Characteristics of the neighbourhood and dwelling most strongly associated with the harmful health effects of heat in low-income areas

Objective: To identify the characteristics of the dwelling and neighbourhood of residence, adjusted for health characteristics, of the people who feel more the harmful impacts of heat on their health, during summer, in the most disadvantaged neighbourhoods of the 9 largest cities in the province of Québec (Canada).

Methods: The study is a cross-sectional study by stratified sample. For each of the cities studied, the 2-step selection procedure produced representative samples. 3,485 people were interviewed in their residences, by means of a questionnaire. The data were weighted to ensure calibration of the survey frequencies on the theoretical frequencies (population). The analyses take into account these weights and the sampling plan.

Results: The prevalence of impacts was 46%; the prevalence of the impacts that led to a health professional being consulted was 12%. In both cases, six indicators were determinant, independent of age, namely dissatisfaction with the temperature inside the dwelling in summer, the perception that the neighbourhood of residence is polluted due to the density of urban traffic, as well as four indicators of state of health. The latter were chronic multimorbidity, a state of health perceived as poor or fair, daily or almost daily perceived stress, and being on long-term disability due to a disease or handicap.

Conclusion: The prevalence of heat-related impacts was very high in these neighbourhoods located in intra-urban heat islands. The few indicators that emerged from this study will help to identify, from existing or future population studies and basic spatial data, subgroups at high risk of suffering the harmful consequences of oppressive heat. This can lead to better targeted interventions by public authorities.