Effect modification of temperature-related mortality by city socioeconomic and demographic characteristics

Keywords: climate change and health, health disparities, urban health
Abstract Type: Virtual Paper Abstract

Abstract

Background: In Latin America, non-optimal ambient temperatures contribute to excess mortality. However, little is known about area-level characteristics that confer vulnerability to temperature-related mortality.

Objectives: Explore city-level socioeconomic and demographic characteristics associated with temperature-related mortality in Latin American cities.

Methods: The dependent variables quantify city-specific associations between temperature and mortality: heat- and cold-related excess death fractions (EDF, or percentages of total deaths attributed to cold/hot temperatures), and the relative mortality risk associated with 1°C difference in temperature in 325 cities during 2002-2015. Random effects meta-regressions were used to investigate whether EDFs and RRs associated with heat and cold varied by city-level characteristics, including population size, population density, built-up area, age-standardized mortality rate, poverty, living conditions, education, income inequality, and residential segregation.

Results: We find limited effect modification of cold-related mortality by area-level characteristics and several unexpected associations for heat-related mortality. Cities in the highest compared to the lowest tertile of income inequality have all-age cold-related excess mortality that is 3.45 percentage points higher (95%CI: 0.33,6.56). Higher poverty and segregation are also associated with higher cold EDFs among those 65+. Cities with high poverty and income inequality experience smaller heat EDFs compared to cities with little poverty and income inequality.

Discussion: Evidence of effect modification of temperature-related mortality in Latin American cities was limited. Socioeconomic deprivation may impact cold-related mortality, particularly among the elderly. Findings of higher levels of poverty and income inequality associated with lower heat-related mortality deserve further investigation given the increasing importance of urban adaptation to climate change.