Understanding heat stress and adverse health outcomes in vulnerable populations in Bangladesh: Can we move the needle by designing low-cost, feasible and culturally acceptable interventions?

PROJECT SUMMARY During the last two decades, nearly half a million people died each year from heat-related causes; climate change is expected to exacerbate the burden of adverse health outcomes. Heat stress has been associated with an increase in all-cause mortality, cardiovascular disease and mortality, chronic respiratory disease, lower

respiratory infection, chronic kidney disease, diabetes, adverse pregnancy outcomes, and poor mental health. In this RO1, we propose to determine personal heat stress of low-income individuals who do not have access to air conditioning, evaluate the effectiveness, acceptability, feasibility, and scalability of

building-level cooling strategies to reduce indoor heat stress among vulnerable individuals, and evaluate the impact of these interventions on heart rate. A disproportionate burden of heat-related death and disease is borne by low-income communities because they do not have access to cooling and suffer from

comorbidities that exacerbate the adverse impacts of heat stress. South Asia faces the greatest current and predicted loss in disability-adjusted life years due to heat stress, and heat stress is particularly strong in informal settlements. As such, we plan to conduct this study in informal settlements in Dhaka, Bangladesh. Our

overall hypothesis is that individuals who live in homes with corrugated iron roofs and walls are at elevated risk of heat stress and that it is possible to modify homes to prevent increases in heart rate associated with heat stress, ultimately reducing cardiovascular morbidity and mortality. Aim 1 will characterize personal heat stress

in individuals across age ranges, occupations, sex, and housing types, and examine heterogeneity in the effect of existing building variation on heat stress. Aim 2 will model building-level interventions, test their ability to cool indoor spaces, and evaluate their impact on heart rate in a randomized-controlled trial. In Phase 1, energy

modeling will be used to evaluate the cooling potential of 12 passive or active building-level infrastructure modifications, material additions, and technologies to identify six strategies with maximum effectiveness for households in informal, low-income settlements in Dhaka, Bangladesh. In Phase 2, we will implement each of

the six strategies in 17 homes to experimentally assess their impact on indoor thermal conditions and determine their feasibility and acceptability. The two most cost-effective interventions will be tested in a randomized controlled trial in 459 houses in Phase 3. Phase 3 will evaluate the impact of the interventions on

residents’ heart rate (primary outcome), blood pressure, self-reported thermal comfort, wellness, productivity, fatigue, and indoor thermal conditions (secondary outcomes).