A cross-national comparison of income gradients in oral health quality-of-life in four welfare states: application of the Korpi and Palme typology
- Anne E Sanders1,
- Gary D Slade1,
- Mike T John2,
- James G Steele3,
- A Liisa Suominen-Taipale4,
- Satu Lahti5,
- Nigel M Nuttall6,
- P Finbarr Allen7
- 1 University of North Carolina at Chapel Hill, United States;
- 2 Department of Diagnostic and Biological Sciences, University of Minnesota, United States;
- 3 Department of Restorative Dentistry, School of Dental Sciences, University of Newcastle upon Tyne, United States;
- 4 National Institute of Health and Welfare, United Kingdom;
- 5 Department of Community Dentistry, Institute of Dentistry, University of Oulu, Finland;
- 6 Dental Public Health & Health Psychology, University of Dundee, Dundee Dental Hospital & School, Finland;
- 7 Department of Restorative Dentistry, University Dental School & Hospital, Wilton, Cork, United Kingdom
- E-mail: anne_sanders{at}dentistry.unc.edu
- Received 20 October 2008
- Accepted 22 February 2009
- Published Online First 6 April 2009
Abstract
Background: The extent to which different welfare states are associated with different health outcomes, we examined associations of welfare state and oral health quality-of-life in four wealthy countries. We hypothesized that targeting the poor is associated with greater income inequality in oral health quality-of-life than providing earnings-related benefits to all citizens.
Methods: Data were from nationally representative surveys in the United Kingdom (n=4064), Finland (n=5078), Germany (n=1454,) and Australia (n=2292) conducted from 1998–2002. The typology of Korpi and Palme classifies these countries into four welfare states. In each survey, subjects answered 14 questions of the Oral Health Impact Profile (OHIP-14) questionnaire which evaluates the adverse consequence of dental conditions on quality-of-life. For each country, survey estimation commands were used to create linear regression models that estimated the slope of the gradient between four quartiles of income and OHIP-14 severity scores. Parameter estimates for income gradients were contrasted across countries using Wald chi-square tests specifying a critical P-value of 0.008, equivalent to a Bonferroni correction of P<0.05 for the six pairwise tests.
Results: Statistically significant income gradients in OHIP-14 severity scores were found in all countries except Germany. A global test confirmed a significant cross-national difference in the magnitude of income gradients. In Australia, where a flat rate of benefits targeted the poor, the mean OHIP severity score reduced by 1.7 units (95% confidence interval: -2.15, -1.34) with each increasing quartile of household income, a significantly steeper gradient than in other countries.
Conclusion: The coverage and generosity of welfare state benefits appear to influence levels of inequality in population oral health quality-of-life.
