Objective To study the association between exposure to transportation noise and blood pressure (BP) reduction during nighttime sleep.

Methods 24-h ambulatory BP measurements at 15-min intervals were carried out on 149 persons living near four major European airports. Noise indicators included total and source-specific equivalent indoor noise, total number of noise events, annoyance scores for aircraft and road traffic nighttime noise. Long-term noise exposure was also determined. Multivariate linear regression analysis was applied.

Results The pooled estimates show that the only noise indicator associated consistently with a decrease in BP dipping is road traffic noise. The effect shows that a 5 dB increase in measured road traffic noise during the study night is associated with 0.8% (−1.55, −0.05) less dipping in diastolic BP. Noise from aircraft was not associated with a decrease in dipping, except for a non-significant decrease noted in Athens, where the aircraft noise was higher. Noise from indoor sources did not affect BP dipping.

Conclusions Road traffic noise exposure may be associated with a decrease in dipping. Noise from aircraft was not found to affect dipping in a consistent way across centres and indoor noise was not associated with dipping.