Assessment of the magnitude of geographical variations and socioeconomic contextual effects on ischaemic heart disease mortality: a multilevel survival analysis of a large Swedish cohort
- 1Community Medicine and Public Health, Department of Clinical Sciences, Malmö University Hospital, Lund University, Malmö, Sweden
- 2Inserm UMR-S 707 (Inserm-Université Pierre et Marie Curie-Paris6), Paris, France
- 3Department of Health Sciences, Malmö University Hospital, Lund University, Malmö, Sweden
- Correspondence to: Dr B Chaix UMR-S 707 Inserm-Université Pierre et Marie Curie-Parise Faculté de Médecine Saint-Antoine, 27 rue Chaligny, 75012 Paris6, France;
- Accepted 29 May 2006
Background: In a public health perspective, it is of interest to assess the magnitude of geographical variations in ischaemic heart disease (IHD) mortality and quantify the strength of contextual effects on IHD.
Objective: To investigate whether area effects vary according to the individual and contextual characteristics of the population, socioeconomic contextual influences were assessed in different age groups and within territories of differing population densities.
Design: Multilevel survival analysis of a 28-year longitudinal database.
Participants: 341 048 residents of the Scania region in Sweden, reaching age 50–79 years in 1996, followed up over 7 years.
Results: After adjustment for several individual socioeconomic indicators over the adult age, Cox multilevel models indicated geographical variations in IHD mortality and socioeconomic contextual effects on the mortality risk. However, the magnitude of geographical variations and strength of contextual effects were modified by the age of individuals and the population density of their residential area: socioeconomic contextual effects were much stronger among non-elderly than among elderly adults, and much larger within urban territories than within rural ones. As a consequence, among non-elderly residents of urban territories, the socioeconomic contextual effect was almost as large as the effect of individual 20-year cumulated income.
Conclusions: Non-elderly residents of deprived urban neighbourhoods constitute a major target for both contextual epidemiology of coronary disease and public health interventions aimed at reducing the detrimental effects of the social environment on IHD.
- ICD, International Classification of Diseases
- IDR, interdecile range
- IHD, ischaemic heart disease
- IHR, interquartile hazard ratio
- IQR, interquartile range
- MHR, median hazard ratio
Funding: This study is part of the LOMAS project (“Socioeconomic disparities in cardiovascular diseases—a longitudinal multilevel analysis”), which is funded by the Swedish Council for Working Life and Social Research (PI Juan Merlo, Dnr 2003–05809) and the Swedish Research Council (PI Juan Merlo, Dnr 2004–6155). BC is also supported by a postdoctoral grant from the French Foundation for Medical Research (SPE20041102299), by the French National Research Agency (Health-Environment program number 00153 05) and by a grant from Région Ile-de-France. MR is also supported by an ALF grant from the Swedish Government (Dnr M:B 39923/2005).
Competing interests: None.