Noise Pollution: A Killer In Disguise?

Noise pollution is more than just a nuisance—it's a serious health risk. According to the World Health Organization, noise pollution causes Western Europeans to lose up to 1.6 million years of healthy living annually, with cardiovascular disease being the leading cause of death. Research has also linked noise pollution to various health issues, including heart disease, type 2 diabetes, cognitive impairment, sleep disturbance, and tinnitus. While the effects of noise pollution on physical health are well-established, the impact on mental health is also significant, with links to stress, depression, and behavioural issues in children. As noise pollution continues to affect millions of people worldwide, it is essential to recognize its detrimental effects and take preventive measures to mitigate its impact on our health and well-being.

Cardiovascular disease

Noise pollution has been linked to a range of cardiovascular issues, including heart attacks, high blood pressure, and coronary heart disease.

Dr Yutong Samuel Cai, an epidemiologist at Imperial College London, found that long-term exposure to traffic noise affects our blood biochemistry, even when factoring out the effects of exhaust fumes. Cai's research showed that noise can have its own effect on the cardiovascular system, separate from air pollution.

The World Health Organization (WHO) has calculated that at least 1 million healthy life-years are lost every year in Western European countries because of environmental noise, with cardiovascular disease contributing to the majority of these deaths. Cardiovascular issues caused by noise pollution include high blood pressure, heart attacks, and coronary heart disease.

It is thought that noise triggers the release of the stress hormone cortisol, which damages blood vessels over time. Humans evolved acute hearing millions of years ago when we were prey animals and had to pinpoint predators, so it is no surprise that we find noise stressful.

Noise-induced stress is thought to be a key factor in the development of noise-induced cardiovascular disease. The extent to which an individual perceives noise as annoying can determine the effects on their health.

A recent study in New Jersey, US, found that people experiencing high levels of noise from cars, trains, or planes were more likely to suffer a heart attack than those in quieter areas. The study attributed 5% of hospitalizations for heart attacks in the state to elevated noise levels, with a 72% higher rate of heart attacks in areas with high transportation noise exposure.

Noise pollution has been linked to chronic stress, sleep disturbances, and emotional distress, all of which can impact cardiovascular health.

Type 2 diabetes

Noise pollution has been linked to a range of adverse health outcomes, including type 2 diabetes. Here is some information on the relationship between noise pollution and type 2 diabetes.

The Impact of Noise Pollution on Type 2 Diabetes

According to various studies, long-term exposure to noise pollution, particularly traffic noise, has been associated with an increased risk of developing type 2 diabetes. This risk is thought to be related to the stress response and sleep disturbances caused by noise. The World Health Organization (WHO) has also acknowledged the impact of noise pollution on health, estimating that at least 1 million healthy life-years are lost each year in Western European countries due to environmental noise.

Mechanisms and Pathways

The exact mechanisms linking noise pollution to type 2 diabetes are not yet fully understood, but several biological pathways have been proposed:

• Stress Response: Noise acts as an environmental stressor, triggering the release of stress hormones like cortisol, which can interfere with insulin secretion and peripheral insulin sensitivity, leading to an increased risk of type 2 diabetes.
• Sleep Disturbance: Noise-induced sleep disturbances can affect glucose regulation, appetite, and energy expenditure, which are all factors that play a role in the development of type 2 diabetes.
• Metabolic Changes: Some studies suggest that noise exposure can lead to metabolic changes, such as increased waist circumference and weight gain, which are risk factors for type 2 diabetes.

Noise Pollution and Type 2 Diabetes: The Evidence

Multiple studies have provided evidence for the link between noise pollution and type 2 diabetes:

• A meta-analysis by Dzhambov (2015) found that people exposed to high residential noise levels (Lden > 60 dB) had a 19-22% higher risk of developing type 2 diabetes compared to those exposed to lower noise levels (Lden < 60-64 dB).
• A cohort study by Sørensen et al. (2013) involving 57,053 Danish adults found that a 10 dB higher level of road traffic noise during a 5-year period was associated with an 11% increased risk of incident diabetes.
• A prospective cohort study by Clark et al. (2017) in British Columbia, Canada, examined the impact of transportation noise and traffic-related air pollution on diabetes incidence. They found a positive association between residential transportation noise and diabetes, with a 6-8% increase in the incidence of diabetes per interquartile range increase in noise exposure.
• A multi-exposure prospective study by Sørensen et al. (2022) in Denmark investigated the association between air pollution, road traffic noise, lack of greenness, and type 2 diabetes. They found that noise exposure, particularly air traffic noise, was independently associated with a higher risk of type 2 diabetes.

Protecting Against Noise Pollution

While complete avoidance of noise pollution may not be possible, there are some measures that can be taken to mitigate its impact:

• Noise Abatement: Local authorities can implement noise abatement measures, such as restricting construction hours or setting noise limits for certain areas.
• Noise-Cancelling Headphones: Using noise-cancelling headphones or earplugs can help reduce noise exposure, especially in loud environments.
• Soundproofing: Improving the sound insulation of your home, such as through double glazing, can reduce the impact of external noise.
• Greener Environments: Spending time in greener environments, such as parks, has been associated with improved diabetic outcomes and a reduced risk of developing type 2 diabetes.

Sleep disturbances

The main source of noise-related sleep disturbances is road traffic noise, which affects 125 million Europeans who experience noise levels greater than 55 decibels, considered harmful to health, day and night. However, other sources such as construction, loud neighbours, and local bars also contribute to sleep interruptions.

The impact of sleep disturbances goes beyond just feeling tired. Lack of sleep can lead to high blood pressure and, in turn, increase the risk of heart disease and death. It can also cause cognitive impairment, affecting reading comprehension, memory, and attention, with potential long-term effects on educational attainment.

To mitigate the impact of noise pollution on sleep, various measures can be taken. These include installing noise barriers between busy roads and residential areas, using low-noise tyres or high-pore road surfaces, and subsidising individual noise-reducing measures such as double-glazing. Additionally, the European Commission has set guideline maximum levels for night-time noise at 40 decibels, similar to the noise level in a library.

Addressing sleep disturbances caused by noise pollution is crucial not only for improving the quality of life but also for reducing the risk of associated health issues such as heart disease and cognitive impairment. By implementing noise reduction strategies and raising awareness about the impact of noise on sleep, we can work towards creating quieter and healthier environments for ourselves and our communities.

Stress and mental health issues

Noise pollution can have a significant impact on mental health and stress levels. Unwanted sounds can trigger anxiety or stress, and continued exposure can increase a person's sensitivity to stress. This can lead to feelings of irritability, frustration, and anger, particularly if the individual feels they have no control over the noise. Environmental noise is a common cause of sleep disturbance, which can further impact a person's mood and ability to concentrate.

Noise pollution has been linked to increased anxiety, depression, and stress. A 2015 German study found that people living near noisy roads were 25% more likely to experience symptoms of depression than those in quieter areas, even when accounting for socioeconomic factors. Another study of people living near European airports found that a 10-decibel increase in aircraft noise was associated with a 28% increase in anxiety medication use.

The stress caused by noise pollution is thought to be a key factor in its detrimental effects on mental health. Noise triggers the brain's "fight or flight" response, activating the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system. This leads to the release of stress hormones, including adrenaline and cortisol, resulting in increased heart rate and blood pressure. Chronic exposure to noise keeps this stress response activated continuously, contributing to mental and physical health issues over time.

Chronic noise exposure can also impair cognitive function and increase the risk of behavioural problems, particularly in children and adolescents. Studies have found associations between traffic noise exposure and abnormal hyperactivity, inattention, conduct problems, and peer relationship issues in children. Additionally, noise-induced sleep disturbance can further impact cognitive performance and mood.

Overall, noise pollution has been shown to have significant effects on stress levels and mental health, contributing to a range of issues such as anxiety, depression, and cognitive impairment.

Hearing damage

Noise pollution can cause hearing damage, also known as noise-induced hearing loss (NIHL). NIHL can be caused by a one-time exposure to loud noise, such as an explosion, or by continuous exposure to loud sounds over an extended period, such as traffic noise or noise generated in a woodworking shop. The louder the sound, the shorter the amount of time it takes for NIHL to occur. Sounds at or above 85 decibels (dBA) can cause hearing loss. To put that into perspective, the noise of a garbage truck is 100 dBA, and an ambulance siren is about 120 dBA.

NIHL can be immediate or take a long time to be noticeable. It can be temporary or permanent and can affect one or both ears. Even if you can't tell that you are damaging your hearing, you may have trouble hearing in the future, such as not being able to understand other people when they talk, especially on the phone or in a noisy room.

Most NIHL is caused by the damage and death of hair cells in the inner ear. Unlike birds and amphibians, human hair cells do not grow back.

Noise exposure has been linked to other health issues, including cognitive impairment and behavioural issues in children, sleep disturbance, heart disease, diabetes, poor work and school performance, irritability, and aggression.

To protect yourself from noise-induced hearing loss, you can:

• Know which noises can cause damage (those above 80 decibels)
• Wear ear protection, such as earplugs or earmuffs, during loud activities
• Move away from loud noises if you can't reduce them or protect yourself
• Make others aware of the hazards of noise

Frequently asked questions