Advances in epidemiology

In document New Horizons (Page 130-135)

This section was authored by Dr Giovanni Leonardi (Public Health England); Tony Fletcher (LSHTM)

Addressing pollution needs a new epidemiology that integrates measurements from across pollution-relevant domains, to human domains. When planning ahead for which chemicals would be safe for society to use, regulatory toxicology has a clear role to play, however once people are unfortunately exposed, epidemiology can have a crucial role. Indication of the value of integrating measurements from several

pollution domains using epidemiology has come from several recent results. These include the recognition and quantification of effects of several environmental exposures on (1) growth and physical development; (2) behavioural and cognitive development; (3) asthma and allergies; (4) sexual and reproductive development. Both toxicology and epidemiology can provide some integration, but have often failed to include information to provide quantitative estimation of parameters sufficiently relevant to a societal level capacity to intervene. The first failure is to ignore population level distribution of benefits and hazards attributable to a chemical compound, mixture, or other environmental factor, the second is to address these aspects by exceedingly weak methods, inadequate to reach conclusions about either causal relationships or relevant interventions. In anticipating future challenges that do not allow time for a prolonged and laborious examination of overlapping and conflicting factors over decades, epidemiology has the potential to provide valuable and quantitative indication of the value of an intervention.

Epidemiology is not a tool or method for public health; it is a science essential to public health.45 Non-communicable disease (NCD) that has been caused by pollution exposure, and for which preventive interventions exist, would not be acted upon in the absence of epidemiologically-based assessment of population risks and benefits. This applies to pollutants too. This may be counterintuitive when epidemiology has often been vilified in the media for proposing implausible and conflicting

interpretations of non-communicable disease. This supposed limitation of

epidemiology may be attributed to the general weakness of a science process that does not recognise the benefits of population thinking when addressing population- level issues, more than to intrinsic deficiencies of either epidemiology or the media. Lack of recognition of the essential value of population thinking may be more an issue of general culture and education than technical competence in any given discipline of science. In any case, epidemiologists have produced findings of unique value to understanding and prevention of non-communicable disease, when clear high exposure groups could be defined, as in the example of smoking and asbestos.

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Even when pollutant exposure has been lower and more widespread, such as in the case of air pollution, epidemiology has managed to document health impacts. So, it is expected that epidemiologists will be capable of producing other findings of comparable value on other themes such as the challenges summarised throughout this report, if adequately trained and supported. In the future, a population-level assessment of health risk will be helpful whether we consider near-term knowledge needs (five years) such as neurological and other emerging health effects of air pollution and transport, health impacts of airport (and other transport hub) noise, health impacts of waste management approaches such as incinerators and landfill sites, or longer term needs (up to 20 years) where additional foreseeable

developments include investigation of potential health impacts of new energy sources (for example shale gas extraction, small modular nuclear reactors), of light from a variety of sources, around current and legacy industrial sites, intensive farming practices, or simply in response to potential needs to revisit issues such as childhood cancer around nuclear sites, power lines, Camelford††††† etc.

Typically, success in epidemiology in these themes has required careful assessment of environmental exposure pathways and burden of socio-economic and other

confounding, and efforts to conduct individual level longitudinal studies as well as ecological and cross-sectional studies before coming to a conclusion on any topic. Examples include results on endocrine effects of persistent pollutant PFOA and other fluoridated compounds, neurological effects of DDT and other chlorinated compounds, and the increasing recognition of the inter-generational effects of pollutants and other environmental stressors by analysis of birth cohort as well as adult cohort studies.

To characterise effective, evidence-based potential interventions to reduce NCD health burden attributable to pollution, epidemiology will be needed as well. This was demonstrated by the experience of Environmental Public Health Tracking (EPHT) programmes in the US and elsewhere, where evaluation of health benefits of complex interventions could be documented by consortia that included agencies responsible for interventions as well as epidemiologists (see box on EPHT in USA – chapter 9). Integration in EPHT of information on a new generation of biomarkers of exposure and disease risk, significantly enriched by mechanistic information, seems feasible.46


In July 1988, 20 tonnes of aluminium sulphate entered the water supply of 20,000 residents of

the Camelford area of Cornwall following accidental contamination. This is considered the largest accidental water contamination in UK history.

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In conclusion, integration of epidemiology with toxicology is likely needed to design valid studies of potential harm of new and emerging pollutants, and integration of epidemiology with sciences adopted by those resourcing interventions is likely needed to design valid studies evaluating benefits of interventions to prevent NCD.

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Box 5 A breath of fresh air: Novel approaches to behaviour change

Carolin Reiner, Michael Hallsworth, Toby Park, Elisabeth Costa of the Behavioural Insights Team

Every day we make decisions that directly affect the air quality around us - be it our commute, our choice of car, or the way we heat and light our homes. Cumulatively, these decisions have large environmental implications. In other words: improving air quality requires changes in behaviour, and therefore a more sophisticated account of human behaviour will allow us to make better policy. Behavioural insights can help provide this more sophisticated account.

Consequently, behavioural insights can either suggest new policy options and new kinds of interventions, or improve existing policy options. In terms of new kinds of policy interventions, a recent study where Virgin Atlantic pilots were encouraged to fly in a more fuel-efficient way, demonstrates how behavioural insights can

successfully reduce emissions.i All 355 pilots in the trial were aware their emissions were being monitored, and this fact alone was enough to increase their fuel

efficiency. Some pilots also received behaviourally informed “interventions”, such as personal emission targets and feedback on their respective performance, leading to even greater reductions in emissions. Overall, the experiment saved 6,828 metric tons of fuel, which amounts to 21,507 tons of carbon dioxide not emitted.ii

There is great potential for similar interventions to reduce road vehicle emissions in the UK. For example, there is a growing trend among business fleet owners to use in-vehicle telematics to monitor driving style, with insurance companies also starting to use the technology to assess driving safety and risk. While the awareness of being observed is often enough to change behaviour, the use of telematics also opens up possibilities for interventions such as in-vehicle prompts about driving behaviour, tailored fuel consumption reports, the salient highlighting of cost savings, and making social comparisons with more efficient drivers. The latter idea is

analogous to successful work by Opower, whose home energy bills have been shown to reduce energy consumption by comparing households’ energy

consumption to their more efficient neighbours.iii Similarly, this social comparison could be applied to reduce air pollution.

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Behavioural insights can also be used to improve existing policy options, like incentives structures used to increase the uptake of a public service or a

recommended product, such as low or zero emission vehicles. Scrappage schemes, punitive taxes on more polluting vehicles, or changes to fuel duty are such possible incentives under consideration, and are examples where behavioural insights can be used to structure incentives for maximum impact. For example, we tend to be loss averse (being more motivated by a loss than by an equivalent gain); we often overweight small probabilities (meaning lotteries and prize draws can be more powerful than flat incentives); and we tend to discount the future (meaning upfront rewards are more motivating than delayed ones, and delayed costs are less off-putting than immediate ones). Specifically, for instance, we could make scrappage schemes more salient by introducing a prize draw for everyone who signs up and thereby encourage the uptake of low or zero emission vehicles. New ‘behavioural’ policy interventions like setting targets to steer driving behaviour are easy to implement and more affordable than traditional policy levers like regulations (for example the diesel ban), and can also improve the effectiveness of existing policies like a scrappage scheme. Their cost-effective nature renders behavioural insights interventions easily scalable and can therefore substantially shift behaviours to clean up the air we breathe.


i Gosnellet et al. (2016). Working Paper (22316). National Bureau of Economic Research ii Lambert et al. (2016). s_Study_Summary_FINAL_170616.pdf

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In document New Horizons (Page 130-135)