Tag Archive: researchers

New Zealand researchers agree: hearing loss is probably a dementia risk factor

By Daniel Fink, MD, Chair, The Quiet Coalition

Many people don’t understand the process of medical and scientific research and how different hypotheses are developed and tested, using different methods in different human populations with animal studies when possible, until a consensus is reached. This was how researchers–including doctors, epidemiologists, researchers using animal models, and scientists doing basic research at the cellular, molecular, and genetic levels–figured out that cigarette smoke causes cancer and many other diseases, and how it does this. Despite the broad scientific and public health consensus, there are still skeptics, such as those at the conservative Heartland Institute, who say there is still doubt about whether smoking causes lung cancer. There is also a Flat Earth Society. Many Americans think that evolution is an unproven theory despite more than a century of research and strong evidence supporting evolution.

For the rest of us who believe in evidence-based science and evidence-based social and economic policies, our understanding of reality is always evolving based on the evidence. Sometimes something long thought to be true is found not to be correct after all. In medicine, one of the best examples may be ulcers in the stomach and small intestine, which for decades were thought to be caused by too much stomach acid but were found to be caused by bacteria. Australians Barry Marshall and J. Robin Warren won the Nobel Prize in 2005 for making this discovery. But most of the time an early hypothesis is confirmed by one study, and then another, and then by studies in animal models, and then by basic science research, until a broad consensus is reached.

This is what is happening with the hypothesis that hearing loss is associated, probably causally, with dementia. Dr. Frank Lin at Johns Hopkins University may be the best-known researcher in this field but other researchers in other countries are studying the same question. This report from New Zealand discusses what is being done there. And this report from the UK discusses research presented there.

It’s always good to have confirmation of research by different researchers using different techniques in different populations. Such confirmation helps validate initial findings in one population and helps move our understanding forward. We know that noise exposure causes hearing loss. If hearing loss is shown to be causally associated with the development of dementia, then preventing hearing loss should help to also prevent dementia. One theory is that the brain needs input to maintain function, and without auditory input and/or social connections, brain function declines. Another theory is that whatever degenerative process causes hearing loss also causes loss of mental function. Ongoing studies, providing hearing aids to those with hearing loss but not to others and then measuring intellectual function over time, may elucidate the cause-effect relationship. Regardless, we don’t need to wait for more evidence for the link. Preserving one’s hearing should be enough reason to avoid loud noise or to wear ear plugs if you can’t.

Dr. Daniel Fink is a leading noise activist based in the Los Angeles area. He serves on the board of the American Tinnitus Association, is the interim chair of Quiet Communities’s Health Advisory Council, and is the founding chair of The Quiet Coalition, an organization of science, health, and legal professionals concerned about the impacts of noise on health, environment, learning, productivity, and quality of life in America.

Noise exposure directly damages rat brains. What does it do to humans?

Daniel Fink, MD, Chair, The Quiet Coalition

The evidence keeps mounting, almost on a daily basis, that noise is a health and public health hazard. Just last month, an article by researchers in Italy found that noise exposure directly damaged rat brains, producing changes in DNA, neurotransmitters, and even morphological changes. (For those who might be skeptical of this report, there is an existing body of research on the effects of noise on the brain. I don’t understand the details of the newer scientific studies, and I’m always cautious because studies have shown that positive results get reported more frequently than negative results, but taken together with the new report, there is a large amount of research pointing to a direct effect of noise on the brain.)

The Italian study exposed rates to noise of 100 decibels for 12 hours. That level exceeds exposure levels for most humans–certainly for a half-day period–but probably not cumulatively for many who attend clubs, rock concerts, or have noisy hobbies such as woodworking or motorcycle riding.

Humans and rats are genetically very similar–experts argue about whether the rat and human genomes are 97% or 99% similar, and about how to measure this similarity–but regardless of the exact percentage, we’re not talking about applying data from a roundworm to humans. The basic similarities are there in organ and cellular biochemistry, structure, and function. So it’s very likely that noise is also a direct toxin to the human brain, with similar genetic, neurotransmitter, and morphological changes, and most likely at lower noise exposure levels, too.

So what can we do? The solution is simple: avoid loud noise exposure, and wear hearing protection if you can’t.

And one last thing–encourage legislators, regulators, and public health authorities to do more to protect us from exposure to unnecessary noise.

Dr. Daniel Fink is a leading noise activist based in the Los Angeles area. He serves on the board of the American Tinnitus Association, is the interim chair of Quiet Communities’s Health Advisory Council, and is the founding chair of The Quiet Coalition, an organization of science, health, and legal professionals concerned about the impacts of noise on health, environment, learning, productivity, and quality of life in America.

Can noise cause fertility problems?

By Daniel Fink, MD, Chair, The Quiet Coalition

A report in the New Scientist indicates the answer is “maybe.” Researchers in Denmark conducted a study that found an exposure-response relationship between noise and difficulty getting pregnant. The researchers made their discovery by analysing data from the Danish National Birth Cohort, a project that ran from 1996 to 2002, and focusing on women who had tried to get pregnant during the project “if traffic noise data was available for where they lived.” The study was controlled for factors like poverty levels and nitrogen oxide pollution.

Earlier research had suggested that 80% of women who were actively trying to get pregnant usually did so within six menstrual cycles, but the research team found that “for every 10 decibels of extra traffic noise around a woman’s home, there was a 5 to 8 per cent increased chance of it taking six months or longer.”  The article notes that it “is unclear whether traffic noise may be affecting women or their partners.”

New Scientist quotes Rachel Smith of Imperial College London, who finds the link between traffic noise and health worrying. Says Smith, “[b]ecause traffic noise is common, even a small effect on health could feasibly have a large impact across a population.”

Just as the Danish study was released, a South Korean study was reported that focused on long-term exposure to a noisy environment and male infertility.  The study by researchers at Seoul National University, which ran for eight years from 2006-2013, looked “at male infertility by analyzing data from 206,492 men aged 20-59 and calculating the participants’ levels of noise exposure.”  3,293 of the participants had an infertility diagnosis.

The researchers “found that, after taking into account factors such as age, income, BMI and smoking, men who were exposed to noise over 55 dB at night (a level equivalent to a suburban street or an air conditioner and above the World Health Organization night noise level) had a significantly higher chance of being diagnosed as infertile.”  Dr. Jin-Young Min, the study’s co-author, noted that infertility was becoming a significant public health issue, adding that it was known noise affected male fertility in animals, but his study was the first to show the risk of environmental noise on male infertility in humans.

Both studies’ findings have to be replicated in other countries and by other researchers, but the data keep mounting and show that environmental noise pollution is a ubiquitous, pervasive, and dangerous health problem.

Dr. Daniel Fink is a leading noise activist based in the Los Angeles area. He serves on the board of the American Tinnitus Association, is the interim chair of Quiet Communities’s Health Advisory Council, and is the founding chair of The Quiet Coalition, an organization of science, health, and legal professionals concerned about the impacts of noise on health, environment, learning, productivity, and quality of life in America.

 

Does the sound of chewing or pen clicking make you enraged?

You are not alone.  Misophonia is a disorder marked by “a hatred of sounds such as eating, chewing or repeated pen clicking.”  It’s not well understood, but the known universe just got a lot bigger thanks to a team of researchers from Newcastle University who have evidence that enraging noises are caused by a brain connection overdrive.

The lead researcher, Dr Sukhbinder Kumar of the Institute of Neuroscience at Newcastle University and the Wellcome Centre for NeuroImaging at University College London, said that, “[f]or many people with misophonia, this will come as welcome news as for the first time we have demonstrated a difference in brain structure and function in sufferers.”   With this news suffers may see the end of one problem they often face; namely, the casual dismissal of their complaints by medical professionals.  As Dr. Kumar notes, “[t]his study demonstrates the critical brain changes as further evidence to convince a sceptical medical community that this is a genuine disorder.”

 

Is nothing safe?

They look so innocent…

Experts Warn Popping Balloons Can Lead To Permanent Hearing Loss. Arrianne Del Rosario, Tech Times, writes about an experiment conducted by researchers at the University of Alberta “to find out how noise from bursting balloons can impact hearing,” and the results were stunning.  The researchers “measured the noise levels from popping balloons in three different ways: poking them with a pin, blowing them with air until they burst, and crushing them until they exploded.”  The loudest bang came from blowing up a balloon with air until it popped.  When it did, it was recorded at almost 168 decibels, “4 decibels louder than a high-powered, 12-gauge shotgun.”

It can’t be that bad, it’s just a balloon, right?  Wrong.  Del Rosario notes that the Canadian Centre for Occupational Health and Safety recommends that “the maximum impulse level should never go beyond 140 decibels.”  She adds that “[c]onstant exposure to noise, even as low as 85 decibels — for example, the noise from cars honking their horns in a city traffic — can make a person vulnerable to hearing loss.”

Del Rosario is right that damage to hearing can occur well under 140 decibles, but wrong to imply that damage only occurs at 85 decibels or higher.  85 decibels is the industrial-strength occupational noise exposure standard. Auditory damage can begin at only 75-78 decibels.  The only evidence-based safe noise exposure level is the EPA’s 70 decibel time weighted average for 24 hours.  Cautions noted noise activist Dr. Daniel Fink, “If it sounds too loud, it is too loud.  Hearing is an important social sense, and once cochlear hair cells and auditory synaptic junctions are damaged, they are gone forever.”

Whatever the decibel reading, the problem is that each exposure to loud noise leaves a mark.  As one of the researchers, Bill Hodgetts, advised:

Hearing loss is insidious — every loud noise that occurs has a potential lifelong impact. We want people to be mindful of hearing damage over a lifetime, because once you get to the back end of life, no hearing aid is as good as the once healthy built-in system in your inner ear.

Here’s some frightening noise news:

Dementia rates “higher near busy roads.”, “[t]he researchers adjusted the data to account for other risk factors like poverty, obesity, education levels and smoking so these are unlikely to explain the link.”

Said Dr. Hong Chen, from Public Health Ontario and one of the paper’s authors, “increasing population growth and urbanisation have placed many people close to heavy traffic, and with widespread exposure to traffic and growing rates of dementia, even a modest effect from near-road exposure could pose a large public health burden.”

Still, the study only suggests that there is a link. As Dr. Chen concludes, “[m]ore research to understand this link is needed, particularly into the effects of different aspects of traffic, such as air pollutants and noise.”

 

 

Noise pollution puts songbirds in danger,

making them more vulnerable to predators. Joanna Lawrence, Natural Science News, reports that researchers have found that “noise pollution prevents songbirds from hearing and responding to alarm calls.”  The researchers discovered that anthropogenic noise, “a form of noise pollution caused by human activities,” makes it difficult for the songbirds to hear alarms, leaving them “vulnerable to predation” (i.e., being eaten by other animals).   The research showed that the birds’ failure to hear and respond to alarms caused them “to continue feeding in dangerous situations.”  More research is needed, adds Lawrence, to “fully understand the ecological impacts of anthropogenic noise.”

Potential relief for those living near wind farms:

wind-turbines

Owl-inspired wing design reduces wind turbine noise by 10 decibels.  Some people living near wind farms have complained about health problems caused by the turbine noise.  While the debate continues as to whether the noise adversely affects human health, relief may be on its way.  Science Daily reports that a team of researchers studying the acoustics of owl flight have been working on pinpointing the mechanisms used by many species of owl that allows them “to hunt in effective silence by suppressing their noise at sound frequencies above 1.6 kilohertz (kHz) — over the range that can be heard by humans.”  The researchers wanted to use those mechanisms “to improve human-made aerodynamic design — of wind turbines, aircraft, naval ships and, even, automobiles”  And apparently they have succeeded in using owl feathers “as a model to inspire the design of a 3-D printed, wing attachment that reduces wind turbine noise by a remarkable 10 decibels — without impacting aerodynamics.”