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 (Lden) 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, Lden 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 Lden on ICH remained stable after adjustment for air pollution. Furthermore, green space modified the association between Lden exposure and incident ICH (Pinteraction = 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.

BACKGROUND:Epidemiologic evidence on whether iron accumulation in brain modified the association between artificial light at night (ALAN) and incident mental disorders is lacking. The authors aims to investigate modification of brain iron deposition on the associations of ALAN with multiple mental disorders in the middle-aged and older adults. METHODS:This prospective study used data from the UK Biobank. ALAN was drawn from satellite datasets. Susceptibility-weighted magnetic resonance imaging was used to ascertain iron content of each brain region. T2* signal loss was used as indices of iron deposition. The main outcomes are impacts of ALAN exposure on onset of wide spectrum of physician-diagnosed mental disorders, which was estimated by time-varying Cox proportional hazard model. The authors further conducted stratified analyses by levels of iron brain deposition to examine the potential modifying effects. RESULTS:Among 298,283 participants followed for a median of 10.91 years, higher ALAN exposure was associated with increased risk of mental disorders. An IQR (11.37 nW/cm2/sr) increase in annual levels of ALAN was associated with an HR of 1.050 (95 % CI: 1.034,1.066) for any mental disorder, 1.076 (95 % CI: 1.053,1.099) for substance use disorder, and 1.036 (95 % CI: 1.004,1.069) for depression disorder in fully adjusted models. The exposure-response curves showed steeper trends at lower ALAN levels and a plateau at higher exposures. The associations were stronger in participants with high iron deposition in left hippocampus, left accumbens and left pallidum. CONCLUSIONS:ALAN was associated with multiple mental disorders in the middle-aged and older adults, and the findings indicated stricter standards of ALAN is needed and targeted preventive measures are warranted, especially with high brain iron deposition.

Background: Green space is a newly modifiable environmental factor which would bring health benefits, and identify-ing potential pathways is important to better promote public health. Nowadays, limited evidence is available on resi-dential green space and risk of incident type 2 diabetes (T2D). To evaluate the longitudinal association between residential green space and incident T2D, and further illustrate the role of air pollution, we conducted a prospective analysis in UK Biobank.Methods: Incident cases of T2D were ascertained through medical linkage of hospital admissions. Residential green space indicated by percentage of green space at 300 m buffer was estimated using land use data. Annual average air pollution was modelled using Land Use Regression model. Cox proportional hazard regression models were used to determine the association between the exposure and incident T2D. Effect modification of air pollution was assessed using log-likelihood tests. Casual mediation analysis including interaction of green space and air pollution was used to quantity pure natural indirect effect of air pollution.Results: Of 379,238 participants at baseline, 15564 incident T2D cases were identified with 12.4 years of follow-up. In main models, individuals who exposed to residential green space at 300 m buffer in high level (>= 75 %) had 14.4 % (95 % CI: 8.0 %, 20.3 %) lower risk of incident T2D compared with those in low level (<25 %). This association was modified by NO2, with green space indicating higher protective effect in low NO2 level (P interaction = 0.098). PM2.5 had a high mediation effect of 37.0 % in the association.Conclusion: Elevated residential green space level was associated with lower risk of incident T2D, and air pollution played an important role in this association. These findings would contribute to policy making and healthy city construction to take air pollution into consideration while planning green space, which would maximize public health benefits.