Aircraft Noise and Cardiovascular Outcomes (ANCO)

Transport noise is an under-studied environmental pollutant that almost everyone is exposed to. Exposure to noise has well known biological effects including sleep disturbance, short-term increases in blood pressure and heart rate, and raised stress levels. There are many studies documenting annoyance in relation to noise exposure but there are relatively few studies looking at health and most of these are on road traffic noise. These previous health studies have shown associations with increases in blood pressure and also increased risk of heart disease and stroke. There are very few studies on aircraft noise. This is of concern as aircraft noise already affects more people in the UK than any other European country according to the Civil Aviation Authority. There are important gaps in the current evidence base relating to health impacts of aircraft noise, which this proposal addresses.

The proposed work assembles a team with internationally recognised expertise in researching population health effects of transport noise and noise exposure assessment. In our previous research we demonstrated associations between road traffic noise and mortality and stroke in London 2003-10, and with heart disease and stroke risk in areas exposed to highest levels of aircraft noise around Heathrow in 2001-2005. We propose to follow-up this work and extend our analyses to 2006-15 and to include other major airports (e.g.Birmingham and Manchester). We will investigate whether there is a link between aircraft noise and mortality and hospital admissions in recent years - although there are more aircraft flying, these are quieter and average noise levels experienced by those living near airports have reduced.

We will also investigate health effects of noise in two different studies of adults followed up for 6-27 years, with a wide range of clinical investigations into functioning of the heart and blood vessels and also blood tests relating to heart disease and diabetes risks. One of these is the very large UK Biobank study, with >100,000 individuals living near large UK airports. A second study is the Southall And Brent REvisited (SABRE) cohort of individuals living in West London (near Heathrow airport), initially investigated in 1988. In both UK Biobank and SABRE we will examine aircraft noise in relation to heart and circulatory disease deaths, hospital admissions and risk factors including high blood pressure and sleep disturbance. A major strength of this study is that, working with the Civil Aviation Authority, we will have access to noise estimates going back to the late 1980s as well as up to the present day

Our analyses will take into account exposures to road traffic noise and to air pollution from both road vehicles and from aeroplanes. For the latter we will make measurements of extremely small particles that are emitted from jet engines and may accompany high noise exposures near airports. This will allow us to produce estimates of health effects of aircraft noise independent from other exposures occurring at the same time. We will also look at different noise metrics to investigate effects of aircraft noise on health. Currently most studies use average noise levels, but we will investigate other metrics including number of noisy events and time of day or night that noise occurs.

Our results will inform national policy relating to aircraft noise and airport planning, and will potentially be used by the Noise and Nuisance Technical and Evidence Team at the Dept for Environment, Food and Rural Affairs (Defra), the Civil Aviation Authority, Public Health England, the NGO Environmental Protection UK (who run 'Noise Action Week') and local councils near large UK airports.

We will use data from SAHSU national postcode and address-level hospitalisation and mortality data, the SABRE cohort (in west London, followed up twice since 1988) and UK Biobank cohort (~120,000 living in conurbations with major airports; repeated measures on 20,000 with potential noise exposure from Manchester airport). We will generate annual aircraft noise exposure estimates for 2006-15 for average (LAeq,16hr, Lnight, Lden), maximum (LAmax) and N70 metrics, and also estimates for Heathrow back to the 1980s at place of residence, using information from the Civil Aviation Authority.

An integrated programme of analyses will be conducted to investigate if exposures are associated with CVD morbidity/mortality and intermediate outcomes related to physiological responses to noise. These will include heart rate variability as a measure of autonomic nervous system activation (SABRE), BP and sleep disturbance (both SABRE and UK Biobank), possible intermediate routes by which noise may affect CVD. In addition in SABRE and UK Biobank we will undertake exploratory hypothesis-generating analyses concerning possible metabolic impacts of aircraft noise stress based on limited previous investigations.

We will account for potential confounding by road noise and air pollution applied to small areas near airports and to recent cohort follow-ups using estimates already integrated into UK Biobank and SABRE cohorts by the applicants. Road traffic estimates come from the CNOSSOS-EU road noise model developed at Imperial and air pollution exposures from the EU European Study of Cohorts and Air Pollution Effects (ESCAPE) project. We will also perform a novel investigation of associations between aircraft noise and ultrafine particles (UFP) from jet engines using mobile monitoring near Gatwick and Heathrow airports and develop models to predict UFP from NO2 and other variables. Sensitivity analyses will examine alternatives to metrics using noise averages and potential confounding by UFPs.

This project will provide a comprehensive and integrated assessment of potential impacts of aircraft noise on CVD and CVD risk factors in the general population, as well as investigate mechanistic pathways to help assess whether any associations detected may be causal. Outputs will provide a major addition to the evidence base in this area. They will provide high quality evidence for stand-alone and meta-analysis use to quantify dose-response and to help quantify and monetise health impacts of environmental noise. The UK is an ideal place to study health effects of aircraft noise as it has several major airports near densely populated urban areas, long-running series of aircraft noise and excellent health data from administrative and cohort sources. Results will be used both nationally and internationally.

Major beneficiaries of this information are policy makers, government departments and regulatory agencies such as the Civil Aviation Authority to inform planning decisions and monitoring; UK airports, which have a potentially large economic impact on both local areas and national business and to the large population in the UK exposed to aircraft noise. This evidence will help provide evidence for health impact assessment. it will help shape developments and planning of future airport design and noise mitigation policies. For example, investigation of potential pathways of action including sleep and important noise metrics for health analyses (e.g. number noisy events vs. average noise; night vs. day-time noise) have relevance for policies on night flights and any noise mitigation strategies. Appropriate metrics for monitoring of noise exposure are currently based on those best to pick up annoyance, but this work will provide specific information on metrics related to health.

The work proposed is a three year project grant, so the major outputs, would be expected to be in the public domain within four years of the start-date. This is a relatively short timeframe for the quality and range of outputs proposed, but this is because it builds on existing collaborations on noise and health by the participants. We are able to make efficient use of existing cohorts and data including our prior experience of integrating road noise and air pollution estimates into the cohorts (including UK Biobank) and previous small area analyses on aircraft noise around London Heathrow airport. Further, our road noise and air pollution confounder estimates come from studies involving use of methods developed by the applicants. We will access and process already collected aircraft noise data from the Civil Aviation Authority and use our knowledge of integrating road exposure estimates to inform integration of aircraft noise estimates into the cohorts.

We will pursue multiple strategies to disseminate the results, including through academic conferences, peer-reviewed publications, meetings with stakeholders, through non-academic members of our project advisory group and through personal contacts. We will also work with the Imperial College and MRC-PHE press offices to reach a wide audience and being in contact with the media. Our established link with Public Health England and their partnership with the Environmental Agency will also allow us to easily get in touch with stakeholders and policy makers in the timeframe of the project.