Association of anthropogenic heat with asthma and related symptoms among children in China: A novel index reflecting climate change

Background: Anthropogenic heat (AH) is defined as the significant release of waste heat into the environment due to human activities, serving as a controllable heat source contributing to global climate change. However, epidemiological evidence establishing a clear association between AH and childhood asthma is currently lacking. Objectives: To explore the relationship between children's exposure to AH and asthma, as well as its related symptoms. Methods: This population-based cross-sectional study, part of the National Chinese Children Health Study from 2012 to 2018, involved 188,145 children aged 6 to 18 years. We used multisource remote sensing images and ancillary data to estimate AH exposure. Data on asthma symptoms were collected through validated self-reported questionnaires. A generalized linear mixed model was applied to determine the associations. Results: Our findings indicate a positive correlation between AH exposure and asthma risk in children. An interquartile range (IQR) increase in total AH was linked to higher odds of current asthma (OR: 1.15, 95 % CI: 1.10, 1.20) after adjusting for covariates. Categorizing AH by source, industrial AH exhibited the strongest effect, with an increased risk of current asthma (OR: 1.16, 95 % CI: 1.11, 1.22). Notably, younger children exhibited stronger associations between AH exposure and asthma-related symptoms, with boys showing heightened susceptibility, particularly for persistent cough. Conclusion: This study suggests that exposure to AH may elevate the risk of asthma and related symptoms, particularly in boys and younger children. Providing a foundation for developing practical strategies to mitigate the adverse impacts of global warming on respiratory health, while also guiding the formulation and evaluation of climate action and public health policies, and supporting sustainable urban development.