International study of temperature, heat and urban mortality: The 'ISOTHURM' project

Anthony J. McMichael, Paul Wilkinson, R. Sari Kovats*, Sam Pattenden, Shakoor Hajat, Ben Armstrong, Nitaya Vajanapoom, Emilia M. Niciu, Hassan Mahomed, Chamnong Kingkeow, Mitja Kosnik, Marie S. O'Neill, Isabelle Romieu, Matiana Ramirez-Aguilar, Mauricio L. Barreto, Nelson Gouveia, Bojidar Nikiforov

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    471 Citations (Scopus)


    Background: This study describes heat- and cold-related mortality in 12 urban populations in low- and middle-income countries, thereby extending knowledge of how diverse populations, in non-OECD countries, respond to temperature extremes. Methods: The cities were: Delhi, Monterrey, Mexico City, Chiang Mai, Bangkok, Salvador, São Paulo, Santiago, Cape Town, Ljubljana, Bucharest and Sofia. For each city, daily mortality was examined in relation to ambient temperature using autoregressive Poisson models (2- to 5-year series) adjusted for season, relative humidity, air pollution, day of week and public holidays. Results: Most cities showed a U-shaped temperature-mortality relationship, with clear evidence of increasing death rates at colder temperatures in all cities except Ljubljana, Salvador and Delhi and with increasing heat in all cities except Chiang Mai and Cape Town. Estimates of the temperature threshold below which cold-related mortality began to increase ranged from 15°C to 29°C; the threshold for heat-related deaths ranged from 16°C to 31°C. Heat thresholds were generally higher in cities with warmer climates, while cold thresholds were unrelated to climate. Conclusions: Urban populations, in diverse geographic settings, experience increases in mortality due to both high and low temperatures. The effects of heat and cold vary depending on climate and non-climate factors such as the population disease profile and age structure. Although such populations will undergo some adaptation to increasing temperatures, many are likely to have substantial vulnerability to climate change. Additional research is needed to elucidate vulnerability within populations.

    Original languageEnglish
    Pages (from-to)1121-1131
    Number of pages11
    JournalInternational Journal of Epidemiology
    Issue number5
    Publication statusPublished - 2008


    Dive into the research topics of 'International study of temperature, heat and urban mortality: The 'ISOTHURM' project'. Together they form a unique fingerprint.

    Cite this