Age-specific vulnerability of kidney diseases to temperature: a nationwide case-crossover study

Background: Extreme temperatures are projected to increase; however, comprehensive mapping of associations between temperature extremes and kidney diseases across age groups and disease subtypes remains limited. Methods: Data were collected for all emergency department (ED) visits for kidney diseases across all ages from South Korea’s national health insurance claims between 2011 and 2019. A time-stratified case-crossover design was used to assess the association between ambient temperature and ED visits for kidney diseases. Results: The study included around 1.9 million ED visits due to kidney diseases. Heat-related risks of kidney disease–related ED visits (99th vs. 75th percentile) were highest among adults aged 50–59 years [odds ratio (OR): 1.28, 95% confidence interval (CI): 1.22–1.34), while cold-related risks (1st vs. 25th percentile) were highest among those aged 30–39 years (OR: 1.13, 95% CI: 1.05–1.20). Heat-related hospitalization risk was primarily driven by urinary tract infection among individuals in their 30s (OR: 1.37; 95% CI: 1.09–1.72) and by acute kidney injury among those in their 40s (OR: 2.29; 95% CI: 1.52–3.44). From a cost-burden perspective, urinary tract infections among adults aged ≥70 years contributed the largest medical cost burden attributable to high and low temperatures. Conclusions: This nationwide study demonstrated age- and disease subtype-specific heterogeneity in temperature-related kidney disease risks. Our findings suggest that, in addition to older adults, younger and middle-aged populations should also be primarily considered in climate change adaptation strategies targeting kidney health. © The Author(s) 2026. Published by Oxford University Press on behalf of the International Epidemiological Association. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/pages/standard-publication-reuse-rights)