How urban characteristics affect vulnerability to heat and cold: a multi-country analysis

Abstract

Background The health burden associated with temperature is expected to increase due to a warming climate. Populations living in cities are likely to be particularly at risk, but the role of urban characteristics in modifying the direct effects of temperature on health is still unclear. In this contribution, we used a multi-country dataset to study effect modification of temperature–mortality relationships by a range of city-specific indicators. Methods We collected ambient temperature and mortality daily time-series data for 340 cities in 22 countries, in periods between 1985 and 2014. Standardized measures of demographic, socio-economic, infrastructural and environmental indicators were derived from the Organisation for Economic Co-operation and Development (OECD) Regional and Metropolitan Database. We used distributed lag non-linear and multivariate meta-regression models to estimate fractions of mortality attributable to heat and cold (AF%) in each city, and to evaluate the effect modification of each indicator across cities. Results Heat- and cold-related deaths amounted to 0.54% (95% confidence interval: 0.49 to 0.58%) and 6.05% (5.59 to 6.36%) of total deaths, respectively. Several city indicators modify the effect of heat, with a higher mortality impact associated with increases in population density, fine particles (PM2.5), gross domestic product (GDP) and Gini index (a measure of income inequality), whereas higher levels of green spaces were linked with a decreased effect of heat. Conclusions This represents the largest study to date assessing the effect modification of temperature–mortality relationships. Evidence from this study can inform public-health interventions and urban planning under various climate-change and urban-development scenarios.

The role of cities in reducing the cardiovascular impacts of environmental pollution in low- and middle-income countries

“…A number of studies have shown associations between increased cardiovascular mortality and both high and low ambient temperature. A recent study of 340 cities and metropolitan areas from 22 countries (9 of which were classified as developing economies) estimated that 0.54% (95% CI: 0.49-0.58%) and 6.05% (95% CI: 5.59-6.36%) of mortality in those cities were respectively attributable to heat and cold [95]. Among the relatively few studies conducted in LMICs, high and low temperatures were associated with increased cardiovascular risk in India [96], many cities across China [97,98], and multiple countries in Latin America and sub-Saharan Africa [99][100][101][102][103].…”

“…Studies in Europe found associations between excess winter deaths from CVD and poor housing conditions, including lack of central heating and poor insulation [108,109]. A recent evaluation of 340 cities observed that the effects of heat on mortality were higher in cities with greater inequality, worse air quality, fewer green spaces, and lower availability of health services [95].…”

Towards health for future

“…Heat-related mortality is, presumably, one of the most comprehensively studied consequences of climate change (Sera et al 2019). More frequent and longer heat waves increase mortality and morbidity, as demonstrated, for example, by Cheng et al (2014) for China and Gomez-Acebo et al (2012) for the north of Spain.…”

Review of thermal comfort infused with the latest big data and modeling progresses in public health

“…Example are city population density, Gross Domestic Product (GDP), Gini Index (a measure of income inequality), and fine particles (PM2.5), etc. [47]. Therefore, in order to apply the health-temperature model and dataset to the thermal comfort study, a systematic investigation should be performed first, which is beyond the scope of this paper and will be discussed in greater details in the future [101].…”