Affiliation: | Department of Epidemiology and Public Health, University College London Medical School, London, England (Dr Hemingway and Mr Shipley); and Outcomes and Equity Research, National Research and Development Centre for Welfare and Health (Drs McCallum, Manderbacka, and Keskimäki), and Population Research Unit, Department of Sociology, University of Helsinki (Dr Martikainen), Helsinki, Finland. |