Climate change epidemiology: methodological challenges

Barriers to climate change and health research in India: a qualitative study

OBJECTIVES

Almost a quarter of the global burden of disease and mortalities is attributable to environmental causes, the magnitude of which is projected to increase in the near future. However, in many low- and middle-income settings, there remains a large gap in the synthesis of evidence on climate-sensitive health outcomes. In India, now the world's most populous country, little remains known about the impacts of climate change on various health outcomes. The objective of this study is to better understand the challenges faced in conducting climate change and health research in Puducherry, India.

DESIGN AND SETTING

In this study, we employed key informant interviews to deepen the understanding of the perceived research barriers in Puducherry. The findings were analysed using data-driven qualitative thematic analysis to elaborate the major perceived barriers to conducting environmental health research.

PARTICIPANTS

This study was conducted among 16 public health professionals, including medical researchers, and professionals involved in environmental policies and planning in Puducherry.

RESULTS

We identify three key barriers faced by public health professionals as key stakeholders, namely: (1) political and institutional barriers; (2) education and awareness barriers; and (3) technical research barriers. We show there is a need, from the professionals' perspective, to improve community and political awareness on climate change and health; strengthen technical research capacity and collaboration among researchers; and strengthen health surveillance, resource allocation and access to health data for research.

CONCLUSION

Evidence informed policies and interventions are a key element in the adaptation response for countries. In the context of the paucity of data on environmental health from India, despite recognised climate change related health vulnerabilities, these findings could contribute to the development and improvement of relevant interventions conducive to a strong research environment.

71Advanced Environmental Epidemiology for Health and Climate Research

Focus and outcomes for participants

The symposium will focus on insights and applications of advanced environmental epidemiology methods in health and climate research. The symposium will help the participants

Rationale for the symposium, including for its inclusion in the Congress

Climate change is the greatest health challenge in the 21st century. The most recent Lancet Countdown report (Watts et al. 2019) and the MJA-Lancet Countdown Australian reports (Zhang et al. 2018; Beggs et al. 2019) on health and climate change research have once again highlighted the global vulnerability to health risks from climate change. Epidemiology plays an important role in informing policy to protect the public’s health from a changing climate. However, limited research has been conducted in the field, which may be due to the methodological challenges to conducting research in climate change epidemiology (Xun et al. 2010). However, there are opportunities for advancing epidemiological research in the context of climate change, as highlighted in the recent paper published in the American Journal of Epidemiology (Anderson et al. 2019). The proposed symposium aligns precisely with the conference theme on methodological innovations in epidemiology and the need for epidemiologists who are keen to address non-traditional epidemiological health risks to support decision-making under a changing climate. This symposium will be a timely event to build capacity needed to address more extreme weather events and disasters related to climate change in Australia and globally.

Presentation program (90 minutes)

The symposium will have 6 presentations, 15 minutes each including Q&A.

Names and short biography of presenters

Toward an Integrated System of Climate Change and Human Health Indicators: A Conceptual Framework

Environmental health indicators are helpful for tracking and communicating complex health trends, informing science and policy decisions, and evaluating public health actions. When provided on a national scale, they can help inform the general public, policy makers, and public health professionals about important trends in exposures and how well public health systems are preventing those exposures from causing adverse health outcomes. There is a growing need to understand national trends in exposures and health outcomes associated with climate change and the effectiveness of climate adaptation strategies for health. To date, most indicators for health implications of climate change have been designed as independent, individual metrics. This approach fails to take into account how exposure-outcome pathways for climate-attributable health outcomes involve multiple, interconnected components. We propose reframing climate change and health indicators as a linked system of indicators, which can be described as follows: upstream climate drivers affect environmental states, which then determine human exposures, which ultimately lead to health outcomes; these climate-related risks are modified by population vulnerabilities and adaptation strategies. We apply this new conceptual framework to three illustrative climate-sensitive health outcomes and associated exposure-outcome pathways: pollen allergies and asthma, West Nile Virus infection, and vibriosis.

Perspectives on the Future of Epidemiology: A Framework for Training

Over the past century, the field of epidemiology has evolved and adapted to changing public health needs. Challenges include newly emerging public health concerns across broad and diverse content areas, new methods, and vast data sources. We recognize the need to engage and educate the next generation of epidemiologists and prepare them to tackle these issues of the 21st century. In this commentary, we suggest a skeleton framework upon which departments of epidemiology should build their curriculum. We propose domains that include applied epidemiology, biological and social determinants of health, communication, creativity and ability to collaborate and lead, statistical methods, and study design. We believe all students should gain skills across these domains to tackle the challenges posed to us. The aim is to train smart thinkers, not technicians, to embrace challenges and move the expanding field of epidemiology forward.

Dengue Incidence and Sociodemographic Conditions in Pucallpa, Peruvian Amazon: What Role for Modification of the Dengue-Temperature Relationship?

Dengue is a climate-sensitive disease with an increasing global burden. Although the relationship between meteorological conditions and dengue incidence is well established, less is known about the modifying nature of sociodemographic variables on that relationship. We assess the strength and direction of sociodemographic effect modification of the temperature-dengue relationship in the second largest city of the Peruvian Amazon to identify populations that may have heightened vulnerability to dengue under varying climate conditions. We used weekly dengue counts and averaged meteorological variables to evaluate the association between disease incidence, meteorological exposures, and sociodemographic effect modifiers (gender, age, and district) in negative binomial regression models. District was included to consider geographical effect modification. We found that being a young child or elderly, being female, and living in the district of Manantay increased dengue's incidence rate ratio (IRR) as a result of 1°C increase in weekly mean temperature (IRR = 2.99, 95% CI: 1.99-4.50 for women less than 5 years old and IRR = 2.86, 95% CI: = 1.93-4.22 for women older than 65 years, both estimates valid for the rainy season). The effect of temperature on dengue depended on season, with stronger effects during rainy seasons. Sociodemographic variables can provide options for intervention to mitigate health impacts with a changing climate. Our results indicate that patterns of baseline risk between regions and sociodemographic conditions can differ substantially from trends in climate sensitivity. These results challenge the assumption that the distribution of climate change impacts will be patterned similarly to existing social gradients in health.

EMD-regression for modelling multi-scale relationships, and application to weather-related cardiovascular mortality

In a number of environmental studies, relationships between nat4ural processes are often assessed through regression analyses, using time series data. Such data are often multi-scale and non-stationary, leading to a poor accuracy of the resulting regression models and therefore to results with moderate reliability. To deal with this issue, the present paper introduces the EMD-regression methodology consisting in applying the empirical mode decomposition (EMD) algorithm on data series and then using the resulting components in regression models. The proposed methodology presents a number of advantages. First, it accounts of the issues of non-stationarity associated to the data series. Second, this approach acts as a scan for the relationship between a response variable and the predictors at different time scales, providing new insights about this relationship. To illustrate the proposed methodology it is applied to study the relationship between weather and cardiovascular mortality in Montreal, Canada. The results shed new knowledge concerning the studied relationship. For instance, they show that the humidity can cause excess mortality at the monthly time scale, which is a scale not visible in classical models. A comparison is also conducted with state of the art methods which are the generalized additive models and distributed lag models, both widely used in weather-related health studies. The comparison shows that EMD-regression achieves better prediction performances and provides more details than classical models concerning the relationship.

The association between wind-related variables and stroke symptom onset: A case-crossover study on Jeju Island

BACKGROUND

Although several studies have investigated the effects of ambient temperature on the risk of stroke, few studies have examined the relationship between other meteorological conditions and stroke. Therefore, the aim of this study was to analyze the association between wind-related variables and stroke symptoms onset.

METHODS

Data regarding the onset of stroke symptoms occurring between January 1, 2006, and December 31, 2007 on Jeju Island were collected from the Jeju National University Hospital stroke registry. A fixed-strata case-crossover analysis based on time of onset and adjusted for ambient temperature, relative humidity, air pressure, and pollutants was used to analyze the effects of wind speed, the daily wind speed range (DWR), and the wind chill index on stroke symptom onset using varied lag terms. Models examining the modification effects by age, sex, smoking status, season, and type of stroke were also analyzed.

RESULTS

A total of 409 stroke events (381 ischemic and 28 hemorrhagic) were registered between 2006 and 2007. The odds ratios (ORs) for wind speed, DWR, and wind chill among the total sample at lag 0-8 were 1.18 (95% confidence interval (CI): 1.06-1.31), 1.08 (95% CI: 1.02-1.14), and 1.22 (95% CI: 1.07-1.39) respectively. The ORs for wind speed, DWR, and wind chill for ischemic stroke patients were slightly greater than for patients in the total sample (OR=1.20, 95% CI: 1.08-1.34; OR=1.09, 95% CI: 1.03-1.15; and OR=1.22, 95% CI: 1.07-1.39, respectively). Statistically significant season-specific effects were found for spring and winter, and various delayed effects were observed. In addition, age, sex, and smoking status modified the effect size of wind speed, DWR, and wind chill.

CONCLUSIONS

Our analyses showed that the risk of stroke symptoms onset was associated with wind speed, DWR, and wind chill on Jeju Island.

Perceptions of capacity for infectious disease control and prevention to meet the challenges of dengue fever in the face of climate change: A survey among CDC staff in Guangdong Province, China

BACKGROUND

Dengue fever is an important climate-sensitive mosquito-borne viral disease that poses a risk to half the world's population. The disease is a major public health issue in China where in 2014 a major outbreak occurred in Guangdong Province. This study aims to gauge health professionals' perceptions about the capacity of infectious disease control and prevention to meet the challenge of dengue fever in the face of climate change in Guangdong Province, China.

METHODS

A cross-sectional questionnaire survey was administered among staff in the Centers for Disease Control and Prevention (CDCs) in Guangdong Province. Data analysis was undertaken using descriptive methods and logistic regression.

RESULTS

In total, 260 questionnaires were completed. Most participants (80.7%) thought climate change would have a negative effect on population health, and 98.4% of participants reported dengue fever had emerged or re-emerged in China in recent years. Additionally, 74.9% of them indicated that the capability of the CDCs to detect infectious disease outbreak/epidemic at an early stage was excellent; 86.3% indicated laboratories could provide diagnostic support rapidly; and 83.1% believed levels of current staff would be adequate in the event of a major outbreak. Logistic regression analysis showed higher levels of CDCs were perceived to have better capacity for infectious disease control and prevention. Only 26.8% of participants thought they had a good understanding of climate change, and most (85.4%) thought they needed more information about the health impacts of climate change. Most surveyed staff suggested the following strategies to curb the public health impact of infectious diseases in relation to climate change: primary prevention measures, strengthening the monitoring of infectious diseases, the ability to actively forecast disease outbreaks by early warning systems, and more funding for public health education programs.

CONCLUSION

Vigilant disease and vector surveillance, preventive practice and health promotion programs will likely be significant in addressing the threat of dengue fever in the future. Further efforts are needed to strengthen the awareness of climate change among health professionals, and to promote relevant actions to minimize the health burden of infectious diseases in a changing climate. Results will be critical for policy makers facing the current and future challenges associated with infectious disease prevention and control in China.

Climate, environmental and socio-economic change: weighing up the balance in vector-borne disease transmission

Arguably one of the most important effects of climate change is the potential impact on human health. While this is likely to take many forms, the implications for future transmission of vector-borne diseases (VBDs), given their ongoing contribution to global disease burden, are both extremely important and highly uncertain. In part, this is owing not only to data limitations and methodological challenges when integrating climate-driven VBD models and climate change projections, but also, perhaps most crucially, to the multitude of epidemiological, ecological and socio-economic factors that drive VBD transmission, and this complexity has generated considerable debate over the past 10-15 years. In this review, we seek to elucidate current knowledge around this topic, identify key themes and uncertainties, evaluate ongoing challenges and open research questions and, crucially, offer some solutions for the field. Although many of these challenges are ubiquitous across multiple VBDs, more specific issues also arise in different vector-pathogen systems.

Climate change, crop production and child under nutrition in Ethiopia; a longitudinal panel study

BACKGROUND

The amount and distribution of rainfall and temperature influences household food availability, thus increasing the risk of child under nutrition. However, few studies examined the local spatial variability and the impact of temperature and rainfall on child under nutrition at a smaller scale (resolution). We conducted this study to evaluate the effect of weather variables on child under nutrition and the variations in effects across the three agro ecologies of Ethiopia.

METHODS

A longitudinal panel study was conducted. We used crop productions (cereals and oilseeds), livestock, monthly rainfall and temperature, and child under nutrition data for the period of 1996, 1998, 2000 and 2004. We applied panel regression fixed effects model.

RESULTS

The study included 43 clusters (administrative zones) and 145 observations. We observed a spatio temporal variability of rainfall, stunting and underweight. We estimated that for a given zone, one standard deviation increase in rainfall leads to 0.242 standard deviations increase in moderate stunting. Additionally, a one standard deviation increase temperature leads to 0.216 standard deviations decrease in moderate stunting. However, wasting was found to be poorly related with rainfall and temperature. But severe wasting showed a positive relationship with the quadratic term of rainfall.

CONCLUSIONS

We conclude that rainfall and temperature are partly predicting the variation in child stunting and underweight. Models vary in predicting stunting and underweight across the three agro ecologic zones. This could indicate that a single model for the three agro ecologies may not be not applicable.

Development of key indicators to quantify the health impacts of climate change on Canadians

OBJECTIVES

This study aimed at developing a list of key human health indicators for quantifying the health impacts of climate change in Canada.

METHODS

A literature review was conducted in OVID Medline to identify health morbidity and mortality indicators currently used to quantify climate change impacts. Public health frameworks and other studies of climate change indicators were reviewed to identify criteria with which to evaluate the list of proposed key indicators and a rating scale was developed. Total scores for each indicator were calculated based on the rating scale.

RESULTS

A total of 77 health indicators were identified from the literature. After evaluation using the chosen criteria, 8 indicators were identified as the best for use. They include excess daily all-cause mortality due to heat, premature deaths due to air pollution (ozone and particulate matter 2.5), preventable deaths from climate change, disability-adjusted life years lost from climate change, daily all-cause mortality, daily non-accidental mortality, West Nile Disease incidence, and Lyme borreliosis incidence.

CONCLUSIONS

There is need for further data and research related to health effect quantification in the area of climate change.

Health risks of climate change: an assessment of uncertainties and its implications for adaptation policies

BACKGROUND

Projections of health risks of climate change are surrounded with uncertainties in knowledge. Understanding of these uncertainties will help the selection of appropriate adaptation policies.

METHODS

We made an inventory of conceivable health impacts of climate change, explored the type and level of uncertainty for each impact, and discussed its implications for adaptation policy. A questionnaire-based expert elicitation was performed using an ordinal scoring scale. Experts were asked to indicate the level of precision with which health risks can be estimated, given the present state of knowledge. We assessed the individual scores, the expertise-weighted descriptive statistics, and the argumentation given for each score. Suggestions were made for how dealing with uncertainties could be taken into account in climate change adaptation policy strategies.

RESULTS

The results showed that the direction of change could be indicated for most anticipated health effects. For several potential effects, too little knowledge exists to indicate whether any impact will occur, or whether the impact will be positive or negative. For several effects, rough 'order-of-magnitude' estimates were considered possible. Factors limiting health impact quantification include: lack of data, multi-causality, unknown impacts considering a high-quality health system, complex cause-effect relations leading to multi-directional impacts, possible changes of present-day response-relations, and difficulties in predicting local climate impacts. Participants considered heat-related mortality and non-endemic vector-borne diseases particularly relevant for climate change adaptation.

CONCLUSIONS

For possible climate related health impacts characterised by ignorance, adaptation policies that focus on enhancing the health system's and society's capability of dealing with possible future changes, uncertainties and surprises (e.g. through resilience, flexibility, and adaptive capacity) are most appropriate. For climate related health effects for which rough risk estimates are available, 'robust decision-making' is recommended. For health effects with limited societal and policy relevance, we recommend focusing on no-regret measures. For highly relevant health effects, precautionary measures can be considered. This study indicated that analysing and characterising uncertainty by means of a typology can be a very useful approach for selection and prioritization of preferred adaptation policies to reduce future climate related health risks.

A healthy turn in urban climate change policies; European city workshop proposes health indicators as policy integrators

BACKGROUND

The EU FP6 HENVINET project reviewed the potential relevance of a focus on climate change related health effects for climate change policies at the city region level. This was undertaken by means of a workshop with both scientists, city representatives from several EU-countries, representatives of EU city networks and EU-experts. In this paper we introduce some important health related climate change issues, and discuss the current city policies of the participating cities.

METHODS

The workshop used a backcasting format to analyse the future relevance of a health perspective, and the main benefits and challenges this would bring to urban policy making.

RESULTS

It was concluded that health issues have an important function as indicators of success for urban climate change policies, given the extent to which climate change policies contribute to public health and as such to quality of life. Simultaneously the health perspective may function as a policy integrator in that it can combine several related policy objectives, such as environmental policies, health policies, urban planning and economic development policies, in one framework for action. Furthermore, the participants to the workshop considered public health to be of strategic importance in organizing public support for climate change policies. One important conclusion of the workshop was the view that the connection of science and policy at the city level is inadequate, and that the integration of scientific knowledge on climate change related health effects and local policy practice is in need of more attention. In conclusion, the workshop was viewed as a constructive advance in the process of integration which hopefully will lead to ongoing cooperation.

CONCLUSIONS

The workshop had the ambition to bring together a diversity of actor perspectives for exchange of knowledge and experiences, and joint understanding as a basis for future cooperation. Next to the complementarities in experience and knowledge, the mutual critical reflection was a bonus, as ideas had the opportunity to be scrutinized by others, leading to more robustness and common ground. The structured backcasting approach was helpful in integrating all of this with one common focus, embracing diversity and complexity, and stimulating reflection and new ideas.

Community perceptions of infectious diseases, antibiotic use and antibiotic resistance in context of environmental changes: a study in Odisha, India

BACKGROUND

The public health impact of environmental changes and the faceless threat of antibiotic resistance are currently among the top global health challenges. Community understanding of health, diseases and medicines in relation to the changing environment is necessary to mitigate the impact of these changes on health and for prudent use of antibiotics.

OBJECTIVE

The objective is to explore community perceptions of infectious diseases, antibiotic use and antibiotic resistance in the context of environmental changes.

METHODS

A qualitative study was conducted among community members with various backgrounds in education, gender, age and occupation of two districts of Odisha, India. Eight focus groups discussions and ten individual interviews were conducted. Data were analysed using content analysis.

RESULTS

Two themes emerged: 'Interpretation of infectious diseases and health hazards in the context of environmental changes', and 'Understanding of antibiotic use and its consequences for resistance development and the environment'. The participants perceived that nowadays there is irregularity in the occurrence of seasons, particularly an increase in average temperature, which is influencing health. Participants' perceptions of infectious diseases, antibiotic use and resistance varied according to their social environment. Furthermore, they perceived that improved sanitation, choice of alternative medicine and awareness and education on prudent use of antibiotics are probably some ways to prevent antibiotic resistance.

CONCLUSIONS

The participants perceived that climate variability is increasing and that this has health consequences for the community. They also hypothesized an interrelationship between the environment, infectious diseases and medicine use, particularly antibiotics. This is helpful for further empirical studies.

Mapping climate change vulnerabilities to infectious diseases in Europe

BACKGROUND

The incidence, outbreak frequency, and distribution of many infectious diseases are generally expected to change as a consequence of climate change, yet there is limited regional information available to guide decision making.

OBJECTIVE

We surveyed government officials designated as Competent Bodies for Scientific Advice concerning infectious diseases to examine the degree to which they are concerned about potential effects of climate change on infectious diseases, as well as their perceptions of institutional capacities in their respective countries.

METHODS

In 2007 and 2009/2010, national infectious disease experts from 30 European Economic Area countries were surveyed about recent and projected infectious disease patterns in relation to climate change in their countries and the national capacity to cope with them.

RESULTS

A large majority of respondents agreed that climate change would affect vector-borne (86% of country representatives), food-borne (70%), water-borne (68%), and rodent-borne (68%) diseases in their countries. In addition, most indicated that institutional improvements are needed for ongoing surveillance programs (83%), collaboration with the veterinary sector (69%), management of animal disease outbreaks (66%), national monitoring and control of climate-sensitive infectious diseases (64%), health services during an infectious disease outbreak (61%), and diagnostic support during an epidemic (54%).

CONCLUSIONS

Expert responses were generally consistent with the peer-reviewed literature regarding the relationship between climate change and vector- and water-borne diseases, but were less so for food-borne diseases. Shortcomings in institutional capacity to manage climate change vulnerability, identified in this assessment, should be addressed in impact, vulnerability, and adaptation assessments.

Climate change and health effects in Northwest Alaska

This article provides examples of adverse health effects, including weather-related injury, food insecurity, mental health issues, and water infrastructure damage, and the responses to these effects that are currently being applied in two Northwest Alaska communities.

From theory to practice: a Canadian case study of the utility of climate change adaptation frameworks to address health impacts

Objective

It is now recognized that climate change affects human health. The question is how to adapt. This article examines mainstreaming climate considerations into public health programs and the utility of climate change and health adaptation frameworks, using Ontario, Canada, as a case study.

Methods

A literature review identified climate change and health adaptation frameworks for comparison with the Ontario Public Health Standards. Key informant interviews gauged the extent to which climate change risks are currently considered in policy and planning.

Results

Ontario’s Public Health Standards already require many of the risk management activities identified in climate change and health adaptation frameworks. However, public health officials require additional information about linkages between climate change and health to manage risks.

Conclusions

Risk management activities such as population health assessments, surveillance and public education and outreach can address many key risks related to climate hazards when information about the risks, vulnerable populations and time scales is made available to health officials. The development, analysis and transfer of this information should be considered a priority at all levels within the public health sector.

Climate change health assessment: a novel approach for Alaska Native communities

OBJECTIVES

Develop a process for assessing climate change impacts on public health that identifies climate-health vulnerabilities and mechanisms and encourages adaptation.

STUDY DESIGN

Multi-stakeholder, participatory, qualitative research.

METHODS

A Climate Change Health Assessment (CCHA) was developed that involved 4 steps: (1) scoping to describe local conditions and engage stakeholders; (2) surveying to collect descriptive and quantitative data; (3) analysis to evaluate the data; and (4) planning to communicate findings and explore appropriate actions with community members. The health effects related to extreme weather, thinning ice, erosion, flooding, thawing permafrost and changing conditions of water and food resources were considered.

RESULTS

The CCHA process was developed and performed in north-west Arctic villages. Refinement of the process took place in Point Hope, a coastal Inupiat village that practices whaling and a variety of other traditional subsistence harvest practices. Local observers identified climate change impacts that resulted in damaged health infrastructure, compromised food and water security and increased risk of injury. Priority health issues included thawing traditional ice cellars, diminished quality of the community water source and increased safety issues related to sea ice change. The CCHA increased awareness about health vulnerability and encouraged informed planning and decision-making.

CONCLUSION

A community-scale assessment process guided by observation-based data can identify climate health impacts, raise awareness and encourage adaptive actions, thereby improving the response capacity of communities vulnerable to climate change.