Risk of hypertension from exposure to road traffic noise in a population-based sample.

OBJECTIVES: To assess the association between hypertension and traffic noise. METHODS: The prevalence and incidence of hypertension were examined in a Swedish municipality partly affected by noise from a highway (20,000 vehicles/24 h) and a railway (200 trains/24 h). A-weighed 24 h average sound levels (L(Aeq,24h)) from road and railway traffic were calculated at each residential building using a geographical information system and a validated model. Physician-diagnosed hypertension, antihypertensive medication and background factors were evaluated in 1953 individuals using postal questionnaires (71% response rate). Prevalence ratios and odds ratios (ORs) were calculated for different noise categories. Based on year of moving into the residence and year of diagnosis, person-years and incidence rates of hypertension were estimated, as well as relative risks including covariates, using Poisson and Cox regression. RESULTS: When road traffic noise, age, sex, heredity and body mass index were included in logistic regression models, and allowing for >10 years of latency, the OR for hypertension was 1.9 (95% CI 1.1 to 3.5) in the highest noise category (56-70 dBA) and 3.8 (95% CI 1.6 to 9.0) in men. The incidence rate ratio was increased in this group of men, and the relative risk of hypertension in a Poisson regression model was 2.9 (95% CI 1.4 to 6.2). There were no clear associations in women or for railway noise. CONCLUSIONS: The study shows a positive association between residential road traffic noise and hypertension among men, and an exposure-response relationship. While prevalence ratios were increased, findings were more pronounced when incidence was assessed.

Aircraft and road traffic noise and children's cognition and health: a cross-national study.

BACKGROUND: Exposure to environmental stressors can impair children's health and their cognitive development. The effects of air pollution, lead, and chemicals have been studied, but there has been less emphasis on the effects of noise. Our aim, therefore, was to assess the effect of exposure to aircraft and road traffic noise on cognitive performance and health in children. METHODS: We did a cross-national, cross-sectional study in which we assessed 2844 of 3207 children aged 9-10 years who were attending 89 schools of 77 approached in the Netherlands, 27 in Spain, and 30 in the UK located in local authority areas around three major airports. We selected children by extent of exposure to external aircraft and road traffic noise at school as predicted from noise contour maps, modelling, and on-site measurements, and matched schools within countries for socioeconomic status. We measured cognitive and health outcomes with standardised tests and questionnaires administered in the classroom. We also used a questionnaire to obtain information from parents about socioeconomic status, their education, and ethnic origin. FINDINGS: We identified linear exposure-effect associations between exposure to chronic aircraft noise and impairment of reading comprehension (p=0.0097) and recognition memory (p=0.0141), and a non-linear association with annoyance (p<0.0001) maintained after adjustment for mother's education, socioeconomic status, longstanding illness, and extent of classroom insulation against noise. Exposure to road traffic noise was linearly associated with increases in episodic memory (conceptual recall: p=0.0066; information recall: p=0.0489), but also with annoyance (p=0.0047). Neither aircraft noise nor traffic noise affected sustained attention, self-reported health, or overall mental health. INTERPRETATION: Our findings indicate that a chronic environmental stressor-aircraft noise-could impair cognitive development in children, specifically reading comprehension. Schools exposed to high levels of aircraft noise are not healthy educational environments.

Effects of noise on mental performance with regard to subjective noise sensitivity.

Objective and subjective effects of moderate levels of recorded traffic noise [Leq = 55 dB(A) and 75 dB(A)] on mental performance were studied in a laboratory setting. A total of 45 subjects (23 males and 22 females) were investigated with respect to subjective noise sensitivity (SNS). Four cognitive tasks were applied involving different psychological functions: Short-Term Memory (STM), Search and Memory 5 (SAM 5) (vigilance), Hidden Figures (HF) (spatial reasoning) and Mental Arithmetic (MA) (parallel processing). Three groups of 15 subjects were defined according to their scores on Weinstein's Noise Sensitivity Scale as tolerant, moderately sensitive or highly sensitive to noise. A similar level of performance was observed in the three groups under quiet conditions [30 dB(A) Leq], but under noisy conditions significant differences (P < 0.05) were seen between them on the STM (words) and MA (total results) tasks, and the lowest performance accuracy was demonstrated by the noise-sensitive subjects. SNS was the primary factor responsible for these differences. There were no significant differences between the groups in respect of the SAM 5 and HF tasks, under either quiet or noisy conditions. Annoyance while performing tasks under noisy conditions was regularly and significantly higher among subjects judged to be noise sensitive on Weinstein's scale, as compared with those judged to have low or moderate SNS.

Noise annoyance with regard to neurophysiological sensitivity, subjective noise sensitivity and personality variables.

To evaluate the relation between annoyance to environmental noise, general neurophysiological sensitivity, subjective noise sensitivity and other individual characteristics, experiments were undertaken in which 93 subjects assessed their subjective annoyance after exposure to noise under laboratory conditions. Evaluations were made of the discomfort threshold for pulsating sound, the light discomfort, and heat and cold discomfort. The heart rate and discomfort after exposure to a series of impulse noises was also determined. Subjective noise sensitivity, attitudes to noise, mood and personality characteristics of the subjects were evaluated using questionnaires. The results show that the annoyance after exposure to noise was not closely related to the general neurophysiological sensitivity, measured as discomfort threshold for noise, heat, cold and light; or to the heart rate reaction or discomfort after exposure to impulse noise. The annoyance was highly correlated with subjectively reported noise sensitivity and with the attitude to noise. There was also a relationship with neuroticism, measured with the EPI scale. It is suggested that the subjective noise sensitivity, attitude and neuroticism for the definition of noise sensitivity be defined in future studies of long term effects of noise exposure.

Sleep disturbance before and after traffic noise attenuation in an apartment building.

A study on traffic noise sleep disturbance was made in an apartment building before and after the installation of noise insulating windows. Three tenants completed a questionnaire each morning one week before and one week after the insulation of windows, and body movements during sleep were recorded during these periods. All persons demonstrated a decrease in the number of body movements after the windows had been insulated and two reported improved sleep quality. The results suggest that subjectively judged sleep quality as well as recordings of bed movements are useful tools for evaluating actions to reduce noise.