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2019
Green, H, Bailey J, Schwarz L, Vanos J, Ebi K, Benmarhnia T.  2019.  Impact of heat on mortality and morbidity in low and middle income countries: A review of the epidemiological evidence and considerations for future research. Environmental Research. 171:80-91.   10.1016/j.envres.2019.01.010   AbstractWebsite

Heat waves and high air temperature are associated with increased morbidity and mortality. However, the majority of research conducted on this topic is focused on high income areas of the world. Although heat waves have the most severe impacts on vulnerable populations, relatively few studies have studied their impacts in low and middle income countries (LMICs). The aim of this paper is to review the existing evidence in the literature on the impact of heat on human health in LMICs. We identified peer-reviewed epidemiologic studies published in English between January 1980 and August 2018 investigating potential associations between high ambient temperature or heat waves and mortality or morbidity. We selected studies according to the following criteria: quantitative studies that used primary and/or secondary data and report effect estimates where ambient temperature or heat waves are the main exposure of interest in relation to human morbidity or mortality within LMICs. Of the total 146 studies selected, eighty-two were conducted in China, nine in other countries of East Asia and the Pacific, twelve in South Asia, ten in Sub-Saharan Africa, eight in the Middle East and North Africa, and seven in each of Latin America and Europe. The majority of studies (92.9%) found positive associations between heat and human morbidity/mortality. Additionally, while outcome variables and study design differed greatly, most utilized a time-series study design and examined overall heath related morbidity/mortality impacts in an entire population, although it is notable that the selected studies generally found that the elderly, women, and individuals within the low socioeconomic brackets were the most vulnerable to the effects of high temperature. By highlighting the existing evidence on the impact of extreme heat on health in LMICs, we hope to determine data needs and help direct future studies in addressing this knowledge gap. The focus on LMICs is justified by the lack of studies and data studying the health burden of higher temperatures in these regions even though LMICs have a lower capacity to adapt to high temperatures and thus an increased risk.

2018
Benmarhnia, T, Alexander S, Price K, Smargiassi A, King N, Kaufman JS.  2018.  The heterogeneity of vulnerability in public health: a heat wave action plan as a case study. Critical Public Health. 28:619-625.   10.1080/09581596.2017.1322176   AbstractWebsite

The concept of vulnerability is frequently used in public health policies to develop tailored interventions or dedicate proportionately more resources to certain sub-populations. However, once segments of the population are identified as vulnerable, they are rarely consulted regarding whether this label is acceptable before instituting interventions. Instead, it is implicitly assumed that the targeted individuals identify themselves as vulnerable and experience an unambiguous and consistent need for public health assistance. In this paper, using public health interventions during heat waves as a case study, we question such assumptions. A qualitative study was conducted in Montreal, Canada involving two focus groups among populations specifically targeted by the heat action plan as vulnerable: one composed of individuals diagnosed with schizophrenia, and one composed of individuals who have alcohol or drug addictions. Findings revealed significant heterogeneity in the definition and experience of vulnerability as it is used in the context of a heat action plan in Montreal. We found differences between the two focus groups in several areas including sources of information they had access to within the heat action plan measures and their perspectives regarding the appropriateness of specific measures in the heat action plan. We then observed differences within each of the focus groups in several areas including their social networks relationships. The concept of vulnerability is often used in public health policies. Yet, while this concept may be convenient for shaping policies to reduce inequalities in health, the heterogeneity of populations defined as vulnerable should not be underestimated.

2017
Benmarhnia, T, Kihal-Talantikite W, Ragettli MS, Deguen S.  2017.  Small-area spatiotemporal analysis of heatwave impacts on elderly mortality in Paris: A cluster analysis approach. Science of the Total Environment. 592:288-294.   10.1016/j.scitotenv.2017.03.102   AbstractWebsite

Background: Heat-waves have a substantial public health burden. Understanding spatial heterogeneity at a fine spatial scale in relation to heat and related mortality is central to target interventions towards vulnerable communities. Objectives: To determine the spatial variability of heat-wave-related mortality risk among elderly in Paris, France at the census block level. We also aimed to assess area-level social and environmental determinants of high mortality risk within Paris. Methods: We used daily mortality data from 2004 to 2009 among people aged >65 at the French census block level within Paris. We used two heat wave days' definitions that were compared to non-heat wave days. A Bernoulli cluster analysis method was applied to identify high risk clusters of mortality during heat waves. We performed random effects meta-regression analyses to investigate factors associated with the magnitude of the mortality risk. Results: The spatial approach revealed a spatial aggregation of death cases during heat wave days. We found that small scale chronic PM10 exposure was associated with a 0.02 (95% CI: 0.001; 0.045) increase of the risk of dying during a heat wave episode. We also found a positive association with the percentage of foreigners and the percentage of labor force, while the proportion of elderly people living in the neighborhoodwas negatively associated. We also found that green space density had a protective effect and inversely that the density of constructed feature increased the risk of dying during a heat wave episode. Conclusion: We showed that a spatial variation in terms of heat-related vulnerability exists within Paris and that it can be explained by some contextual factors. This study can be useful for designing interventions targeting more vulnerable areas and reduce the burden of heat waves. (C) 2017 Elsevier B.V. All rights reserved.