Health effects of railway-induced vibration combined with railway noise - A systematic review with exposure-effect curves.

BACKGROUND: The combined health impact of concurrent railway noise and railway vibration exposure is not yet well understood. OBJECTIVES: This systematic review gives an overview of epidemiological studies on health effects from railway vibration, aiming to quantify this association with exposure-effect curves. Moreover, the combined health effects of vibration and concurrent noise were investigated. METHODS: We converted the vibration metric to an equivalent noise level and calculated an overall noise level by energetically summing the equivalent and railway noise level. The combined health effect was determined by using published evidence-based exposure-effect formulas. RESULTS: Studies included in this systematic review predominately investigated annoyance and self-reported sleep disturbances; no studies on manifest diseases were identified. For the combined effects of vibration and noise on "total" annoyance, the results based on the pooled analysis of CargoVibes project are recommended as conservative approach. DISCUSSION: Converting railway vibration into equivalent noise levels in dB may offer a pragmatic approach to assess the combined health effects of railway noise and railway vibration exposure. Future studies should include cardiovascular and mental diseases in addition to vibration-induced annoyance and sleep disturbances. Furthermore, future studies should include in-depth investigations of the interaction between railway noise and railway vibration to allow for a more accurate assessment of the railway-induced burden of disease.

Burden of disease due to transportation noise in the Nordic countries.

BACKGROUND: Environmental noise is of increasing concern for public health. Quantification of associated health impacts is important for regulation and preventive strategies. AIM: To estimate the burden of disease (BoD) due to road traffic and railway noise in four Nordic countries and their capitals, in terms of DALYs (Disability-Adjusted Life Years), using comparable input data across countries. METHOD: Road traffic and railway noise exposure was obtained from the noise mapping conducted according to the Environmental Noise Directive (END) as well as nationwide noise exposure assessments for Denmark and Norway. Noise annoyance, sleep disturbance and ischaemic heart disease were included as the main health outcomes, using exposure-response functions from the WHO, 2018 systematic reviews. Additional analyses included stroke and type 2 diabetes. Country-specific DALY rates from the Global Burden of Disease (GBD) study were used as health input data. RESULTS: Comparable exposure data were not available on a national level for the Nordic countries, only for capital cities. The DALY rates for the capitals ranged from 329 to 485 DALYs/100,000 for road traffic noise and 44 to 146 DALY/100,000 for railway noise. Moreover, the DALY estimates for road traffic noise increased with up to 17% upon inclusion of stroke and diabetes. DALY estimates based on nationwide noise data were 51 and 133% higher than the END-based estimates, for Norway and Denmark, respectively. CONCLUSION: Further harmonization of noise exposure data is required for between-country comparisons. Moreover, nationwide noise models indicate that DALY estimates based on END considerably underestimate national BoD due to transportation noise. The health-related burden of traffic noise was comparable to that of air pollution, an established risk factor for disease in the GBD framework. Inclusion of environmental noise as a risk factor in the GBD is strongly encouraged.

Long-term exposure to traffic noise and risk of incident colon cancer: A pooled study of eleven Nordic cohorts.

Background Colon cancer incidence is rising globally, and factors pertaining to urbanization have been proposed involved in this development. Traffic noise may increase colon cancer risk by causing sleep disturbance and stress, thereby inducing known colon cancer risk-factors, e.g. obesity, diabetes, physical inactivity, and alcohol consumption, but few studies have examined this. Objectives The objective of this study was to investigate the association between traffic noise and colon cancer (all, proximal, distal) in a pooled population of 11 Nordic cohorts, totaling 155,203 persons. Methods We identified residential address history and estimated road, railway, and aircraft noise, as well as air pollution, for all addresses, using similar exposure models across cohorts. Colon cancer cases were identified through national registries. We analyzed data using Cox Proportional Hazards Models, adjusting main models for harmonized sociodemographic and lifestyle data. Results During follow-up (median 18.8 years), 2757 colon cancer cases developed. We found a hazard ratio (HR) of 1.05 (95% confidence interval (CI): 0.99-1.10) per 10-dB higher 5-year mean time-weighted road traffic noise. In sub-type analyses, the association seemed confined to distal colon cancer: HR 1.06 (95% CI: 0.98-1.14). Railway and aircraft noise was not associated with colon cancer, albeit there was some indication in sub-type analyses that railway noise may also be associated with distal colon cancer. In interaction-analyses, the association between road traffic noise and colon cancer was strongest among obese persons and those with high NO2-exposure. Discussion A prominent study strength is the large population with harmonized data across eleven cohorts, and the complete address-history during follow-up. However, each cohort estimated noise independently, and only at the most exposed façade, which may introduce exposure misclassification. Despite this, the results of this pooled study suggest that traffic noise may be a risk factor for colon cancer, especially of distal origin.

Occupational noise exposure and risk of incident stroke: a pooled study of five Scandinavian cohorts.

OBJECTIVES: To investigate the association between occupational noise exposure and stroke incidence in a pooled study of five Scandinavian cohorts (NordSOUND). METHODS: We pooled and harmonised data from five Scandinavian cohorts resulting in 78 389 participants. We obtained job data from national registries or questionnaires and recoded these to match a job-exposure matrix developed in Sweden, which specified the annual average daily noise exposure in five exposure classes (LAeq8h): <70, 70-74, 75-79, 80-84, ≥85 dB(A). We identified residential address history and estimated 1-year average road traffic noise at baseline. Using national patient and mortality registers, we identified 7777 stroke cases with a median follow-up of 20.2 years. Analyses were conducted using Cox proportional hazards models adjusting for individual and area-level potential confounders. RESULTS: Exposure to occupational noise at baseline was not associated with overall stroke in the fully adjusted models. For ischaemic stroke, occupational noise was associated with HRs (95% CI) of 1.08 (0.98 to 1.20), 1.09 (0.97 to 1.24) and 1.06 (0.92 to 1.21) in the 75-79, 80-84 and ≥85 dB(A) exposure groups, compared with <70 dB(A), respectively. In subanalyses using time-varying occupational noise exposure, we observed an indication of higher stroke risk among the most exposed (≥85 dB(A)), particularly when restricting analyses to people exposed to occupational noise within the last year (HR: 1.27; 95% CI: 0.99 to 1.63). CONCLUSIONS: We found no association between occupational noise and risk of overall stroke after adjustment for confounders. However, the non-significantly increased risk of ischaemic stroke warrants further investigation.

Long-term exposure to air pollution, coronary artery calcification, and carotid artery plaques in the population-based Swedish SCAPIS Gothenburg cohort.

Long-term exposure to air pollution is associated with cardiovascular events. A main suggested mechanism is that air pollution accelerates the progression of atherosclerosis, yet current evidence is inconsistent regarding the association between air pollution and coronary artery and carotid artery atherosclerosis, which are well-established causes of myocardial infarction and stroke. We studied associations between low levels of long-term air pollution, coronary artery calcium (CAC) score, and the prevalence and area of carotid artery plaques, in a middle-aged population-based cohort. The Swedish CArdioPulmonary bioImage Study (SCAPIS) Gothenburg cohort was recruited during 2013-2017 and thoroughly examined for cardiovascular risk factors, including computed tomography of the heart and ultrasonography of the carotid arteries. In 5070 participants (age 50-64 years), yearly residential exposures to air pollution (PM2.5, PM10, PMcoarse, NOx, and exhaust-specific PM2.5 1990-2015) were estimated using high-resolution dispersion models. We used Poisson regression to examine associations between long-term (26 years' mean) exposure to air pollutants and CAC score, and prevalence of carotid artery plaques, adjusted for potential confounders. Among participants with carotid artery plaques, we also examined the association with plaque area using linear regression. Mean exposure to PM2.5 was low by international standards (8.5 µg/m3). There were no consistent associations between long-term total PM2.5 exposure and CAC score or presence of carotid artery plaques, but an association between total PM2.5 and larger plaque area in participants with carotid plaques. Associations with traffic-related air pollutants were consistently positive for both a high CAC score and bilateral carotid artery plaques. These associations were independent of road traffic noise. We found stronger associations among men and participants with cardiovascular risk factors. The results lend some support to atherosclerosis as a main modifiable pathway between low levels of traffic-related ambient air pollution and cardiovascular disease, especially in vulnerable individuals.

The impact of nocturnal road traffic noise, bedroom window orientation, and work-related stress on subjective sleep quality: results of a cross-sectional study among working women.

OBJECTIVE: To examine the effect of work-related stress and road noise exposure on self-rated sleep and potential additive interaction effects. METHODS: Sleep and predictor variables were surveyed within two subsamples with 2191 and 1764 working women in a cross-sectional study. Sleep was assessed using a single question on general sleep quality and four questions on specific sleep problems and subsequently dichotomized (poor sleep vs. no poor sleep). Work-related stress was operationalized by job strain and effort-reward imbalance. Nocturnal exposure to road traffic noise was assessed as (a) the orientation of the bedroom window to a quiet façade vs. a low-, medium- or high-trafficked street and (b) energy-equivalent sound pressure levels for night-time modelled at the most exposed façade (Lnight). We distinguished between low (< 45 dB(A)), medium (45-50 dB(A)) and high exposure (> 50 dB(A)). RESULTS: Poor sleep was associated with job strain and effort-reward imbalance. The prevalence of poor sleep did not increase with increasing Lnight, but bedroom window orientation showed a non-significant trend. A quiet façade had a protective effect on sleep in each Lnight category. We found a non-significant trend for an additive interaction between bedroom window orientation and job strain. CONCLUSION: Noise levels modelled for the most exposed façade likely overestimate the actual exposure and thus may not be a precise predictor of poor sleep. Bedroom window orientation seems more relevant. Potential additive interaction effects between bedroom window orientation and job strain should be considered when interpreting epidemiological study results on noise-induced sleep disturbances.

Road traffic noise, air pollution and cardiovascular events in a Swedish cohort.

Urbanization and increasing road traffic cause exposure to both noise and air pollution. While the levels of air pollutants such as nitrogen oxides (NOx) have decreased in Sweden during the past decades, exposure to traffic noise has increased. The association with cardiovascular morbidity is less well established for noise than for air pollution, and most studies have only studied one of the two highly spatially correlated exposures. The Swedish Primary Prevention Study cohort consists of men aged 47 to 55 when first examined in 1970-1973. The cohort members were linked to the Swedish patient registry through their personal identity number and followed until first cardiovascular event 1970-2011. The address history during the entire study period was used to assign annual modelled residential exposure to road traffic noise and NOx. The Cox proportional hazards model with age on the time axis and time-varying exposures were used in the analysis. The results for 6304 men showed a non-significant increased risk of cardiovascular disease for long-term road traffic noise at the home address, after adjusting for air pollution. The hazard ratios were 1.08 (95% CI 0.90-1.28) for cardiovascular mortality, 1.14 (95% CI 0.96-1.36) for ischemic heart disease incidence and 1.07 (95% CI 0.85-1.36) for stroke incidence, for noise above 60 dB, compared to below 50 dB. This study found some support for cardiovascular health effects of long-term exposure to road traffic noise above 60 dB, after having accounted for exposure to air pollution.

Noise exposure and childhood asthma up to adolescence.

OBJECTIVE: Increasing evidence indicates aggravation of immune-mediated diseases due to physiological and psychological stress. Noise is a stressor, however, little is known about its effects on children's respiratory health. This study investigates the association between pre- or postnatal road traffic or occupational noise exposure and asthma as well as related symptoms from infancy to adolescence. METHODS: The study was conducted in the Swedish birth cohort BAMSE, including over 4000 participants followed with repeated questionnaires and clinical tests until 16 years of age. Pre- and postnatal residential road traffic noise was assessed by estimating time-weighted average noise levels at the most exposed façade. Maternal occupational noise exposure during pregnancy was evaluated using a job-exposure-matrix. The associations between noise exposure and asthma-related outcomes were explored using logistic regression and generalised estimating equations. RESULTS: We observed non-significant associations for asthma ever up to 16 years with residential road traffic noise exposure in infancy ≥55 dBLden (adjusted OR = 1.22; 95% CI 0.90-1.65), as well as prenatal occupational noise exposure ≥80 dBLAeq,8h (1.18, 0.85-1.62). In longitudinal analyses, however, no clear associations between pre- or postnatal exposure to residential road traffic noise, or average exposure to noise since birth, were detected in relation to asthma or wheeze until 16 years. CONCLUSION: We did not find a clear overall association between exposure to noise during different time periods and asthma or wheeze up to adolescence.

Long-term transportation noise exposure and incidence of ischaemic heart disease and stroke: a cohort study.

BACKGROUND: There is limited evidence from longitudinal studies on transportation noise from different sources and development of ischaemic heart disease (IHD) and stroke. OBJECTIVES: This cohort study assessed associations between exposure to noise from road traffic, railway or aircraft and incidence of IHD and stroke. METHODS: In a cohort of 20 012 individuals from Stockholm County, we estimated long-term residential exposure to road traffic, railway and aircraft noise. National Patient and Cause-of-Death Registers were used to identify IHD and stroke events. Information on risk factors was obtained from questionnaires and registers. Adjusted HR for cardiovascular outcomes related to source-specific noise exposure were computed using Cox proportional hazards regression. RESULTS: No clear or consistent associations were observed between transportation noise and incidence of IHD or stroke. However, noise exposure from road traffic and aircraft was related to IHD incidence in women, with HR of 1.11 (95% CI 1.00 to 1.22) and 1.25 (95% CI 1.09 to 1.44) per 10 dB Lden, respectively. For both sexes taken together, we observed a particularly high risk of IHD in those exposed to all three transportation noise sources at≥45 dB Lden, with a HR of 1.57 (95% CI 1.06 to 2.32), and a similar tendency for stroke (HR 1.42; 95% CI 0.87 to 2.32). CONCLUSION: No overall associations were observed between transportation noise exposure and incidence of IHD or stroke. However, there appeared to be an increased risk of IHD in women exposed to road traffic or aircraft noise as well as in those exposed to multiple sources of transportation noise.

Traffic noise exposure in relation to adverse birth outcomes and body mass between birth and adolescence.

BACKGROUND: There is growing evidence that traffic noise exposure is associated with adiposity among adults but data in children are limited. OBJECTIVE: This longitudinal study examined whether pre- and postnatal noise exposure is associated with body mass index (BMI) between birth and adolescence or with adverse birth outcomes. METHODS: The study was conducted using data from the BAMSE birth cohort, which included 4089 children born in Stockholm County, Sweden. Data on BMI from birth to adolescence were collected via questionnaires, clinical examinations and health care records. A national register provided information on birth outcomes. Road traffic noise levels at the most exposed façade were estimated for all residences of the children during follow-up, as well as of their mothers during pregnancy, and time-weighted average exposure was calculated for different time windows. Maternal occupational noise exposure was obtained from a job-exposure-matrix. Logistic- and quantile regression models were used to estimate associations between noise exposure and health outcomes. RESULTS: We found residential road traffic noise exposure to be associated with increases in BMI from school age to adolescence, but not at earlier ages. In the age groups 8-11 years and 12-16 years the BMI increments were 0.11 kg/m2 per 10 dB Lden (95% CI 0.08-0.13) and 0.20 kg/m2 per 10 dB Lden (95% CI 0.17-0.22), respectively. Maternal noise exposure during pregnancy was generally unrelated to adverse birth outcomes and BMI from birth to adolescence in the children, however, traffic noise exposure was associated with a decreased risk of preterm birth CONCLUSION: Residential road traffic noise exposure was associated with BMI increases from school age to adolescence, but not at earlier ages. Maternal occupational noise exposure or exposure from road traffic during pregnancy were not consistently related to birth outcomes or BMI from birth to adolescence.

Road traffic noise abatement scenarios in Gothenburg 2015 - 2035.

Exposure to high levels of road traffic noise at the most exposed building facade is increasing, both due to urbanization and due to overall traffic increase. This study investigated how different noise reduction measures would influence the noise exposure on a city-wide scale in Gothenburg, a city in Sweden with approximately 550,000 inhabitants. Noise exposure was estimated under several different scenarios for the period 2015-2035, using the standardized Nordic noise prediction method together with traffic flow measurements and population statistics. The scenarios were based on reducing speed limits, reducing traffic flows, introducing more electrically powered vehicles and introducing low-noise tires and pavements. The most effective measures were introducing low-noise tires or pavements, which in comparison to business as usual produced between 13% and 29% reduction in the number of inhabitants exposed above 55 dB equivalent level.

Low-frequency outdoor-indoor noise level difference for wind turbine assessment.

To increase the understanding of wind turbine noise on sleep, human physiological reactions need to be studied in a controlled laboratory setting. The paper presents an outdoor-indoor noise level difference as a function of frequency, applicable to creating wind turbine indoor sounds with the outdoor sounds as input. For this, a combination of measurement data and modeling results has been used. The suggested data are provided in a table.

Evaluation of a sound environment intervention in an ICU: A feasibility study.

BACKGROUND: Currently, it is well known that the sound environment in intensive care units (ICU) is substandard. Therefore, there is a need of interventions investigating possible improvements. Unfortunately, there are many challenges to consider in the design and performance of clinical intervention studies including sound measurements and clinical outcomes. OBJECTIVES: (1) explore whether it is possible to implement a full-scale intervention study in the ICU concerning sound levels and their impact on the development of ICU delirium; (2) discuss methodological challenges and solutions for the forthcoming study; (3) conduct an analysis of the presence of ICU delirium in the study group; and (4) describe the sound pattern in the intervention rooms. METHODS: A quasi-randomized clinical trial design was chosen. The intervention consisted of a refurbished two-bed ICU patient room (experimental) with a new suspended wall-to-wall ceiling and a low frequency absorber. An identical two-bed room (control) remained unchanged. INCLUSION CRITERIA: Patients >18 years old with ICU lengths of stay (LoS) >48h. The final study group consisted of 31 patients: six from the rebuilt experimental room and 25 from the control room. Methodological problems and possible solutions were continuously identified and documented. RESULTS: Undertaking a full-scale intervention study with continuous measurements of acoustic data in an ICU is possible. However, this feasibility study demonstrated some aspects to consider before start. The randomization process and the sound measurement procedure must be developed. Furthermore, proper education and training are needed for determining ICU delirium. CONCLUSION: This study raises a number of points that may be helpful for future complex interventions in an ICU. For a full-scale study to be completed a continuously updated cost calculation is necessary. Furthermore, representatives from the clinic need to be involved in all stages during the project.

Physiological effects of railway vibration and noise on sleep.

This paper evaluates the relative contribution of vibration and noise from railway on physiological sleep outcomes. Vibration from railway freight often accompanies airborne noise, yet is almost totally absent in the existing literature. In an experimental investigation, 23 participants, each sleeping for six nights in the laboratory, were exposed to 36 simulated railway freight pass-bys per night with vibration alone (aWd,max = 0.0204 ms-2), noise alone (LAF,max = 49.8 dB), or both vibration and noise simultaneously. A fourth exposure night involved 52 pass-bys with concurrent vibration and noise. Sleep was measured with polysomnography. Cardiac activity was measured with electrocardiography. The probability of cortical arousals or awakenings was greater following all exposures, including vibration alone, than spontaneous reaction probability (p < 0.05). The effects of vibration exposure and noise exposure on changes of sleep stage and arousals were directly additive. Vibration and noise exposure both induced heart rate acceleration above spontaneously expected fluctuations at baseline. The results indicate that vibration and noise are processed in the brain separately yet in parallel, with both contributing towards the likelihood of sleep disruption. The findings show that vibration is of importance when considering the impact of railway freight on sleep.

Long-term exposure to transportation noise in relation to global cognitive decline and cognitive impairment: Results from a Swedish longitudinal cohort.

BACKGROUND AND AIMS: Transportation noise is an environmental exposure with mounting evidence of adverse health effects. Besides the increased risk of cardiovascular and metabolic diseases, recent studies suggest that long-term noise exposure might accelerate cognitive decline in older age. We examined the association between transportation noise and cognitive function in a cohort of older adults. METHODS: The present study is based on 2594 dementia-free participants aged 60 + years from the Swedish National study on Aging and Care in Kungsholmen (SNAC-K). Global cognition score and CIND (cognitive impairment, no dementia) were assessed with a comprehensive neuropsychological battery at baseline and up to 16 years. Residential transportation noise resulting from road traffic, railway, and aircraft were estimated at the most exposed façade and the time-weighted average exposure was assessed. Linear mixed-effect models were used to assess the effect of long-term traffic noise exposure on the rate of change in global cognition score. Hazard ratios (HRs) and 95 % confidence intervals (CIs) of CIND by transportation noise exposure were obtained with Cox proportional hazard models. RESULTS: Global cognition score decreased at an average rate of -0.041 (95 %CI -0.043, -0.039) per year. Aircraft noise was associated with a 0.007 (per 10 dB Lden; 95 %CI -0.012, -0.001) faster annual rate of decline. Global cognition score seems to be not affected by road traffic and railway noise. During the follow-up, 422 (21 %) participants developed CIND. A 10-dB Lden difference in exposure to aircraft and railway noise was associated with a 16 % (HR 1.16, 95 %CI 0.91, 1.49) and 26 % (HR 1.26, 95 %CI 1.01, 1.56) increased hazard of CIND in the multi-pollutant model, respectively. No association was found for road traffic (HR 1.00, 95 %CI 0.83, 1.21). CONCLUSIONS: Transportation noise was linked to cognitive impairment and faster cognitive decline among older adults. Future studies are warranted to confirm our results.

Long-term ambient air pollution and coronary atherosclerosis: Results from the Swedish SCAPIS study.

BACKGROUND AND AIMS: Despite firm evidence for an association between long-term ambient air pollution exposure and cardiovascular morbidity and mortality, results from epidemiological studies on the association between air pollution exposure and atherosclerosis have not been consistent. We investigated associations between long-term low-level air pollution exposure and coronary atherosclerosis. METHODS: We performed a cross-sectional analysis in the large Swedish CArdioPulmonary bioImaging Study (SCAPIS, n = 30 154), a random general population sample. Concentrations of total and locally emitted particulate matter <2.5 µm (PM2.5), <10 µm (PM10), and nitrogen oxides (NOx) at the residential address were modelled using high-resolution dispersion models. We estimated associations between air pollution exposures and segment involvement score (SIS), coronary artery calcification score (CACS), number of non-calcified plaques (NCP), and number of significant stenoses, using ordinal regression models extensively adjusted for potential confounders. RESULTS: Median 10-year average PM2.5 exposure was 6.2 µg/m3 (range 3.5-13.4 µg/m3). 51 % of participants were women and 51 % were never-smokers. None of the assessed pollutants were associated with a higher SIS or CACS. Exposure to PM2.5 was associated with NCP (adjusted OR 1.34, 95 % CI 1.13, 1.58, per 2.05 µg/m3). Associations with significant stenoses were inconsistent. CONCLUSIONS: In this large, middle-aged general population sample with low exposure levels, air pollution was not associated with measures of total burden of coronary atherosclerosis. However, PM2.5 appeared to be associated with a higher prevalence of non-calcified plaques. The results suggest that increased risk of early-stage atherosclerosis or rupture, but not increased total atherosclerotic burden, may be a pathway for long-term air pollution effects on cardiovascular disease.

Road-traffic noise exposure and coronary atherosclerosis in the Swedish CArdioPulmonary bioImage Study (SCAPIS).

Background: Road-traffic noise may influence the development of cardiovascular events such as stroke and myocardial infarction, but etiological mechanisms remain unclear. This study aimed to assess the relationship between long-term road-traffic noise exposure and coronary atherosclerosis in Sweden. Methods: In the Swedish CArdioPulmonary bioImage Study (SCAPIS) cohort, including 30,154 subjects aged 50-65 years, recruited between 2013 and 2018, coronary atherosclerosis was measured based on computer tomography (CT) scans as coronary artery calcium score, segment involvement score (SIS), and non-calcified plaques (NCP) at enrollment. Based on modified Nordic model, road-traffic noise exposure was modeled for 2000, 2013, and 2018 with interpolation for intermediate years. We investigated the association between time-weighted long-term exposure to road-traffic noise (Lden) and the prevalence of atherosclerosis using ordinal logistic regression models adjusting for potential socioeconomic, behavioral, and environmental confounders, including air pollution. Results: No clear associations were found between road-traffic noise and coronary atherosclerosis. The odds ratio for coronary artery calcium score was 1.00 (95% confidence interval [CI] = 0.96, 1.04), SIS 0.99 (0.96, 1.03), and NCP 0.98 (0.90, 1.03) per interquartile range (9.4 dB Lden) for road-traffic noise exposure during 10 years before enrollment. No consistent associations were observed in site-specific analyses or using shorter exposure periods. Furthermore, exposure-response analyses revealed no clear trends, and there were no strong interactions between road-traffic noise and cardiovascular risk factors in relation to the atherosclerosis markers. Conclusions: Long-term exposure to road-traffic noise was not linked to coronary atherosclerosis or calcification in relatively healthy, middle-aged populations in Sweden.

Residential exposure to transportation noise and risk of incident atrial fibrillation: a pooled study of 11 prospective Nordic cohorts.

Background: Transportation noise has been linked with cardiometabolic outcomes, yet whether it is a risk factor for atrial fibrillation (AF) remains inconclusive. We aimed to assess whether transportation noise was associated with AF in a large, pooled Nordic cohort. Methods: We pooled data from 11 Nordic cohorts, totaling 161,115 participants. Based on address history from five years before baseline until end of follow-up, road, railway, and aircraft noise was estimated at a residential level. Incident AF was ascertained via linkage to nationwide patient registries. Cox proportional hazards models were utilized to estimate associations between running 5-year time-weighted mean transportation noise (Lden) and AF after adjusting for sociodemographics, lifestyle, and air pollution. Findings: We identified 18,939 incident AF cases over a median follow-up of 19.6 years. Road traffic noise was associated with AF, with a hazard ratio (HR) and 95% confidence interval (CI) of 1.02 (1.00-1.04) per 10-dB of 5-year mean time-weighted exposure, which changed to 1.03 (1.01-1.06) when implementing a 53-dB cut-off. In effect modification analyses, the association for road traffic noise and AF appeared strongest in women and overweight and obese participants. Compared to exposures ≤40 dB, aircraft noise of 40.1-50 and > 50 dB were associated with HRs of 1.04 (0.93-1.16) and 1.12 (0.98-1.27), respectively. Railway noise was not associated with AF. We found a HR of 1.19 (1.02-1.40) among people exposed to noise from road (≥45 dB), railway (>40 dB), and aircraft (>40 dB) combined. Interpretation: Road traffic noise, and possibly aircraft noise, may be associated with elevated risk of AF. Funding: NordForsk.

Long-term exposure to transportation noise and obesity: A pooled analysis of eleven Nordic cohorts.

Background: Available evidence suggests a link between exposure to transportation noise and an increased risk of obesity. We aimed to assess exposure-response functions for long-term residential exposure to road traffic, railway and aircraft noise, and markers of obesity. Methods: Our cross-sectional study is based on pooled data from 11 Nordic cohorts, including up to 162,639 individuals with either measured (69.2%) or self-reported obesity data. Residential exposure to transportation noise was estimated as a time-weighted average Lden 5 years before recruitment. Adjusted linear and logistic regression models were fitted to assess beta coefficients and odds ratios (OR) with 95% confidence intervals (CI) for body mass index, overweight, and obesity, as well as for waist circumference and central obesity. Furthermore, natural splines were fitted to assess the shape of the exposure-response functions. Results: For road traffic noise, the OR for obesity was 1.06 (95% CI = 1.03, 1.08) and for central obesity 1.03 (95% CI = 1.01, 1.05) per 10 dB Lden. Thresholds were observed at around 50-55 and 55-60 dB Lden, respectively, above which there was an approximate 10% risk increase per 10 dB Lden increment for both outcomes. However, linear associations only occurred in participants with measured obesity markers and were strongly influenced by the largest cohort. Similar risk estimates as for road traffic noise were found for railway noise, with no clear thresholds. For aircraft noise, results were uncertain due to the low number of exposed participants. Conclusion: Our results support an association between road traffic and railway noise and obesity.