Modification of green space on the associations between long-term road traffic noise exposure and incident intracerebral hemorrhage: A prospective cohort study.

BACKGROUND

Intracerebral hemorrhage (ICH) is a subtype of stroke that would cause high mortality and disability. Environmental factors may play an important role in the incident risk of ICH. Evidence on how long-term road traffic noise exposure affects incident ICH is still scarce, and whether green space has a modification effect is unknown. We conducted a prospective analysis based on UK Biobank to assess the longitudinal association between road traffic noise exposure and incident ICH, and the potential modification of green space.

METHODS

Algorithms based on medical records and linkage were utilized to identify ICH incident cases in the UK Biobank. The Common Noise Assessment Methods in Europe noise model was used to calculate the road traffic noise exposure at the residential level. The relationship between weighted average 24-h road traffic noise level (L) and incident ICH was assessed using Cox proportional hazard models, and the modification effect of green space was examined using stratified analysis with interaction terms.

RESULTS

Over a median follow-up of 12.5 years, 1 459 incident ICH cases were ascertained in the 402 268 baseline individuals. After adjustment for potential confounders, L was significantly related to an elevated risk of incident ICH with a hazard ratio (HR) of 1.14 (95% CI: 1.01, 1.28) for a 10 dB [A] increment. The detrimental influence of L on ICH remained stable after adjustment for air pollution. Furthermore, green space modified the association between L exposure and incident ICH (P = 0.035), and no association was found for higher green space.

CONCLUSIONS

Long-term residential road traffic noise exposure was associated with an increased risk of ICH, but only for those who live in areas with less green space, indicating that green space may alleviate the negative impacts of road traffic noise exposure on ICH.