Many different factors can affect your heart health, from race to diet to alcohol consumption. New research suggests living near busy roads can also have negative consequences. A new study, published in European Heart Journal, links long-term exposure to both traffic noise and air pollution to a higher risk of heart disease.
Researchers examined data from 144,000 adults in Norway and the Netherlands. They looked at blood biochemistry for clues about how air pollution and traffic noise affected the risk of heart disease. Since busy roads produce both noise pollution (which can disrupt sleep, raise blood pressure, and increase stress) and ambient air pollution (which increases the risk of heart disease and stroke), it made sense to study them together.
They examined a number of markers, including lipids and triglycerides, which when found at higher levels are linked to heart attacks; blood sugar levels, which when elevated are associated with heart disease, diabetes, and stroke; and C-reactive protein (CRP), which signals inflammation and can lead to heart disease.
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Noise above 60 decibels (dB)—a normal conversation level—is considered pollution; a freeway at 10 AM from 50 feet away reaches about 76dB. The study found that an increase of 5dB in neighborhood noise levels was linked to 0.3 percent higher blood sugar levels, compared to quieter neighborhoods. (That's after correcting for variables such as age, sex, education, employment, alcohol consumption, and smoking status.)
Increases in air pollution also showed a link: a 10 µg/m3—that's micrograms per cubic meter, a way of measuring air contaminants by volume—increase in air pollution levels was associated with 2.3 percent higher blood sugar levels, a 2.6 percent increase in CRP levels, and a 10 percent increase in triglycerides. Those effects were independent of traffic noise levels, suggesting both noise and air pollution matter for health. Before you start Googling property in Amish country, however, know that the news isn't all grim if you happen to be an urban type. Previous studies, for instance, have found that people who live in the country are one-fifth more likely to be obese than city dwellers.
So what does all this really mean? In addition to the elevated biological markers in the blood, the researchers suggest noise pollution could be disrupting sleep, creating long-term psychological stress that produces more stress hormones and increases the risk of heart disease. Research has also linked traffic proximity to atherosclerosis, where plaque builds up inside your arteries; there, too, researchers found both air pollution and night-time traffic noise to have independent, negative effects.
There's a limited body of knowledge about how traffic noise and pollution affect people who live nearby. Researchers hope to remedy that with follow-up studies. Until then, the intuitive conclusion might be best: Clean air and quiet nights are better for your health. How much did you say that lot in Amish country was going for again?
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