Residential indoor temperatures and health: A scoping review of observational studies
Janelle R Edwards, Anneclaire J. De Roos, Chima Cyril Hampo, Wanyu Huang, Emily Lincoln, Simi Hoque, Leah H. Schinasi
Abstract
Adults spend most of their time indoors, especially in higher income countries. Indoor temperature exposures can vary substantially across households, even within a single geographic area. It is therefore critical to understand links between indoor temperature exposures and health or well-being outcomes, and to understand safe maximum indoor residential temperature thresholds that support health, well-being, and comfort. We systematically identified peer-reviewed, observational studies that quantified associations between residential indoor temperatures and mortality/morbidity outcomes. We extracted information on study location; population, health or well-being outcomes; indoor temperature exposure assessment methods; and, when available, empirically quantified safe maximum indoor temperature thresholds. In total, 29 papers were included in the review. The studies were conducted in the following continents: North America (N = 10), Europe (N = 5), Asia (N = 9), Australia (N = 4), and Africa (N = 1). The most common outcomes were cardiovascular morbidity (N = 10) and respiratory morbidity (N = 8) and thermal comfort (N = 9). Exposure assessment methods included data sensors, thermometers, data-driven models, and energy-based simulations. Despite variation in exposure assessment methods and outcomes assessed, results predominately suggested that warmer indoor temperatures were associated with adverse health or well-being outcomes, although in a handful of studies, associations were either null or in the unexpected, protective direction. Empirically identified safe thresholds for indoor temperature ranged from 18 °C to 35 °C and varied according to outcome. Results from this review may be used to inform the design of future studies of associations between indoor temperatures and morbidity or mortality outcomes.