back pain ranged from 21.5% (China) to 57.5% (Poland). In the multivariable analysis, compared to BMI 18.5-24.9 kg/m(2), significantly higher odds for back pain were observed for BMI ≥35 kg/m(2) in Finland (OR 3.33), Russia (OR 2.20), Poland (OR 2.03), Spain (OR 1.56), and South Africa (OR 1.48); BMI 30.0-34.0 kg/m(2) in Russia (OR 2.76), South Africa (OR 1.51), and Poland (OR 1.47); and BMI 25.0-29.9 kg/m(2) in Russia (OR 1.51) and Poland (OR 1.40). No significant associations were found in the other countries.
  
  
  CONCLUSIONS
  The strength of the association between obesity and back pain may vary by country. Future studies are needed to determine the factors contributing to differences in the associations observed.
authors.affiliation: Research and Development Unit, Parc Sanitari Sant Joan de Déu, Fundació Sant Joan de Déu, Dr. Antoni Pujadas, 42, Sant Boi de Llobregat, Barcelona, Spain. a.koyanagi@pssjd.org.|Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Salud Mental, Cibersam, Spain. a.koyanagi@pssjd.org.
authors.forename: Ai
authors.initials: A
authors.lastname: Koyanagi
authors.affiliation: Department of Human Ecology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan. andrew.stickley@sh.se.|Stockholm Centre on Health of Societies in Transition (SCOHOST), Södertörn University, Huddinge, Sweden. andrew.stickley@sh.se.
authors.forename: Andrew
authors.initials: A
authors.lastname: Stickley
authors.affiliation: Research and Development Unit, Parc Sanitari Sant Joan de Déu, Fundació Sant Joan de Déu, Dr. Antoni Pujadas, 42, Sant Boi de Llobregat, Barcelona, Spain. noe.garin@pssjd.org.|Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Salud Mental, Cibersam, Spain. noe.garin@pssjd.org.
authors.forename: Noe
authors.initials: N
authors.lastname: Garin
authors.affiliation: Department of Psychiatry, Universidad Autónoma de Madrid, Madrid, Spain. marta.miret@uam.es.|Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Salud Mental, Cibersam, Spain. marta.miret@uam.es.|Department of Psychiatry, Hospital Universitario de La Princesa, Instituto de Investigación Sanitaria Princesa (IP), Madrid, Spain. marta.miret@uam.es.
authors.forename: Marta
authors.initials: M
authors.lastname: Miret
authors.affiliation: Department of Psychiatry, Universidad Autónoma de Madrid, Madrid, Spain. joseluis.ayuso@uam.es.|Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Salud Mental, Cibersam, Spain. joseluis.ayuso@uam.es.|Department of Psychiatry, Hospital Universitario de La Princesa, Instituto de Investigación Sanitaria Princesa (IP), Madrid, Spain. joseluis.ayuso@uam.es.
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Ayuso-Mateos
authors.affiliation: Department of Neurology, Public Health and Disability Unit, Neurological Institute Carlo Besta IRCCS Foundation, Milan, Italy. matilde.leonardi@istituto-besta.it.
authors.forename: Matilde
authors.initials: M
authors.lastname: Leonardi
authors.affiliation: National Institute for Health and Welfare, Helsinki, Finland. seppo.koskinen@thl.fi.
authors.forename: Seppo
authors.initials: S
authors.lastname: Koskinen
authors.affiliation: Department of Epidemiology, Jagiellonian University Medical College, Krakow, Poland. aleksander.galas@uj.edu.pl.
authors.forename: Aleksander
authors.initials: A
authors.lastname: Galas
authors.affiliation: Research and Development Unit, Parc Sanitari Sant Joan de Déu, Fundació Sant Joan de Déu, Dr. Antoni Pujadas, 42, Sant Boi de Llobregat, Barcelona, Spain. jmharo@pssjd.org.|Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Salud Mental, Cibersam, Spain. jmharo@pssjd.org.
authors.forename: Josep Maria
authors.initials: JM
authors.lastname: Haro
mesh_terms: D000368:Aged; D000375:Aging; D001416:Back Pain / Q000453:epidemiology*; D015992:Body Mass Index; D001837:Body Weights and Measures; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D014943:Global Health; D006801:Humans; D007182:Income; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology*; D057566:Self Report; D014944:World Health Organization