Trends in geographic mortality inequalities and their association with population changes in France, 1975-2006.

BACKGROUND: Although some studies have reported that population change is associated with spatial mortality inequalities, few of them have tried to take a dynamic approach to the association. The aim of this study was to explore and interpret the ecological association between the change in cause-specific mortality inequalities and population change over a 30-year period in areas exhibiting different deprivation and urbanization levels in France. METHODS: The French communes were classified by category of demographic change during the period 1962-2006. The changes in standardized mortality ratios were analysed by category over 5 inter-censal periods, taking into account degree of urbanization and deprivation quintile. The magnitude and significance of the associations for various causes of death were estimated using a Generalised Estimating Equation Poisson model. RESULTS: Overall, the change in relative mortality was negatively associated with population growth. For a compound annual population growth rate of 1% in 1990-99, the standardized mortality ratios decreased, on average, by 2.1% (95% confidence interval: -1.45 to -2.72). The association was stronger in urban areas, and reversed in the least deprived areas. The association was stronger and more significant for men, subjects aged less than 65 years and alcohol-related and violent deaths. CONCLUSION: This study highlights the significance of dynamic approaches. Population growth was associated with a decrease in relative mortality level; the direction and strength of the association varied depending on the socio-territorial characteristics. As is the case for English-speaking countries, in France, population growth may be considered a component of current social dynamics that are not measured by usual indicators.