Long-term aircraft noise exposure and body mass index, waist circumference, and type 2 diabetes: a prospective study.

BACKGROUND: Long-term aircraft noise exposure may increase the risk of cardiovascular disease, but no study has investigated chronic effects on the metabolic system. OBJECTIVES: The aim of this study was to investigate effects of long-term aircraft noise exposure on body mass index (BMI), waist circumference, and type 2 diabetes. Furthermore, we explored the modifying effects of sleep disturbance. METHODS: This prospective cohort study of residents of Stockholm County, Sweden, followed 5,156 participants with normal baseline oral glucose tolerance tests (OGTT) for up to 10 years. Exposure to aircraft noise was estimated based on residential history. Information on outcomes and confounders was obtained from baseline and follow-up surveys and examinations, and participants who developed prediabetes or type 2 diabetes were identified by self-reported physician diagnosis or OGTT at follow-up. Adjusted associations were assessed by linear, logistic, and random-effects models. RESULTS: The mean (± SD) increases in BMI and waist circumference during follow-up were 1.09 ± 1.97 kg/m2 and 4.39 ± 6.39 cm, respectively. The cumulative incidence of prediabetes and type 2 diabetes was 8% and 3%, respectively. Based on an ordinal noise variable, a 5-dB(A) increase in aircraft noise was associated with a greater increase in waist circumference of 1.51 cm (95% CI: 1.13, 1.89), fully adjusted. This association appeared particularly strong among those who did not change their home address during the study period, which may be a result of lower exposure misclassification. However, no clear associations were found for BMI or type 2 diabetes. Furthermore, sleep disturbances did not appear to modify the associations with aircraft noise. CONCLUSIONS: Long-term aircraft noise exposure may be linked to metabolic outcomes, in particular increased waist circumference.

Joint effects of job strain and road-traffic and occupational noise on myocardial infarction.

OBJECTIVES: The aim of this study was to assess the joint effect of job strain and both road-traffic and occupational noise on myocardial infarction (MI). METHOD: We conducted a population based case-control study on first time MI in Stockholm County during 1992-1994. Participants answered a questionnaire and underwent a physical examination. Residential road-traffic noise exposure was based on residential history combined with information on traffic intensity and distance to nearby roads. Occupational noise exposure was assessed by occupational history combined with a job-exposure matrix derived from measurements. Job strain was based on questions regarding psychological demands and decision latitude. A total of 3050 study participants (1252 cases and 1798 controls) were included in the study. RESULTS: An increased risk of MI was indicated among participants exposed to road-traffic noise [odds ratio (OR) 1.23, 95% confidence interval (95% CI) 1.01-1.51], occupational noise (OR 1.17, 95% CI 0.98-1.41) and job strain (OR 1.39, 95% CI 1.17-1.65). Participants exposed to one, two, or three of these factors showed an increased risk (OR 1.16, 95% CI 0.97-1.40, OR 1.57, 95% CI 1.24-1.98, and OR 2.27, 95% CI 1.41-3.64, respectively). Exposure to two or three of these factors occurred among about 20% of the controls. CONCLUSION: Our results indicate that exposure to a combination of noise exposure and job strain increases the risk of MI substantially. Such exposures affect a considerable part of the population, which has relevance for prioritization of preventative measures.

Exposure modifiers of the relationships of transportation noise with high blood pressure and noise annoyance.

In the cross-sectional hypertension and exposure to noise near airports study the relationship between road traffic noise, aircraft noise and hypertension and annoyance was investigated. The data collection comprised a variety of potentially exposure modifying factors, including type of housing, location of rooms, window opening habits, use of noise-reducing remedies, shielding due to obstacles, lengths of exposure. In the present paper the quantitative role of these factors on the relationship between road and aircraft noise exposure and outcomes was analyzed. Multiple logistic and linear regression models were calculated including these co-factors and related interaction terms with noise indicators, as well as stratified analyses. Type of housing, length of residence, location of rooms and the use of noise reducing remedies modified the relationship between noise and hypertension. However, the effects were not always in the direction of a stronger association in higher exposed subjects. Regarding annoyance, type of housing, location of rooms, noise barriers, window opening habits, noise insulation, the use of noise reducing remedies, hours spent at home during daytime were significant effect modifiers. The use of noise-reducing remedies turned out to be indicators of perceived noise disturbance rather than modifiers reducing the annoyance.

Cardiovascular effects of environmental noise: research in Sweden.

In Sweden, as in many other European countries, traffic noise is an important environmental health issue. At present, almost two million people are exposed to average noise levels exceeding the outdoor national guideline value (55 dB(A)). Despite efforts to reduce the noise burden, noise-related health effects, such as annoyance and sleep disturbances, are increasing. The scientific interest regarding more serious health effects related to the cardiovascular system is growing, and several experimental and epidemiological studies have been performed or are ongoing. Most of the studies on cardiovascular outcomes have been related to noise from road or aircraft traffic. Few studies have included railway noise. The outcomes under study include morning saliva cortisol, treatment for hypertension, self-reported hypertension, and myocardial infarction. The Swedish studies on road traffic noise support the hypothesis of an association between long-term noise exposure and cardiovascular disease. However, the magnitude of effect varies between the studies and has been shown to depend on factors such as sex, number of years at residence, and noise annoyance. Two national studies have been performed on the cardiovascular effects of aircraft noise exposure. The first one, a cross-sectional study assessing self-reported hypertension, has shown a 30% risk increase per 5 dB(A) noise increase. The second one, which to our knowledge is the first longitudinal study assessing the cumulative incidence of hypertension, found a relative risk (RR) of 1.10 (95% CI 1.01 - 1.19) per 5 dB(A) noise increase. No associations have been found between railway noise and cardiovascular diseases. The findings regarding noise-related health effects and their economic consequences should be taken into account in future noise abatement policies and community planning.

Aircraft noise and incidence of hypertension--gender specific effects.

Recent studies show associations between aircraft noise and cardiovascular outcomes such as hypertension. However, these studies were mostly cross-sectional and there are uncertainties regarding potential gender differences as well as sensitive subgroups. In this study, we investigated the cumulative incidence of hypertension in relation to aircraft noise exposure among Swedish men and women living in Stockholm County. A total of 4721 subjects, aged 35-56 at baseline, were followed for 8-10 years. The population was selected according to family history of diabetes, which was present for half of the subjects. The exposure assessment was performed by geographical information systems and based on residential history during the period of follow-up. Blood pressure was measured at baseline and at the end of follow-up. Additional information regarding diagnosis and treatment of hypertension as well as various lifestyle factors was provided by questionnaires. In the overall population, no increased risk for hypertension was found among subjects exposed to aircraft noise ≥ 50 dB(A) L(den); relative risk (RR) 1.02 (95% CI 0.90-1.15). When restricting the cohort to those not using tobacco at the blood pressure measurements, a significant risk increase per 5 dB(A) of aircraft noise exposure was found in men; RR 1.21 (1.05-1.39), but not in women; RR 0.97 (0.83-1.13). In both sexes combined, an increased risk of hypertension related to aircraft noise exposure was indicated primarily among those reporting annoyance to aircraft noise; RR 1.42 (1.11-1.82). No consistent effect modification was detected for any of the cardiovascular risk factors under investigation although a family history of diabetes appeared to modify the risk in women. In conclusion, the results suggest an increased risk of hypertension following long-term aircraft noise exposure in men, and that subjects annoyed by aircraft noise may be particularly sensitive to noise related hypertension.

Annoyance due to aircraft noise has increased over the years--results of the HYENA study.

In the HYENA study (HYpertension and Exposure to Noise near Airports) noise annoyances due to aircraft and road traffic noise were assessed in subjects that lived in the vicinity of 6 major European airports using the 11-point ICBEN scale (International Commission on Biological Effects of Noise). A distinction was made between the annoyance during the day and during the night. L(den) and L(night) were considered as indicators of noise exposure. Pooled data analyses showed clear exposure-response relationships between the noise level and the noise annoyance for both exposures. The exposure-response curves for road noise were congruent with the EU standard curves used for predicting the number of highly noise annoyed subjects in European communities. Annoyance ratings due to aircraft noise, however, were higher than predicted by the EU standard curves. The data supports other findings suggesting that the people's attitude towards aircraft noise has changed over the years, and that the EU standard curve for aircraft noise should be modified.

Long-term exposure to road traffic noise and myocardial infarction.

BACKGROUND: An association has been reported between long-term exposure to road traffic noise and the risk of myocardial infarction (MI), but the evidence is limited and inconclusive. No previous study has simultaneously analyzed the role of exposure to noise and air pollution from road traffic in the risk of MI. METHODS: A population-based case-control study on MI was conducted 1992-1994 in Stockholm County. Participants answered a questionnaire and underwent a physical examination. Residential exposure to noise and air pollution from road traffic between 1970 and 1992-1994 was assessed for 3666 participants (1571 cases of MI and 2095 controls), based on residential history combined with information on traffic intensity and distance to nearby roads. Information was also obtained on factors potentially affecting the relationship between noise exposure and MI, such as noise annoyance. RESULTS: The correlation between long-term individual exposure to noise and air pollution from traffic was high (r = 0.6). The adjusted odds ratio for MI associated with long-term road traffic noise exposure of 50 dBA or higher was 1.12 (95% confidence interval = 0.95-1.33). In a subsample, defined by excluding persons with hearing loss or exposure to noise from other sources, the corresponding odds ratio was 1.38 (1.11-1.71), with a positive exposure-response trend. No strong effect modification was apparent by sex or cardiovascular risk factors, including air pollution from road traffic. CONCLUSIONS: The results lend some support to the hypothesis that long-term exposure to road traffic noise increases the risk for MI.

Saliva cortisol and exposure to aircraft noise in six European countries.

BACKGROUND: Several studies show an association between exposure to aircraft or road traffic noise and cardiovascular effects, which may be mediated by a noise-induced release of stress hormones. OBJECTIVE: Our objective was to assess saliva cortisol concentration in relation to exposure to aircraft noise. METHOD: A multicenter cross-sectional study, HYENA (Hypertension and Exposure to Noise near Airports), comprising 4,861 persons was carried out in six European countries. In a subgroup of 439 study participants, selected to enhance the contrast in exposure to aircraft noise, saliva cortisol was assessed three times (morning, lunch, and evening) during 1 day. RESULTS: We observed an elevation of 6.07 nmol/L [95% confidence interval (CI), 2.32-9.81 nmol/L] in morning saliva cortisol level in women exposed to aircraft noise at an average 24-hr sound level (L(Aeq,24h)) > 60 dB, compared with women exposed to L(Aeq,24h) < or = 50 dB, corresponding to an increase of 34%. Employment status appeared to modify the response. We found no association between noise exposure and saliva cortisol levels in men. CONCLUSIONS: Our results suggest that exposure to aircraft noise increases morning saliva cortisol levels in women, which could be of relevance for noise-related cardiovascular effects.

Hypertension and exposure to noise near airports: the HYENA study.

BACKGROUND: An increasing number of people are exposed to aircraft and road traffic noise. Hypertension is an important risk factor for cardiovascular disease, and even a small contribution in risk from environmental factors may have a major impact on public health. OBJECTIVES: The HYENA (Hypertension and Exposure to Noise near Airports) study aimed to assess the relations between noise from aircraft or road traffic near airports and the risk of hypertension. METHODS: We measured blood pressure and collected data on health, socioeconomic, and lifestyle factors, including diet and physical activity, via questionnaire at home visits for 4,861 persons 45-70 years of age, who had lived at least 5 years near any of six major European airports. We assessed noise exposure using detailed models with a resolution of 1 dB (5 dB for United Kingdom road traffic noise), and a spatial resolution of 250 x 250 m for aircraft and 10 x 10 m for road traffic noise. RESULTS: We found significant exposure-response relationships between night-time aircraft as well as average daily road traffic noise exposure and risk of hypertension after adjustment for major confounders. For night-time aircraft noise, a 10-dB increase in exposure was associated with an odds ratio (OR) of 1.14 [95% confidence interval (CI), 1.01-1.29]. The exposure-response relationships were similar for road traffic noise and stronger for men with an OR of 1.54 (95% CI, 0.99-2.40) in the highest exposure category (> 65 dB; p(trend) = 0.008). CONCLUSIONS: Our results indicate excess risks of hypertension related to long-term noise exposure, primarily for night-time aircraft noise and daily average road traffic noise.

Acute effects of night-time noise exposure on blood pressure in populations living near airports.

AIMS: Within the framework of the HYENA (hypertension and exposure to noise near airports) project we investigated the effect of short-term changes of transportation or indoor noise levels on blood pressure (BP) and heart rate (HR) during night-time sleep in 140 subjects living near four major European airports. METHODS AND RESULTS: Non-invasive ambulatory BP measurements at 15 min intervals were performed. Noise was measured during the night sleeping period and recorded digitally for the identification of the source of a noise event. Exposure variables included equivalent noise level over 1 and 15 min and presence/absence of event (with LAmax > 35 dB) before each BP measurement. Random effects models for repeated measurements were applied. An increase in BP (6.2 mmHg (0.63-12) for systolic and 7.4 mmHg (3.1, 12) for diastolic) was observed over 15 min intervals in which an aircraft event occurred. A non-significant increase in HR was also observed (by 5.4 b.p.m.). Less consistent effects were observed on HR. When the actual maximum noise level of an event was assessed there were no systematic differences in the effects according to the noise source. CONCLUSION: Effects of noise exposure on elevated subsequent BP measurements were clearly shown. The effect size of the noise level appears to be independent of the noise source.

Aircraft noise and incidence of hypertension.

BACKGROUND: An association between aircraft noise exposure and hypertension prevalence has been suggested but there are no longitudinal studies of this association. Our aim was to investigate the influence of aircraft noise on the incidence of hypertension. METHODS: A cohort of 2754 men in 4 municipalities around Stockholm Arlanda airport was followed between 1992-1994 and 2002-2004. The cohort was based on the Stockholm Diabetes Preventive Program; half of the study subjects had a family history of diabetes. Residential aircraft noise exposure (expressed as time-weighted equal energy and maximal noise levels) was assessed by geographical information systems techniques among those living near the airport. Incident cases of hypertension were identified by physical examinations, including blood pressure measurements, and questionnaires in which subjects reported treatment or diagnosis of hypertension and information on cardiovascular risk factors. Analyses were restricted to 2027 subjects who completed the follow-up examination, were not treated for hypertension, and had a blood pressure below 140/90 mm Hg at enrollment. RESULTS: For subjects exposed to energy-averaged levels above 50 dB(A) the adjusted relative risk for hypertension was 1.19 (95% CI = 1.03-1.37). Maximum aircraft noise levels presented similar results, with a relative risk of 1.20 (1.03-1.40) for those exposed above 70 dB(A). Stronger associations were suggested among older subjects, those with a normal glucose tolerance, nonsmokers, and subjects not annoyed by noise from other sources. CONCLUSION: These findings suggest that long-term aircraft noise exposure may increase the risk for hypertension.

Road traffic noise and hypertension.

BACKGROUND: It has been suggested that noise exposure increases the risk of hypertension. Road traffic is the dominant source of community noise exposure. OBJECTIVE: To study the association between exposure to residential road traffic noise and hypertension in an urban municipality. METHODS: The study population comprised randomly selected subjects aged 19-80 years. A postal questionnaire provided information on individual characteristics, including diagnosis of hypertension. The response rate was 77%, resulting in a study population of 667 subjects. The outdoor equivalent traffic noise level (Leq 24 h) at the residence of each individual was determined using noise-dispersion models and manual noise assessments. The individual noise exposure was classified in units of 5 dB(A), from <45 dB(A) to >65 dB(A). RESULTS: The odds ratio (OR) for hypertension adjusted for age, smoking, occupational status and house type was 1.38 (95% confidence interval (CI) 1.06 to 1.80) per 5 dB(A) increase in noise exposure. The association seemed stronger among women (OR 1.71; 95% CI 1.17 to 2.50) and among those who had lived at the address for >10 years (OR 1.93; 95% CI 1.29 to 2.83). Analyses of categorical exposure variables suggested an exposure-response relationship. The strongest association between exposure to traffic noise and hypertension was found among those with the least expected misclassification of true individual exposure, as indicated by not having triple-glazed windows, living in an old house and having the bedroom window facing a street (OR 2.47; 95% CI 1.38 to 4.43). CONCLUSION: The results of our study suggest an association between exposure to residential road traffic noise and hypertension.

Hypertension and Exposure to Noise near Airports (HYENA): study design and noise exposure assessment.

An increasing number of people live near airports with considerable noise and air pollution. The Hypertension and Exposure to Noise near Airports (HYENA) project aims to assess the impact of airport-related noise exposure on blood pressure (BP) and cardiovascular disease using a cross-sectional study design. We selected 6,000 persons (45-70 years of age) who had lived at least 5 years near one of six major European airports. We used modeled aircraft noise contours, aiming to maximize exposure contrast. Automated BP instruments are used to reduce observer error. We designed a standardized questionnaire to collect data on annoyance, noise disturbance, and major confounders. Cortisol in saliva was collected in a subsample of the study population (n = 500) stratified by noise exposure level. To investigate short-term noise effects on BP and possible effects on nighttime BP dipping, we measured 24-hr BP and assessed continuous night noise in another subsample (n = 200). To ensure comparability between countries, we used common noise models to assess individual noise exposure, with a resolution of 1 dB(A). Modifiers of individual exposure, such as the orientation of living and bedroom toward roads, window-opening habits, and sound insulation, were assessed by the questionnaire. For four airports, we estimated exposure to air pollution to explore modifying effects of air pollution on cardiovascular disease. The project assesses exposure to traffic-related air pollutants, primarily using data from another project funded by the European Union (APMoSPHERE, Air Pollution Modelling for Support to Policy on Health and Environmental Risks in Europe).

Saliva cortisol--a new approach in noise research to study stress effects.

Several studies have indicated an association between noise exposure and cardiovascular disease. A noise-induced release of stress hormones has been considered to be a biological pathway of importance in this respect. The described method is of special interest since concentration of cortisol in saliva reflects the concentration of free cortisol in serum and repeated saliva samples can easily be collected. Our objective is to overview the use of saliva cortisol to measure stress in relation to noise as a tool for research on noise-related cardiovascular risk. Previous studies of saliva cortisol in relation to noise exposure are reviewed. In summary, repeated assessments of saliva cortisol seems to be a feasible method to apply in field studies in noise research.

Daily intake of magnesium and calcium from drinking water in relation to myocardial infarction.

BACKGROUND: A decreased risk for cardiovascular disease has been related to the hardness of drinking water, particularly high levels of magnesium. However, the evidence is still uncertain, especially in relation to individual intake from water. METHODS: We used data from the Stockholm Heart Epidemiology Program, a population-based case-control study conducted during 1992-1994, to study the association between myocardial infarction and the daily intake of drinking water magnesium and calcium. Our analyses are based on 497 cases age 45-70 years, and 677 controls matched on age, sex, and hospital catchment area. Individual data on magnesium, calcium, and hardness of the domestic drinking water were assessed from waterwork registers or analyses of well water. RESULTS: After adjustment for the matching variables and smoking, hypertension, socioeconomic status, job strain, body mass index, diabetes, and physical inactivity, the odds ratio for myocardial infarction was 1.09 (95% confidence interval = 0.81-1.46) associated with a tap water hardness above the median (>4.4 German hardness degrees) and 0.88 (0.67-1.15) associated with a water magnesium intake above the median (>1.86 mg/d). There was no apparent sign of any exposure-response pattern related to water intake of magnesium or calcium. CONCLUSIONS: This study does not support previous reports of a protective effect on myocardial infarction associated with consumption of drinking water with higher levels of hardness, magnesium, or calcium.

A 5-year follow-up of airway symptoms after nitrogen dioxide exposure in an indoor ice arena.

The authors investigated whether exposure to high levels of nitrogen dioxide (NO2) in an indoor ice hockey arena might be associated with airway symptoms 5 yr later. A follow-up questionnaire was answered by 71 subjects who had experienced such an exposure, accompanied by acute respiratory illness, in Stockholm in 1994. The same questionnaire was answered by 40 reference subjects. The overall response rate for both groups was 71%. Information was obtained regarding various background factors, such as smoking and respiratory symptoms since 1994. For those who had stopped playing ice hockey during the follow-up period, the exposure to high NO2 levels appeared to be associated with an increase in upper airways symptoms (i.e., nasal blockage or rhinitis) (odds ratio = 3.1, 95% confidence interval = 1.1, 8.8), after adjustment for age, smoking, and family history of allergy. These data suggest that exposure to high NO2 levels in an indoor ice arena may be associated with increased airway symptoms several years later.