Residential exposure to aircraft noise and hospital admissions for cardiovascular diseases: multi-airport retrospective study.


Abstract

Objective To investigate whether exposure to aircraft noise increases the risk of hospitalization for cardiovascular diseases in older people (≥65 years) residing near airports.

Design Multi-airport retrospective study of approximately 6 million older people residing near airports in the United States. We superimposed contours of aircraft noise levels (in decibels, dB) for 89 airports for 2009 provided by the US Federal Aviation Administration on census block resolution population data to construct two exposure metrics applicable to zip code resolution health insurance data: population weighted noise within each zip code, and 90th centile of noise among populated census blocks within each zip code.

Setting 2218 zip codes surrounding 89 airports in the contiguous states.

Participants 6 027 363 people eligible to participate in the national medical insurance (Medicare) program (aged ≥65 years) residing near airports in 2009.

Main outcome measures Percentage increase in the hospitalization admission rate for cardiovascular disease associated with a 10 dB increase in aircraft noise, for each airport and on average across airports adjusted by individual level characteristics (age, sex, race), zip code level socioeconomic status and demographics, zip code level air pollution (fine particulate matter and ozone), and roadway density.

Results Averaged across all airports and using the 90th centile noise exposure metric, a zip code with 10 dB higher noise exposure had a 3.5% higher (95% confidence interval 0.2% to 7.0%) cardiovascular hospital admission rate, after controlling for covariates.

Conclusions Despite limitations related to potential misclassification of exposure, we found a statistically significant association between exposure to aircraft noise and risk of hospitalization for cardiovascular diseases among older people living near airports.

What is already known on this topic

·         Noise has been associated with hypertension, myocardial infarction, and ischemic heart disease

·         Aircraft noise in particular has been associated with several hypertension outcomes

·         Few studies, however, have investigated the relation of aircraft noise to cardiovascular disease, in part because studies surrounding a small number of airports are not typically adequately powered

What this study adds

·         Long term exposure to aircraft noise is positively associated with hospitalization for cardiovascular disease

·         The association between aircraft noise and hospitalization for cardiovascular disease is not confounded by air pollution, road density, or area level socioeconomic status

·         There may be a threshold for the association between aircraft noise and hospitalization for cardiovascular disease

·         Source:BMJ

Aircraft Noise and CVD: Two New Studies Bolster Link.


Aircraft noise from some of the world’s busiest airports is linked to an increased risk of hospital admissions for cardiovascular disease, according to two new papers. The studies broaden concerns about the impact of living close to airports; previously, aircraft noise, as well as other “sound pollutants,” has been linked to hypertension.

In the first of two studies published online October 8, 2013 in BMJ,Dr Anna L Hansell (Imperial College London, UK) and colleagues assessed hospital admissions for 3.6 million people living near Heathrow Airport. Their paper linked daytime and nighttime aircraft noise and hospital visits for stroke, coronary heart disease, and cardiovascular disease by comparing residents in the noisiest areas with those living farther from the airport.

They found that, after adjustment for confounders, high-noise areas (>63 dB) had significantly increased risks for all three diagnostic codes as compared with the quieter areas (<51 dB).

High vs Low Aircraft Noise Exposure

Admission diagnosis Relative risk 95% CI
Stroke 1.24 1.08–1.43
Coronary artery disease 1.21 1.12–1.31
Cardiovascular disease 1.14 1.08–1.20

In the second paper, Dr Andrew W Correia (NMR Group, Somerville, MA) and colleagues looked at hospitalization for cardiovascular disease among subjects 65 years or older according to “contours of aircraft noise levels” around 89 airports in the US[2].

They report that every 10-dB increase in noise exposure (by zip code) was associated with a 3.5% higher rate of hospital admissions for cardiovascular disease. The observation held up after they controlled for other covariates, including air pollution as well as ethnic and socioeconomic factors. Importantly, note the authors, the effects were particularly marked at the highest levels of aircraft noise (above the 90th percentile for noise exposure) suggesting a threshold effect above 55 dB.

In an accompanying editorial[3], Dr Stephen Stansfeld (Barts and the London School of Medicine, UK) asserts: “the link seems real.”

The findings also echo a somewhat larger body of work looking at traffic noise, including the large HYENAstudy. He notes that a link between aircraft noise and stroke, seen in the Hansell et al paper, “is new and fits with associations between aircraft noise and hypertension and between road traffic noise and death from stroke.”

Other factors that could not be controlled for in the current analyses include individual-level confounders, including smoking status and household income, he notes. “There is a need for prospective cohort studies of exposure to aircraft and road traffic noise . . . that might also take account of air pollution, social disadvantage, and migration in and out of study areas,” Stansfeld writes.

Still, he continues, the results have implications for the siting of airports, he concludes. “Planners need to take this into account when expanding airports in heavily populated areas or planning new airports.”

Hansell disclosed receiving consultancy fees from AECOM as part of a UK Department for Environment, Food and Rural Affairs report on health effects of environmental noise. Disclosures for the coauthors are listed in the paper. Stansfeld disclosed being a member of the Acoustic Review Group for High Speed 2. Correia et al had no conflicts of interest.