Road Traffic Noise Exposure Research Articles

Road traffic noise pollution and prevalence of ischemic heart disease: modelling potential association and abatement strategies in noise-exposed areas.

In many developing countries with surging vehicular traffic and inadequate traffic management, excessive road traffic noise exposure poses substantial health concerns, linked to increased stress, insomnia and other metabolic disorders. This study aims to assess the linkage between sociodemographic factors, traffic noise levels in residential areas and health effects using a cross-sectional study analyzing respondents' perceptions and reports. Noise levels were measured at 57 locations in Srinagar, India, using noise level meter. Sound PLAN software was employed to generate noise contour maps, enabling the visualization of noise monitoring locations and facilitating the assessment of noise levels along routes in proximity to residential areas. Correlation analysis showed a strong linear relationship between field-measured and modelled noise (r2 = 0.88). Further, a questionnaire-based survey was carried out near the sampling points to evaluate the association of ischemic heart disease with traffic noise. Residents exposed to noise levels (Lden > 60dB(A)) were found to have a 2.24 times higher odds ratio. Compared to females, males reported a 16% higher prevalence of the disease. Multi-faceted policy strategies involving noise mapping initiatives, source noise standards, traffic flow urban mobility optimization, smart city initiatives and stringent litigatory measures could significantly reduce its detrimental impact on public health. Finally, this study envisions a region-specific strong regulatory framework for integrating noise pollution mitigation strategies into the public health action plans of developing nations.

Psychophysiological effects of walking in forests and urban built environments with disparate road traffic noise exposure: study protocol of a randomized controlled trial

BackgroundStress is a widespread phenomenon and reality of everyday life, entailing negative consequences for physical and psychological wellbeing. Previous studies have indicated that exposure to greenspaces and nature-based interventions are promising approaches to reducing stress and promoting restoration. However, an increasing percentage of the population lives in urban regions with limited opportunities to spend time in greenspaces. In addition, urban settings typically feature increased levels of noise, which represents a major environmental stressor. Although various studies have compared the effects of exposure to greenspaces versus urban built environments, evidence of the effects of noise in this context is very limited. Psychophysiological benefits of exposure to greenspaces compared to urban built environments reported in earlier studies might be less (or at least not only) due to features of the greenspaces than to additional stressors, such as road traffic noise in the urban built environment. Hence, differences in the effects attributed to greenness in previous studies may also be due to potentially detrimental noise effects in comparison settings. This paper reports the study protocol for a randomized, controlled intervention study comparing the effects of walking in forest versus urban built environments, taking road traffic noise exposure during walks in the respective settings into account.MethodsThe protocol envisages a field study employing a pretest–posttest design to compare the effects of 30-min walks in urban built environments and forests with different road traffic noise levels. Assessments will consist of self-reported measures, physiological data (salivary cortisol and skin conductance), an attention test, and noise, as well as greenness measurements. The outcomes will be restoration, stress, positive and negative affect, attention, rumination, and nature connectedness.DiscussionThe results will inform about the restorative effect of walking in general, of exposure to different types of environments, and to different noise levels in these sites. The study will provide insights into the benefits of walking and nature-based interventions, taking into account the potential detrimental effects of noise exposure. It will thus facilitate a better understanding of low-threshold interventions to prevent stress and foster wellbeing.Trial registrationISRCTN48943261; Registered 23.11.2023.

The impact of co-exposure to air and noise pollution on the incidence of metabolic syndrome from a health checkup cohort

Previous studies have found associations between the incidence of metabolic syndrome (MetS) and exposure to air pollution or road traffic noise. However, investigations on environmental co-exposures are limited. This study aimed to investigate the association between co-exposure to air pollution and road traffic noise and MetS and its subcomponents. Participants living in Taipei City who underwent at least two health checkups between 2010 and 2016 were included in the study. Data were sourced from the MJ Health database, a longitudinal, large-scale cohort in Taiwan. The monthly traffic noise exposure (Lden and Lnight) was computed using a dynamic noise map. Monthly fine particulate data at one kilometer resolution were computed from satellite imagery data. Cox proportional hazards regression models with month as the underlying time scale were used to estimate hazard ratios (HRs) for the impact of PM2.5 and road traffic noise exposure on the risk of developing MetS or its subcomponents. Data from 10,773 participants were included. We found significant positive associations between incident MetS and PM2.5 (HR: 1.88; 95% CI 1.67, 2.12), Lden (HR: 1.10; 95% CI 1.06, 1.15), and Lnight (HR: 1.07; 95% CI 1.02, 1.13) in single exposure models. Results further showed significant associations with an elevated risk of incident MetS in co-exposure models, with HRs of 1.91 (95% CI 1.69, 2.16) and 1.11 (95% CI 1.06, 1.16) for co-exposure to PM2.5 and Lden, and 1.90 (95% CI 1.68, 2.14) and 1.08 (95% CI 1.02, 1.13) for co-exposure to PM2.5 and Lnight. The HRs for the co-exposure models were higher than those for models with only a single exposure. This study provides evidence that PM2.5 and noise exposure may elevate the risk of incident MetS and its components in both single and co-exposure models. Therefore, preventive approaches to mitigate the risk of MetS and its subcomponents should consider reducing exposure to PM2.5 and noise pollution.

Association of Road Traffic Noise with Obesity and the Role of Meat Intake: A Prospective Study from UK Biobank.

Emerging evidence has indicated the linkage of traffic noise with cardiovascular diseases, However, there's a lack of extensive studies exploring the linkage of traffic noise with cardio-metabolic risk factors such as obesity. Additionally, the role of diet in the associations remains unknown. The aim is to prospectively examine the linkage of road traffic noise with obesity, especially by focusing on evaluating the impact of meat. Participants recruited in the UK Biobank with at least one repeated measurement of obesity indicators including body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WhR), and waist-to-height ratio (WhtR) were included. The Common Noise Assessment Methods of the simplified version were used to estimate road traffic noise exposure. Participants were categorized into "less meat intake" and "more meat intake" based on the median of meat intake, assessed by the frequency of unprocessed red meat and processed meat consumption. Modified Poisson regression models were employed to evaluate the linkage of road traffic noise with obesity. Additionally, the modification effects of meat intake on this relationship were evaluated. The incidence risk ratios (IRRs) and 95% confidence interval (CI) of overall obesity, WC-based central obesity, WhR-based central obesity, and WhtR-based central obesity were 1.11 (1.02, 1.21), 1.09 (1.03, 1.14), 1.06 (1.02, 1.10), and 1.08 (1.02, 1.13), respectively, for every 10 dB(A) increase for noise. Compared with individuals with lower meat intake, those with higher meat intake exhibited a stronger linkage of road traffic noise with central obesity. The prospective study demonstrates a linkage of road traffic noise with obesity, emphasizing the significance of diet on traffic noise-related obesity risk.

Road Traffic Noise Annoyance and Cardiovascular Disease Risk in Population: A Case Series Study in Kota Bharu, Malaysia

Noise pollution can cause annoyance, significantly threatening the population’s health and well-being. This study aimed to find an association between road traffic noise exposure and cardiovascular disease (CVD) risk among residents in Kota Bharu, Malaysia. This descriptive study used a case series approach and surveyed 34 residents in selected residential areas near main roads. An adapted questionnaire was distributed to residents using a purposive sampling method. Questions related to sociodemographic information, self-reporting about CVD, and road traffic noise assessment were asked to investigate the underlying risk factors for CVD. The average score of CVD assessment was classified as moderate risk. No significant association between noise annoyance and CVD was found using multiple linear regression. However, the association between cardiovascular risk and sociodemographic variables, particularly the length of residency at the current address, was statistically significant. Although noise annoyance was not associated with CVD, the length of residency could mediate CVD risk as those living longer in residence might be less vulnerable to the noise. Future longitudinal studies are recommended, which include a noise exposure assessment with a larger sample.

Road traffic noise exposure assessment based on spatiotemporal data fusion

The current static assessment methods for road traffic noise exposure have limitations in representing spatiotemporal variations and only account for the noise exposure of registered residents. To address these issues, this study proposes an assessment method by fusing spatiotemporal noise and population distributions. This approach estimates spatiotemporal noise distributions through real-time noise monitoring data and an update model of noise source intensity calibrated by historical noise monitoring data and road segment speed data. Meanwhile, spatiotemporal population distributions are generated by aggregating standardized spatiotemporal trajectories of users extracted from mobile phone data. The proposed method is applied to evaluate the population exposure to traffic noise in a Chinese city in different hourly periods. The results demonstrate that this method is a quantitative tool for assessing road traffic noise exposure dynamically, providing policymakers with valuable information to locate hotspots of traffic noise over short periods of time.

Association between residential exposure to road traffic noise and cognitive and motor function outcomes in children and preadolescents

BackgroundExposure to environmental noise is increasing in recent years but most of the previous literature in children has evaluated the effect of aircraft noise exposure at schools on cognition. ObjectiveTo assess whether residential exposure to road traffic noise during pregnancy and childhood is associated with cognitive and motor function in children and preadolescents. MethodsThe study involved 619 participants from the Spanish INMA-Sabadell cohort and 7,115 from the Dutch Generation R Study. We used noise maps to estimate the average day-evening-night road traffic noise levels at each participant’s residential address during pregnancy and childhood periods. Validated tests were administered throughout childhood in both cohorts to assess non-verbal and verbal intelligence, memory, processing speed, attentional function, working memory, cognitive flexibility, risky decision-making, and fine and gross motor function. Linear models, linear mixed models, and negative binomial models were run depending on the outcome in cohort-specific analysis and combined with a random-effects meta-analysis. All models were adjusted for several socioeconomic and lifestyle variables and results corrected for multiple testing. ResultsAverage road traffic noise exposure levels during pregnancy and childhood were 61.3 (SD 6.0) and 61.5 (SD 5.4) dB for the INMA-Sabadell cohort and 54.6 (SD 7.9) and 53.5 (SD 6.5) dB for the Generation R Study, respectively. Road traffic noise exposure during pregnancy and childhood was not related to any of the cognitive and motor function outcomes examined in this study (e.g. −0.92 (95 % CI −2.08; 0.24) and 0.20 (95 % CI −0.96; 1.35) in overall estimates of memory and fine motor function, respectively, when road traffic noise increases by 10 dB during childhood). ConclusionsThese findings suggest that child’s cognitive or motor functions are not affected by residential exposure to road traffic noise. However, more studies evaluating this association at school and home settings as well as noise events are needed.

Association of road traffic noise exposure and school childrens’ cognition: A structural equation model approach

This study explores the complex relationship between traffic noise and school children's cognition, acknowledging existing empirical inconsistencies and aiming to contribute to a richer understanding of this pivotal issue. Schools adjacent to noisy roads were selected, and outdoor noise levels were measured employing a Kimo dB300 sound level meter, focusing on noise level indices LAeq, L10, and L90. Subsequent calculations were performed to determine the noise pollution level (Lnp), noise climate (NC), and traffic noise index (TNI), revealing a severe noise exposure when compared to standard guidelines. A perception questionnaire for various noise and acoustic factors influencing cognition was developed, and 1524 student responses were collected. Data analysis incorporated Principal Component Analysis (PCA) and Exploratory Factor Analysis (EFA) for dimension reduction, revealing three latent factors labelled 'annoyance,' 'behaviour,' and 'cognition'. Further, Structural Equation Modeling (SEM) was utilized to explore multivariate relationships between variables and latent factors. Resultant path coefficients were obtained as 0.12, 0.98, and 0.10 for the impact of 'behaviour' and 'annoyance' on 'cognition' and the correlation between 'annoyance' and 'behaviour', respectively. Findings underscore a potent positive impact of annoyance, stemming from acute ambient noise exposure, on the deterioration of children's cognition. While suggesting that ambient noise may be correlated with adverse health impacts due to its influence on cognition, this study emphasizes the pressing necessity for noise mitigation in roadside schools and stringent enforcement of noise pollution guidelines in academic zones.

Health impact assessment of road traffic noise exposure – A case study of a pre- and post-densification scenario

Health impact assessment of road traffic noise exposure – A case study of a pre- and post-densification scenario

Decision trees and labeling of low noise pavements as support for noise action plans

Low noise pavements (LNPs) are a market driven trend to mitigate the high road traffic noise exposure levels. Their improvement towards acoustic efficiency and durability over time is a challenge since these factors can conflict with road primary functions, such as safety. LNPs are not always the most cost-effective solution in health effects prevention. Whilst Green Public Procurement (GPP) highlighted the importance of reducing rolling noise emissions by introducing new regulations for new-layed LNPs, the fixed minimum requirements are not exhaustive. Generally, limits are set following the Close ProXimity method, which is only source oriented. This method does not consider real traffic flows and it is not aimed at evaluating citizens’ disturbance. This work presents strategy tools that could assist policymakers in choosing LNPs, when truly effective, over other mitigations. The approach includes a variety of indicators that would allow for comparing different facets of noise assessment. The proposed methodology does not require additional efforts from stakeholders because the measurements required for the estimation of the indicators must already be carried out for both verification of legal limits and GPP. The strategy tools are a decisional tree to support the evaluation of the applicability of a LNP before its approval, and an evaluation flowchart applicable after its laying to evaluate its efficiency. Finally, a first LNP labeling approach, based on the same set of indicators, is proposed. As a case study, these tools are applied to measurements performed before and after the laying of twelve LNPs part of the LIFE NEREiDE project.

Evaluation of Sound Absorption Coefficient – Acoustic Properties of Pattamadai mat

Noise has become one of the most critical problems to address in contemporary cities, and the awareness of the consequences of noise pollution has been increasing lately. Road traffic noise exposure is considered a serious environmental health hazard, as excessive exposure to noise increases cardiovascular diseases and anxiety. People spend most of their time in residences where they become tolerant of noisy environments and are unaware of the effects caused by them. Indoor acoustic comfort in residences is one of the unexplored parts of Indoor environmental quality (IEQ). Achieving sufficient acoustic comfort is of the main priorities in achieving IEQ. Facades are the constructive elements which act as a barrier between outdoor and indoor sound transmission. The main aim of this research is to optimize the characteristics of different elements of the façade of a residential building to enhance indoor acoustic comfort. A case study residence is chosen at Guindy, Chennai, to study the outdoor sound pattern and the corresponding indoor sound level. The outdoor sound level is measured continuously at 1 m from the facade. The indoor sound level is measured at the centre of each room at regular time intervals. Field measurements were conducted in the 2 BHK apartment, and the results were processed to assign each room's acoustic class and determine the residence’s Key Performance Index in terms of acoustic comfort. The results of this research will be optimized in the upcoming research phase using Pachyderm (Grasshopper plugin) to find the best design parameters for the facade to achieve good acoustic comfort in a residence.

Automated simulation for household road traffic noise exposure: Application and field evaluation in a high-density city

Road traffic noise is a major nuisance and a risk factor of poor health for urban dwellers. A household's exposure to road traffic noise, especially in a high-density city, can be easily modified by the surrounding built environment, i.e., roads, traffic, buildings, and the topography. This leads to high variation in noise exposure between neighboring households. Existing simulation-based studies were limited in accounting for the variation of noise exposure at the household level, which restricted their applications in public health research involving large numbers of participants. This paper describes a novel simulation-based workflow to assess household traffic noise exposure, which consists of 1) a source model to assess road traffic noise levels, 2) a propagation model to simulate noise propagation in complex three-dimensional urban areas, 3) an automation algorithm to process large quantity of simulation runs and data. The workflow has been evaluated using field studies conducted in Sham Shui Po District, Hong Kong, with reasonably good agreements between simulated and measured data. It was then used to assess road traffic noise exposure for a sample of 6158 households enrolled in the FAMILY Cohort, representing Hong Kong's population dwelling in the dense urban areas. Results showed that 83% of sampled households have been exposed to excessive road traffic noise above the World Health Organization (WHO) standard, or 30% above the local standard. The estimated burden of disease is over 45,000 disability-adjusted life-years (DALYs) from both high annoyance and sleep disturbance for households in Hong Kong. The study has contributed to the methodologies and datasets in evaluating noise exposure in high-density cities, which can further support urban noise mitigation policies and planning and population-based health studies in the next steps.

Long-Term Exposure to Road Traffic Noise and Incident Heart Failure: Evidence From UK Biobank

BackgroundEvidence on road traffic noise and heart failure (HF) is limited, and little is known on the potential mediation roles of acute myocardial infarction (AMI), hypertension, or diabetes. ObjectivesThe purpose of this study was to evaluate the impacts of long-term road traffic noise exposure on the risk of incident HF considering air pollution, and explore the mediations of the previously mentioned diseases. MethodsThis prospective study included 424,767 participants without HF at baseline in UK Biobank. The residential-level noise and air pollution exposure was estimated, and the incident HF was identified through linkages with medical records. Cox proportional hazard models were used to estimate HRs. Furthermore, time-dependent mediation was performed. ResultsDuring a median 12.5 years of follow-up, 12,817 incident HF were ascertained. The HRs were 1.08 (95% CI: 1.00-1.16) per 10 dB[A] increase in weighted average 24-hour road traffic noise level (Lden), and 1.15 (95% CI: 1.02-1.31) for exposure to Lden >65 dB[A] compared with the reference category (Lden ≤55 dB[A]), respectively. Furthermore, the strongest combined effects were found in those with both high exposures to road traffic noise and air pollution including fine particles and nitrogen dioxide. Prior AMI before HF within 2 years’ time interval mediated 12.5% of the association of road traffic noise with HF. ConclusionsMore attention should be paid and a preventive strategy should be considered to alleviate the disease burden of HF related to road traffic noise exposure, especially in participants who survived AMI and developed HF within 2 years.

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

BackgroundIntracerebral 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. MethodsAlgorithms 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. ResultsOver 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. ConclusionsLong-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.

A study on the impact of road traffic noise exposure on work efficiency of housewives.

Housewives are individuals who take on the caregiving role in the family in virtually every society and while discharging their duties experience serious psychological difficulties due to external environmental pollutants like air, noise, etc., which influences their efficiency of performing household activities. This study hypothesizes a causal association between perception of traffic noise and the reduction in performance of housewives in their daily household activities. A simple mediation model was utilized for the study with traffic noise perception as the exposure variable. The sensitivity to traffic noise, annoyance caused due to traffic noise, and the effect of traffic noise on housewives were evaluated using questionnaire survey. Of the respondents, 57.33% reported high level of traffic noise perception, while 65.81% reported high annoyance due to traffic noise perception. Of the respondents, 88.69% reported higher levels of agreement with regard to negative effect of traffic noise on their household activities. The results supported the hypothesis with respondents belonging to high and moderate noise perception groups reporting a higher reduction in performance as compared to those belonging to the low noise perception group at higher values of sensitivity. There was no significant direct effect among those who perceived traffic noise as high and moderate. However, the indirect path revealed that there was a significantly higher reduction in performance among those belonging to the high and moderate noise perception group as compared to those belonging to the low noise perception group while those who perceived traffic noise as high and moderate did not differ significantly only at higher levels of sensitivity. Using OGRS computational tool, a sensitivity value of 5.586 was identified as the Johnson-Neyman boundary of significance for the direct effect. The results from the study highlight the need for including environmental noise related regulations with regard to residential structures by the concerned authorities and also the need for undertaking more rigorous studies by health authorities and organizations so that the effects are minimized if not eliminated completely.

Health impact assessment of road traffic noise exposure based on different densification scenarios in Malmö, Sweden

While urbanization provides many opportunities to those arriving in thriving urban areas, a greater number of residents necessitates the expansion of housing and infrastructure. This is often achieved through densification, which can lead to increased noise, particularly through increased road traffic. A key challenge of promoting healthy urban planning is to understand potential health effects, especially on the local level. The aim of the present study is, therefore, to estimate and compare the health impacts of road traffic noise exposure for various urban densification scenarios within a neighborhood (Lorensborg) in Malmö, Sweden. The three scenarios include 1) Present-day, representing the study area as it is presently organized; 2) Planned municipal strategy (the city of Malmö’s own densification plans) and 3) Health-centred, which involves major structural alterations and reflects an effort prioritize a health-centred approach. Noise was modelled using the Nordic prediction method for road traffic. Health outcomes included noise annoyance, adverse sleep disturbance, ischemic heart disease (IHD) incidence and mortality. Within all scenarios, a large proportion of the study population was exposed above the WHO’s health-based guideline value (Lden 53 dB): >80% for Present-day and Planned municipal strategy scenarios, and almost 50% in the Health-centred scenario. Still, densifying Lorensborg (population ≈9,600) according to the Health-centred scenario could prevent 549 cases of highly annoyed, 193 cases of adverse sleep disturbance, 4.7 new cases of IHD (8.9% of total cases), and 1.5 deaths due to IHD (17.8% of IHD mortality) annually. The results demonstrated that it is possible to considerably lower the health impact with a more health-centred densification strategy. Important co-benefits for public and environmental health include air pollution reduction and green space creation, although their health effects were not quantified in the present study. Urban planning initiatives must be more ambitious in order to create healthy, sustainable cities.

Road Traffic Noise and Incidence of Primary Hypertension: A Prospective Analysis in UK Biobank

BackgroundThe quality of evidence regarding the associations between road traffic noise and hypertension is low due to the limitations of cross-sectional study design, and the role of air pollution remains to be further clarified. ObjectivesThe purpose of this study was to evaluate the associations of long-term road traffic noise exposure with incident primary hypertension; we conducted a prospective population-based analysis in UK Biobank. MethodsRoad traffic noise was estimated at baseline residential address using the common noise assessment method model. Incident hypertension was ascertained through linkage with medical records. Cox proportional hazard models were used to estimate hazard ratios (HRs) for association in an analytical sample size of over 240,000 participants free of hypertension at baseline, adjusting for covariates determined via directed acyclic graph. ResultsDuring a median of 8.1 years follow-up, 21,140 incident primary hypertension (International Classification of Diseases-10th Revision [ICD-10]: I10) were ascertained. The HR for a 10 dB[A] increment in mean weighted average 24-hour road traffic noise level (Lden) exposure was 1.07 (95% CI: 1.02-1.13). A dose-response relationship was found, with HR of 1.13 (95% CI: 1.03-1.25) for Lden >65 dB[A] vs ≤55 dB[A] (P for trend <0.05). The associations were all robust to adjustment for fine particles (PM2.5) and nitrogen dioxide (NO2). Furthermore, high exposure to both road traffic noise and air pollution was associated with the highest hypertension risk. ConclusionsLong-term exposure to road traffic noise was associated with increased incidence of primary hypertension, and the effect estimates were stronger in presence of higher air pollution.

The effects of exposure to road traffic noise at school on central auditory pathway functional connectivity

As the world becomes more urbanized, more people become exposed to traffic and the risks associated with a higher exposure to road traffic noise increase. Excessive exposure to environmental noise could potentially interfere with functional maturation of the auditory brain in developing individuals. The aim of the present study was to assess the association between exposure to annual average road traffic noise (LAeq) in schools and functional connectivity of key elements of the central auditory pathway in schoolchildren. A total of 229 children from 34 representative schools in the city of Barcelona with ages between 8 and 12 years (49.2% girls) were evaluated. LAeq was obtained as the mean of 2-consecutive day measurements inside classrooms before lessons started following standard procedures to obtain an indicator of long-term road traffic noise levels. A region-of-interest functional connectivity Magnetic Resonance Imaging (MRI) approach was adopted. Functional connectivity maps were generated for the inferior colliculus, medial geniculate body of the thalamus and primary auditory cortex as key levels of the central auditory pathway. Road traffic noise in schools was significantly associated with stronger connectivity between the inferior colliculus and a bilateral thalamic region adjacent to the medial geniculate body, and with stronger connectivity between the medial geniculate body and a bilateral brainstem region adjacent to the inferior colliculus. Such a functional connectivity strengthening effect did not extend to the cerebral cortex. The anatomy of the association implicating subcortical relays suggests that prolonged road traffic noise exposure in developing individuals may accelerate maturation in the basic elements of the auditory pathway. Future research is warranted to establish whether such a faster maturation in early pathway levels may ultimately reduce the developing potential in the whole auditory system.

Socioeconomic inequalities in burden of disease due to traffic noise in the Nordic countries

Environmental noise is the second largest environmental risk factor in disease burden estimates for Europe. While socioeconomic inequalities in noise exposure have been reported, the impact of socioeconomic status (SES) on the disease burden attributable to noise exposure has to our knowledge not been reported previously. The aim of this study is to assess the impact of SES on traffic noise exposure and the associated disease burden in selected Nordic populations. We employed nationwide data on road traffic noise exposure and SES from Danish and Norwegian Nationwide Models. The impact of household income and education on traffic noise exposure was assessed using linear regression analyses. Burden of disease estimates were calculated for populations stratified according to their level of income and education in terms of Disability-Adjusted Life Years (DALY) for high degree of noise annoyance, high degree of sleep disturbance and ischaemic heart disease. The most consistent finding observed for the Danish population was that, compared to medium and low household income, high household income was associated with lower noise exposure. Moreover, the burden of disease estimates for high noise annoyance were up to 20% lower in the high compared to the lower household income groups.

Associations of road traffic noise and its frequency spectrum with prevalent depression in Taichung, Taiwan.

Exposure to road traffic noise has been reported to be associated with depression in many epidemiological studies, but the association between noise frequency spectrum and depression remains unclear. This community-based study investigated the associations between road traffic noise exposure and its frequency components with prevalent depression. A total of 3,191 residents living in Taichung who participated in the Taiwan Biobank between 2010 and 2017, were included as study participants. The land-use regression models were used to evaluate individual annual average values of A-weighted equivalent sound level over 24 h (Leq,24h) and particulate matter with an aerodynamic diameter <2.5 μm (PM2.5) using the geographic information system. Multiple logistic regression was applied to estimate the odds ratios (ORs) for depression after adjusting for potential risk factors and PM2.5. An interquartile range increase in Leq,24h at full frequency (4.7 dBA), 1,000 Hz (5.2 dB), and 2,000 Hz (4.8 dB) was significantly associated with an elevated risk for depression with ORs of 1.62 (95% confidence interval [CI]: 1.03, 2.55), 1.58 (95% CI: 1.05, 2.37), and 1.58 (95% CI:1.03, 2.43), respectively, by controlling for PM2.5. The high-exposure group (≥3rd quartile median of noise levels) at full frequency, 1,000 Hz, and 2,000 Hz had an increased risk for depression with ORs of 2.65 (95% CI: 1.16-6.05), 2.47 (95% CI: 1.07-5.70), and 2.60 (95% CI: 1.10-6.12), respectively, compared with the reference group (<1st quartile of noise levels) after adjustment for PM2.5. Significant exposure-response trends were observed between the prevalent depression and noise exposure by quartiles at full frequency, 1,000 Hz, and 2,000 Hz (all p < 0.05). Exposure to road traffic noise may be associated with an increased prevalence of depression, particularly at 1,000 and 2,000 Hz.