(RxWiki News) You might expect to hear that aircraft noise could lead to hearing troubles, but that wasn't the focus of two new studies. The studies both explored connections between exposure to airport noise and cardiovascular disease.One study focused on older adults living near a number of different US airports and the other on people of all ages living near one United Kingdom (UK) airport.
Both studies found an association between higher aircraft noise levels and higher risk for cardiovascular issues.
"Wear ear protection when around loud sounds."
The first study, led by Andrew W. Correia, PhD, Quantitative Analyst with NMR Group in Somerville, Massachusetts, focused on people aged 65 years or older who lived near 89 different US airports.
Aircraft noise levels for the airports (measured in decibels, or dB) were provided by the US Federal Aviation Administration for the year 2009.
Census population data and health insurance data for 2,218 zip codes surrounding the airports were analyzed alongside the noise information. Health insurance data came from the national medical insurance (Medicare) program for people aged 65 or older and accounted for 6,027,363 people in the included zip codes.
After adjusting for factors like demographics and pollution levels, Dr. Correia and team found that on average, a zip code with 10 dB higher noise exposure had a 3.5 percent higher hospital admission rate for cardiovascular issues.
"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," Dr. Correia and team concluded.
The second study, led by Anna L Hansell, PhD, MSc, Assistant Director of the UK Small Area Health Statistics Unit of Imperial College London's School of Public Health, focused on one airport and a possible association with stroke, coronary heart disease and cardiovascular disease in people of all ages.
Dr. Hansell and team conducted their study on 12 London boroughs and nine districts to the west of London that were exposed to aircraft noise from London's Heathrow airport. This area included about 3.6 million residents.
Aircraft noise information was provided by the Civil Aviation Authority. The researchers also looked at the risk for hospital admissions for cardiovascular conditions and risk for death from these conditions using information from the Office for National Statistics and Department of Health for the years 2001 through 2005. Data was adjusted for factors like age, gender and ethnicity.
The study showed an association between risk for both hospital admission and death from a cardiovascular condition and higher levels of both daytime and nighttime aircraft noise.
Areas experiencing the highest levels of daytime aircraft noise (greater than 63 dB) were found to have 1.24 times the stroke risk compared to areas with the lowest levels of noise (51 dB or less). The risk for coronary heart disease was 1.21 and the risk for cardiovascular disease was 1.14 when comparing the areas with the most noise to the areas with the least noise.
Similar, but weaker, results were seen for risks of death between areas with higher and lower aircraft noise levels.
Dr. Hansell and team explained that exposure to noise could potentially activate the neuroendocrine system, possibly leading to increases in heart rate, blood pressure or stress hormone levels. Additional research is needed to explore the possible link between aircraft noise and cardiovascular disease.
Both sets of study authors noted that a number of other factors could have played a role in these findings. Further research needs to be completed to confirm the findings of both Dr. Correia's US study and Dr. Hansell's UK study.
Both studies were published online October 8 by the British Medical Journal (BMJ). Dr. Correia and team reported no conflicts of interest. Two authors from Dr. Hansell's team reported receiving consulting funds from AECOM (a global design firm) for work on a report about the health effects of environmental noise.