Living near a busy road may do more than disturb your sleep — it could also affect your cholesterol levels.

A large study of 272,229 European adults found that people exposed to higher levels of nighttime traffic noise had elevated LDL “bad” cholesterol and increased blood fats. While researchers did not establish a direct cause-and-effect relationship, they identified a significant association between road noise and unfavorable lipid profiles.

The link began at about 50 decibels (dB) of nighttime noise — roughly the sound of a quiet conversation or soft background music, according to Study Finds. The association grew stronger at 55 dB and above, a level still considered moderate but one that may disrupt sleep.

Researchers believe sleep disturbance could be one pathway linking traffic noise to heart health.

The study, published in the journal Environmental Research, used an advanced technique called nuclear magnetic resonance metabolomics. This method allowed scientists to analyze 155 different fats, proteins, and molecules in blood samples collected from large population databases in the United Kingdom, the Netherlands, and Finland.

Participants were divided into four groups based on estimated nighttime noise exposure, ranging from below 45 dB (the baseline group) to 55 dB and above. Because traffic noise often coincides with air pollution, researchers adjusted for pollution levels to better isolate the impact of noise itself.

The findings were consistent across all three countries. In the highest-noise group, 20 blood metabolites were elevated. Of those, 11 were lipoproteins — particles that transport cholesterol through the bloodstream. Four direct measures of cholesterol were also higher in the louder-noise group.

These changes were not observed in participants exposed to lower noise levels.

“This study provides evidence that nighttime road traffic noise exposure from 50 dB upward is associated with alterations in blood cholesterol and lipid profiles in adults,” wrote the study authors.

While more research is needed to determine whether noise directly causes these changes, the findings add to growing evidence that environmental factors — including sound pollution — may influence cardiovascular health.