Study: Heart attack linked to traffic noise

Must Read; Heart attack linked to Lagos traffic noise...

 

One of the greatest challenges associated with living close to a highway or in the heart of a town is interruption or lack of sleep due to traffic noise. A new study by the

Danish Cancer Society has indicated that beyond being prone to frequent insomnia, people who are exposed to louder sounds of traffic near their homes have a higher risk of heart attack.

The researchers found that for every 10-decibel increase in traffic noise, there was 12 per cent higher risk of heart attack. They also add that they began seeing increases in risk starting at around 40 dB.

In the study published in PLoS ONE journal, lead author, Mette Sorensen, and her fellow researchers followed more than 50,000 men and women, ages 50 to 64, living in Copenhagen and Aarhus, two of Denmark’s largest cities.

Each participant reported their lifestyle behaviours like diet and physical activity, as well as the place each lived over a 10-year period. The researchers monitored the participants’ health over the course of the study, comparing it to the geographic location of their homes. The researchers also figured out how much traffic noise each person had been exposed to by analysing traffic patterns around the participants’ homes.

During the 10-year study period, 1,600 people had a first attack and the louder the traffic noise near their homes was, the greater the risk they faced. The link between noise and heart attacks held even after the researchers accounted for other factors like air pollution exposure, diet, gender and weight.

“There are a variety of things that could explain the association: stress, for one. People who live in hectic urban centers tend to have more stress than those in quieter locales, and stress is a well-known trigger of heart attack. The noise itself probably does increase stress and the levels of stress hormones like adrenaline. Your blood pressure is probably going up as well,” said Dr. Robert Bonow, a professor of Medicine at the Northwestern Feinberg School of Medicine.

The study also suggests that traffic noise does not have to be deafening to affect your health.

Forty decibels, they added, is about as loud as a bird call or the inside of a library and, by comparison, a vacuum cleaner is 70 dB, and a passenger car travelling at 65 miles per hour measures 77 dB from 25 feet away. The researchers recommended that people, who live near traffic prone areas, should sleep in a quieter interior room.

This is not the first time that traffic has been linked to cardiovascular diseases. A report published in BMJ.com last year established that exposure to high levels of traffic pollution may boost the risk of a heart attack. But it it found out that the risk was transient, lasting one to six hours, and that rather than increasing overall risk of heart attack, exposure to pollution appeared to precipitate cardiac events in people who were already at higher-than-average risk.

The researchers looked at heart attack risk for 72 hours after exposure to pollution, but found that the risk remained elevated for only six hours. The findings were in line with those of previous researches that found air pollution to have an immediate and negative impact on heart health.

Also, earlier in the year, two separate studies showed that exposure to air pollution can boost the odds of heart attack or stroke — by as much as five per cent and 34 per cent respectively.

While previous studies on air pollution and heart attack risk have not been very conclusive; some showed a positive link while others found no association with heart problems.Others suggested that only select pollutants appeared to increase the risk of heart problems.

Overall, researchers found that people exposed to higher levels of particulates and polluting gases, which include carbon monoxide, nitrogen dioxide and sulfur dioxide, were anywhere from 0.5 per cent to five per cent more likely to experience a heart attack on the day of that exposure or on the following day.

Last month, researchers at the Washington University revealed that the longer the daily commute, the more likely an individual is to have high blood pressure, an oversized waistline, and other health problems that increase the risk for chronic diseases.

“Long commutes really get under the skin in terms of affecting people’s health,” said lead author, Christine Hoehner, an assistant professor of Public Health Sciences at Washington University, in St. Louis.

People with longer commutes tend to be less physically active, even after the researchers took into account extenuating factors such as age, race, educational levels and family size. Seventy-six per cent of people who worked within five miles from their homes averaged at least 30 minutes of moderate-to-vigorous exercise per day, compared to just 70 per cent of those whose commute exceeded 30 miles round-trip.

In addition, people in the 30-mile-and-up club were more likely to be obese and to have an unhealthy waist size (40 inches for men, 35 inches for women).

Excess belly fat is a known risk factor for diabetes, heart disease, strokes and other serious health problems.

Blood pressure appeared to be even more sensitive to commuting distance. Even people whose commute was just 20 miles round-trip had an increased risk of elevated blood pressure, which the researchers defined as the so-called pre-hypertension stage.

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