Scientists' call to action: Microbes, planetary health, and the Sustainable Development Goals.

Microorganisms, including bacteria, archaea, viruses, fungi, and protists, are essential to life on Earth and the functioning of the biosphere. Here, we discuss the key roles of microorganisms in achieving the United Nations Sustainable Development Goals (SDGs), highlighting recent and emerging advances in microbial research and technology that can facilitate our transition toward a sustainable future. Given the central role of microorganisms in the biochemical processing of elements, synthesizing new materials, supporting human health, and facilitating life in managed and natural landscapes, microbial research and technologies are directly or indirectly relevant for achieving each of the SDGs. More importantly, the ubiquitous and global role of microbes means that they present new opportunities for synergistically accelerating progress toward multiple sustainability goals. By effectively managing microbial health, we can achieve solutions that address multiple sustainability targets ranging from climate and human health to food and energy production. Emerging international policy frameworks should reflect the vital importance of microorganisms in achieving a sustainable future.

Climate change, human health, and resilience in the Holocene.

Climate change is an indisputable threat to human health, especially for societies already confronted with rising social inequality, political and economic uncertainty, and a cascade of concurrent environmental challenges. Archaeological data about past climate and environment provide an important source of evidence about the potential challenges humans face and the long-term outcomes of alternative short-term adaptive strategies. Evidence from well-dated archaeological human skeletons and mummified remains speaks directly to patterns of human health over time through changing circumstances. Here, we describe variation in human epidemiological patterns in the context of past rapid climate change (RCC) events and other periods of past environmental change. Case studies confirm that human communities responded to environmental changes in diverse ways depending on historical, sociocultural, and biological contingencies. Certain factors, such as social inequality and disproportionate access to resources in large, complex societies may influence the probability of major sociopolitical disruptions and reorganizations-commonly known as "collapse." This survey of Holocene human-environmental relations demonstrates how flexibility, variation, and maintenance of Indigenous knowledge can be mitigating factors in the face of environmental challenges. Although contemporary climate change is more rapid and of greater magnitude than the RCC events and other environmental changes we discuss here, these lessons from the past provide clarity about potential priorities for equitable, sustainable development and the constraints of modernity we must address.

Urban visual intelligence: Uncovering hidden city profiles with street view images.

A longstanding line of research in urban studies explores how cities can be understood through their appearance. However, what remains unclear is to what extent urban dwellers' everyday life can be explained by the visual clues of the urban environment. In this paper, we address this question by applying a computer vision model to 27 million street view images across 80 counties in the United States. Then, we use the spatial distribution of notable urban features identified through the street view images, such as street furniture, sidewalks, building façades, and vegetation, to predict the socioeconomic profiles of their immediate neighborhood. Our results show that these urban features alone can account for up to 83% of the variance in people's travel behavior, 62% in poverty status, 64% in crime, and 68% in health behaviors. The results outperform models based on points of interest (POI), population, and other demographic data alone. Moreover, incorporating urban features captured from street view images can improve the explanatory power of these other methods by 5% to 25%. We propose "urban visual intelligence" as a process to uncover hidden city profiles, infer, and synthesize urban information with computer vision and street view images. This study serves as a foundation for future urban research interested in this process and understanding the role of visual aspects of the city.

Harnessing the potential of mutation breeding, CRISPR genome editing, and beyond for sustainable agriculture.

By 2050, the global population is projected to exceed 9.5 billion, posing a formidable challenge to ensure food security worldwide. To address this pressing issue, mutation breeding in horticultural crops, utilizing physical or chemical methods, has emerged as a promising biotechnological strategy. However, the efficacy of these mutagens can be influenced by various factors, including biological and environmental variables, as well as targeted plant materials. This review highlights the global challenges related to food security and explores the potential of mutation breeding as an indispensable biotechnological tool in overcoming food insecurity. This review also covers the emergence of CRISPR-Cas9, a breakthrough technology offering precise genome editing for the development of high-yield, stress-tolerant crops. Together, mutation breeding and CRISPR can potentially address future food demands. This review focuses into these biotechnological advancements, emphasizing their combined potential to fortify global food security in the face of a booming population.

Gender equality in medical research: A cardiology-informed examination.

Despite a perceived increase in attention to gender differences in medicine, a comprehensive assessment of gender equality research, particularly in cardiology, remains underexplored. This observational retrospective study, focusing on documents related to "Gender Equality" according to the Sustainable Development Goals, reveals cardiology as a significant area for gender equality research, albeit with a decline in publications post-2018. The analysis highlighted a concentrated effort in the United States and a considerable impact gap between gender-focused and general cardiology research. The global academic community must intensify research into gender disparities, which is essential for achieving professional gender equality and addressing the burden of cardiovascular diseases.

Peer support for people living with hepatitis B virus-A foundation for treatment expansion.

Chronic hepatitis B infection (CHB) affects 300 million people worldwide and is being targeted by the United Nations 2030 Sustainable Development Goals (SDGs) and the World Health Organisation (WHO), working towards elimination of hepatitis B virus (HBV) as a public health threat. In this piece, we explore the evidence and potential impact of peer support to enhance and promote interventions for people living with CHB. Peer support workers (PSWs) are those with lived experience of an infection, condition or situation who work to provide support for others, aiming to improve education, prevention, treatment and other clinical interventions and to reduce the physical, psychological and social impacts of disease. Peer support has been shown to be a valuable tool for improving health outcomes for people living with human immunodeficiency virus (HIV) and hepatitis C virus (HCV), but to date has not been widely available for communities affected by HBV. HBV disproportionately affects vulnerable and marginalised populations, who could benefit from PSWs to help them navigate complicated systems and provide advocacy, tackle stigma, improve education and representation, and optimise access to treatment and continuity of care. The scale up of peer support must provide structured and supportive career pathways for PSWs, account for social and cultural needs of different communities, adapt to differing healthcare systems and provide flexibility in approaches to care. Investment in peer support for people living with CHB could increase diagnosis, improve retention in care, and support design and roll out of interventions that can contribute to global elimination goals.

Enhanced nitrous oxide emission factors due to climate change increase the mitigation challenge in the agricultural sector.

Effective nitrogen fertilizer management is crucial for reducing nitrous oxide (N2O) emissions while ensuring food security within planetary boundaries. However, climate change might also interact with management practices to alter N2O emission and emission factors (EFs), adding further uncertainties to estimating mitigation potentials. Here, we developed a new hybrid modeling framework that integrates a machine learning model with an ensemble of eight process-based models to project EFs under different climate and nitrogen policy scenarios. Our findings reveal that EFs are dynamically modulated by environmental changes, including climate, soil properties, and nitrogen management practices. Under low-ambition nitrogen regulation policies, EF would increase from 1.18%-1.22% in 2010 to 1.27%-1.34% by 2050, representing a relative increase of 4.4%-11.4% and exceeding the IPCC tier-1 EF of 1%. This trend is particularly pronounced in tropical and subtropical regions with high nitrogen inputs, where EFs could increase by 0.14%-0.35% (relative increase of 11.9%-17%). In contrast, high-ambition policies have the potential to mitigate the increases in EF caused by climate change, possibly leading to slight decreases in EFs. Furthermore, our results demonstrate that global EFs are expected to continue rising due to warming and regional drying-wetting cycles, even in the absence of changes in nitrogen management practices. This asymmetrical influence of nitrogen fertilizers on EFs, driven by climate change, underscores the urgent need for immediate N2O emission reductions and further assessments of mitigation potentials. This hybrid modeling framework offers a computationally efficient approach to projecting future N2O emissions across various climate, soil, and nitrogen management scenarios, facilitating socio-economic assessments and policy-making efforts.

Interventions targeting social determinants of mental disorders and the Sustainable Development Goals: a systematic review of reviews.

Globally, mental disorders account for almost 20% of disease burden and there is growing evidence that mental disorders are socially determined. Tackling the United Nations Sustainable Development Goals (UN SDGs), which address social determinants of mental disorders, may be an effective way to reduce the global burden of mental disorders. We conducted a systematic review of reviews to examine the evidence base for interventions that map onto the UN SDGs and seek to improve mental health through targeting known social determinants of mental disorders. We included 101 reviews in the final review, covering demographic, economic, environmental events, neighborhood, and sociocultural domains. This review presents interventions with the strongest evidence base for the prevention of mental disorders and highlights synergies where addressing the UN SDGs can be beneficial for mental health.

Green Hydrogen Production From Non-Traditional Water Sources: A Sustainable Energy Solution With Hydrogen Storage and Distribution.

Green hydrogen development plays an essential role in creating a sustainable and environmentally conscious society while reducing reliance on traditional fossil fuels. Proton Exchange Membrane Water Electrolysers (PEMWEs), are sensitive to water quality, with various impurities impacting their efficiency, the quality of the hydrogen produced, and the device's lifespan. High-purity water is required for PEM electrolyzers; Type II water, which is required for commercial electrolyzers, must have a resistivity greater than 1 MΩ cm, sodium, and chloride concentrations less than 5 µg/L, and total organic carbon (TOC) content less than 50 parts per billion. The majority of electrolyzers operate on freshwater, or total dissolved solids (TDS) <0.5 g/kg, whereas brackish, rainwater, wastewater, and seawater have TDSs of 1-35 g/kg, 0.01-0.15 g/kg, 0.5-2 g/kg, and 35-45 g/kg, respectively. This critical review offers, for the first time, a comprehensive overview of relevant impurities in operating electrolyzers and their impact. The findings of this study indicate that electrolysis-based H2 processes are promising options that contribute to the H2 production capacity but require improvements to produce larger competitive volumes. In addition, the main challenges and opportunities for generating, storing, transporting, and distributing hydrogen, as well as large-scale adoption are discussed.

Extremophiles in a changing world.

Extremophiles and their products have been a major focus of research interest for over 40 years. Through this period, studies of these organisms have contributed hugely to many aspects of the fundamental and applied sciences, and to wider and more philosophical issues such as the origins of life and astrobiology. Our understanding of the cellular adaptations to extreme conditions (such as acid, temperature, pressure and more), of the mechanisms underpinning the stability of macromolecules, and of the subtleties, complexities and limits of fundamental biochemical processes has been informed by research on extremophiles. Extremophiles have also contributed numerous products and processes to the many fields of biotechnology, from diagnostics to bioremediation. Yet, after 40 years of dedicated research, there remains much to be discovered in this field. Fortunately, extremophiles remain an active and vibrant area of research. In the third decade of the twenty-first century, with decreasing global resources and a steadily increasing human population, the world's attention has turned with increasing urgency to issues of sustainability. These global concerns were encapsulated and formalized by the United Nations with the adoption of the 2030 Agenda for Sustainable Development and the presentation of the seventeen Sustainable Development Goals (SDGs) in 2015. In the run-up to 2030, we consider the contributions that extremophiles have made, and will in the future make, to the SDGs.

The Grenada Learning and Memory Scale: Psychometric features and normative data in Caribbean preschool children.

OBJECTIVE: Neuropsychological assessment of preschool children is essential for early detection of delays and referral for intervention prior to school entry. This is especially pertinent in low- and middle-income countries (LMICs), which are disproportionately impacted by micronutrient deficiencies and teratogenic exposures. The Grenada Learning and Memory Scale (GLAMS) was created for use in limited resource settings and includes a shopping list and face-name association test. Here, we present psychometric and normative data for the GLAMS in a Grenadian preschool sample. METHODS: Typically developing children between 36 and 72 months of age, primarily English speaking, were recruited from public preschools in Grenada. Trained Early Childhood Assessors administered the GLAMS and NEPSY-II in schools, homes, and clinics. GLAMS score distributions, reliability, and convergent/divergent validity against NEPSY-II were evaluated. RESULTS: The sample consisted of 400 children (190 males, 210 females). GLAMS internal consistency, inter-rater agreement, and test-retest reliability were acceptable. Principal components analysis revealed two latent factors, aligned with expected verbal/visual memory constructs. A female advantage was observed in verbal memory. Moderate age effects were observed on list learning/recall and small age effects on face-name learning/recall. All GLAMS subtests were correlated with NEPSY-II Sentence Repetition, supporting convergent validity with a measure of verbal working memory. CONCLUSIONS: The GLAMS is a psychometrically sound measure of learning and memory in Grenadian preschool children. Further adaptation and scale-up to global LMICs are recommended.

Highlighting the importance of biodiversity conservation through the Holy Qur'an.

Religious environmentalism relies upon religious texts and leadership to promote effective and long-lasting change for environmental problems, such as responsible use and conservation of natural resources and biodiversity. World religions note the importance of biodiversity and humanity's responsibility in stewarding biodiversity as a member of ecological communities. We reviewed Quranic verses that relate to biodiversity and align with United Nations Sustainable Development Goals (SDGs). The Holy Quran was reviewed in electronic and hard copy formats, and verses related to biodiversity were translated to English and tabulated by Qur'anic chapter, verse, and narrative citation. Twenty-one Qur'anic verses were identified that addressed biodiversity. Scriptures were divided into 5 groups that addressed provision of resources, governance or stewardship of resources, nature as a teacher, and human life in nature's communities or described creation of biodiversity. Qur'anic verses were aligned with 4 SDGs (goals 12-15), which address sustainable consumption of natural resources, global climate change, life in marine environments, and life in terrestrial environments, including freshwater ecosystems. This alignment demonstrates the interconnectedness of life, that conservation of biodiversity is referenced in the Quran, and how positive management of natural recourses can be beneficial to Muslim communities on local, national, and global scales. Positive movement toward ecofriendly practices, sound environmental resource use and management, biodiversity conservation, and governmental policies on conservation can be promoted through scriptures from the Holy Qur'an.

Énfasis en la importancia de la conservación de la biodiversidad con el Sagrado Corán Resumen El ambientalismo religioso depende de los textos y el liderazgo religioso para promover un cambio efectivo y duradero de los problemas ambientales, como el uso y conservación de los recursos naturales y la biodiversidad. Las religiones del mundo destacan la importancia de la biodiversidad y la responsabilidad de la humanidad en el cuidado de la biodiversidad como miembros de las comunidades ecológicas. Revisamos los versos del Corán que se relacionan con la biodiversidad y que se alinean con los Objetivos de Desarrollo Sustentable (ODGs) de las Naciones Unidas. Revisamos el Sagrado Corán en formato físico y electrónico y tradujimos al inglés los versos relacionados con la biodiversidad para luego tabularlos según la cita del capítulo, verso y narrativa del Corán. Identificamos 21 versos del Corán en los que se aborda la biodiversidad. Clasificamos las escrituras en cinco grupos de acuerdo con si abordan el suministro de recursos, la administración o cuidado de los recursos, a la naturaleza como docente y a la vida humana dentro de las comunidades naturales o si describen la creación de la biodiversidad. Los versos del Corán se alinearon con cuatro de los ODGs (del 12 al 15), lo cuales abordan el consumo sustentable de los recursos naturales, el cambio climático mundial y la vida marina y terrestre, incluyendo los ecosistemas de agua dulce. Esta alineación demuestra la interconexión de la vida, que el Corán tiene referencias a la conservación de la biodiversidad y cómo la gestión positiva de los recursos naturales puede ser benéfica para las comunidades musulmanes a escala local, nacional y mundial. El Sagrado Corán puede usarse para promover un movimiento positivo hacia las prácticas amigables con el ambiente, el uso y manejo sensato de los recursos naturales, la conservación de la biodiversidad y políticas gubernamentales para la conservación.

Multitask Deep Learning Enabling a Synergy for Cadmium and Methane Mitigation with Biochar Amendments in Paddy Soils.

Biochar has demonstrated significant promise in addressing heavy metal contamination and methane (CH4) emissions in paddy soils; however, achieving a synergy between these two goals is challenging due to various variables, including the characteristics of biochar and soil properties that influence biochar's performance. Here, we successfully developed an interpretable multitask deep learning (MTDL) model by employing a tensor tracking paradigm to facilitate parameter sharing between two separate data sets, enabling a synergy between Cd and CH4 mitigation with biochar amendments. The characteristics of biochar contribute similar weightings of 67.9% and 62.5% to Cd and CH4 mitigation, respectively, but their relative importance in determining biochar's performance varies significantly. Notably, this MTDL model excels in custom-tailoring biochar to synergistically mitigate Cd and CH4 in paddy soils across a wide geographic range, surpassing traditional machine learning models. Our findings deepen our understanding of the interactive effects of Cd and CH4 mitigation with biochar amendments in paddy soils, and they also potentially extend the application of artificial intelligence in sustainable environmental remediation, especially when dealing with multiple objectives.

Chlorine Water Taste Threshold and Acceptability among Indigenous and Non-Indigenous Populations in Rural Panama.

Although gains in access to water services over the past two decades have been large, more than two billion people still lack access to safely managed drinking water. This study examines and compares free chlorine taste and acceptability thresholds of rural Indigenous Ngäbe and rural Latino Panamanians to study if taste aversion may be a limiting factor in chlorination of community systems in Panama using the three-alternative forced choice test methodology. This study is the first to establish a best-estimate taste threshold for a rural Indigenous group and the only study in Latin America to report best-estimate taste thresholds using those methods. Median taste thresholds were 0.87 mg/L Cl2 for Indigenous Ngäbe participants (n = 82) and 1.64 mg/L Cl2 for Latino participants (n = 64), higher than both the minimum concentration for biologically safe water (0.2 mg/L) and the recommended concentration range in Panama (0.3-0.8 mg/L). Median acceptability thresholds were established much higher than taste thresholds at 3.45 mg/L Cl2. The results show that the ability to accurately taste chlorine may not be the limiting factor for adoption of safe water initiatives in remote and Indigenous communities.

Promoting Sustainable Development Goals by Optimizing City-Level Solar Photovoltaic Deployment in China.

Solar photovoltaic (PV) installations, which enable carbon neutrality, are expected to surge in the coming decades. This growth will support sustainable development goals (SDGs) via reductions in power-generation-related environmental emissions and water consumption while generating new jobs. However, where and to what extent PVs should be utilized to support SDGs must be thoroughly addressed. Here, we use multiple PV deployment scenarios to compare the benefits of PVs and related SDGs progress in 366 prefectural-level cities in China. We developed an assessment framework that integrates a PV allocation model, an electricity system optimization model, and a benefit assessment approach. We identify vast differences in PV distribution and electricity transmission and elucidate trade-offs and synergies among the SDGs under various PV implementation scenarios. The water conservation-oriented scenario yields substantial carbon reduction, air pollutant mitigation, and water saving cobenefits, leading to the greatest SDGs improvements. Prioritizing employment creation enhances job-relevant SDGs but inhibits environmental resource benefits. SDGs in less developed cities present greater progress across all scenarios. This study highlights the need to consider spatial heterogeneity and the potential trade-offs between different SDGs and regions when designing energy transition strategies.

Climate-Driven Increases in Source Water Natural Organic Matter: Implications for the Sustainability of Drinking Water Treatment.

This study presents an updated analysis spanning over two decades (1999-2023) of climate, water quality, and operational data from two drinking water facilities in Atlantic Canada that previously experienced gradual increases in the natural organic matter (NOM) concentration and brownification. The goal was to assess the impact of recent extreme weather events on acute NOM concentration increases and drinking water treatment processes. In 2023, a dry spring combined with a warm and wet summer caused NOM in the water supplies to increase by >67% (as measured by color). To mitigate increased NOM concentration, the alum dose nearly doubled in 2023 compared to that in 2022. Disinfection byproducts were elevated following the event but remained within the compliance levels. From 1999 to 2023, the two plants responded to gradual climate change impacts and brownification, with alum dose increases of between 4.1 and 8.3 times. Equivalent CO2 emissions were estimated for alum usage, which increased by 3 to 7-fold in 2023 compared to when the plants were commissioned decades prior. The plants were not only adversely impacted by climate change but also contributed to the global CO2 burden. Thus, a paradigm shift toward sustainable alternatives for NOM removal is required in the water sector, and climate change adaptation and mitigation principles are urgently needed.

Assessing the Progress toward a Water-Efficient Economy in the United States from 1985 to 2015.

United Nations Sustainable Development Goal 6 tackles the long-neglected economic dimension of water utilization by monitoring nations' water use efficiency (WUE). However, it is imperative to emphasize the need for consistent spatial-temporal subnational WUE estimates, rather than relying solely on recent national trends, which can obscure crucial water use concerns and improvement opportunities. Here, a time series analysis of national, state, and sectoral (e.g., industrial, service, and agriculture) WUE from 1980 to 2015 was developed by compiling the most comprehensive and disaggregated water and economic data from 3243 US counties and 50 US states. The US total WUE increased by 181% from 16.2 (1985) to 45.6 USD/m3 (2015), driven by service sector WUE enhancements. The increased industry and service WUEs in most states were more strongly correlated with decreased per capita water withdrawal than with economic growth. Simultaneously, reductions in agriculture WUE were observed in 18 states potentially because of the complicated interaction of diverse factors specific to local communities. Expanding WUE gaps between affluent and less affluent states, and persisting WUE gaps between water-abundant andwater-scarce states highlight the need to advance policies to support under-resourced communities in effective water planning and water pricing for advancing equitable development.

Income inequality as a determinant of neonatal mortality in the Americas during 2000-2019: implications for the attainment of Sustainable Development Goal target 3.2.

BACKGROUND: The work of the WHO Commission on the Social Determinants of Health has been fundamental to provide a conceptual framework of the social determinants of health. Based on this framework, this study assesses the relationship of income inequality as a determinant of neonatal mortality in the Americas and relates it to the achievement of the Sustainable Development Goal target 3.2 (reduce neonatal mortality to at least as low as 12 deaths per 1,000 live births). The rationale is to evaluate if income inequality may be considered a social factor that influences neonatal mortality in the Americas. METHODS: Yearly data from 35 countries in the Americas during 2000-2019 was collected. Data sources include the United Nations Inter-agency Group for Child Mortality Estimation for the neonatal mortality rate (measured as neonatal deaths per 1,000 live births) and the United Nations University World Institute for Development Economics Research for the Gini index (measured in a scale from 0 to 100). This is an ecological study that employs a linear regression model that relates the neonatal mortality rate (dependent variable) to the Gini index (independent variable), while controlling for other factors that influence neonatal mortality. Coefficient estimates and their robust standard errors were obtained using panel data techniques. RESULTS: A positive relationship between income inequality and neonatal mortality is found in countries in the Americas during the period studied. In particular, the analysis suggests that a unit increase in a country's Gini index during 2000-2019 is associated with a 0.27 (95% CI [- 0.04, 0.57], P =.09) increase in the neonatal mortality rate. CONCLUSION: The analysis suggests that income inequality may be positively associated with the neonatal mortality rate in the Americas. Nonetheless, given the modest magnitude of the estimates and Gini values and trends during 2000-2019, the findings suggest a potential limited scope for redistributive policies to support reductions in neonatal mortality in the region. Thus, policies and interventions that address higher coverage and quality of services provided by national health systems and reductions in socio-economic inequalities in health are of utmost importance.

Female genital mutilation: trends, economic burden of delay and basis for public health interventions.

BACKGROUND: The practice of female genital mutilation (FGM) is a health and social problem. Millions of girls and women have undergone FGM or will soon, and more information is needed to effectively reduce the practice. The aim of this research is to provide an overview of the FGM trendlines, the inequality of its prevalence, and the economic burden. The findings shed light on 30-year trends and the impact of the pandemic on planned efforts to reduce FGM which helps with public health interventions. METHODS: Temporal trend analysis, and graphical analysis were used to assess the change and inequality over the last 30 years. We included 27 countries in which FGM is prevalent. We calculated the extra economic burden of delayed interventions to reduce FGM like COVID-19. RESULTS: For the 27 countries analyzed for temporal trendlines, 13 countries showed no change over time while 14 had decreasing trends. Among the 14, nine countries, Uganda, Togo, Ghana, Benin, Kenya, Nigeria, Central African Republic, Chad, and Ethiopia had high year-decrease (CAGR - 1.01 and - 10.26) while five, Côte d'Ivoire, Egypt, Gambia, Djibouti, and Mali had low year-decrease (CAGR>-1 and < 0). Among these five are the highest FGM prevalence similar distribution regardless the wealth quintiles or residence. There is an economic burden of delay or non-decline of FGM that could be averted. CONCLUSION: Findings indicate that some countries show a declining trend over time while others not. It can be observed that there is heterogeneity and homogeneity in the FGM prevalence within and between countries which may indicate inequality that deserves further investigation. There is considerable economic burden due to delays in the implementation of interventions to reduce or eliminate FGM. These insights can help in the preparation of public health interventions.

Rural‒urban disparities in household catastrophic health expenditure in Bangladesh: a multivariate decomposition analysis.

BACKGROUND: Rural‒urban disparity in catastrophic healthcare expenditure (CHE) is a well-documented challenge in low- and middle-income countries, including Bangladesh, limiting financial protection and hindering the achievement of the Universal Health Coverage target of the United Nations Sustainable Development Goals. However, the factors driving this divide remain poorly understood. Therefore, this study aims to identify the key determinants of the rural‒urban disparity in CHE incidence in Bangladesh and their changes over time. METHODS: We used nationally representative data from the latest three rounds of the Bangladesh Household Income and Expenditure Survey (2005, 2010, and 2016). CHE incidence among households seeking healthcare was measured using the normative food, housing, and utilities method. To quantify covariate contributions to the rural‒urban CHE gap, we employed the Oaxaca-Blinder multivariate decomposition approach, adapted by Powers et al. for nonlinear response models. RESULTS: CHE incidence among rural households increased persistently during the study period (2005: 24.85%, 2010: 25.74%, 2016: 27.91%) along with a significant (p-value ≤ 0.01) rural‒urban gap (2005: 9.74%-points, 2010: 13.94%-points, 2016: 12.90%-points). Despite declining over time, substantial proportions of CHE disparities (2005: 87.93%, 2010: 60.44%, 2016: 61.33%) are significantly (p-value ≤ 0.01) attributable to endowment differences between rural and urban households. The leading (three) covariate categories consistently contributing significantly (p-value ≤ 0.01) to the CHE gaps were composition disparities in the lowest consumption quintile (2005: 49.82%, 2010: 36.16%, 2016: 33.61%), highest consumption quintile (2005: 32.35%, 2010: 15.32%, 2016: 18.39%), and exclusive reliance on informal healthcare sources (2005: -36.46%, 2010: -10.17%, 2016: -12.58%). Distinctively, the presence of chronic illnesses in households emerged as a significant factor in 2016 (9.14%, p-value ≤ 0.01), superseding the contributions of composition differences in household heads with no education (4.40%, p-value ≤ 0.01) and secondary or higher education (7.44%, p-value ≤ 0.01), which were the fourth and fifth significant contributors in 2005 and 2010. CONCLUSIONS: Rural‒urban differences in household economic status, educational attainment of household heads, and healthcare sources were the key contributors to the rural‒urban CHE disparity between 2005 and 2016 in Bangladesh, with chronic illness emerging as a significant factor in the latest period. Closing the rural‒urban CHE gap necessitates strategies that carefully address rural‒urban variations in the characteristics identified above.