Cunrui Huang

Background: Antimicrobial resistance (AMR) is an escalating global health crisis being worsened by climate change. Studies of temperature–AMR associations remain limited by geographic scope, time frames and linear approaches. We aimed to identify temperature thresholds where AMR dynamics shift across pathogen–drug combinations, periods and socioeconomic contexts. Methods: We analysed data from 56 countries and territories over 24 years (1999–2022), focusing on six WHO-designated ‘critical’ antibiotic-resistant pathogens. Using segmented regression models with mean ambient temperature as the primary independent variable, we divided the study period into three intervals (1999–2006, 2007–2014, 2015–2022) and incorporated 16 socioeconomic and environmental covariates. Model robustness was validated through bootstrap cross-validation with 1000 resamples. Findings: We identified distinct temperature association thresholds for each pathogen–drug combination (5.7°C–18.4°C). Below these thresholds, resistance rates consistently decreased with rising temperatures; above thresholds, responses varied by phenotype and time period. For third-generation cephalosporin-resistant Escherichia coli , each 1°C rise above 16.5°C corresponded to a 0.46% increase (95% CI 0.28% to 0.65%; pAcinetobacter baumannii ( β =−1.40, p<0.001). Interpretation: Phenotype-specific temperature association thresholds provide descriptive, hypothesis-generating reference points for understanding how AMR burden varies along the global temperature gradient. The observed temporal heterogeneity suggests complex patterns requiring long-term monitoring and climate-adaptive AMR control strategies considering both phenotype-specific temperature sensitivities and socioeconomic contexts.

Background: Children are especially vulnerable to accelerating climate change, particularly in low- and middle-income countries (LMICs). We aimed to assess the spatial distribution, temporal trends, and key factors of child health vulnerability in LMICs. Methods: Using data from 19 LMICs (2008-2022), we constructed a national-level child health vulnerability index through principal component analysis (PCA). Subsequently, we identified vulnerability driving patterns and temporal shifts for each country based on dimensional indices analysis. Finally, we applied machine learning to examine the association between vulnerability factors and under-5 mortality rates (U5MR). Findings: Between 2008 and 2022, the number of moderately to highly vulnerable countries increased from seven to ten. Three vulnerability driving patterns as exposure-driven (e.g., Bangladesh, Pakistan), adaptive‑deficit‑driven (e.g., Mali, Kenya), and adaptive-deficit-exposure-driven (e.g., Guinea, Sierra Leone) emerged. The original vulnerability factors accurately predicted U5MR using random forest models (validation R² up to 80·6%). Key protective factors included improved water sources (threshold 5·3%), full vaccination coverage (38·7%), minimum dietary diversity (22·4-25·9%), and weekly media exposure (34·4%). Key risk factors were financial barriers to healthcare (51·1%), unimproved toilet facilities (38·9-41·1%), and proportion of the population under 5 years (14·8%). Exposure factors had limited direct influence on U5MR. Interpretation: To our knowledge, this study provides the first dynamic, multidimensional framework for assessing child health vulnerability across LMICs. Additionally, the predictive power of vulnerability factors for U5MR underscores the importance of addressing child vulnerability to improve health outcomes, offering an evidence-based foundation for targeted, staged interventions.

Background: Extreme heat exposure is increasing globally due to climate change and poses a growing threat to cardiovascular health. While the short-term effects of heat exposure on acute cardiovascular events are well established, the long-term cardiovascular consequences of sustained extreme heat exposure remain unclear, particularly among older adults. Frailty may represent an important but underexplored pathway linking environmental risk factors to cardiovascular disease (CVD).Methods: We constructed a longitudinal cohort based on the nationally representative data from the China Health and Retirement Longitudinal Study between (2011–2018). Cox proportional hazards models were used to estimate associations between cumulative long-term extreme heat exposure and CVD incidence. Mediation and interaction analyses were performed to assess the role of frailty in the relationship between extreme heat exposure and CVD.Findings: Long-term extreme heat exposure has a stable, cumulative effect on CVD risk, with the effect magnified in pre-frail individuals and those with worsening frailty, who experience elevated risks of 5·9% to 9·8% per additional day. For frail individuals, cumulative exposure exceeding 60 days showed a significant synergistic interaction with frailty, accounting for 28·7% of excess CVD risk. Higher-intensity heat exposure required fewer exposure days to increase risk, decreasing from 50 to 25 days as the exposure threshold increased from the 90th to 95th percentile. Mediation analysis showed that frailty explained 14·6% of the total effect of extreme heat exposure on CVD.Interpretation: Long-term extreme heat exposure and frailty jointly contribute to CVD risk through both mediation and interaction pathways. Individuals in the pre-frailty stage represent a particularly vulnerable group and a potential target for early intervention. These findings highlight the importance of integrating climate adaptation strategies with ageing-focused CVD prevention in the context of rising global temperatures.

The online version contains supplementary material available at 10.1038/s41598-026-48668-z.

Introduction: Health impact attribution research is critical for quantifying the health burdens of anthropogenic climate change and informing evidence-based climate policies. However, current literature remains fragmented, with inconsistencies in how uncertainty is handled. This study provides a systematic synthesis of the contribution of anthropogenic climate change to health and identifies the primary methodological drivers of uncertainty in this field. Method: We systematically searched PubMed, Web of Science, and Scopus (inception to October 2025) for English-language peer-reviewed studies on health impact attribution. We conducted a narrative synthesis of contributions of anthropogenic climate change to diverse health outcomes and performed a meta-analysis to pool the attributable proportions for high temperature- and heatwave-related mortality. Additionally, we applied a structured assessment tool to categorize sources of uncertainty across the included studies. The study protocol was registered with PROSPERO (CRD420251074587). Result: We identified 25 eligible studies, of which 16 were classified as high-quality. Research predominantly focused on mortality related to climate hazards (16 studies), with a notable scarcity of data from vulnerable countries. Our synthesis indicates that anthropogenic climate change has exacerbated health burden and economic losses across most climate hazards, although it has partially mitigated cold-related mortality. Meta-analysis showed an attributable fraction of 50% (95% CI: 44·0%–56·0%) for high temperature-related deaths and 34·0% (95% CI: 19·0%–61·0%) for heatwave-related deaths. We categorized seven dimensions of uncertainty, primarily stemming from exposure-response formulations, climate model selection, and counterfactual scenario construction, yet most studies addressed fewer than two of these factors. Interpretation: This study demonstrates that a substantial proportion of current heat-related mortality is directly attributable to human-induced climate change. Our findings indicate a critical imbalance in research intensity, particularly in vulnerable regions and populations. Future research must adopt more rigorous, multi-dimensional uncertainty frameworks to ensure that climate-health assessments are both robust and actionable for policymakers.

Climate change is escalating the frequency and severity of extreme heat events, significantly augmenting disease burden through heat exposure. However, understanding of the underlying mechanisms remains insufficient, hindering the development of targeted interventions for heat related illnesses. This review summarizes the multifaceted mechanisms by which heat exposure induces systemic and organ specific damage. It elucidates how heat stress not only triggers systemic physiological dysfunction but also exacerbates specific organ injuries, thereby increasing morbidity and mortality risks across populations. These mechanisms drive shifts in disease profiles toward acute heat related illnesses, cardiovascular diseases, renal disorders, and other conditions, particularly affecting vulnerable groups. Susceptibility to heat exposure spans the entire life course, from prenatal stages to old age, and is amplified by socioeconomic disparities. The review proposes initiatives to reduce negative health outcomes and advocates for the integration of heat exposure into clinical practice guidelines, to safeguard public health in an era of unprecedented thermal challenges.