Effects of aircraft noise cessation on blood pressure, cardio- and cerebrovascular endothelial function, oxidative stress, and inflammation in an experimental animal model

Large epidemiological studies have shown that traffic noise promotes the development of cardiometabolic diseases. It remains to be established how long these adverse effects of noise may persist in response to a noise-off period. We investigated the effects of acute aircraft noise exposure (mean sound level of 72 dB(A) applied for 4d) on oxidative stress and inflammation mediating vascular dysfunction and increased blood pressure in male C57BL/6 J mice. 1, 2 or 4d of noise cessation after a 4d continuous noise exposure period completely normalized noise-induced endothelial dysfunction of the aorta (measured by acetylcholine-dependent relaxation) already after a 1d noise pause. Vascular oxidative stress and the increased blood pressure were partially corrected, while markers of inflammation (VCAM-1, IL-6 and leukocyte oxidative burst) showed a normalization within 4d of noise cessation. In contrast, endothelial dysfunction, oxidative stress, and inflammation of the cerebral microvessels of noise-exposed mice did not improve at all. These data demonstrate that the recovery from noise-induced damage is more complex than expected demonstrating a complete restoration of large conductance vessel function but persistent endothelial dysfunction of the microcirculation. These findings also imply that longer noise pauses are required to completely reverse noise-induced vascular dysfunction including the resistance vessels.

Mitigation of aircraft noise-induced vascular dysfunction and oxidative stress by exercise, fasting, and pharmacological α1AMPK activation: molecular proof of a protective key role of endothelial α1AMPK against environmental noise exposure

AIMS

Environmental stressors such as traffic noise represent a global threat, accounting for 1.6 million healthy life years lost annually in Western Europe. Therefore, the noise-associated health side effects must be effectively prevented or mitigated. Non-pharmacological interventions such as physical activity or a balanced healthy diet are effective due to the activation of the adenosine monophosphate-activated protein kinase (α1AMPK). Here, we investigated for the first time in a murine model of aircraft noise-induced vascular dysfunction the potential protective role of α1AMPK activated via exercise, intermittent fasting, and pharmacological treatment.

METHODS AND RESULTS

Wild-type (B6.Cg-Tg(Cdh5-cre)7Mlia/J) mice were exposed to aircraft noise [maximum sound pressure level of 85 dB(A), average sound pressure level of 72 dB(A)] for the last 4 days. The α1AMPK was stimulated by different protocols, including 5-aminoimidazole-4-carboxamide riboside application, voluntary exercise, and intermittent fasting. Four days of aircraft noise exposure produced significant endothelial dysfunction in wild-type mice aorta, mesenteric arteries, and retinal arterioles. This was associated with increased vascular oxidative stress and asymmetric dimethylarginine formation. The α1AMPK activation with all three approaches prevented endothelial dysfunction and vascular oxidative stress development, which was supported by RNA sequencing data. Endothelium-specific α1AMPK knockout markedly aggravated noise-induced vascular damage and caused a loss of mitigation effects by exercise or intermittent fasting.

CONCLUSION

Our results demonstrate that endothelial-specific α1AMPK activation by pharmacological stimulation, exercise, and intermittent fasting effectively mitigates noise-induced cardiovascular damage. Future population-based studies need to clinically prove the concept of exercise/fasting-mediated mitigation of transportation noise-associated disease.

Long-term aircraft noise exposure and risk of hypertension in postmenopausal women

BACKGROUND

Studies of the association between aircraft noise and hypertension are complicated by inadequate control for potential confounders and a lack of longitudinal assessments, and existing evidence is inconclusive.

OBJECTIVES

We evaluated the association between long-term aircraft noise exposure and risk of hypertension among post-menopausal women in the Women's Health Initiative Clinical Trials, an ongoing prospective U.S.

COHORT

METHODS

Day-night average (DNL) and night equivalent sound levels (Lnight) were modeled for 90 U.S. airports from 1995 to 2010 in 5-year intervals using the Aviation Environmental Design Tool and linked to participant geocoded addresses from 1993 to 2010. Participants with modeled exposures ≥45 A-weighted decibels (dB [A]) were considered exposed, and those outside of 45 dB(A) who also did not live in close proximity to unmodeled airports were considered unexposed. Hypertension was defined as systolic/diastolic blood pressure ≥140/90 mmHg or inventoried/self-reported antihypertensive medication use. Using time-varying Cox proportional hazards models, we estimated hazard ratios (HRs) for incident hypertension when exposed to DNL or Lnight ≥45 versus <45 dB(A), controlling for sociodemographic, behavioral, and environmental/contextual factors.

RESULTS/DISCUSSION

There were 18,783 participants with non-missing DNL exposure and 14,443 with non-missing Lnight exposure at risk of hypertension. In adjusted models, DNL and Lnight ≥45 db(A) were associated with HRs of 1.00 (95% confidence interval [CI]: 0.93, 1.08) and 1.06 (95%CI: 0.91, 1.24), respectively. There was no evidence supporting a positive exposure-response relationship, and findings were robust in sensitivity analyses. Indications of elevated risk were seen among certain subgroups, such as those living in areas with lower population density (HRinteraction: 0.84; 95%CI: 0.72, 0.98) or nitrogen dioxide concentrations (HRinteraction: 0.82; 95%CI: 0.71, 0.95), which may indicate lower ambient/road traffic noise. Our findings do not suggest a relationship between aircraft noise and incident hypertension among older women in the U.S., though associations in lower ambient noise settings merit further investigation.

Long-term aircraft noise exposure and risk of hypertension in the Nurses' Health Studies

BACKGROUND

Aircraft noise can affect populations living near airports. Chronic exposure to aircraft noise has been associated with cardiovascular disease, including hypertension. However, previous studies have been limited in their ability to characterize noise exposures over time and to adequately control for confounders.

OBJECTIVES

The aim of this study was to examine the association between aircraft noise and incident hypertension in two cohorts of female nurses, using aircraft noise exposure estimates with high spatial resolution over a 20-year period.

METHODS

We obtained contour maps of modeled aircraft noise levels over time for 90 U.S. airports and linked them with geocoded addresses of participants in the Nurses' Health Study (NHS) and Nurses' Health Study II (NHS II) to assign noise exposure for 1994-2014 and 1995-2013, respectively. We used time-varying Cox proportional hazards models to estimate hypertension risk associated with time-varying noise exposure (dichotomized at 45 and 55 dB(A)), adjusting for fixed and time-varying confounders. Results from both cohorts were pooled via random effects meta-analysis.

RESULTS

In meta-analyses of parsimonious and fully-adjusted models with aircraft noise dichotomized at 45 dB(A), hazard ratios (HR) for hypertension incidence were 1.04 (95% CI: 1.00, 1.07) and 1.03 (95% CI: 0.99, 1.07), respectively. When dichotomized at 55 dB(A), HRs were 1.10 (95% CI: 1.01, 1.19) and 1.07 (95% CI: 0.98, 1.15), respectively. After conducting fully-adjusted sensitivity analyses limited to years in which particulate matter (PM) was obtained, we observed similar findings. In NHS, the PM-unadjusted HR was 1.01 (95% CI: 0.90, 1.14) and PM-adjusted HR was 1.01 (95% CI: 0.89, 1.14); in NHS II, the PM-unadjusted HR was 1.08 (95% CI: 0.96, 1.22) and the PM-adjusted HR was 1.08 (95% CI: 0.95, 1.21). Overall, in these cohorts, we found marginally suggestive evidence of a positive association between aircraft noise exposure and hypertension.

Aircraft noise exposure drives the activation of white blood cells and induces microvascular dysfunction in mice

Epidemiological studies showed that traffic noise has a dose-dependent association with increased cardiovascular morbidity and mortality. Whether microvascular dysfunction contributes significantly to the cardiovascular health effects by noise exposure remains to be established. The connection of inflammation and immune cell interaction with microvascular damage and functional impairment is also not well characterized. Male C57BL/6J mice or gp91phox^−/y mice with genetic deletion of the phagocytic NADPH oxidase catalytic subunit (gp91phox or NOX-2) were used at the age of 8 weeks, randomly instrumented with dorsal skinfold chambers and exposed or not exposed to aircraft noise for 4 days. Proteomic analysis (using mass spectrometry) revealed a pro-inflammatory phenotype induced by noise exposure that was less pronounced in noise-exposed gp91phox^−/y mice. Using in vivo fluorescence microscopy, we found a higher number of adhesive leukocytes in noise-exposed wild type mice. Dorsal microvascular diameter (by trend), red blood cell velocity, and segmental blood flow were also decreased by noise exposure indicating microvascular constriction. All adverse effects on functional parameters were normalized or improved at least by trend in noise-exposed gp91phox^−/y mice. Noise exposure also induced endothelial dysfunction in cerebral microvessels, which was associated with higher oxidative stress burden and inflammation, as measured using video microscopy. We here establish a link between a pro-inflammatory phenotype of plasma, activation of circulating leukocytes and microvascular dysfunction in mice exposed to aircraft noise. The phagocytic NADPH oxidase was identified as a central player in the underlying pathophysiological mechanisms.

•

Noise exposure induces a pro-thrombo-inflammatory phenotype in mouse plasma.

•

Aircraft noise increases leukocyte-endothelium interactions in dorsal microvessels.

•

Noise decreases segmental blood flow/red blood cell velocity in dorsal microvessels.

•

Noise increases cerebral microvascular dysfunction and oxidative stress.

•

Nox2 deficiency (gp91phox^-/y) improves noise-induced adverse effects.

Ablation of lysozyme M-positive cells prevents aircraft noise-induced vascular damage without improving cerebral side effects

Aircraft noise induces vascular and cerebral inflammation and oxidative stress causing hypertension and cardiovascular/cerebral dysfunction. With the present studies, we sought to determine the role of myeloid cells in the vascular vs. cerebral consequences of exposure to aircraft noise. Toxin-mediated ablation of lysozyme M+ (LysM+) myeloid cells was performed in LysMCreiDTR mice carrying a cre-inducible diphtheria toxin receptor. In the last 4d of toxin treatment, the animals were exposed to noise at maximum and mean sound pressure levels of 85 and 72 dB(A), respectively. Flow cytometry analysis revealed accumulation of CD45+, CD11b+, F4/80+, and Ly6G-Ly6C+ cells in the aortas of noise-exposed mice, which was prevented by LysM+ cell ablation in the periphery, whereas brain infiltrates were even exacerbated upon ablation. Aircraft noise-induced increases in blood pressure and endothelial dysfunction of the aorta and retinal/mesenteric arterioles were almost completely normalized by ablation. Correspondingly, reactive oxygen species in the aorta, heart, and retinal/mesenteric vessels were attenuated in ablated noise-exposed mice, while microglial activation and abundance in the brain was greatly increased. Expression of phagocytic NADPH oxidase (NOX-2) and vascular cell adhesion molecule-1 (VCAM-1) mRNA in the aorta was reduced, while NFκB signaling appeared to be activated in the brain upon ablation. In sum, we show dissociation of cerebral and peripheral inflammatory reactions in response to aircraft noise after LysM+ cell ablation, wherein peripheral myeloid inflammatory cells represent a dominant part of the pathomechanism for noise stress-induced cardiovascular effects and their central nervous counterparts, microglia, as key mediators in stress responses.

The role of aircraft noise annoyance and noise sensitivity in the association between aircraft noise levels and medication use: results of a pooled-analysis from seven European countries

BACKGROUND

Few studies have considered aircraft noise annoyance and noise sensitivity in analyses of the health effects of aircraft noise, especially in relation to medication use. This study aims to investigate the moderating and mediating role of these two factors in the relationship between aircraft noise levels and medication use among 5860 residents of ten European airports included in the HYENA and DEBATS studies.

METHODS

Information on aircraft noise annoyance, noise sensitivity, medication use, and demographic, socio-economic and lifestyle factors was collected during a face-to-face interview at home. Medication was coded according to the Anatomical Therapeutic Chemical (ATC) classification. Outdoor aircraft noise exposure was estimated by linking the participant's home address to noise contours using Geographical Information Systems (GIS) methods. Logistic regressions with adjustment for potential confounding factors were used. In addition, Baron and Kenny's recommendations were followed to investigate the moderating and mediating effects of aircraft noise annoyance and noise sensitivity.

RESULTS

A significant association was found between aircraft noise levels at night and antihypertensive medication only in the UK (OR = 1.43, 95%CI 1.19-1.73 for a 10 dB(A)-increase in L_night). No association was found with other medications. Aircraft noise annoyance was significantly associated with the use of antihypertensive medication (OR = 1.33, 95%CI 1.14-1.56), anxiolytics (OR = 1.48, 95%CI 1.08-2.05), hypnotics and sedatives (OR = 1.60, 95%CI 1.07-2.39), and antasthmatics (OR = 1.44, 95%CI 1.07-1.96), with no difference between countries. Noise sensitivity was significantly associated with almost all medications, with the exception of the use of antasthmatics, showing an increase in ORs with the level of noise sensitivity, with differences in ORs among countries only for the use of antihypertensive medication. The results also suggested a mediating role of aircraft noise annoyance and a modifying role of both aircraft noise annoyance and noise sensitivity in the association between aircraft noise levels and medication use.

CONCLUSIONS

The present study is consistent with the results of the small number of studies available to date suggesting that both aircraft noise annoyance and noise sensitivity should be taken into account in analyses of the health effects of exposure to aircraft noise.

Self-rated health status in relation to aircraft noise exposure, noise annoyance or noise sensitivity: the results of a cross-sectional study in France

BACKGROUND

Noise is a major public health issue because of its negative impacts on health, including annoyance, sleep disturbance, cardiovascular diseases and altered cognitive performance among children. Self-rated health status (SRHS) can be considered as a reliable indicator of quality of life, morbidity and mortality but few studies have considered SRHS in relation to aircraft noise exposure. The present study aims to investigate the association between this exposure and SRHS of people living near airports in France, and to consider the mediating or moderating role of aircraft noise annoyance and noise sensitivity in this association.

METHODS

This cross-sectional study included 1242 participants older than 18 and living near three major French airports. Information on their SRHS, aircraft noise annoyance, noise sensitivity and demographic, socioeconomic and lifestyle factors was collected during a face-to-face interview performed at home. Outdoor aircraft noise levels were estimated for each participant's home address using noise maps. Logistic regressions with adjustment for potential confounders were used. The moderating and mediating effects of aircraft noise annoyance and noise sensitivity were investigated following Baron and Kenny's recommendations.

RESULTS

A significant association was shown between aircraft noise levels and a fair/poor SRHS, only in men (OR=1.55, 95%CI 1.01-2.39, for a 10 dB(A)-increase in L_den). This relationship was higher in men highly sensitive to noise (OR=3.26, 95%CI 1.19-8.88, for a 10 dB(A)-increase in L_den). Noise sensitivity was associated with a fair/poor SRHS significantly in women (OR=1.74, 95%CI 1.12-2.68) and at the borderline of significance in men (OR=1.68, 95% CI 0.94-3.00), whereas aircraft noise annoyance was associated with a fair/poor SRHS only in men (OR=1.81, 95%CI 1.00-3.27).

CONCLUSION

The present study confirms findings in the small number of available studies to date suggesting a positive association between aircraft noise levels and a fair/poor SRHS. These results also support the hypothesis that noise sensitivity would moderate this association. However, a mediating effect of annoyance cannot be excluded.

The role of aircraft noise annoyance and noise sensitivity in the association between aircraft noise levels and hypertension risk: Results of a pooled analysis from seven European countries

INTRODUCTION

Many studies, including the HYENA and the DEBATS studies, showed a significant association between aircraft noise exposure and the risk of hypertension. Few studies have considered aircraft noise annoyance and noise sensitivity as factors of interest, especially in relation to hypertension risk, or as mediating or modifying factors. The present study aims 1) to investigate the risk of hypertension in relation to aircraft noise annoyance or noise sensitivity; and 2) to examine the role of modifier or mediator of these two factors in the association between aircraft noise levels and the risk of hypertension.

METHODS

This study included 6,105 residents of ten European airports from the HYENA and DEBATS studies. Information on aircraft noise annoyance, noise sensitivity, and demographic, socioeconomic and lifestyle factors was collected during an interview performed at home. Participants were classified as hypertensive if they had either blood pressure levels above the WHO cut-off points or physician-diagnosed hypertension in conjunction with the use of antihypertensive medication. Outdoor aircraft noise exposure was estimated for each participant's home address. Poisson regression models with adjustment for potential confounders were used. Interactions between noise exposure and country were tested to consider possible differences between countries.

RESULTS

An increase in aircraft noise levels at night was weekly but significantly associated with an increased risk of hypertension (RR = 1.03, 95% CI 1.01-1.06 for a 10-dB(A) increase in L_night). A significant association was found between aircraft noise annoyance and hypertension risk (RR = 1.06, 95%CI 1.00-1.13 for highly annoyed people compared to those who were not highly annoyed). The risk of hypertension was slightly higher for people highly sensitive to noise compared to people with low sensitivity in the UK (RR = 1.29, 95%CI 1.05-1.59) and in France (RR = 1.11, 95%CI 0.68-1.82), but not in the other countries. The association between aircraft noise levels and the risk of hypertension was higher among highly sensitive participants (RR = 1.00, 95%CI 0.96-1.04; RR = 1.03, 95%CI 0.90-1.11; RR = 1.12, 95%CI 1.01-1.24, with a 10-dB(A) increase in L_night for low, medium, and high sensitive people respectively) or, to a lesser extent, among highly annoyed participants (RR = 1.06, 95%CI 0.95-1.18 for a 10-dB(A) increase in L_night among highly annoyed participants, and RR = 1.02, 95%CI 0.99-1.06 among those not highly annoyed).

CONCLUSIONS

The present study confirms findings in the small number of available studies to date suggesting adverse health effects associated with aircraft noise annoyance and noise sensitivity. The findings also indicate possible modifier effects of aircraft noise annoyance and noise sensitivity in the relationship between aircraft noise levels and the risk of hypertension. However, further investigations are needed to better understand this role using specific methodology and tools related to mediation analysis and causal inference.

The impact of aircraft noise on vascular and cardiac function in relation to noise event number: a randomized trial

Aims

Nighttime aircraft noise exposure has been associated with increased risk of hypertension and myocardial infarction, mechanistically linked to sleep disturbance, stress, and endothelial dysfunction. It is unclear, whether the most widely used metric to determine noise exposure, equivalent continuous sound level (L_eq), is an adequate indicator of the cardiovascular impact induced by different noise patterns.

Methods and results

In a randomized crossover study, we exposed 70 individuals with established cardiovascular disease or increased cardiovascular risk to two aircraft noise scenarios and one control scenario. Polygraphic recordings, echocardiography, and flow-mediated dilation (FMD) were determined for three study nights. The noise patterns consisted of 60 (Noise60) and 120 (Noise120) noise events, respectively, but with comparable L_eq, corresponding to a mean value of 45 dB. Mean value of noise during control nights was 37 dB. During the control night, FMD was 10.02 ± 3.75%, compared to 7.27 ± 3.21% for Noise60 nights and 7.21 ± 3.58% for Noise120 nights (P < 0.001). Sleep quality was impaired after noise exposure in both noise scenario nights (P < 0.001). Serial echocardiographic assessment demonstrated an increase in the E/E′ ratio, a measure of diastolic function, within the three exposure nights, with a ratio of 6.83 ± 2.26 for the control night, 7.21 ± 2.33 for Noise60 and 7.83 ± 3.07 for Noise120 (P = 0.043).

Conclusions

Nighttime exposure to aircraft noise with similar L_eq, but different number of noise events, results in a comparable worsening of vascular function. Adverse effects of nighttime aircraft noise exposure on cardiac function (diastolic dysfunction) seemed stronger the higher number of noise events.

Saliva cortisol in relation to aircraft noise exposure: pooled-analysis results from seven European countries

BACKGROUND

Many studies have demonstrated adverse effects of exposure to aircraft noise on health. Possible biological pathways for these effects include hormonal disturbances. Few studies deal with aircraft noise effects on saliva cortisol in adults, and results are inconsistent.

OBJECTIVE

We aimed to assess the effects of aircraft noise exposure on saliva cortisol levels and its variation in people living near airports.

METHODS

This study focused on the 1300 residents included in the HYENA and DEBATS cross-sectional studies, with complete information on cortisol sampling. All the participants followed a similar procedure aiming to collect both a morning and an evening saliva cortisol samples. Socioeconomic and lifestyle information were obtained during a face-to-face interview. Outdoor aircraft noise exposure was estimated for each participant's home address. Associations between aircraft noise exposure and cortisol outcomes were investigated a priori for male and female separately, using linear regression models adjusted for relevant confounders. Different approaches were used to characterize cortisol levels, such as morning and evening cortisol concentrations and the absolute and relative variations between morning and evening levels.

RESULTS

Statistically significant increases of evening cortisol levels were shown in women with a 10-dB(A) increase in aircraft noise exposure in terms of LA_{eq, 16h} (exp(β) = 1.08; CI95% = 1.00-1.16), L_den (exp(β) = 1.09; CI95% = 1.01-1.18), L_night (exp(β) = 1.11; CI95% = 1.02-1.20). A statistically significant association was also found in women between a 10-dB(A) increase in terms of L_night and the absolute variation per hour (exp(β) = 0.90; CI95% = 0.80-1.00). Statistically significant decreases in relative variation per hour were also evidenced in women, with stronger effects with the L_night (exp(β) = 0.89; CI95% = 0.83-0.96) than with other noise indicators. The morning cortisol levels were unchanged whatever noise exposure indicator considered. There was no statistically significant association between aircraft noise exposure and cortisol outcomes in men.

CONCLUSIONS

The results of the present study show statistically significant associations between aircraft noise exposure and evening cortisol levels and related flattening in the (absolute and relative) variations per hour in women. Further biological research is needed to deepen knowledge of the pathway between noise exposure and disturbed hormonal regulation, and specially the difference in effects between genders.

The impact of aircraft noise exposure on objective parameters of sleep quality: results of the DEBATS study in France

BACKGROUND

Noise in the vicinity of airports is a public health issue. Exposure to aircraft noise has been shown to have adverse effects on health and particularly on sleep. Many studies support the hypothesis that noise at night can affect subjective sleep quality. Fewer studies, however, have performed objective measurements of sleep.

OBJECTIVES

This study aimed to investigate by actigraphy the relationship between aircraft noise exposure and objective parameters of sleep quality in the population living near two French airports.

METHODS

This study includes 112 participants living in the vicinity of Paris-Charles de Gaulle and Toulouse-Blagnac airports. Wrist actigraphy measurements were performed during eight nights to evaluate objective parameters of sleep quality such as sleep onset latency (SOL), wake after sleep onset (WASO), total sleep time (TST), time in bed (TB) and sleep efficiency (SE). Acoustic measurements were made simultaneously both inside the participants' bedrooms and outside (at the exterior frontage) to estimate aircraft noise levels. Energy indicators related to the sound energetic average for a given period of time, as well as indicators related to noise events (eg, the number of events that exceed a given threshold), were estimated. Logistic and linear regression models were used, taking into account potential confounders: age; gender; marital status; education; and body mass index (BMI).

RESULTS

Energy indicators, in particular, indicators related to noise events were significantly associated with objective parameters of sleep quality. Increased levels of aircraft noise and increased numbers of aircraft noise events increased the time required for sleep onset (SOL) and the total wake time after sleep onset (WASO) and decreased sleep efficiency (SE). An association was also observed between aircraft noise exposure and an increase in total sleep time (TST) and time in bed (TB).

CONCLUSION

The findings of the present study contribute to the overall evidence suggesting that nocturnal aircraft noise exposure may decrease the objective quality of sleep. Aircraft noise exposure affects objective parameters of sleep quality, not only regarding noise levels but also regarding the number of events. Mechanisms for adapting to sleep deprivation could be observed.