Business of Well-being

A Noisy Workplace Raises Risk of Heart Disease

Nobel Prize Winner Robert Koch said in 1910 that "One day man will have to fight noise as fiercely as cholera and pest" and studies are beginning to prove this statement right. A study recently released by the Centers for Disease Control and Prevention (CDC) and published this month in the American Journal of Industrial Medicine has associated high cholesterol and high blood pressure with loud noise at the workplace.

High blood pressure and high cholesterol are the major risk factors for cardiovascular disease which is the leading cause of death in the United States, and loud noise constitutes one of the major health hazards in the workplace. According to the CDC's National Institute for Occupational Safety and Health (NIOSH), about a quarter of US workers, about 41 million people, reported a history of exposure to loud noise at work.

The effect of noise on health is increasingly being recognized. Beyond its negative impact on hearing, loud noise causes sleep disturbance, poor cognitive performance, and may trigger or worsen migraine attacks in people who suffer from migraine. "Reducing workplace noise levels is critical not just for hearing loss prevention - it may also impact blood pressure and cholesterol," said John Howard, M.D NIOSH Director.

"Worksite health and wellness programs that include screenings for high blood pressure and cholesterol should also target noise-exposed workers." The researchers at the institute analyzed data from the National Health Interview Survey done in 2014 to study the prevalence of workplace noise exposure, hearing difficulty, and heart disease within US industries and jobs. The researchers checked the data for the trends and association between occupational noise exposure and heart disease.

Findings from the study revealed that 25% of current workers have been exposed to work-related noise, as compared to only 14% in the last year. Furthermore, the results noted that 12% of the current workers experienced hearing difficulty, 24% developed high blood pressure, and 28% had high cholesterol levels. The researchers found that occupational noise exposure was responsible for 58%, 14%, and 9% respectively of these cases.

"A significant percentage of the workers we studied have hearing difficulty, high blood pressure, and high cholesterol that could be attributed to noise at work," said study co-author Liz Masterson, Ph.D. "If noise could be reduced to safer levels in the workplace, more than 5 million cases of hearing difficulty among noise-exposed workers could potentially be prevented.

This study provides further evidence of an association of occupational noise exposure with high blood pressure and high cholesterol, and the potential to prevent these conditions if noise is reduced. It is important that workers be screened regularly for these conditions in the workplace or through a healthcare provider, so interventions can occur. As these conditions are more common among noise-exposed workers, they could especially benefit from these screenings.

"The study further noted that the mining industry has the highest prevalence (61%) of workplace noise exposure, followed by construction (51%) and manufacturing (47%) industries. In addition, the occupations with the highest prevalence of worksite noise exposure were production (55%) jobs, followed by construction and extraction (54%), and jobs involving installation, maintenance, and repair (54%).

In a similar study published in 2015 in the journal Occupational Environmental Medicine, researchers found that there was a link between heart disease and loud workplace noise, with the risk highest in people with high-frequency hearing loss, another complication of chronic exposure to loud noise. "Compared with people with normal high-frequency hearing, people with bilateral high-frequency hearing loss were approximately two times more likely to have coronary heart disease," said lead author of the study, Dr. Wen Qi Gan of the University of Kentucky College Of Public Health in Lexington, in a mail to Reuters.

This results of these studies are in agreement with a study published in February in the Journal of the American College of Cardiology which showed that exposure to noise in the workplace increased the risk of heart disease. In the study conducted by researchers from Johannes Gutenberg University in Germany analyzed data from previous studies that linked loud noise with heart disease and other health problems.

The study authors say noise disrupts the body's normal process, inducing stress responses and activating a "fight or flight" response of the nervous system. In time, these stress hormones cause subtle changes in the blood vessels which eventually damaging them causing a wide spectrum of cardiovascular diseases. "When we're exposed to loud noises, the sympathetic nervous system dominates," said James O'Keefe MD, a cardiologist at the Mid America Heart Institute, Saint Luke's Hospital, Kansas City.

"That can really put your system on alert and makes you jumpy, which can wear down your resilience - just like any other type of physical or mental stress." Added O'keefe, who was not part of the study. In addition, the researchers said that noise triggers oxidative stress and some metabolic problems which could contribute to other chronic diseases such as diabetes. Workplace noise costs the US economy over $242 million every year to compensate people who develop hearing loss from occupational noise exposure.

By focusing on limiting this risk factor in the workplace, the risk of heart disease among workers will reduce, ultimately cutting down expenses on heart disease and other noise-related ailments. Lead author of the study, Dr Thomas Munzel, director of the department of internal medicine at the University, said that although no threshold for sound has been established to prevent heart disease, chronic exposure to sound over 60 decibels, corresponding to the sound of a typical office conversation, has the potential of causing cardiovascular disease.

For comparison, the sound made when a telephone rings is about 80 decibels while the sound an airplane makes on takeoff is about 120 decibels. The study recommends the use of earplugs or noise-canceling headphones to muffle loud noise may benefit workers in preventing health problems associated with noise.

Recommendations for employers in tackling this problem include provision of Personal Protective Equipment (PPE), replacing noisy machinery with quiet alternatives, use of sound dampeners or noise barriers at the source of the noise to prevent its transmission, and introducing other noise control measures such as job rotation and readjustment of workers' duties to minimize their exposure to noise at the workplace.

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