A multilevel analysis to explain self-reported adverse health effects and adaptation to urban heat: a cross-sectional survey in the deprived areas of 9 Canadian cities.

Diane Bélanger,Elhadji A Laouan Sidi,Pierre Valois,Pierre Gosselin,Belkacem Abdous

doi:10.1186/s12889-016-2749-y

Abstract

BackgroundThis study identifies the characteristics and perceptions related to the individual, the dwelling and the neighbourhood of residence associated with the prevalence of self-reported adverse health impacts and an adaptation index when it is very hot and humid in summer in the most disadvantaged sectors of the nine most populous cities of Québec, Canada, in 2011.Methods The study uses a cross-sectional design and a stratified representative sample; 3485 people (individual-level) were interviewed in their residence. They lived in 1647 buildings (building-level) in 87 most materially and socially disadvantaged census dissemination areas (DA-level). Multilevel analysis was used to perform 3-level models nested one in the other to examine individual impacts as well as the adaptation index.ResultsFor the prevalence of impacts, which is 46 %, the logistic model includes 13 individual-level indicators (including air conditioning and the adaptation index) and 1 building-level indicator. For the adaptation index, with values ranging from -3 to +3, the linear model has 10 individual-level indicators, 1 building-level indicator and 2 DA-level indicators. Of all these indicators, 9 were associated to the prevalence of impacts only and 8 to the adaptation index only.ConclusionThis 3-level analysis shows the differential importance of the characteristics of residents, buildings and their surroundings on self-reported adverse health impacts and on adaptation (other than air conditioning) under hot and humid summer conditions. It also identifies indicators specific to impacts or adaptation. People with negative health impacts from heat rely more on adaptation strategies while low physical activity and good dwelling/building insulation lead to lower adaptation. Better neighbourhood walkability favors adaptations other than air conditioning. Thus, adaptation to heat in these neighbourhoods seems reactive rather than preventive. These first multi-level insights pave the way for the development of a theoretical framework of the process from heat exposure to impacts and adaptation for research, surveillance and public health interventions at all relevant levels.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-016-2749-y) contains supplementary material, which is available to authorized users.

Highlights

This study identifies the characteristics and perceptions related to the individual, the dwelling and the neighbourhood of residence associated with the prevalence of self-reported adverse health impacts and an adaptation index when it is very hot and humid in summer in the most disadvantaged sectors of the nine most populous cities of Québec, Canada, in 2011
The 3-level model (M000:12) is adjusted for thirteen individual-level covariables and a building-level covariable. It is not influenced by the season in which the interview took place (p = 0.0580), nor by the presence of intra-urban heat islands (66 % of visited buildings were located in a heat island and 32 % within 50 metres of one, p = 0.5380), and none of the dissemination areas (DAs)-level covariables were statistically significant
The results of random parts of the analyses show that a 3-level model supports the identification of indicators associated with self-reported adverse health impacts and the adaptation index when it is very hot and humid in summer

Summary

Introduction

This study identifies the characteristics and perceptions related to the individual, the dwelling and the neighbourhood of residence associated with the prevalence of self-reported adverse health impacts and an adaptation index when it is very hot and humid in summer in the most disadvantaged sectors of the nine most populous cities of Québec, Canada, in 2011. Our study exploits the perceptual approach to estimating the adverse health impacts of heat exposure as used or recommended elsewhere [9, 12,13,14,15]. This approach has the significant advantage of considering the wide range of factors potentially having a negative effect on health but which are difficult to measure directly [12, 16] and which have to be validated [17,18,19]. The perceptual approach has been used for the evaluation of environmental exposure [22] In this regard perception of room temperature is a proximal variable of thermal comfort associated with various health problems [12, 17]. This method has recently been described as an alternative to traditional techniques for measuring ambient temperature [23]

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