dB Lden Research Articles

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

BackgroundThere is growing evidence that traffic noise exposure is associated with adiposity among adults but data in children are limited. ObjectiveThis 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. MethodsThe 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. ResultsWe 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 ConclusionResidential 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.

Transportation noise and incidence of hypertension.

The evidence on exposure to transportation noise and development of hypertension is inconclusive, mostly because of a lack of high quality studies of longitudinal design. This cohort study aimed at investigating the association between exposure to road traffic, railway or aircraft noise and incidence of hypertension. We also assessed effects of varying lengths of exposure as well as of multiple sources of exposure. Based on the residential histories of a cohort of 4854 men and women from Stockholm County, we estimated the residential exposure to road traffic, railway and aircraft noise in 1, 5 and 10 year time-periods. Hypertension was assessed by blood pressure measurements, information from questionnaires and hospital diagnoses. Extensive information on potential confounders was available from repeated questionnaires and registers. Hazard Ratios (HR) and 95% confidence intervals (CI) of hypertension related to noise exposure was computed from Cox regression models. We observed a positive association between aircraft noise exposure and incidence of hypertension with a HR of 1.16 (95% CI 1.08-1.24) per 10 dB Lden 5 years preceding the event. No clear differences in risk were indicated between the three exposure time windows. Road traffic and railway noise were not associated with incidence of hypertension during any of the exposure periods. There appeared to be a particularly high risk of hypertension among persons exposed to both aircraft and road traffic noise ≥45 dB Lden with an HR of 1.39 (95% CI 1.14-1.70). Exposure to aircraft noise may result in increased risk of hypertension.

Home as a Place of Noise Control for the Elderly? A Cross-Sectional Study on Potential Mediating Effects and Associations between Road Traffic Noise Exposure, Access to a Quiet Side, Dwelling-Related Green and Noise Annoyance.

Urban residents’ need to be in control of their home environment can be constrained by perceived uncontrollability of exposure to road traffic noise. Noise annoyance may indicate a psychological stress reaction due to this uncontrollability perception, thereby undermining the restoration process. Environmental resources, such as having access to a quiet side at home and dwelling-related green, may reduce noise annoyance both directly by shielding acoustically and indirectly by enhancing residents’ perceived noise control. We assessed the potential mediating role of perceived noise control in independent and joint associations of road traffic noise exposure (>65 dB Lden) and of an absent dwelling-related environmental resource (three indicators concerning quiet sides and one indicator concerning dwelling-related green) with noise annoyance. In our cross-sectional, questionnaire-based study on elderly urban citizens (N = 1812), we observed a statistically significant indirect effect of noise exposure on noise annoyance through perceived noise control (39%, 95%CI 26–55%). Statistical mediation between indicators of absent environmental resources and noise annoyance was weaker. The potential indirect effect was confirmed for combinations of noise exposure with each of the four indicators of an absent environmental resource. Our findings may call for mitigating noise levels while fostering quietness and green at residents’ homes.

Road traffic noise and determinants of saliva cortisol levels among adolescents.

The understanding of determinants for saliva cortisol levels in adolescents is limited. This study investigated the role of road traffic noise exposure, noise annoyance and various other factors for saliva cortisol levels. We collected morning and evening saliva samples from 1751 adolescents from the BAMSE birth cohort based in Stockholm County. Façade noise levels from road traffic were estimated at the residences of the study subjects and repeated questionnaires and medical examinations provided extensive information on various exposures and conditions, including annoyance to noise from different sources. Cortisol was measured using radioimmunoassay. Associations between determinants and saliva cortisol levels were analysed using linear regression. Morning saliva cortisol levels were significantly higher in females than in males (geometric mean 42.4 and 35.0 nmol/l, respectively) as well as in subjects with allergy related diseases. Height and age were related to saliva cortisol levels as well as sampling season. Road traffic noise exposure was not associated with saliva cortisol, however, annoyance to noise tended to increase the levels. Saliva cortisol levels appeared particularly high among those who were highly annoyed and exposed to road traffic noise levels ≥ 55 dB Lden (50.5 nmol/l, p = 0.02). Our findings suggest that individual perception of noise may be of importance for saliva cortisol levels. The results also point to the complexity of using saliva cortisol as a marker of noise exposure in adolescents.

Road traffic noise exposure in relation to waist circumference, diabetes and hypertension – A longitudinal study

Background: Recent studies indicate adverse health effects of long-term exposure to traffic-related noise, including cardiovascular and metabolic diseases. Noise exposure may also result in annoyance and sleep disturbances as well as increased saliva cortisol levels, indicating physiological stress. There are, however, few longitudinal studies on chronic effects of exposure to traffic noise. Aim: This cohort study focused on the association between exposure to road traffic noise and change in waist circumference and development of type 2 diabetes and hypertension. Methods: The study included 5,249 men and women living in Stockholm County and followed from 1992 to 2006. Clinical examinations and questionnaires provided information on outcomes and confounders. Individual traffic noise exposure during follow-up was modeled for each participant using traffic characteristics at residential addresses. We used linear and logistic regression to assess associations between noise exposure and the different outcomes. Results: We found statistically significant associations at road traffic noise exposure above 60 dB Lden for change in waist circumference (+3.04 cm; 95% CI: 0.63-5.44) and hypertension (hazard ratio 2.75; 95% CI: 1.02-6.65) with adjustment for potential confounding factors. A similar tendency was seen for type 2 diabetes (HR 2.75; 95% CI 0.79-9.56). A clear exposure-response relation between noise exposure and waist circumference increase was observed (+0.46 cm per 10 dB; 95% CI 0.28-0.64); however, such a relation was not evident for a cumulative incidence of type 2 diabetes or hypertension. Conclusions: Our findings suggest that long-term exposure to road traffic noise is related to the development of waist circumference and hypertension, and possibly also to type 2 diabetes.

Road traffic noise exposure association with self-reported body mass index

New epidemiological evidence is starting to emerge about the association between road traffic noise (RTN) exposure and markers of obesity, but results have been controversial. This study aimed to determine the association between RTN exposure and self-reported body mass index (BMI) in the city of Plovdiv, Bulgaria. A cross-sectional non-probabilistic survey was carried out among 513 residents (18-83 years). BMI was calculated from self-reported body weight and height and linked to individual exposure to RTN. Linear and Poisson regression models were set up to explore the total and direct effects of RTN on BMI and obesity. Total effects were 0.48 kg/m2 (95% CI: 0.15-0.81) increase in BMI per 5 dB Lden in thewhole sample and 0.63 kg/m2 (95%CI: 0.01-1.24) among long-term residents (?20 years). The relative risks of obesity were 1.03 (95% CI: 1.01-1.05) among all participants and 1.05 (95%CI: 1.01-1.09) among long-term residents. Direct effects were also significant. In conclusion, RTN exposure was significantly and positively associated with BMI and obesity. Future research is necessary in order to overcome the limitations of this study and extend its inferences to the general population

Traffic noise and mortality in the ESCAPE study

Background: It has been suggested that long-term exposure to road traffic noise could lead to premature mortality from cardiovascular causes. Aims: To assess effects of road traffic noise exposure on cause-specific mortality in existing cohort studies in the ESCAPE project (European Study of Cohorts for Air Pollution Effects, www.escapeproject.eu). Methods: Standardised data on mortality due to all cardiovascular diseases (CVD) and due to ischemic hearth diseases (IHD) and potential confounders were analysed in ten cohorts from Finland, Sweden, Norway, Denmark, Germany, The Netherlands and Italy. ESCAPE made use of data from local assessments carried out for the first round of noise mapping in the EU (2007)or for specific cohorts. The Lden (day-evening-night equivalent level) was calculated for the most exposed façade of the residential address. Outdoor air pollution (PM2.5, PM2.5 absorbance, NO2, NOx) was assessed at the address using land use regression models. Cox regression analyses were carried out per cohort followed by meta-analysis to obtain combined effect estimates. Results: Data from 87,001 subjects from 6 cohorts (cohort ranges between 2,106 and 35,843 subjects) with a total of 1,573 deaths due to CVD and 771 due to IHD were included so far. Fifty-six % of the subjects (cohort range 27-68%) was exposed to noise levels above 55 dB Lden. The pooled hazard ratio (HR) for CVD mortality was 1.14 [95% CI 1.03-1.26] per 10 dB increase; for IHD mortality the HR was 1.12 [95% CI 0.95-1.30] per 10 dB increase. For both endpoints a threshold of 55 dB was assumed. Inclusion of air pollutants in the statistical model marginally changed the effect estimates. Statistical analyses are ongoing and will affect effect estimates. Conclusion: The ESCAPE project will provide data on the association of road traffic noise with mortality from cardiovascular causes.

Community response to aircraft noise around three airports in Vietnam

To assess the effect of aircraft noise on people in Vietnam, socio-acoustic surveys on community response to aircraft noise were conducted in residential areas around three airports in Ho Chi Minh City, Hanoi, and Da Nang. The community response was obtained by face-to-face interviews during the daytime on weekends. The aircraft noise was measured for seven successive days. Aircraft noise exposures ranged from 53 to 71 dB, from 48 to 61 dB, and from 52 to 64 dB Lden in Ho Chi Minh, Hanoi, and Danang, respectively. A representative dose-response relationship for aircraft annoyance in Vietnam has been proposed based on 3487 responses and noise data obtained by field measurements at 25 sites. It has been found that the curve for Vietnam is slightly higher than but rather almost consistent to the EU's curve. The respondents in each surveyed city have different levels of annoyance for the same aircraft noise exposure.

Annoyance Analysis of Population Affected By Railway Noise—EU Strategic Noise Mapping

ISEE-157 Objective: According to the Directive 2002/49/EC the EU member states are obliged to elaborate strategic noise maps (SNM) and should apply the noise indicators Lden (overall annoyance) and Lnight (10 pm to 6 am) for strategic noise mapping. The SNM for rail transport noise in the Czech Republic was elaborated in the National Laboratory for GIS. Material and Methods: Railways track, Census 2001, and geographic data were elaborated using the Dutch methodology RMR2 for calculation of models. The annoyance analysis was elaborated using the software LimA, advanced. The actual limit was stated as 70 dB for Lden and 65 dB for Lnight. Results: The results of annoyance analysis are performed as a sum of population (houses, school, and hospitals) living/being situated in the noise level below 55 dB Lden and 45 dB for Lnight (lower cutoff), over 70 dB Lden and 65 dB for Lnight (limit value) and the categories between by 5 dB. In the area of interest about 542 thousands inhabitants are living. For indicator Lden 524,000 people live below lower cutoff and 300 over limit value. For indicator Lnight 485,000 people live below lower cutoff and 200 over limit value. Of the 38,700 houses 37,000 is placed in lower cutoff and 50 over limit value for Lden and 35,000 houses in lower cutoff and 27 houses over limit value for Lnight. Most of the 495 schools are situated below lower cutoff for Lden (484 schools). Of the 26 hospitals the majority (24) is situated in lower cutoff for Lden and 15 hospitals for Lnight. Neither school nor hospital is being situated in area with over limit value both for Lden and Lnight. Conclusions: The results of annoyance analysis indicated population living and houses being situated in areas exceeding the limit noise level. In future the strategic noise maps (and its noise levels by 5 dB) may be used in public health whenever the limit noise value will be decreased.

Noise annoyance and activity disturbance before and after the erection of a roadside noise barrier

Questionnaire studies were conducted in a residential area before and after the erection of a 2.25 m high noise barrier of conventional type along a heavily traveled road (19,600 vehicles/24 h). The interval between studies was two years. Houses closest to the barrier received a sound-level reduction from -70.0 to 62.5 dB Lden at the most exposed facade. The sound-level reduction decreased with distance to the road, and was negligible for houses at more than 100 m distance. Up to this distance, the noise barrier reduced residents' noise annoyance outdoors and indoors as well as improved speech communication outdoors. Indoors, speech communication and sleep disturbance were slightly but nonsignificantly improved. Predictions of the number of annoyed persons from published exposure-response curves (in Lden) agreed with the percentage of residents being annoyed when indoors, before and after the barrier. Conversely, the percentage of residents being annoyed when outdoors clearly exceeded the predictions. These results suggest that these exposure-response curves may be used in predicting indoor situations, but they should not be applied in situations where outdoor annoyance is at focus.