53dB threshold: Road noise increases risk of depression and anxiety in teens and young adults

A large Finnish registry study was published in Environmental Research: in 114,353 residents of the Finnish capital region, followed from childhood to young adulthood (average 8.7 years), long-term exposure to road noise above ~53 dB (Lden) was associated with a higher risk of newly diagnosed depression and anxiety disorders. For every +10 dB at the “noisiest” façade of the house, the risk of depression increased by 5%, anxiety by 4%. The effect of anxiety was stronger in men and in those whose parents did not have mental disorders. Nighttime levels and combined road+rail noise gave similar results.

Background

• Why teenagers and "young people"? At this age, circadian rhythms are rebuilt, sleep becomes more vulnerable, and lack of sleep is closely associated with the risks of anxiety and depression. Any chronic stressor that shifts the sleep phase or fragments it (including traffic noise) can "support" mental disorders. Teenagers living in noisy areas are more likely to have later bedtimes and a shift in rhythm even without a clear reduction in sleep duration.
• What guidelines and reports have already said. WHO recommends reducing average daily road noise levels below 53 dB Lden (and nighttime noise levels below ~45 dB Lnight) — adverse health effects increase above these thresholds. The European Environment Agency states that at least every fifth European lives with chronically harmful noise levels, which affect both somatic and mental health.
• What was the mental health “baggage” before the current article? Early systematic reviews gave a mixed picture (for road noise, the effect on depression was often weak/unstable), but as prospective studies appeared, the signal strengthened, especially in young people and students. The new Finnish registry work adds precisely the long-term exposure with annual updates of addresses/noise levels and outcomes by diagnosis.
• Why is the geometry of the house important - "the quiet facade"? Even if one facade faces the highway, having a quiet side of the building reduces noise irritation and sleep disturbances; this is a recognized urban principle of health protection. Therefore, researchers increasingly take into account the noise of the "noisiest" and "quietest" facades, and for housing planning recommend placing bedrooms on the quiet side.
• Mechanisms: How 50–60 dB “non-sound” hits the psyche. Nighttime and background traffic noise activates the sympathetic nervous system and the HPA (hypothalamic–pituitary–adrenal) axis, fragments sleep, and supports inflammation and oxidative stress—all of which are linked to anxiety and depression. Reviews emphasize the “indirect route”: not through hearing injury, but through chronic stress and sleep disruption at levels of 50–70 dB(A).
• Noise rarely comes alone: the role of accompanying factors. In the city, traffic noise often correlates with air pollution, so modern studies try to separate them statistically; however, both air and noise separately are associated with mental risks. This is why results that are stable after adjustments for NO₂/PM₂.₅ are considered especially convincing.
• What the new Finnish cohort adds. It shows a threshold relationship of about 53–55 dB Lden and an increase in the risks of diagnosed depression/anxiety with long-term exposure to noisy roads in adolescence and young adulthood. This threshold rhymes well with the figure of 53 dB from the WHO guidelines and translates into specific urban planning solutions: “quiet facades”, green buffers, reduced speeds and “quiet” surfaces.
• Why it matters for practice and policy. This group lays down the “tracks” of mental health for years to come. Reducing night and daytime noise is not only about comfort, but about preventing depression and anxiety at the population level, and with measures that simultaneously improve both sleep and cardiovascular risks.

What and how was studied

The researchers took all those born in 1987–1998 and living in Helsinki and its suburbs in 2007. For each address, the average daily level of transport noise (Lden indicator — average for day-evening-night) was modeled annually at the noisiest and quietest façade of the building, and night noise was assessed separately. New cases of depression/anxiety were taken from Finnish medical registries and the risk was calculated using Cox models adjusted for individual and regional factors. As a result, they obtained a threshold effect: starting from approximately 53–55 dB on the “quiet” façade, the risk increased especially; at >53 dB, the risk was generally higher in adolescents and young adults.

Specific figures

• +10 dB at the noisiest façade (Ldenmax) → depression: HR 1.05 (1.02–1.09); anxiety: HR 1.04 (1.01–1.07).
• J-shaped dependence for alarm on the “quiet” facade (increase after ≈53–55 dB).
• Night noise (Ln) and the road+railway combination gave a comparable signal.

Why 53 dB is important

The threshold at which the study sees a clear increase in mental risks coincides with the WHO recommendation: reduce road noise below 53 dB Lden, since adverse health effects increase above it. That is, the “safe line” from the WHO guide is also confirmed in mental health outcomes in young people.

What does this mean for cities and for us?

The authors directly translate the results into urban solutions:

• plan bedrooms on the "quiet side" of buildings,
• reduce speed limits,
• develop "quiet" tires and surfaces,
• Maintain green buffers along highways.
  It's not just about comfort: a recent EEA report reminds us that traffic noise in Europe is linked to tens of thousands of premature deaths and thousands of cases of depression every year - and the number of people chronically "disturbed" by noise is still huge.

Biological plausibility

Noise is a chronic stressor: it disrupts sleep, activates stress response axes, maintains inflammation, and impairs emotion regulation. Current reviews link traffic noise to increased risk of depression/anxiety, although there have been many cross-sectional and mixed studies in the past. The new Finnish study adds prospectivity and precision to the exposure.

Important Disclaimers

This is an observational study: it carefully estimates associations but does not prove causation. Noise was modeled by address rather than measured inside apartments; human behavior (headphones, ventilation, sleeping by the window/in the yard) is difficult to account for. Still, the sample size, the registration of diagnoses, and the consistency of signals across different noise metrics make the conclusion robust.

Summary

For teenagers and young adults, living near a noisy road is not only about fatigue and poor sleep, but also about an increased risk of depression and anxiety, especially at levels above 53 dB Lden. “Quiet facades”, traffic slowdown, green barriers and reasonable acoustics of housing are no longer “nice bonuses”, but elements of mental disorder prevention in the city. Oulun yliopistoiris.who.int

Source: Main article ( Environmental Research, 2025) and materials from the University of Oulu; background from WHO recommendations and the European Environment Agency report. DOI: 10.1016/j.envres.2025.122443