Physicians' Academy for Cardiovascular Education

High exposure to aircraft noise increases CV morbidity and mortality

Literature - Hansell, Correia et al., BMJ Oct 2013 - BMJ. 2013 Oct 8


Aircraft noise and cardiovascular disease near Heathrow airport in London: small area study.

Hansell AL, Blangiardo M, Fortunato L et al.
BMJ. 2013 Oct 8;347:f5432. doi: 10.1136/bmj.f5432
 

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

Correia AW, Peters JL, Levy JI, et al.
BMJ. 2013 Oct 8;347:f5561. doi: 10.1136/bmj.f5561
 

Airport noise and cardiovascular disease.

Stansfeld S.
BMJ. 2013 Oct 8;347:f5752. doi: 10.1136/bmj.f5752
 

Background

BMJ recently published two observational studies that aimed to investigate a possible association of aircraft noise with risk of stroke, coronary heart disease and cardiovascular (CV) disease in the general population.
Although annoyance of the population about aircraft noise has often been described, little effort has been directed at studying the potential effects of this type of noise on cardiovascular health. Studies that have been performed mostly focused on blood pressure and the risk of hypertension, but results are inconsistent.
Noise is associated with activation of the sympathetic nervous system [1]. Chronic exposure to noise has been shown to increase blood pressure in animal models [2,3] and to higher noradrenaline levels in humans [4]. Acute exposure to non-habitual loud noise yields an increase in adrenaline levels [4], and raised blood pressure [5] and heart rate [6] in humans in an experimental setting.
 
Hansell and co-workers studied the risk of stroke, coronary heart disease and CV disease hospital admission and mortality in areas near Heathrow Airport (West-London), one of the busiest airports in the world. A standard noise metric was used to express the relative loudness perceived by human hearing.
  • Stroke, coronary heart disease and CV disease all showed increased risk of hospital admission with increasing exposure to aircraft noise.
  • When comparing daytime aircraft noise of >63 dB with <51 dB, the relative risk for stroke was 1.24 (95%CI: 1.08-1.43), for coronary heart disease it was 1.21 (95%CI: 1.12-1.31) and for CV disease it was 1.14 (95%CI: 1.08-1.20).  Exposure to high night-time aircraft noise (>55 dB vs. <50 dB) yielded similarly increased risks.
  • Relative risks of mortality at higher noise exposure were numerically similar to those for hospital admissions, but with wider confidence intervals, reflecting the lower number of events.
  • Adjustment for particulate air pollution and road traffic noise did not significantly change the results.
Hansell et al. conclude that the population exposed to the highest level of daytime and night time aircraft noise are at excess risk of stroke, coronary heart disease and CV disease.
 
Correia and colleagues investigated the relationship between airport-related noise and risk of hospital admission for CV disease in persons aged over 65 years residing near 89 airports across the United States.
  • Consistent associations between noise and cardiovascular admission rates were only seen in the highest exposure group (>55 dB).
    In a statistical model that corrected for age, sex and race, an increase of 10 dB was related to an increase of 2.9% (95%CI: 0.8%-5.0%) in hospital admission rate, in people who were exposed to the highest 10% of noise within zip code areas. After further adjustment for zip code level socioeconomic status and demographic variables, the relative rate dropped to a marginally significant 1.6% excess hospital admission (95%CI: -0.2% to 3.5%). When pollution variables were further added to the model, an increase of the noise by 10 dB in the 90th centile of noise was associated with an increase of 3.5% (95%CI: 0.2-7.0) in the rate of hospital admission for CV reasons.
  • Associations were not sensitive to adjustment for a proxy for road noise and near-road air pollution.
  • It was calculated that 2.3% of hospital admissions for cardiovascular disease in this Medicare cohort were attributable to aircraft noise. 23% of the cohort was exposed to a noise level greater than 55 dB, and this population contributed half of the attributable hospitalisations.
Correia et al. conclude that high aircraft noise exposure is statistically significantly associated with a higher relative rate of hospital admission for CV disease in people aged 65 or older who live near airports. The data suggest that there may be a threshold for the effect of noise exposure on CV hospitalisations.
 
In an editorial, S Stansfeld comments on these two studies in light of previous work relating aircraft  noise to cardiovascular disease. The current studies are better powered and show a new link between aircraft noise and death with stroke, which fits with earlier observations between aircraft noise and hypertension, and road traffic noise and death from stroke.
Naturally, these studies could not take individual-level confounding factors, such as income and smoking, into account. Nevertheless, these studies provide evidence that aircraft noise may increase morbidity and mortality from cardiovascular disease. These findings imply that aircraft noise is not only a source of annoyance, sleep disturbance and reduced quality of life, but that it may also directly affect health of the population living near an airport.
 

References

1. Babisch W. The noise/stress concept, risk assessment and research needs. Noise Health 2002;4:1-11.
2. Medoff HS, Bongiovanni AM. Blood pressure in rats subjected to audiogenic stimulation. Am J Physiol 1945;143:300-5.
3.Yeakel EH, Shenkin HA, McCann SM. Blood pressures of rats subjected to auditory stimulation. Am J Physiol 1948;155:118-27.
4. Ising H, Braun C. Acute and chronic endocrine effects of noise: review of the research conducted at the Institute for Water, Soil and Air Hygiene. Noise Health 2000;2:7.
5. Andrén L, Hansson L, Björkman M, Jonsson A. Noise as a contributory factor in the development of elevated arterial pressure. Acta Med Scand 1980;207:493-8.
6. Holand S, Girard A, Laude D, Meyer-Bisch C, Elghozi JL. Effects of an auditory startle stimulus on blood pressure and heart rate in humans. J Hypertens 1999;17:1893-7.
 

Find the paper by Hansell et al. on Pubmed
Find the paper by Correia et al. on Pubmed
Find the editorial by Stansfeld et al. on Pubmed