Five Challenges in the Future of Environmental Epidemiology

The world is changing at a vertiginous rate and science must keep pace or be left behind. This is particularly true in the case of environmental epidemiology, a scientific field that must deal with immense change over the next 25 years to remain relevant in public health and preventive medicine. This is the thesis of a recent article published in the journal Environment International that originated at a symposium held in Barcelona in November 2015 to commemorate the 10th anniversary of CREAL (now ISGlobal Campus Mar).

Five Challenges for the Coming 25 years

The essay, coordinated by ISGlobal researcher Cathryn Tonne, identifies five issues as the driving forces that will shape the future of environmental epidemiology, the scientific field that studies the effects of the environment on our health.

1. Demographics and Urbanisation

“Future environmental epidemiologists will work in a world characterised by much longer lifespans than we see today and also by a greater burden of chronic health conditions” explains Cathryn Tonne. There will also be notable differences in the geographic distribution of the population, as people continue to migrate from rural to urban areas. Forecasts indicate that almost 90% of population growth will be concentrated in Asia and Africa, and especially in three countries: India, China and Nigeria  

Large-scale migration will add further complexity to studies, presenting challenges for the follow-up of study participants. Previous places of residence and exposures accumulated from an early age will also be factors to consider.

2. Global Changes in the Environment

In the future, environmental epidemiology will be marked by the phenomenon that has been called “the biggest global health threat of the 21st-century”: climate change. Heatwaves will have an ever greater effect on an aging population, and other extreme weather phenomena—storms and floods—could also have direct health repercussions. 

At the same time, periods of drought may lead to food insecurity, malnutrition and the spread of diseases such as cholera and infection with Escherichia coli. Rising temperatures are also likely to accelerate the spread of vector-borne diseases to new areas. Finally, the number of chemicals to which the population is exposed will probably continue to increase in coming years.

3. Technology

The article’s authors envisage that the rapid evolution of technology will generate new opportunities but will also represent a challenge: the need to ensure that the scientific agenda is driven by the priorities of public health rather than by technological capacities.

Greater availability of geo-localised data will open the door to environmental epidemiology in middle- and low-income countries, where few studies have been carried out to date. 

Measurement of environmental exposures by satellite, social networks, and e/m-health technologies (health care mediated by mobile devices) will become increasingly important. 

Finally, the authors predict an ever greater role in the assessment of the effects of environmental factors on biological systems for OMICS technologies (any group of measurements covering the totality or a large proportion of the dimension of a variable such as a gene, molecule or process). 

4. Data Availability

We are already seeing a situation in which data creation is exceeding worldwide storage capacity. This presents a challenge for data processing in the era of big data and, in many cases, raw data will be discarded and only relevant summaries will be stored.

5. Study Design and Models of Research

The current trend in environmental epidemiology is towards the use of ever larger sample sizes, even the entire population. As a result, new statistical techniques are needed to deal with the complexity of the data.

The authors also point to the likelihood that citizen science will play a greater role in the field, enriching a model of scientific production that until now has been focused on single analyses, often performed by a single research group.

Recommendations

After identifying the principal challenges, the authors of the article make the following recommendations on how environmental epidemiology needs to adapt to prepare for the challenges ahead:

• prioritise healthy aging through a better understanding of the effects of environmental exposures on age-related diseases;
• remedy the current lack of information on certain countries or populations to achieve greater equity in the distribution of data on environmental exposures and their health effects;
• improve data collection methods to reduce the burden on study participants;
• adopt theoretical frameworks that will make it easier to handle complexity and to study the system of health determination as a whole;
• formalise data analysis to reduce subjectivity;
• adapt the training of future environmental epidemiologists to include new statistical methods, with a particular focus on transdisciplinary work.

Reference

Tonne, C., Basagaña, X., Chaix, B. et al. New frontiers for environmental epidemiology in a changing world. Environment International (2017), http://dx.doi.org/10.1016/j.envint.2017.04.003