Exposure to road traffic and railway noise and associations with blood pressure and self-reported hypertension: a cohort study

<p>Abstract</p> <p>Background</p> <p>Epidemiological studies suggest that long-term exposure to transport noise increases the risk for cardiovascular disorders. The effect of transport noise on blood pressure and hypertension is uncertain.</p> <p>Methods</p> <p>In 1993-1997, 57,053 participants aged 50-64 year were enrolled in a population-based cohort study. At enrolment, systolic and diastolic blood pressure was measured. Incident hypertension during a mean follow-up of 5.3 years was assessed by questionnaire. Residential long-term road traffic noise (L_den) was estimated for 1- and 5-year periods preceding enrolment and preceding diagnosis of hypertension. Residential exposure to railway noise was estimated at enrolment. We conducted a cross-sectional analysis of associations between road traffic and railway noise and blood pressure at enrolment with linear regression, adjusting for long-term air pollution, meteorology and potential lifestyle confounders (N = 44,083). Incident self-reported hypertension was analyzed with Cox regression, adjusting for long-term air pollution and potential lifestyle confounders.</p> <p>Results</p> <p>We found a 0.26 mm Hg higher systolic blood pressure (95% confidence intervals (CI): -0.11; 0.63) per 10 dB(A) increase in 1-year mean road traffic noise levels, with stronger associations in men (0.59 mm Hg (CI: 0.13; 1.05) per 10 dB(A)) and older participants (0.65 mm Hg (0.08; 1.22) per 10 dB(A)). Road traffic noise was not associated with diastolic blood pressure or hypertension. Exposure to railway noise above 60 dB was associated with 8% higher risk for hypertension (95% CI: -2%; 19%, P = 0.11).</p> <p>Conclusions</p> <p>While exposure to road traffic noise was associated with systolic blood pressure in subgroups, we were not able to identify associations with hypertension.</p

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

Cortisol awakening response (CAR), a considerable increase in cortisol concentrations post-awakening, is considered a reliable indicator of the reactivity of the hypothalamus-pituitary-adrenal axis (HPA). As noise has been shown to activate the HPA-axis, this analysis focuses on CAR as a possible indicator of noise-induced sleep disturbances. This analysis focuses on CAR using two studies. In Study 1, six women and six men (18-26 years) slept for 13 nights each in the laboratory. They were exposed to the noises of three different trains, each with 20, 40 or 80 pass-bys, with equivalent noise levels varying between 44 and 58 dBA, on nine nights. In Study 2, 23 persons slept first for four nights and then four days, in the laboratory; finally 23 persons slept in the reverse order. During six sleep periods, they were randomly exposed to road or rail traffic noises with L Aeq varying between 42 and 56 dBA. To determine the CAR, salivary cortisol concentrations were ascertained in both studies after night sleep immediately after awakening, and 15 and 45 minutes later; in Study 2 also after 30 and 60 minutes later. The time of awakening was determined using the polysomnogram and the participants rated their subjective sleep quality every morning. Subjective sleep quality was rated worse after noisy when compared to quiet nights. CAR was, however, attenuated only after the noisiest nights in a subgroup of Study 2. These persons had just performed a sequence of four consecutive night shifts. They were obviously still in the process of re-adjustment to their usual day-oriented schedule and probably in a state of elevated vulnerability. The study concludes that nocturnal noise exposure affects the CAR only if a person is in a state of at least temporarily elevated vulnerability

Awakenings related to noises from various traffic modes

AIM: To test the hypothesis that aircraft noise causes more awakenings and alterations of sleep structure than rail and road traffic noise. METHODS: 12 women and 12 men (19-28 years) slept, following a habituation night, 4 nights each during 3 consecutive weeks in the laboratory. They were exposed with weekly changes to road-, rail-, or aircraft noise. Each week consisted of a random sequence of a quiet night and 3 nights with equivalent noise levels of 39, 44 and 50 dBA indoors. The polysomnogram was recorded throughout all nights, sleep quality was assessed and performance tests were completed in the morning. RESULTS: Noise-induced awakenings and structural parameters of sleep, subjective quality and performance indicated more disturbances with increasing noise levels. Where decreased subjective sleep quality was not related to the type of noise, noise-induced awakenings and other physiological parameters of sleep were most affected by rail and least by road traffic noise. CONCLUSIONS: As road-, rail- and aircraft noise caused the same after-effects but different physiological effects integrated noise metrics might be suitable for the prediction of subjective sleep quality but not for the physiological disturbances of sleep

FIFTH INTERNATIONAL CONGRESS ON SOUND AND VIBRATION THE SIGNIFICANCE OF VIBRATION DIRECTION FOR SUBJEC- TIVE EVALUATION OF DUAL-AXIS WHOLE-BODY VIBRATIONS

ABSTRACT Sixteen female and fifteen male subjects, 19-51 years of age participated in the present study. Its purpose was to determine various combinations of sinusoidal simultaneously presented (dual-axis) vertical and lateral whole-body vibrations that are sensed as equally strong as a preceding single-axis reference (aW= 1.25 ins-2 r.m.s.) which was applied in either of both directions only and which had the same frequency, namely 1.6, 3.15,6.3 or 12.5 Hz. The test motion consisted of a constant predefine and a variable component. The first was applied in the same direction and with either of 5 predefine percentages of the acceleration of the reference The curves of equally sensed combinations determined for the 4 frequencies were bended right-downwards as expected due to ISO/DIS 2631. But there were remarkable quantitative discrepancies for frequencies above 1.6 Hz with an underestimation of lateral vibrations; the factor kYbeing 1.5-1.9 greater than in the standard. It is concluded that the weighting factors for lateral vibrations above 1.6 Hz need to be corrected for the proper evaluation of discomfort caused by multi-axis whole-body vibrations