Systematic review of individual-level, community-level, and healthcare system-level factors contributing to socioeconomic differences in healthcare utilisation in OECD countries with universal health coverage.

OBJECTIVES: Countries with universal health coverage (UHC) strive for equal access for equal needs without users getting into financial distress. However, differences in healthcare utilisation (HCU) between socioeconomic groups have been reported in countries with UHC. This systematic review provides an overview individual-level, community-level, and system-level factors contributing to socioeconomic status-related differences in HCU (SES differences in HCU). DESIGN: Systematic review following the Preferred Reporting Items for Systematic review and Meta-Analysis (PRISMA) guidelines. The review protocol was published in advance. DATA SOURCES: Embase, PubMed, Web of Science, Scopus, Econlit, and PsycInfo were searched on 9 March 2021 and 9 November 2022. ELIGIBILITY CRITERIA: Studies that quantified the contribution of one or more factors to SES difference in HCU in OECD countries with UHC. DATA EXTRACTION AND SYNTHESIS: Studies were screened for eligibility by two independent reviewers. Data were extracted using a predeveloped data-extraction form. Risk of bias (ROB) was assessed using a tailored version of Hoy's ROB-tool. Findings were categorised according to level and a framework describing the pathway of HCU. RESULTS: Of the 7172 articles screened, 314 were included in the review. 64% of the studies adjusted for differences in health needs between socioeconomic groups. The contribution of sex (53%), age (48%), financial situation (25%), and education (22%) to SES differences in HCU were studied most frequently. For most factors, mixed results were found regarding the direction of the contribution to SES differences in HCU. CONCLUSIONS: SES differences in HCU extensively correlated to factors besides health needs, suggesting that equal access for equal needs is not consistently accomplished. The contribution of factors seemed highly context dependent as no unequivocal patterns were found of how they contributed to SES differences in HCU. Most studies examined the contribution of individual-level factors to SES differences in HCU, leaving the influence of healthcare system-level characteristics relatively unexplored.

Does the healthcare decentralization provide better public health security capacity and health services satisfaction? An analysis of OECD countries.

PURPOSE: Decentralization has profound implications for many health systems. This study investigates the effect of health system decentralization in Organization for Economic Co-operation and Development (OECD) countries on public health security capacity and health service satisfaction. DESIGN/METHODOLOGY/APPROACH: Multiple linear regression analyses were employed for variables related to the level of health security capacity and satisfaction with the healthcare system while controlling for all socio-demographic variables from the European Social Survey, including over 44,000 respondents from 25 OECD countries. The Health Systems in Transition series of countries were used for assessing the decentralization level. FINDINGS: The result of multiple linear regression analyses showed that the level of decentralization in health systems was significantly associated with higher health security capacity (ß-coefficient 3.722, 95% confidence interval (CI) [3.536 3.908]; p=<0.001) and health service satisfaction (ß-coefficient 1.463, 95% CI [1.389 1.536]; p=<0.001) in the study. Countries with a higher level of decentralization in health policy tasks and areas were significantly likely to have higher health services satisfaction, whereas this satisfaction had a significant negative relation with the lower level of decentralization status of secondary/tertiary care services in OECD countries (ß-coefficient -5.250, 95% CI [-5.757-4.743]; p = 0.001). ORIGINALITY/VALUE: This study contributes to a better understanding of the extent to which decentralization of health services affects public health safety capacity and satisfaction with health services, whereas the level of decentralization in OECD countries varies considerably. Overall, the findings highlight the importance of public health security and satisfaction with health care delivery in assessing the effects of decentralization in health services.

Legal and regulatory instruments for NCD prevention: a scoping review and descriptive analysis of evaluations in OECD countries.

CONTEXT: Public health law is an important tool in non-communicable disease (NCD) prevention. There are different approaches available for achieving policy objectives, including government, co-, quasi- and self-regulation. However, it is often unclear what legal design features drive successes or failures in particular contexts. This scoping review undertakes a descriptive analysis, exploring the design characteristics of legal instruments that have been used for NCD prevention and implemented and evaluated in OECD countries. METHODS: A scoping review was conducted across four health and legal databases (Scopus, EMBASE, MEDLINE, HeinOnline), identifying study characteristics, legal characteristics and regulatory approaches, and reported outcomes. Included studies focused on regulation of tobacco, alcohol, unhealthy foods and beverages, and environmental pollutants. FINDINGS: We identified 111 relevant studies evaluating 126 legal instruments. Evaluation measures most commonly assessed implementation, compliance and changes to the built and lived environment. Few studies evaluated health or economic outcomes. When examining the design and governance mechanisms of the included legal instruments, government regulation was most commonly evaluated (n = 90) and most likely to be reported effective (64%). Self-regulation (n = 27) and quasi-regulation (n = 5) were almost always reported to be ineffective (93% and 100% respectively). There were few co-regulated instruments evaluated (n = 4) with mixed effectiveness. When examining public health risks, food and beverages including alcohol were more likely to be self- or quasi-regulated and reported as ineffective more often. In comparison, tobacco and environmental pollutants were more likely to have government mandated regulation. Many evaluations lacked critical information on regulatory design. Monitoring and enforcement of regulations was inconsistently reported, making it difficult to draw linkages to outcomes and reported effectiveness. CONCLUSIONS: Food and alcohol regulation has tended to be less successful in part due to the strong reliance on self- and quasi-regulation. More work should be done in understanding how government regulation can be extended to these areas. Public health law evaluations are important for supporting government decision-making but must provide more detail of the design and implementation features of the instruments being evaluated - critical information for policy-makers.

POLICY POINTS: Government regulation is reported as more effective than co-regulation, quasi-regulation or self-regulation. Voluntary approaches, including voluntary government regulation, are reported less effective due to low uptake and limited accountability. In public health law mandated government regulation should be strived for.Food and alcohol sectors are more likely to adopt self- or quasi-regulation and are frequently reported as ineffective. More work should be done to support government regulation in these areas.Many public health law evaluations are lacking critical design information for policy makers. This may make it difficult to learn from successes or failures and replicate interventions in other jurisdictions.

Energy transition and environmental stability prospects for OECD economies: The prominence role of environmental governance, and economic complexity: Does the geopolitical risk matter?

The global increase in temperature and climate change signals the need for humanity to reduce greenhouse gas emissions and to adopt eco-friendly lifestyles. The 2023 United Nations Climate Change Conference (COP28) in the UAE emphasized this, urging nations to commit to the Paris Agreement and pursue a greener, carbon-free future. In recent decades, climate change has become a critical issue, primarily because of the extensive use of fossil fuels and conventional energy resources. Economic growth has led to an increase in energy consumption and widespread environmental damage. The present study empirically explores whether any changes in environmental governance, economic complexity, geopolitical risk, and the interaction term influence energy transition and environmental stability in OECD economies over the period 1990-2021. Novel econometric methods, including Westerlund co-integration and the Method of Moments Quantile Regression (MMQR), are employed to address complexities such as cross-sectional dependency and panel causality. The key findings from the MMQR technique showed a positive link between environmental governance and economic complexity in driving sustainable energy transitions, thus bolstering environmental resilience in OECD countries. However, economic complexity counterbalances environmental stability. Significantly, geopolitical risk acts as a moderating variable, enhancing the effects of governance and complexity on sustainable energy practices and environmental stability. Based on these insights, this study recommends strategic initiatives, including investment in eco-friendly technologies, to fast-track the shift to clean energy and strengthen environmental resilience in OECD countries. These strategies align with the broader objectives of global sustainable development, offering a path towards a greener and more sustainable future.

Science at risk? Considering the importance of academic freedom for STEM research production across 17 OECD countries.

Since 2011, a declining trend in academic freedom globally has paralleled a rising tide of neo-nationalism. We use fixed effects models to examine data from the Varieties of Democracy (V-DEM) academic freedom index and bibliometric data for 17 OECD countries across nearly three decades (1981-2007) that precede the recent decline in academic freedom. We find substantial, statistically significant, positive relationships between cross-nationally comparable and longitudinal measures of academic freedom and volume of STEM publications. Additionally, academic freedom positively influenced the quality of STEM publications as measured by journal rankings. Our findings were relatively consistent across various measures of academic freedom and model specifications. We discuss implications for safeguarding academic freedom, applying neo-institutional theory, and identifying directions for future research.

The nexus among CO2 emission, health expenditure and economic development in the OECD countries: New insights from a cross-sectional ARDL model.

To find a way to realize sustainable development, this paper applied a cross-sectional ARDL (CS-ARDL) method to explore the interaction between carbon emissions, economic development, and health care expenditure for OECD countries. Firstly, we conduct a cross-sectional test to check whether the data is confronted with this issue. Secondly, we conduct a panel unit root test and cointegration test to confirm whether the ARDL-based method is suitable for our data. Thirdly, we analyze the results and provide possible explanations. Lastly, we conduct a short-term causality test to detect the connection between different variables. The main conclusion of our study includes: 1) Health care is a necessity in OECD countries. 2) Environmental deterioration places a heavy burden on health care expenditure in OECD countries. 3) Health care expenditure of last year negatively affects health care expenditure. 4) There is a short-run causality relationship from CO2, economic development, and dependency rate of youth to health care expenditure in OECD countries. Related policy proposals are provided according to our analysis of the results.

Factors influencing deceased organ donation rates in OECD countries: a panel data analysis.

OBJECTIVES: This study aims to investigate factors with a significant influence on deceased organ donation rates in Organisation for Economic Co-operation and Development (OECD) countries and determine their relative importance. It seeks to provide the necessary data to facilitate the development of more efficient strategies for improving deceased organ donation rates. DESIGN: Retrospective study. SETTING: Publicly available secondary annual data. PARTICIPANTS: The study includes 36 OECD countries as panel members for data analysis. OUTCOME MEASURES: Multivariable panel data regression analysis was employed, encompassing data from 2010 to 2018 for all investigated variables in the included countries. RESULTS: The following variables had a significant influence on deceased organ donation rates: 'opt-in' system (ß=-4.734, p<0.001, ref: 'opt-out' system), only donation after brain death (DBD) donors allowed (ß=-4.049, p=0.002, ref: both DBD and donation after circulatory death (DCD) donors allowed), number of hospital beds per million population (pmp) (ß=0.002, p<0.001), total healthcare employment pmp (ß=-0.00012, p=0.012), World Giving Index (ß=0.124, p=0.008), total tax revenue as a percentage of gross domestic product (ß=0.312, p=0.009) and percentage of population aged ≥65 years (ß=0.801, p<0.001) as well as high education population in percentage (ß=0.118, p=0.017). CONCLUSIONS: Compared with the promotion of socioeconomic factors with a positive significant impact on deceased organ donation rates, the following policies have been shown to significantly increase rates of deceased organ donation, which could be further actively promoted: the adoption of an 'opt-out' system with presumed consent for deceased organ donation and the legal authorisation of both DBD and DCD for transplantation.

Ecological footprint in the OECD countries: do energy efficiency and renewable energy matter?

Ecological footprint (EFP) measures the amount of area, that is land or sea, which is required to absorb the waste generated through human activities or to support the production of resources consumed by populations. EFP index therefore includes six dimensions that are cropland, forestland, carbon, fishing grounds, grazing land, and built-up area. Human activities have impacted the environment, leading to global warming, widespread droughts, and diseases. The present study aims to investigate the role of renewable energy (RE) and energy efficiency on the EFP index. Past researchers have widely used carbon emission (CE) to represent environmental impact, and recent studies have shown that EFP index is a better proxy of environmental degradation. Therefore, the present research differs from past studies in that it compares on how the determinants of environmental degradation affects EFP index and CE. Panel dataset of the OECD countries from 1990 to 2020 is employed. The CS-ARDL, DCCEMG, and AMG techniques, which overcome dynamics, heterogeneity, and cross-sectional dependence, are employed. The main findings depict that RE significantly reduces EFP and CE, while economic growth significantly exacerbates them. Energy efficiency reduces CE, but does not significantly affect EFP. Non-renewable energy and research & development significantly increase CE, while an insignificant positive effect is observed with EFP. This paper shows that factors that significantly influence CE may not always significantly affect the EFP index. Thus, to reduce environmental degradation it is fundamental to understand on how each dimension of EFP is influenced.

A Review of Current Approaches to Evaluating and Reimbursing New Medicines in a Subset of OECD Countries.

OBJECTIVES: The aim of this study was to review the current evaluation and funding processes for new drugs in different developed countries, to provide a comparative framework with detailed, homogeneous, and up-to-date information. METHODS: Scientific publications, reports and websites were reviewed between July and December 2021 using PubMed, Google Scholar, and grey literature sources. The main items searched were actors and processes, including timelines, characteristics of clinical and economic evaluations, participation of stakeholders, elements of price and reimbursement decisions, cost-effectiveness thresholds and specific funds. The analysed 13 countries were Australia, Canada, England, France, Germany, Italy, Japan, the Netherlands, Portugal, Scotland, South Korea, Spain and Sweden. RESULTS: Eight countries perform the assessment process separated from the pricing decision. Countries measure each drug's added therapeutic value through multi-attribute value scales, algorithms, non-prescriptive lists of criteria, or quality-adjusted life years (QALYs). Health technology assessment (HTA) methodologies differ in their outcome measures, elicitation techniques, comparators, and perspectives. The criteria used for pricing and reimbursement include humanistic, clinical, and economic aspects. Only Scotland, England, the Netherlands, Canada and Portugal use explicit efficiency thresholds. Health care professionals participate in all assessment committees, and patients are becoming increasingly involved in most countries. The official time from marketing authorisation to the completion of the evaluation and pricing processes varied from 126 to 540 days. CONCLUSIONS: Most analysed countries show a trend towards value-based approaches that consider value for money to society, but also other economic, clinical, and humanistic criteria. Good practices included robustness, transparency, independence, and participation.

Acute care pathway assessed through performance indicators during the COVID-19 pandemic in OECD countries (2020-2021): a scoping review.

BACKGROUND: The COVID-19 pandemic severely impacted care for non-COVID patients. Performance indicators to monitor acute care, timely reported and internationally accepted, lacked during the pandemic in OECD countries. This study aims to summarize the performance indicators available in the literature to monitor changes in the quality of acute care in OECD countries during the first year and a half of the pandemic (2020-July 2021) and to assess their trends. METHODS: Scoping review. Search in Embase and MEDLINE (07-07-2022). Acute care performance indicators and indicators related to acute general surgery were collected and collated following a care pathway approach. Indicators assessing identical clinical measures were grouped under a common indicator title. The trends from each group of indicators were collated (increase/decrease/stable). RESULTS: A total of 152 studies were included. 2354 indicators regarding general acute care and 301 indicators related to acute general surgery were included. Indicators focusing on pre-hospital services reported a decreasing trend in the volume of patients: from 225 indicators, 110 (49%) reported a decrease. An increasing trend in pre-hospital treatment times was reported by most of the indicators (n = 41;70%) and a decreasing trend in survival rates of out-of-hospital cardiac arrest (n = 61;75%). Concerning care provided in the emergency department, most of the indicators (n = 752;71%) showed a decreasing trend in admissions across all levels of urgency. Concerning the mortality rate after admission, most of the indicators (n = 23;53%) reported an increasing trend. The subset of indicators assessing acute general surgery showed a decreasing trend in the volume of patients (n = 50;49%), stability in clinical severity at admission (n = 36;53%), and in the volume of surgeries (n = 14;47%). Most of the indicators (n = 28;65%) reported no change in treatment approach and stable mortality rate (n = 11,69%). CONCLUSION: This review signals relevant disruptions across the acute care pathway. A subset of general surgery performance indicators showed stability in most of the phases of the care pathway. These results highlight the relevance of assessing this care pathway more regularly and systematically across different clinical entities to monitor disruptions and to improve the resilience of emergency services during a crisis.

Linkages between ICT diffusion, renewable energy consumption, and carbon emissions: a comparative analysis of SAARC, MENA, and OECD countries.

This paper examines the linkages between information and communication technology (ICT) diffusion, renewable energy consumption (REC), and carbon (CO2) emissions across three distinct regions: the South Asian Association for Regional Cooperation (SAARC), Middle East and North Africa (MENA), and Organization for Economic Cooperation and Development (OECD) nations. We explore the causal pathways linking these variables and perform a comparative assessment of region-specific patterns with their policy implications. Utilizing a panel dataset of 28 countries from 1998 to 2019, we employ panel ARDL, FMOLS, DOLS, and D-H causality tests. The comprehensive analysis of the sample reveals that ICT development enhances CO2 emissions, whereas REC reduces emissions. However, the comparative analysis suggests a positive linkage between ICT diffusion and CO2 emissions in MENA and OECD countries but a negative linkage in SAARC countries. Further, REC substantially reduces emissions in MENA and OECD countries but has an insignificant effect in SAARC countries. Our findings corroborate the first-order effect of ICT (negative environmental impact) in MENA and OECD countries, with contextual variations attributed to economic structure, financial sector growth, trade openness, and industrialization. These findings offer pivotal insights for policymakers to leverage ICT capabilities and REC to attain sustainable development and mitigate climate change consequences.

Development of an in silico evaluation system that quantitatively predicts skin sensitization using OECD Guideline No. 497 ITSv2 defined approach for skin sensitization classification.

The Integrated Testing Strategy version 2 (ITSv2) Defined Approach, which is a reliable skin sensitization hazard and multi-step risk assessment method, does not support quantitative risk assessment such as local lymph node assay EC3 values. In this study, we developed a high-performance in silico evaluation system that quantitatively predicts the EC3 values of chemical substances by combining the ITSv2 Defined Approach for hazard identification (ITSv2 HI) with machine learning models. This system uses in chemico/in vitro test data, molecular descriptors, and distance information based on read-across concepts as explanatory variables. The system achieves an R2 value of 0.617 on external-validation data. Substances misclassified in ITSv2 HI are considered to have properties that do not match the correspondence between tests expressing the adverse outcome pathway assumed in the ITSv2 Defined Approach and skin sensitization. Therefore, ITSv2 HI is assumed to be correct within the applicability domains of this system. When using only substances within the applicability domains to reconstruct CatBoost models, the R2 value reached 0.824 on the external-validation data, representing an improvement in system performance. The results demonstrate the utility of explanatory variables that reflect the read-across concept and the advantages of integrating multiple prediction methods.

Segmentation of OECD countries on the basis of selected global environmental indicators using k-means non-hierarchical clustering.

In order to allocate resources and describe progress, frequently nations are grouped together by many international authorities. A variety of pertinent indicators can provide a more useful basis for classification for each specific area of interest. Based on commonalities between various variables connected to the global environmental sector, we developed a novel typology of country clusters. Four indicators were chosen after a review of the literature. In order to optimize data availability across as many OECD nations as feasible, indicators were chosen based on their relevance for all the OECD countries. Countries were arranged into a natural cluster using the hierarchical clustering method. Four groups, covering 31 countries, were the result of two stages of grouping. These four clusters were found to be more compact and clearly divided which gives policymakers a clear-cut idea as to how these environmental indicators are deteriorating day by day and year by year and what needs to be done to be more environmentally sustainable and responsible.

Can technological progress, renewable and nuclear energy consumption be the remedy for global climate crises? An examination of leading OECD countries.

Energy is the most critical input for production and consumption. The inputs of energy cause irreversible damage to the environment. The studies carried out to reduce the environmental impact of the methods used in energy production are extremely valuable. This study aims to reveal the effects of technological development, nuclear energy consumption, and renewable energy use on environmental degradation. The patent numbers, technological development, GDP, renewable energy, and nuclear energy consumption data of 16 OECD countries covering the years 1996-2019 were used in the empirical analysis. The findings of panel FMOLS and DOLS methods reveal that technological progress, nuclear, and renewable energy consumption significantly reduce CO2 emissions. In line with these findings, critical policy implications have been suggested.

Green innovation and environmental quality in OECD countries: the mediating role of renewable energy and carbon taxes.

The exceptional rise in overall economic activities has deteriorated environmental sustainability around the world. However, countries around the globe are implementing strategies for reaching the global climate objective. For this purpose, OECD countries committed many efforts, although their pledges and results are not parallel to the level of the Paris Agreement's ambition. This study examines the impact of eco-innovation, environmental taxes, and renewable energy consumption on the environmental performance of selected OECD countries over the period of 2006 to 2020. This study uses the generalized method of moments (GMM) and instrumental variables 2 stage least square (2SLS) methods. For robustness checks, this study uses a quantile regression approach. We conclude that an increase in the adoption of renewable energy and green innovation has a statistically significant impact on controlling CO2 emissions. Moreover, the empirical model is expanded by incorporating environmental taxes as an explanatory variable. The expanded model showed that the imposition of environmental taxes has a detrimental impact on the reduction of CO2 emissions. Moreover, on the contrary, an increase in economic activities, measured by GDP, is responsible for rising CO2 emissions in OECD countries. In light of the results we obtained, policy recommendations are provided.

New supporting data to guide the use of evident toxicity in acute oral toxicity studies (OECD TG 420).

Currently there are three test guidelines (TG) for acute oral toxicity studies of substances or mixtures from the Organisation for Economic Co-operation and Development (OECD). TG 423 and TG 425 use lethality as an endpoint, while TG 420 replaces death with 'evident toxicity', defined as clear signs that exposure to a higher dose would result in death. However, the perceived subjectivity of 'evident toxicity' may be preventing wider use of TG 420. To address this, the UK National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs) and the European Partnership for Alternative Approaches to Animal Testing (EPAA) collaborated to provide recommendations on the recognition of 'evident toxicity'. Historical data from acute oral toxicity studies were analysed for clinical signs at the lower dose that could have predicted death at the higher dose. Several signs including ataxia, laboured respiration, and eyes partially closed, alone or in combination, are highly predictive. Others such as lethargy, decreased respiration, and loose faeces have lower but still appreciable positive predictive value (PPV). The data has been used to develop recommendations to promote use of TG 420 and thus reduce the suffering and numbers of animals used in acute oral toxicity studies.

AI maturity in health care: An overview of 10 OECD countries.

BACKGROUND: Artificial Intelligence (AI) and its applications in health care are on the agenda of policymakers around the world, but a major challenge remains, namely, to set policies that will ensure wide acceptance and capture the value of AI while mitigating associated risks. OBJECTIVE: This study aims to provide an overview of how OECD countries strategize about how to integrate AI into health care and to determine their actual level of AI maturity. METHODS: A scan of government-based AI strategies and initiatives adopted in 10 proactive OECD countries was conducted. Available documentation was analyzed, using the Broadband Commission for Sustainable Development's roadmap to AI maturity as a conceptual framework. RESULTS: The findings reveal that most selected OECD countries are at the Emerging stage (Level 2) of AI in health maturity. Despite considerable funding and a variety of approaches to the development of an AI in health supporting ecosystem, only the United Kingdom and United States have reached the highest level of maturity, an integrated and collaborative AI in health ecosystem (Level 3). CONCLUSION: Despite policymakers looking for opportunities to expedite efforts related to AI, there is no one-size-fits-all approach to ensure the sustainable development and safe use of AI in health. The principles of equifinality and mindfulness must thus guide policymaking in the development of AI in health care.

Testing the environmental Kuznets curve hypothesis in the transport sector for OECD countries: a dynamic panel threshold approach.

This study tests the environmental Kuznets curve (EKC) hypothesis in the transport sector for 28 OECD countries from 1990 to 2019. As a novelty, the relationship between gross domestic product (GDP) and carbon dioxide (CO2) emissions from the transport sector is investigated with the estimation of the dynamic panel threshold regression based on the generalized method of moments (GMM) estimator by Seo and Shin (Seo and Shin, J Econom 2:169-186, 2016). This approach enables us to test EKC and capture possible nonlinearities between variables. Along with the analysis of the EKC hypothesis, our study also investigates the effects of road petroleum products consumption, renewable energy consumption, and trade openness on transport CO2 emissions. The threshold regression results, where GDP per capita is employed as the transition variable, support the nonlinear relationship between CO2 emissions from the transportation sector and GDP by rejecting the null hypothesis of no threshold effect. This finding indicates the existence of two different regimes, i.e., the lower and upper regimes, based on the optimum value of the GDP per capita. Economic growth damages the environment in the lower regime, whereas it improves environmental quality in the upper regime. Therefore, the results indicate the presence of an inverted U-shaped relationship and support the EKC hypothesis in the OECD transportation sector. As a result, it is concluded that achieving sustainable economic growth is critical for investing in environmentally friendly technologies required to achieve the goal of reducing transportation-related CO2.

Changes in agricultural nitrogen (N) balance of OECD countries and its causes and impacts.

The Organization for Economic Co-operation and Development (OECD) developed soil surface nutrient balance and made it mandatory for member countries to report annual nutrient budgets since 1990. This study aimed to evaluate the status of nitrogen (N) management in member countries and to figure out why N surplus levels differ across countries and how they relate to other agri-environmental indicators, by analyzing the N budgets from 35 OECD countries over the last 30 years. Of the three factors determining N balance (agricultural land area, N input, and N output), agricultural land area decreased in most OECD countries, negatively affecting N balance reduction. However, OECD's average N balance highly decreased from 91 to 46 kg ha-1 over the last 30 years due to the decrease in N input through inorganic fertilizers and manure, especially in EU countries with high N input levels, while N output did not meaningfully change. In comparison, in Japan and Korea, the N balance slightly increased and they became the highest N balance country recently. A higher N balance led to lower N use efficiency and higher ammonia (NH3) and nitrous oxide (N2O) emission intensities. More densely populated countries with smaller agricultural land per capita (ranging from 0.03 to 0.47 ha capita-1) showed a higher N balance (228-80 kg ha-1), presumably due to higher N input for more agricultural production on limited land. The most densely populated countries among OECD members (Belgium, the Netherlands, Korea, and Japan) had similar N input levels. However, two EU countries had much higher N output than two Asian countries due to higher pasture production, which led to a lower N balance and higher N use efficiency. Therefore, highly populated countries with small arable land areas per capita might need multilateral efforts to alleviate agricultural N balance.