Depression risk, mental health issues higher in people living in cities with loud traffic noise: study

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There's a good reason why noise pollution is called such and a new study published in Environmental Health Perspectives has revealed how traffic noise can affect a person's mental health, City Lab reports. Researchers from the Center for Urban Epidemiology at University Hospital Essen, Germany have found that people who live in areas where traffic is high are 25 percent more at risk for developing depression, compared to their counterparts who lived in places with minimal road noise. Additionally, the risk was also more evident in those who were poor, unemployed, had limited education, were smokers, or had insomnia.

Led by epidemiologist Ester Orban, the study analyzed collected data on 3,300 people aged 45 to 75 years old, who participated in the Heinz Nixdorf Recall study, all of which did not show signs of depression when they were first surveyed from 2000 to 2003. Five years later, the same participants took the survey once more, and researchers sought out signs of self-reported depressive symptoms.

HealthDay reports that researchers defined depressive symptoms as feelings of loneliness, sadness, difficulty concentrating, and feelings of failure and depression. Researchers also checked for consumption of anti-depressants among survey participants.

Researchers found that one-third of the participants was exposed to traffic noise at 55 decibels, which is more or less as loud as chatter in a restaurant or the sound of an old dishwasher, or more for 24 hours a day. One fourth of the participants were exposed to the same noise levels only at night.

Surprisingly, researchers found that the mental health effects were most evident not in those who lived in the noisiest neighborhoods, but those who were exposed to "intermediate" traffic noise of 60 to 65 decibels for 24 hours a day.

"Low-income groups, which have been studied before, are more likely to have depression," Orban explained. "But we can’t say why the association between noise and a depressive symptom is stronger in this population."

Researchers also found that there was stronger evidence of depressive symptoms among those who reported sleep disruptions during the first survey.

Simon Rego of the Montefiore Medical Center/Albert Einstein College of Medicine in New York City told WebMD that this study adds to the evidence that exposure to noise plays a role in the increase of depressive symptoms.

"This suggests that, along with targeting biological factors with medications and psychological factors with treatments such as cognitive behavioral therapy, interventions may also be aimed at targeting environmental factors," Rego commented.

Stephen Stansfeld, a psychiatrist at the University of London and author of the book Noise, Noise Sensitivity and Psychiatric Disorder, also commented, "There's very clear evidence that transport noise causes annoyances. So it’s always a bit strange not to find strong relationships with mental health."