title: Income inequality and periodontal diseases in rich countries: an ecological cross-sectional study.
abstract: There are adverse effects of income inequality on morbidity and mortality. This relationship has not been adequately examined in relation to oral health.
  
  
  OBJECTIVE
  To examine the relationship between income inequality and periodontal disease in rich countries.
  
  
  METHODS
  Adults aged 35-44 years in 17 rich countries with populations of more than 2 million.
  
  
  METHODS
  National level data on periodontal disease, income inequality and absolute national income were collected from 17 rich countries with populations of more than 2m. Pearson and partial correlations were used to examine the relationship between income inequality and percentage of 35-44-year-old adults with periodontal pockets > or = 4 mm and > or = 6 mm deep, adjusting for absolute national income.
  
  
  RESULTS
  Higher levels of income inequality were significantly associated with higher levels of periodontal disease, independently of absolute national income. Absolute income was not associated with levels of periodontal disease in these 17 rich countries.
  
  
  CONCLUSIONS
  Income inequality appears to be an important contextual determinant of periodontal disease. The results emphasise the importance of relative income rather than absoluteincome in relation to periodontal disease in rich countries.
authors.affiliation: Department of Epidemiology and Public Health, University College London, London, UK. w.sabbah@ucl.ac.uk
authors.forename: Wael
authors.initials: W
authors.lastname: Sabbah
authors.forename: Aubrey
authors.initials: A
authors.lastname: Sheiham
authors.forename: Eduardo
authors.initials: E
authors.lastname: Bernabé
mesh_terms: D000328:Adult; D044362:Australasia / Q000453:epidemiology; D003430:Cross-Sectional Studies; D019049:Developed Countries / Q000191:economics; D005060:Europe / Q000453:epidemiology; D005202:Asia, Eastern / Q000453:epidemiology; D059066:Gross Domestic Product; D054624:Health Status Disparities; D006801:Humans; D007182:Income / Q000706:statistics & numerical data*; D010512:Periodontal Index; D010514:Periodontal Pocket / Q000191:economics / Q000453:epidemiology*; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology