Experimental studies on the effects of nocturnal noise on cortisol awakening response

Road Traffic Noise, Obesity, and the Risk of Incident Type 2 Diabetes: A Cohort Study in UK Biobank

Objectives: To assess the association of road traffic noise exposure with Type 2 Diabetes (T2D) risk, and to explore the potential moderation effect of obesity. Methods: A total of 305,969 participants from the UK Biobank Cohort - an open access cohort of 500,000 participants recruited in the United Kingdom (UK) between 2006 and 2010 - were included in the study. A Cox proportional hazard model was fitted to assess the association between road traffic noise exposure and T2D. Results: A total of 19,303 participants were diagnosed with T2D during the 11.9-year median follow-up period. For every 10 dB increase in road traffic noise, there was a 4% increase in T2D risk (HR = 1.04, 95%CI: 1.01, 1.07). Besides, a significant positive interaction was observed between obesity and road traffic noise (P interaction <0.001) for the risk of T2D. The association of road traffic noise with T2D was stronger in overweight and obese participants (HR = 1.04, 95% CI: 1.01-1.08), but not significant among lean ones (HR = 0.96, 95% CI: 0.86-1.07). Conclusion: Our study observed a longitudinal association of road traffic noise exposure with T2D risk, which was stronger among overweight and obese individuals than the lean ones.

Traffic-related Noise Exposure and Late-life Dementia and Cognitive Impairment in Mexican-Americans

BACKGROUND

Recently, it has been suggested that environmental exposures from traffic sources including noise may play a role in cognitive impairment in the elderly. The objective of the study was to investigate the association between local traffic-related noise pollution and incident dementia or cognitive impairment without dementia (CIND) during a 10-year follow-up period.

METHODS

1612 Mexican-American participants from the Sacramento Area Latino Study on Aging (SALSA) were followed every 12-15 months via home visits from 1998 to 2007. We used the SoundPLAN software package to estimate noise originating from local traffic with the input of Annual Average Daily Traffic (AADT) data from Metropolitan Planning Organizations (MPO) based on geocoded residential addresses at baseline (1998-1999). We estimated the risks of incident dementia or CIND from 24-hour and nighttime noise exposure using Cox proportional hazard models.

RESULTS

During the follow-up, we identified 159 incident dementia or CIND cases in total. Per 11.6 dB (interquartile range width) increase in 24-hour noise, the hazard of developing dementia or CIND increased (hazard ratio = 1.3 [1.0, 1.6]) during follow-up; estimates were slightly lower (hazard ratio = 1.2 [0.97, 1.6]) when adjusting for modeled local air pollution exposure from traffic sources. Overall, the risk of dementia/CIND was elevated when 24-hour and nighttime noise were higher than 75 and 65 dB respectively. See video Abstract: http://links.lww.com/EDE/B728.

CONCLUSIONS

In our study, traffic-related noise exposure was associated with increased risk of dementia or CIND in elderly Mexican-Americans. Future studies taking into account other noise sources and occupational noise exposure before retirement are needed.

Metabolic dysfunction modifies the influence of traffic-related air pollution and noise exposure on late-life dementia and cognitive impairment: A cohort study of older Mexican-Americans

Supplemental Digital Content is available in the text.

Cognitive impairment has been linked to traffic-related air pollution and noise exposure as well as to metabolic syndrome or some of its individual components. Here, we investigate whether the presence of metabolic dysfunction modifies associations between air pollution or noise exposures and incident dementia or cognitive impairment without dementia (CIND).

Transportation noise impairs cardiovascular function without altering sleep: The importance of autonomic arousals

AIMS

Chronic exposure to nocturnal transportation noise has been linked to cardiovascular disorders with sleep impairment as the main mediator. Here we examined whether nocturnal transportation noise affects the main stress pathways, and whether it relates to changes in the macro and micro structure of sleep.

METHODS AND RESULTS

Twenty-six young healthy participants (12 women, 24.6 ± 0.7 years, mean ± SE) spent five consecutive 24-h days and one last morning in the laboratory. The first (baseline) and last (recovery) nights comprised a quiet ambient scenario. In-between, four different noise scenarios (low/medium/high intermittent road or rail scenarios with an identical equivalent continuous sound level of 45 dB) were randomly presented during the 8-h nights. Participants felt more annoyed from the transportation noise scenarios compared to the quiet ambient scenario played back during the baseline and recovery nights (F_5,117 = 10.2, p < 0.001). Nocturnal transportation noise did not significantly impact polysomnographically assessed sleep macrostructure, blood pressure, nocturnal catecholamine levels and morning cytokine levels. Evening cortisol levels increased after sleeping with highly intermittent road noise compared to baseline (p = 0.002, noise effect: F_4,83 = 4.0, p = 0.005), a result related to increased cumulative duration of autonomic arousals during the noise nights (F_5,106 = 3.4, p < 0.001; correlation: r_pearson = 0.64, p = 0.006).

CONCLUSION

Under controlled laboratory conditions, highly intermittent nocturnal road noise exposure at 45 dB increased the cumulative duration of autonomic arousals during sleep and next-day evening cortisol levels. Our results indicate that, without impairing sleep macrostructure, nocturnal transportation noise of 45 dB is a physiological stressor that affects the hypothalamic-pituitary-adrenal axis during the following day in healthy young good sleepers.

Air pollution, noise exposure, and metabolic syndrome - A cohort study in elderly Mexican-Americans in Sacramento area

BACKGROUND

Previous studies suggested that air pollutants may increase the incidence of metabolic syndrome, but the potential impact from traffic sources is not well-understood. This study aimed to investigate associations between traffic-related nitrogen oxides (NOx) or noise pollution and risk of incident metabolic syndrome and its components in an elderly Mexican-American population.

METHODS

A total of 1,554 Mexican-American participants of the Sacramento Area Latino Study on Aging (SALSA) cohort were followed from 1998 to 2007. We used anthropometric measures and biomarkers to define metabolic syndrome according to the recommendations of the Third Adult Treatment Panel of the National Cholesterol Education Program (NCEP ATP III). Based on participants' residential addresses at baseline, estimates of local traffic-related NOx were generated using the California Line Source Dispersion Model version 4 (CALINE4), and of noise employing the SoundPLAN software package. We used Cox regression models with calendar time as the underlying time scale to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations of air pollution or noise with metabolic syndrome or its components.

RESULTS

Each per unit increase of traffic-related NOx (2.29 parts per billion (ppb)) was associated with a 15% (HR = 1.15, 95% CI: 1.04-1.28) lower level of high-density lipoprotein cholesterol (HDL-cholesterol), and each 11.6 decibels (dB) increase in noise increased the risk of developing metabolic syndrome by 17% (HR = 1.17, 95% CI: 1.01-1.35).

CONCLUSION

Policies aiming to reduce traffic-related air pollution and noise might mitigate the risk of metabolic syndrome and its components in vulnerable populations.

Exposure to residential road traffic noise prior to conception and time to pregnancy

OBJECTIVES

To examine the association between residential road traffic noise and fecundity estimated by time to pregnancy (TTP).

DESIGN

We identified 65,201 mothers from the Danish National Birth Cohort with self-reported information on TTP collected through computer assisted telephone interviews. Road traffic noise was modelled at all historical addresses and expressed as time-weighted means for periods corresponding to individual TTP. Associations were analyzed using logistic regression for analyses of dichotomous outcomes and ordinal logistic regression for TTP in four categories, adjusting for maternal age at conception, disposable household income, education and air pollution (NO_x).

RESULTS

Ordinal logistic regression showed a 10dB increase in road traffic noise to be associated with a 8% increased risk of 6-12month TTP (95% CI:1.03; 1.12) whereas we found no statistically significant associations for ≥12months TTP (OR=1.04, 95% CI: 0.99; 1.09) when compared to 0-2months TTP. Similarly, when exploring TTP as a binary outcome we found a 10dB higher road traffic noise to be associated with a 5% higher risk of TTP of 6months or more (95% CI: 1.01; 1.08) as compared with <6months TTP, whereas when the cut-point was 12months TTP no association was found.

CONCLUSION

Road traffic noise was associated with an increased risk of 6-12month TTP, but not with risk of longer TTP, indicating that noise may have a small impact on sub-fecundity.

Effects of chronic noise on glucose metabolism and gut microbiota-host inflammatory homeostasis in rats

Chronic noise exposure has been implicated in increased risk of diabetes. However, there is limited experimental evidence of the mechanisms linking chronic noise stress and glucose metabolism. We addressed this in the present study by examining glucose metabolism, immune response, and changes in gut microbiota/host inflammatory homeostasis in rats exposed to noise for 30 consecutive days. Chronic noise exposure increased blood glucose and corticosterone levels for at least 14 days after cessation of noise. Stressed rats also exhibited elevated levels of glycogen and triglyceride in the liver and impaired hepatic insulin production via insulin-induced insulin receptor/insulin receptor substrate 1/glycogen synthase kinase 3β signalling, which persisted for 3–14 days after cessation of noise exposure. Chronic noise altered the percentage of Proteobacteria and Actinobacteria in the gut, increasing Roseburia but decreasing Faecalibacterium levels in the cecum relative to controls. Immunoglobulin A, interleukin 1β, and tumor necrosis factor α levels were also elevated in the intestine of these animals, corresponding to noise-induced abnormalities in glucose regulation and insulin sensitivity. These results suggest that lifelong environmental noise exposure could have cumulative effects on diabetes onset and development resulting from alterations in gut microbiota composition and intestinal inflammation.

Pregnancy and childhood exposure to residential traffic noise and overweight at 7years of age

BACKGROUND

Exposure to road traffic noise has been associated with adiposity and diabetes in adults. The suggested pathways have been through sleep disturbance and stress. Children may be particularly susceptible to noise induced sleep disturbance and stress and the effects hereof.

OBJECTIVES

To examine the association between traffic noise exposure during pregnancy and early childhood and adiposity in children.

METHODS

We identified 40,974 singletons from the Danish National Birth Cohort with parentally given questionnaire information on weight and height at 7-years of age. Road and railway traffic noise were modeled at all historical addresses and expressed as time-weighted means for two exposure periods (pregnancy and childhood). Adiposity was assessed using BMI z-scores and a dichotomous measure of childhood overweight based on age and sex specific cut-offs. Associations were analyzed using linear regression for BMI z-scores and logistic regression for risk of childhood overweight, adjusting for socioeconomic position, maternal BMI, maternal smoking, maternal age, parity and degree of urbanization.

RESULTS

We found both pregnancy and childhood exposure to road traffic noise to be associated with a higher risk for childhood overweight (odds ratio (OR)=1.06 per 10dB, 95% confidence interval (CI): 1.00-1.12 for exposure during pregnancy and OR=1.06 per 10dB, 95% CI: 0.99-1.12 for childhood exposure). There were no associations between road traffic noise and BMI z-scores. We found no associations between railway noise and adiposity.

CONCLUSIONS

We found suggestions of a positive association between road traffic noise and risk of overweight in 7-years old children.

Exploring the effect of sound and music on health in hospital settings: A narrative review

BACKGROUND

Sound in hospital space has traditionally been considered in negative terms as both intrusive and unwanted, and based mainly on sound levels. However, sound level is only one aspect of the soundscape. There is strong evidence that exploring the positive aspect of sound in a hospital context can evoke positive feelings in both patients and nurses. Music psychology studies have also shown that music intervention in health care can have a positive effect on patient's emotions and recuperating processes. In this way, hospital spaces have the potential to reduce anxiety and stress, and make patients feel comfortable and secure. This paper describes a review of the literature exploring sound perception and its effect on health care.

DATA SOURCES AND REVIEW METHODS

This review sorted the literature and main issues into themes concerning sound in health care spaces; sound, stress and health; positive soundscape; psychological perspective of music and emotion; music as a complementary medicine for improving health care; contradicting arguments concerning the use of music in health care; and implications for clinical practice. Using Web of Science, PubMed, Scopus, ProQuest Central, MEDLINE, and Google, a literature search on sound levels, sound sources and the impression of a soundscape was conducted. The review focused on the role and use of music on health care in clinical environments. In addition, other pertinent related materials in shaping the understanding of the field were retrieved, scanned and added into this review.

RESULTS

The result indicated that not all noises give a negative impression within healthcare soundscapes. Listening to soothing music was shown to reduce stress, blood pressure and post-operative trauma when compared to silence. Much of the sound conveys meaningful information that is positive for both patients and nurses, in terms of soft wind, bird twitter, and ocean sounds.

CONCLUSIONS

Music perception was demonstrated to bring about positive change in patient-reported outcomes such as eliciting positive emotion, and decreasing the levels of stressful conditions. Whilst sound holds both negative and positive aspects of the hospital ecosystem and may be stressful, it also possesses a soothing quality that induces positive feelings in patients. Conceptualizing the nature of sound in the hospital context as a soundscape, rather than merely noise can permit a subtler and socially useful understanding of the role of sound and music in the hospital setting, thereby creating a means for improving the hospital experience for patients and nurses.

Road Traffic and Railway Noise Exposures and Adiposity in Adults: A Cross-Sectional Analysis of the Danish Diet, Cancer, and Health Cohort

BACKGROUND

Traffic noise has been associated with cardiovascular and metabolic disorders. Potential modes of action are through stress and sleep disturbance, which may lead to endocrine dysregulation and overweight.

OBJECTIVES

We aimed to investigate the relationship between residential traffic and railway noise and adiposity.

METHODS

In this cross-sectional study of 57,053 middle-aged people, height, weight, waist circumference, and bioelectrical impedance were measured at enrollment (1993-1997). Body mass index (BMI), body fat mass index (BFMI), and lean body mass index (LBMI) were calculated. Residential exposure to road and railway traffic noise exposure was calculated using the Nordic prediction method. Associations between traffic noise and anthropometric measures at enrollment were analyzed using general linear models and logistic regression adjusted for demographic and lifestyle factors.

RESULTS

Linear regression models adjusted for age, sex, and socioeconomic factors showed that 5-year mean road traffic noise exposure preceding enrollment was associated with a 0.35-cm wider waist circumference (95% CI: 0.21, 0.50) and a 0.18-point higher BMI (95% CI: 0.12, 0.23) per 10 dB. Small, significant increases were also found for BFMI and LBMI. All associations followed linear exposure-response relationships. Exposure to railway noise was not linearly associated with adiposity measures. However, exposure > 60 dB was associated with a 0.71-cm wider waist circumference (95% CI: 0.23, 1.19) and a 0.19-point higher BMI (95% CI: 0.0072, 0.37) compared with unexposed participants (0-20 dB).

CONCLUSIONS

The present study finds positive associations between residential exposure to road traffic and railway noise and adiposity.

Long-term exposure to residential traffic noise and changes in body weight and waist circumference: A cohort study

BACKGROUND

Traffic noise can act as a stressor and disturb sleep, and has been associated with cardiovascular disease. Recent studies suggest a possible association to metabolic outcomes and adiposity through biological mechanisms related to physiological stress and sleep disturbance.

OBJECTIVES

We aimed to investigate the association between long-term residential traffic noise and changes in adiposity.

MATERIALS AND METHODS

The study was based on 39,720 middle-aged Danish men and women from a cohort, with information on weight and waist circumference at two points in time. Residential exposure to traffic noise was calculated for all participants' present and historical addresses using the Nordic prediction method. The associations between traffic noise and changes in adiposity measures after a mean follow-up of 5.3 years were analyzed by linear and logistic regression with adjustments for age, sex, socioeconomic position and lifestyle factors in three models with increasing adjustment.

RESULTS

In linear models adjusted for sex, age, socioeconomic position and competing noise sources we found road traffic noise to be significantly associated with small gains in both weight and waist circumference. For example, time-weighted mean exposure 5-years preceding follow-up was associated with a yearly weight gain of 15.4 g (95% confidence interval (CI): 2.14; 28.7) and a yearly increase in waist circumference of 0.22 mm (95% CI: 0.018; 0.43) per 10dB. Similarly, in Poisson regression models we found an 10% increased risk for gaining more than 5 kg body weight during follow-up (95% CI: 1.04; 1.15) per 10 dB higher 5 years exposure preceding follow-up. Exposure to railway noise above 55 dB was associated with weight gain (39.9 g/year (95% CI: 10.2; 69.6)), but not with a significant change in waist circumference. We found baseline BMI (p<0.001) and waist circumference (p=0.001) to be significant effect modifiers for the association between road traffic noise and waist circumference, with gain in waist circumference only among the obese (BMI≥30) participants (1.20 mm/year (95% CI: 0.68; 1.72)) and participants with a large waist circumference (0.83 mm/year (95% CI: 0.42; 1.23)).

CONCLUSION

The findings supports previous studies suggesting that traffic noise may be associated with development of adiposity. However, the potential effects are small and suggest an effect mainly among obese participants.

Sleep and the Housing and Neighborhood Environment of Urban Latino Adults Living in Low-Income Housing: The AHOME Study

Sleep is implicated in the risk of many chronic diseases; however, little is known about the living conditions that influence sleep. In this study of 371 low-income Latino residents, household crowding was associated with reduced odds of long sleep duration relative to average and short sleep duration. Neighborhood disorder and perceived building problems were associated with more sleep disturbances and poor sleep quality. Building problems were associated with prolonged sleep latency. There was a significant cumulative effect of adverse housing and neighborhood conditions on sleep outcomes. These results show that adverse conditions of both the housing and neighborhood environments are associated with poor sleep outcomes.

Improvement of intensive care unit sound environment and analyses of consequences on sleep: an experimental study

OBJECTIVE

Uninterrupted sleep is of vital importance for restoration and regaining health. In intensive care units (ICUs) where recovering and healing is crucial, patients' sleep often is fragmented and disturbed due to noise from activities from oneself, other patients, and alarms. The aim of our study was to explore if sleep could be improved by modifying the sound environment in a way that is practically feasible in ICUs.

METHODS

We studied the effects of originally recorded ICU noise and peak reduced ICU noise on sleep in healthy male participants. Sleep was registered with polysomnography (PSG) during four nights: one adaptation night, one reference (REF) night, and the two exposed nights with similar equivalent sound levels (47dB LAeq) but different maximum sound levels (56- vs 64-dB LAFmax). The participants answered questionnaires and saliva cortisol was sampled in the morning.

RESULTS

During ICU exposure nights, sleep was more fragmented with less slow-wave sleep (SWS), more arousals, and more time awake. The effects of reduced maximum sound level were minor. The subjective data supported the polysomnographic findings, though cortisol levels were not significantly affected by the exposure conditions.

CONCLUSIONS

Noise in ICUs impairs sleep and the reduction of maximal A-weighted levels from 64 to 56dB is not enough to have a clear improved effect on sleep quality.