Intersecting paths: environmental and health policies against climate and immune challenges 

The response to the COVID-19 pandemic across the Organisation for Economic Co-operation and Development (OECD) underscored a crucial lesson: the resilience of societies and health systems against major shocks is largely dependent on population health (1). Countries or regions with healthier populations, notably those with lower obesity levels or chronic disease prevalence, tended to report lower excess mortality, even when accounting for other policy measures (2). 

Despite the widespread acknowledgment of the necessity for enhanced emphasis on preventive measures to achieve healthier populations, OECD countries allocated merely 5.0% of their total health spending towards prevention in 2021, a figure that encompasses the extraordinary expenditure on prevention related to the COVID-19 pandemic response (3). This stark statistic highlights the pressing need for innovative policy approaches, particularly in light of emerging challenges such as climate change-related environmental hazards and the growing burden of immune-related conditions. These issues underscore the necessity of intersectoral policies that leverage synergies across various policy domains to promote both environmental sustainability and public health. 

The urgency of policy transformation 

OECD projections suggest that by 2060, outdoor air pollution could cause 6–9 million premature deaths annually worldwide and cost about 1% of the global gross domestic product (GDP) (3). In the 38 OECD countries, exposure to hot summer days has increased significantly, with a 48% rise in the average value for 2018–2022 compared with 2001–2005 (Figure 1). These statistics are just a small fraction of the potential negative health impacts associated with climate change.  

The evidence on immune-related conditions shows that there are potentially many more overlooked and unaccounted determinants of ill health that will continue to add pressure to health systems and societies everywhere in the decades to come (4). Immediate action is needed to reshape this policy landscape. The broader health impacts of climate change suggest that integrating environmental, health, social, and economic policies could be a cost-effective strategy to mitigate these effects. The current political economy, concerned with the immediate costs of environmental transitions (5, 6), may find the argument that environmental health contributes to overall public health compelling, potentially increasing the public support for necessary policy measures. A unified effort among environmental scientists, health professionals, policymakers, and the broader community is crucial to highlight these connections. 

Advancing intersectoral policies through comprehensive data 

The OECD’s intersectoral nature is a key asset in promoting collaborations that address these complex challenges. By compiling and standardizing data on environmental exposures, healthcare access, socioeconomic factors, and their health impacts, the OECD provides a crucial platform for international benchmarking and policy dialogue. The weekly excess mortality dataset published during the COVID-19 pandemic serves as an example of how data collection can spur policy analysis and development (7), particularly when linked to environmental factors such as extreme temperatures. 

This initiative should encourage governments to establish platforms for collecting and disseminating detailed, georeferenced data on healthcare utilization, which can be correlated with environmental data such as temperature and pollen counts. This approach will help identify populations at risk for climate-associated immune diseases and inform effective policy strategies. 

Beyond traditional health metrics 

While life expectancy has followed a general trend of increase across OECD countries over the last several decades, a significant portion of the population is likely to live with disabilities or functional limitations for longer, including those caused by immune-related conditions. Across 30 OECD and accession countries, only half of the years beyond age 65 are expected to be lived in good health (Figure 2) (8). This reality necessitates a new generation of health outcome measures that extend beyond traditional mortality and morbidity statistics to include well-being and quality of life. Fundamentally, a paradigm shift is needed whereby health and social care systems are orientated toward improving human functioning (integrating biological health and “lived” health), as well as morbidity and mortality (9). 

The OECD’s Patient-Reported Indicators Survey, which has collected health outcomes from over 100,000 patients in 20 countries, represents a significant step forward in this regard (10). The survey's comprehensive approach to measuring health, including physical, mental, and social well-being, sets a precedent for future health metrics that capture the broader impacts of climate change on public health. 

Optimizing policy through comprehensive health impact assessments 

Policies to mitigate climate change can have substantial co-benefits for population health. For example, increasing walking, cycling, and tree coverage in urban areas, as well as improved agricultural and food practices are mitigation strategies contribute to reducing greenhouse gas emissions and have substantial health benefits (11). Therefore, the health sector's experience of evaluating the cost-effectiveness of new medical treatments (12) should extend to assessing the health impacts of non-healthcare interventions. Policies promoting active urban mobility and plant-based diets (13, 14), often do not receive full recognition for their potential to reduce healthcare costs and improve public health. A more integrated approach to health impact assessments could reveal the full benefits of policies that simultaneously address environmental and health objectives. 

In conclusion, the intertwined challenges of climate change and immune-related health conditions necessitate a robust, intersectoral policy approach. Leveraging the strengths of environmental, health, and economic policies not only offers a path to mitigate these pressing issues but also presents an opportunity for enhancing overall societal resilience and well-being. The OECD, with its comprehensive datasets and collaborative platform, is uniquely positioned to spearhead this transformative agenda and to provide data and analysis for researchers and policymakers to lead their own initiatives. 

References 

1. Organisation for Economic Co-operation and Development. Ready for the Next Crisis? Investing in Health System Resilience. Paris: OECD Publishing (2023). doi: 10.1787/1e53cf80-en 

2. Arulanandam B, Beladi H, Chakrabarti A. COVID-19 mortality and the overweight: Cross-Country Evidence. Public Health Pract (2021) 2:100179. doi: 10.1016/j.puhip.2021.100179 

3. Organisation for Economic Co-operation and Development International Programme for Actions on Climate (IPAC). Climate Actions Dashboard, 2023. Paris: OECD Publishing (2023). Available at: https://www.iea.org/data-and-statistics/data-tools/weather-for-energy-tracker?tab=Climate+Hazard+Exposure+Tracker 

4. Agache I, Akdis M, Akdis C, Al-Hemoud A, Annesi-Maesano I, Balmes J, et al. Immune-mediated disease caused by climate change-associated environmental hazards: mitigation and adaptation. Front Sci (2024) 2:1279192. doi: 10.3389/fsci.2024.1279192 

5. Gilmore EA, Buhaug H. Climate mitigation policies and the potential pathways to conflict: outlining a research agenda. WIREs Clim Change (2021) 12:e722. doi: 10.1002/wcc.722 

6. Kamali Saraji M, Streimikiene D. Challenges to the low carbon energy transition: a systematic literature review and research agenda. Energy Strategy Rev (2023) 49:101163. doi.org/10.1016/j.esr.2023.101163 

7. Organisation for Economic Co-operation and Development. Excess mortality by week. OECD Health Statistics (2023). Available at: https://stats.oecd.org/Index.aspx?DataSetCode=HEALTH_MORTALITY. 

8. Eurostat. Healthy life years statistics. Available at: https://ec.europa.eu/eurostat/statistics-explained/index.php?title=Healthy_life_years_statistics#Healthy_life_years_at_age_65 

9. Bickenbach J, Rubinelli S, Baffone C, Stucki G. The human functioning revolution: implications for health systems and sciences. Front Sci (2023) 1:1118512. doi: 10.3389/fsci.2023.1118512  

10. de Boer D, van den Berg M, Ballester M, Bloemeke J, Boerma W, de Bienassis K, et al. Assessing the outcomes and experiences of care from the perspective of people living with chronic conditions, to support countries in developing people-centred policies and practices: study protocol of the International Survey of People Living with Chronic Conditions (PaRIS survey). BMJ Open (2022) 12:e061424. doi: 10.1136/bmjopen-2022-061424 

11. Fernandez-Guzman D, Lavarello R, Yglesias-González M, Hartinger SM, Rojas-Rueda D. A scoping review of the health co-benefits of climate mitigation strategies in South America. Lancet Reg Health Am (2023) 26:100602. doi: 10.1016/j.lana.2023.100602 

12. Ofori-Asenso R, Hallgreen CE, De Bruin ML. Improving interactions between health technology assessment bodies and regulatory agencies: A systematic review and cross-sectional survey on processes, progress, outcomes, and challenges. Front Med (2020) 7:582634. doi: 10.3389/fmed.2020.582634 

13. Dietz WH, Pryor S. How can we act to mitigate the global syndemic of obesity, undernutrition, and climate change?. Curr Obes Rep (2022) 11:61–69. doi: 10.1007/s13679-021-00464-8 

14. Organisation for Economic Co-operation and Development. Healthy Eating and Active Lifestyles: Best Practices in Public Health. Paris: OECD Publishing (2022). doi:10.1787/40f65568-en