Nighttime Traffic Noise Associated With Poor Self-reported Sleep Quality

Nocturnal road traffic noise was strongly linked to a range of insomnia symptoms, highlighting the potential impact of noise pollution on public health in large populations.

As the world continues to develop and new environmental stressors emerge, new public health risks also come to light. One such risk is traffic noise at night, which can affect a population’s quality and quantity of sleep. A study published in Environmental Science and Pollution Research found an association between insomnia and traffic noises in northern India, suggesting more research on large populations is necessary to minimize the impact of nocturnal noise on public health.

This study aimed to analyze the relationship between traffic noise exposure at night and self-reported sleep problems, as well as evaluate subgroups that may be more vulnerable based on sociodemographic characteristics and health-related problems. The study authors note that in India, the acoustic environment is “alarming” compared with Western developed countries, and therefore research on traffic noise exposure and sleep problems should be a priority.

“Insomnia is one of the most common sleep disorders present in adults,” the authors wrote. “In the present study, the respondents were required to answer the queries about sleep disturbance in general without any specific mention of traffic noise.” This was meant to help reduce the potential for participants’ bias compared with discussing traffic noise specifically with respondents and creating an association between traffic noise and sleep problems.

A total of 4525 participants took part in the study and answered a questionnaire survey between October 2020 and March 2021. A standard noise model called TNM 2.5, developed by the Federal Highway Administration and used in a previous study of the same area, was used to determine the nocturnal noise exposure level for each respondent’s home. The assessment of insomnia-related symptoms was done using the Jenkins sleep problem scale. The Depression, Anxiety and Stress Scale - 21 Items scale was used to evaluate the mental health of respondents.

Study limitations include the modeled noise levels, which might be different than actual noise levels but allow a larger, population-based study compared with laboratory experiments, and the self-reported nature of the questionnaires.

The study data revealed associations between nocturnal traffic noise and all insomnia symptoms in the questionnaire, including:

  • Difficulty in falling asleep
  • Difficulty in maintaining sleep (includes waking up too early)
  • Waking up several times during night
  • Feeling worn out after usual sleep

Those who reported experiencing a symptom 5 to 6 times per week or more were considered to have that symptom.

“Difficulty in falling asleep” had the strongest association with noise exposure in the overall study population (odds ratio [OR], 1.45; 95% CI, 1.01-2.07). In general, those with bedrooms facing the street were at a higher risk of insomnia symptoms compared with the overall population. “Difficulty in maintaining sleep” risk was highest in this subgroup of participants (OR, 1.65; 95% CI, 1.08-2.51).

The study also reported a trend of increasing levels of mental disorders with higher noise levels. While 18.6% of respondents reported using sleep medication, no significant association was found between nocturnal noise exposure and sleep medication use.

The data suggest that, overall, there are significant associations between nocturnal noise exposure and insomnia symptoms. This is in line with past global data, although more research is warranted in developing countries, according to the study authors.

They conclude, “a multipronged strategy involving natural and social sciences, law implementations, political will, and usage of noise barriers can help in the long run and ensure minimum damage to the physical and mental health of the population.”

Reference

Gilani TA, Mir MS. A study on road traffic noise exposure and prevalence of insomnia. Environ Sci Pollut Res. Published online January 27, 2022. doi:10.1007/s11356-021-18291-8