Low Frequency Noise and Health

Here are two recent slideshow presentations that were given to residents of our community.
Click the images to download the PDF files (less than 2 Mb each).

Please visit the Acoustic Ecology Institute's News Page.

The anechoic chamber presentation was given by NMCARES member Dr. Eileen Mulvihill.
Read her July 08, 2009 article, Wind Farms' Effects on Health, in the Las Vegas Optic.

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Vibroacoustc Disease

ILFN is the term for infrasound (0-20Hz) + low frequency sound(20-500Hz)
Vibroacoustic disease (VAD) is the name given to pathology resulting from long-term exposure to ILFN. A small number of people are immediately sensitive to ILFN, mainly through the impact on the vestibular system and these symptoms are often described by people living close to large turbines, fans, airport runways or busy freeways. Chronic exposure to high levels of ILFN over a period of years will impact most people, and was first described in aeronautical workers.
Suspicion of ILFN should arise if a patient exhibits one or more of the following complaints:

• "I wake up tired, I don't rest during my sleep".
• "I hear too much, I'm very sensitive to noise, noise drives me crazy".
• "Sometimes, while in a mall or restaurant I feel like I can't breathe".
• "I have a lot of palpitations".
• "I have this cough and I don't smoke, my throat is constantly irritated and I get hoarse for no reason".

Or if the patient enters with one of the following diagnosis:

• Late-onset epilepsy.
• Balance disorders.
• Migraines
• Respiratory tract tumor, especially if a non-smoker.

It has been twenty-five years since the final version of the Hearing Conservation Amendment was issued by the Occupational Safety and Health Administration in the U.S. Department of Labor. Since that time, some things have changed and others have stayed exactly the same. Certainly the noise-exposed workforce is more knowledgeable about the hazards of noise, and the use of hearing protection devices (HPDs) has greatly increased. There have been significant strides in the technology for measuring noise and for protecting hearing through HPDs. But there is considerable room for improvement. Some of the noise regulation's provisions are embarrassingly outdated, some are in dire need of improvement, and others, such as the requirements for engineering noise control, are not being enforced. Sadly, there seems to be little progress in reducing overall noise exposure levels.

There also seems to be a tremendous disconnect between the accepted reality of occupational hazards associated with low frequency sound and the widespread ignoring of chronic environmental exposure of whole communities to the ILFN of airports, traffic and now.....Industrial Wind Farms.

The presentation below is a summary in response to reports suggesting that identification of "Wind Turbine Syndrome" is unnecessarily alarming and misleading to the general public and that VAD, or Vibroacoustic Disease, is part of some conspiracy. Many proponents of industrial wind facilities charge that there are no adverse effects of low-frequency noise on human health because there are no "peer-reviewed" studies published on the subject (peer review is a process scientific journals use, sending the paper being considered for publication to 2-3 people who are considered experts in the field. The paper is only published if it meets the standards of the reviewers). According to Wind Industry publications, surveys of peer-reviewed scientific literature have found no evidence linking wind turbines to human health concerns. That comment is misleading. It is true that no peer-reviewed publication specifically identifies wind turbines as the cause of a variety of health affects, but the literature has many examples of studies demonstrating the adverse effect of low-frequency sound. Turbines produce a lot of low-frequency sound although the practice in the Industry is to use sound meters that are not calibrated to detect it. One of their references cited Health Impact Of Wind Turbines, prepared by the Municipality of Chatham-Kent Health & Family Services Public Health Unit. This review is of interest because of recent articles identifying a cover-up by civil servants who removed warnings of health effects of noise from wind turbines from a government study of 133 windfarms.

• Marciniak W, Rodriguez E, Olszowska K, Botvin I, et al.in Aviation, Space & Environmental Medicine 1999; 70 (3, Suppl): A46-53. Echocardiography in 485 aeronautical workers exposed to different noise environments This is the most thorough medical study we found. The overall results of the echocardiographic evaluation of 485 aeronautical workers with long term occupational exposure to low frequency sound found increased thickening of mitral, tricuspid, aortic and pulmonary valves, pericardium and endocardium that correlated with the level of noise exposure. The findings were unusual for the population at large of the same age group (average 37yr, range 19-63), and led the authors to speculate that this form of thickening is VAD specific and caused by exposure to ILF noise.
• A paper presented at the RTO AVT Symposium on "Ageing Mechanisms and Control: Developments in Computational Aero- and Hydro-Acoustics", held in Manchester, UK, 8-11 October 2001, and published in RTO-MP-079(I) Low Frequency Noise: A Major Risk Factor in Military Operations by Col. N.A.A. Castelo Branco, MD. Noise is a major risk factor in many military environments. Noise is treated as a pollutant that can cause hearing damage and speech interference within the various vehicles and manned stations. Thus, when protection against noise becomes an issue, the audible frequency bands (which coincide with those where speech occurs) are the focus of regulation and targeted for minimization. Protection against noise is thus focused on these higher frequencies (>500 Hz), while the bands of lower frequencies (<500 Hz) are neglected, and non-audible bands, infrasound (<20Hz) are ignored. This decades-old policy is based on an erroneous assumption: "Noise only affects the ear." This assumption pervades standard noise assessment procedures, the most blatant example of which is the use of the A-weighting system. This filtering system imitates human hearing, i.e., it de-emphasizes the lower frequencies and, naturally, ignores the non-audible infrasonic bands of acoustic phenomena
• A Science & Global Security 2001 article by Jurgen Altmann "Acoustic Weapons- A Prospective Assessment" reviews 164 publications. In his review he states "infrasound does not have the alleged drastic effects on humans" Whereas the effects are not powerful enough to be useful as an acoustic weapon, he recognizes that "annoyance, discomfort and pain are the consequence of increase pressure levels...beyond hearing, some disturbance of the equilibrium, and intolerable sensations mainly in the chest can occur."
• An October 2004 study published by Vinokur and associates entitled "Acoustic noise as a nonlethal weapon" states. "In the short run, high-intensity noise is dangerous to the auditory and respiratory systems and provokes negative psychological effects" (fear and panic). The long-term effects (that last hours and more) are not discussed in this article.
• James Jauchem and Michael Cook published an article in Feb 2007 entitled "High-Intensity Acoustics for Military Nonlethal Applications: A Lack of Useful Systems" They review 138 articles and state that study results are often conflicting- "Although high-intensity infrasound significantly disrupted animal behavior in some experiments, the generation of such energy in a volume large enough to be of practical use in unlikely because of basic physical principles."

There is also a large collection of literature published by a number of public health agencies both in the US and in Europe (as well as many other foreign countries).

• In November 2001 the National Institute of Environmental Health (NIEHS) published a review Infrasound Toxicologoical Summary. where they reviewed over 100 relevant studies that differed widely in their experimental design and selection of endpoints for evaluation. They state that the study variability somewhat limits the conclusions that can be drawn regarding the potential to cause adverse health effects in humans without further expert evaluation and review. Among the more consistent findings in humans were changes in blood pressure, respiratory rate, and balance. Their report concludes with; "In summary, though a number of biological effects have been reported attributed to infrasound exposure in experimental settings, any assessment of potential adverse human health effects resulting from environmental infrasound exposure is hampered by numerous gaps in our current knowledge." Examples of critical data gaps include a lack of high quality long-term experimental studies of infrasound, and inadequate characterization of environmental infrasound in community settings. "Thus, this document may serve as a starting point for determining what types of experimental toxicology research or testing may be useful for further characterizing of potential adverse health effects of infrasound exposure in humans." Unfortunately, there is no indication that there was ever any follow-up by the NIEHS. An examination of the NIEHS website found only 3 additional articles on low frequency sound effects on human health. Nothing after 2005. If the Bush administration was able to muzzle NASA and all of the science associated with global warming, ask yourself how the NIEHS was operating over the previous 8 years.
• In July of 2002, Ising and Ising published a study Chronic Cortisol Increases in the First Half of the Night Caused by Road Traffic Noise that discusses how noise, perceived as a threat, stimulates release of cortisol. This also occurs during sleep, thus increasing the level of night cortisol, which may interrupt recreative and other qualities of sleep. Measurements were made of the effect on children who, because of traffic changes, had become exposed to a high level of night lorry noise. The indoor noise spectrum for high levels typically peaked at around 60Hz, at 65dB, with a difference of maximum LC and LA of 26dB. The difference of average levels was 25dB, thus indicating a low frequency noise problem. Children exposed to the higher noise levels in the sample had significantly more problems with concentration, memory and sleep and also had higher cortisol.
• Also in July of 2002 Wolfgang Babisch published his first review The Noise/Stress Concept, Risk Assessment and Research Needs that states:In principle, the noise/stress hypothesis is well understood: Noise activates the pituitary-adrenal-cortical axis and the sympathetic-adrenal-medullary axis. Changes in stress hormones including epinephrine, norepinephrine and cortisol are frequently found in acute and chronic noise experiments. The catecholamines and steroid hormones affect the organism's metabolism. Cardiovascular disorders are especially in focus for epidemiological studies on adverse noise effects. However, not all biologically notifiable effects are of clinical relevance. The relative importance and significance of health outcomes to be assessed in epidemiological noise studies follow a hierarchical order, i.e. changes in physiological stress indicators, increase in biological risk factors, in.... Noise policy largely depends on considerations about cost-effectiveness, which may vary between populations. Limit or guideline values have to be set within the range between social and physical well-being - between nuisance and health. The cardiovascular risk is a key-outcome in non-auditory noise effects' research because of the high prevalence of related diseases in our communities.
• The followup CORDIS study was published in 2002 The joint effect of industrial noise exposure and job comlexity on all-cause mortality - The CORDIS study (Abstract) where authors Melamed and Froom continue to analyze their results. They found that noise exposure is particularly detrimental to health for workers engaged in complex jobs. Therefore in this 12-year study we attempted to determine the combined effect of job complexity and noise exposure on all-cause mortality in 2606 industrial workers. We divided the workers into four groups based on a combination of either high or low noise exposure, and whether they performed simple or complex jobs. There was an increased risk for all-cause mortality (OR = 1.86, 95% CI = 1.04-3.32), in workers who performed complex jobs under high noise exposure levels compared to those who performed simple jobs under low noise exposure. This remained significant even after adjusting for possible confounding variables. There was a trend for a more pronounced effect among less educated workers, among blue-collar workers, and in those with higher tenure.
• In May of 2003 Dr. Geoff Leventhall prepared A Review of Published Research on Low Frequency Noise and its Effects for DEFRA, the Department of Environment, Food and Rural Affairs. This article sites over 200 publications and explores similar findings from authors all over the world. He concludes with, We know that problems arise fairly widely, and on an international scale.It is no longer necessary to make a case for work on low frequency noise, but rather the direction of research should maximize the benefit to the suffers.
• In June of 2004, H. Ising and B. Kruppa from the German Federal Environmental Agency published a review in Noise & Health 2004 Vol 6: 5-13. Health effects caused by noise: Evidence in the literature from the past 25 years (Abstract). They cite 41 articles, and identify traffic noise as the most important source of environmental annoyance, followed by airplanes taking off and landing. "For an immediate triggering of protective reactions (fight/flight or defeat reactions) the information conveyed by noise is very often more relevant than the sound level. For this reason, even during sleep the noise may be categorized as danger signals and induce the release of stress hormones." The Environmental Expert Council reports that "these studies show a consistent trend towards an increased cardiovascular risk if the daytime immission level exceeds 65 dB(A)." And, "most of the previous studies on the extra-aural effects of occupational noise have been invalidated by exposure misclassifications. In future studies on health effects of noise a correct exposure assessment is one of the most important preconditions."
• Also in 2004, W. Babisch from the Division of Environment and Health of the Federal Environmental Agency in Berlin published a review, Health Aspects Of Extra-Aural Noise Research. The WHO definition of "health" is critically discussed in its broad context. Decision making in noise policy has to be made in the evaluation range between social and physical well-being. The term "adverse" is a crucial one in the process of risk characterization. In toxicological terms it refers to the single event itself; in psychosocial terms it refers to the relative number of people affected. The evidence of the association between community noise and cardiovascular outcomes is evaluated. The results of epidemiological studies in this field can be used for decision making when assessing maximum acceptable noise levels in the community. Since dose response relationships were mostly studied with respect to road traffic noise, inferences have to be made with respect to aircraft noise. Issues of statistical inferring are discussed.
• 2005 saw several studies on ILFN and an increased incidence of hypertension. Occupational exposure to noise and hypertension in pilots. The role of occupational exposure to noise as a hypertension risk factor has not been established sufficiently. The aim of the study is to evaluate whether chronic exposure to different levels of noise in two groups of pilots, operating with two types of aircraft, could be a risk for hypertension, what relevance the parameters (intensity, duration and type) of exposure can have and, lastly, whether there are any links between hearing impairment and hypertension. After excluding pilots with confounding factors, a study was made of 77 male pilots of turboprop planes (group A) and 224 male pilots of jet aircraft (group B), matched by age and working life. Blood pressure (supine and standing positions) and heart rate were measured. Electrocardiogram, stress tests on a cycle ergometer, sound-level measurement and audiometric tests were also done. Pilots of group A were exposed to Leq of 93 dBA while pilots of group B were exposed to the Leq of 79 dBA. Significant results in group A compared to group B were found between heart rate, blood pressure, drop in blood pressure, parameters (intensity, duration and type) of exposure to noise and between hearing damage and hypertension. The findings suggest that chronic exposure to noise is a risk factor for blood hypertension in pilots exposed to high noise levels, and that the drop in blood pressure may be a sign of more sensitive effect of noise on blood pressure, according to other studies in literature.
• A 2006 study Noise-induced annoyance and morbidity results from the pan-European LARES study (Abstract) found that traffic noise (road noise, railway noise, aircraft noise, noise of parking cars), is the most dominant source of annoyance in the living environment of many European countries. The subjective experience of noise stress can, through central nervous processes, lead to an inadequate neuro-endocrine reaction and finally lead to regulatory diseases. Within the context of the LARES-survey (Large Analysis and Review of European housing and health Status), noise annoyance in the housing environment was collected and evaluated in connection with medically diagnosed illnesses. Adults who indicated chronically severe annoyance by neighbourhood noise were found to have an increased health risk for the cardiovascular system and the movement apparatus, as well as an increased risk of depression and migraine. Furthermore adults with chronically strong annoyance by traffic noise additionally showed an increased risk for respiratory health problems. With regards to older people both neighbourhood and traffic noise indicated in general a lower risk of noise annoyance induced illness than in adults. It can be assumed that the effect of noise-induced annoyance in older people is concealed by physical consequences of age (with a strong increase of illnesses). With children the effects of noise-induced annoyance from traffic, as well as neighbourhood noise, are evident in the respiratory system. The increased risk of illness in the respiratory system in children does not seem to be caused primarily by air pollutants, but rather, as the results for neighbourhood noise demonstrate, by emotional stress.
• An update by W. Babisch in 2006 Transportation noise and cardiovascular risk: Updated Review and synthesis of epidemiological studies indicate that the evidence has increased. (Abstract) The review provides an overview of epidemiological studies that were carried out in the field of community noise and cardiovascular risk. The studies and their characteristics are listed in the tables. Risk estimates derived from the individual studies are given for 5 dB(A) categories of the average A-weighted sound pressure level during the day. The noise sources considered in the studies are road and aircraft noise. The health endpoints are mean blood pressure, hypertension and ischaemic heart disease, including myocardial infarction. Study subjects are children and adults. The evidence of an association between transportation noise and cardiovascular risk has increased since the previous review published in Noise and Health in the year 2000.
• In 2008 a large Indian study was published. The relationship between noise frequency components and physical, physiological and psychological effects of industrial workers (Abstract) This paper has made an attempt to identify various noise frequency components to which the workers of six major industries in Mysore (Karnataka State, India) are being exposed, and their effects on the physical, physiological, and psychological systems of the working community with respect to their noisy industrial environment. The study results showed that the sampled industrial workers were repeatedly being exposed to noise of dominant low- and mid-octave band center frequencies. It is found that symptoms such as 'eye ball pressure,' 'awakening from sleep,' 'pains in neck,' 'frequent ear vibration,' 'chronic fatigue,' 'repeated headache,' 'backache,' and 'repeated ear pulsation' are observed to be highly associated with low- and mid-octave band center frequency noise exposure among the sampled workers. Furthermore, among the major psychological symptoms identified to be associated with octave band center frequencies, it is evident that 'irritability' is highly associated with low- and mid-octave band noise frequency characteristics.
• Another 2008 study Hypertension and Exposure to Noise Near Airports: the HYENA StudyThe HYENA (Hypertension and Exposure to Noise near Airports) study aimed to assess the relations between noise from aircraft or road traffic near airports and the risk of hypertension. We measured blood pressure and collected data on health, socioeconomic, and lifestyle factors, including diet and physical activity, via questionnaire at home visits for 4,861 persons 45-70 years of age, who had lived at least 5 years near any of six major European airports. We assessed noise exposure using detailed models with a resolution of 1 dB (5 dB for United Kingdom road traffic noise), and a spatial resolution of 250 x 250 m for aircraft and 10 x 10 m for road traffic noise. Results We found significant exposure-response relationships between night-time aircraft as well as average daily road traffic noise exposure and risk of hypertension after adjustment for major confounders. For night-time aircraft noise, a 10-dB increase in exposure was associated with an odds ratio (OR) of 1.14 [95% confidence interval (CI), 1.01-1.29]. The exposure-response relationships were similar for road traffic noise and stronger for men with an OR of 1.54 (95% CI, 0.99-2.40) in the highest exposure category (> 65 dB; ptrend = 0.008). Our results indicate excess risks of hypertension related to long-term noise exposure, primarily for night-time aircraft noise and daily average road traffic noise.
• And in 2009, Risk of hypertension from exposure to road traffic noise in a population-based sample Prevalence and incidence of hypertension were examined in a Swedish municipality, partly affected by noise from a highway (20000 vehicles/24h) and a railway (200 trains/24h). A-weighed 24-hour average sound levels (LAeq,24h) from road and railway traffic were calculated at each residential building using a geographic information system and a validated model. Physician-diagnosed hypertension, antihypertensive medication, and background factors were evaluated in 1953 persons using postal questionnaires (71% response rate). Prevalence ratios and odds ratios (ORs) were calculated for different noise categories. Based on year of moving into the residence and year of diagnosis, person-years and incidence rates of hypertension were estimated, as well as relative risks including covariates, using Poisson and Cox regression. RESULTS: When road traffic noise, age, sex, heredity, and body mass index were included in logistic regression models, the OR for hypertension was 1.9 (95% CI 1.1 to 3.5) in the highest noise category (56-70 dBA), allowing for >10 years of 'latency', and in men it was 3.8 (95% CI 1.6 to 9.0). The incidence rate ratio was increased in this group of men, and the relative risk of hypertension in a Poisson regression model was 2.9 (95% CI 1.4 to 6.2). There were no clear associations in women or for railway noise. CONCLUSIONS: The study shows a positive association between residential road traffic noise and hypertension among men, and an exposure-response relationship. While prevalence ratios were increased, findings were more pronounced when incidence was assessed.

The VAD team was formed in 1980 to investigate the biological effects of low frequency noise exposure. They have a series of peer-reviewed articles describing their identification of vibroacoustic disease. Their leader, Dr. N.A.A.Castelo Branco has been the senior investigator on this subject for over 25 years. He has been thorough and consistent in his push to have VAD recognized as a global problem that needs to be addressed by all governments. The WHO recognizes his outstanding contribution.

Biographies of Drs. M. Alves-Pereira and Nuna Alvares de Abreu Castelo Branco

Nuno Alvares de Abreu Castelo Branco, joined the Portuguese Air Force in 1962 and is a retired Colonel of this branch of the Armed Forces. He graduated from Lisbon University Medical School in 1971 and in 1977 was awarded the degree of Aerospace Pathology Specialist by the Armed Forces Institute of Pathology in Washington, D.C., USA and a degree in Aerospace Medicine at Brooks Air Force Base in San Antonio, TX, USA. He became a Medical Specialist in Surgical Pathology, at the Civilian Hospitals of Lisbon, Portugal. In 1979 he was promoted to chief medical officer at an aircraft manufacturing rework and maintenance facility owned and operated by the Portuguese Air Force. Since 1980, he has coordinated a team of researchers who investigate the biological effects of low frequency noise exposure, known as the VAD Team. M. Alves-Pereira has a B.S. in Physics from SUNY at Stony Brook and a Masters in Biomedical Engineering from Drexel University in Philadelphia. She is currently concluding her Doctoral studies at the Department of Environmental Engineering and Sciences at the New University of Lisbon, in Portugal. She has been working with the VAD Team since 1988 and has been the Assistant Coordinator of this team since 1999.

An overview of the VAD team's publications

Links to many of the VAD team articles can be found on the side panel at the top of this page.Initial VAD studies focused on occupational settings within a military aeronautical plant. In late 1980's, they expanded to military fixed- and rotary winged aircraft. In 1999, the VAD team began its studies within commercial airliners and expanded to other occupations with significant exposure to low frequency sound. The results of these studies demonstrated the importance of infrasound as an agent of disease. These are peer reviewed articles that report on research related to mechanisms in cells that stimulate biological effects in response to infrasound and low frequency noise. VAD (vibroacoustic disease) involves an abnormal growth of elastin and collagen within the extracellular matrix surrounding the heart, kidney, lung and trachea of VAD patients. Exposure to low frequency noise results in cellular growth that reinforces the structure of the above-mentioned organs and causes a change in communication between and through cells in the body. Until about 2004, mainstream acoustic science embraced the idea that only auditory noise causes hearing loss by effecting cellular communication through biochemical pathways. The authors of these articles challenge that view and recognize that there are biomechanical forces involved in a wider range of impacts on human health.

The authors go on to suggest that the current state of inquiry in this science of auditory and sub-auditory effects is primitive. They suggest that acoustical phenomenon - both auditory and sub auditory - have effects on biological tissue. VAD is a result of exposure to ILFN (Infrasound and low-frequency noise) thought to be within the range of 0-500 HZ. Measuring noise in A-weighted decibels is not sufficient according to the authors. The authors suggest that we can understand noise as we have learned to understand electromagnetic energy, i.e., we may not see it or feel it but it has effects (such as x-rays). The authors suggest that ILFN affects organs differentially because each the tissue in each organ has its own resonance properties.

Anyone who is skilled in the art of physical therapy knows that the mechanical properties, behavior and movement of our bodies are as important for human health as chemicals and genes. However, only recently have scientists and physicians begun to appreciate the key role which mechanical forces play in biological control at the molecular and cellular levels. An article by Dr. D. Ingber, who first described the model of tensegrity, describes what his team has learned over the past 30 years as a result of their research focused on the molecular mechanisms by which cells sense mechanical forces and convert them into changes in intracellular biochemistry and gene expression-a process called "mechanotransduction". Ingbers Prog Biophys Mol Biol. 2008 Jun-Jul;97(2-3):163-79. Epub 2008 Feb 13 work has revealed that molecules, cells, tissues, organs, and our entire bodies use "tensegrity" architecture to mechanically stabilize their shape, and to seamlessly integrate structure and function at all size scales. Through the use of this tension-dependent building system, mechanical forces applied at the macroscale produce changes in biochemistry and gene expression within individual living cells. This structure-based system provides a mechanistic basis to explain how application of physical impacts, such as low frequency sound, might influence cell and tissue physiology.

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