[Blood cadmium levels in mother and child].
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Biomedical subjects
Publications and source records attributed to W Babisch.
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New circumaural earphones were tested in the frequency range from 100 Hz to 20 kHz and compared to commonly used supra-aural earphones. The circumaural earphone HD 230 (Sennheiser) generates test stimuli at up to 20 kHz with almost constant sound pressure levels when its pos ed on an artificial ear. The reproducibility of hearing threshold mea ed with a new microprocessor-controlled Békésy audiometer using the ne was nearly as good as under free-field conditions. The practicabil diagnostic value of high-frequency audiometry have been demonstrated er field conditions. For this application, the good sound attenuation these earphones (30 dB above 1 kHz) are important. High-frequency he ds of healthy pupils and of pupils with a history of otitis media are kHz, the hearing threshold level difference between both groups reached 20 dB.
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Noise-induced hearing loss (NIHL) is significantly greater in rats fed a magnesium-deficient diet than in rats on a magnesium-rich diet. The hearing loss was found to be negatively correlated with the magnesium concentration of the perilymph. It is suggested that also in man, the magnesium concentration in the perilymph may be of importance in determining susceptibility to NIHL.
As part of the Caerphilly study, traffic noise exposure and risk for ischemic heart disease (IHD) were studied in a sample of 2,512 men aged 45-59 yr. The traffic noise emission level ranged between Leq = 51-70 dB(A) (6-22 hr, 10 min). No association was found between traffic noise and prevalence of IHD. Associations were found between noise and potential IHD risk factors including systolic blood pressure, oestradiol, total cholesterol, plasma viscosity, antithrombin III (increases), cortisol, and platelet count (decrease). Not all results supported the hypothesis that traffic noise increases the risk for IHD. The possibility of confounding cannot be excluded, although an extensive range of potential confounding variables were included in the analysis.
As part of the Speedwell study, traffic noise exposure and risk factors for ischemic heart disease were studied in a sample of 2,348 men whose ages ranged from 45 to 63 y. The road traffic noise emission level, Leq, ranged between 51 and 70 dB(A) (6-22 h, 10-m distance). Significant associations were found between noise and potential ischemic heart disease risk factors, including total triglycerides, platelet count, plasma viscosity, glucose (increases), and systolic and diastolic blood pressure (decreases). Not all results support the hypothesis that traffic noise increases ischemic heart disease risk. The results were controlled for a number of potential confounding factors.
As part of the Caerphilly and the Speedwell collaborative heart disease studies, associations between outdoor traffic noise level, risk factors for ischemic heart disease, and prevalence and incidence of ischemic heart disease were studied in two samples of 2,512 and 2,348 men, respectively, who were 45-63 y of age. Compared with the lowest noise category [Leq,6-22 h = 51-55 dB(A)], the subjects in the highest noise category [Leq,6-22 = 66-70 dB(A)] showed a slightly worse risk factor profile with respect to 9 identified endogenous risk factors. Logistic regression analysis suggested a marginal increase in risk (relative risk = 1.1) for ischemic heart disease incidence for these men based on risk factors. The prevalence of ischemic heart disease was slightly higher (relative risk = 1.2) in this noise group. The observed incidence of major ischemic heart disease within an observation period of approximately 4 y was slightly lower (relative risk = 0.8) for men in the highest noise group.
The authors tested the hypothesis that prolonged exposure to road traffic noise causes ischemic heart disease in a 10-y follow-up cohort study of middle-aged men. In the Caerphilly and Speedwell studies, 2512 and 2348 men, respectively, who were 45-59 y of age were seen in the initial cross-sectional phase and at follow-up intervals of 10 y. Adjusted odds ratios of 1.1 (95% confidence interval = 0.6, 1.9) and 0.9 (95% confidence interval = 0.6, 1.4) were found in the total cohorts. However, the relative risk was 1.3 (95% confidence interval = 0.8, 2.2) in the pooled reconstructed cohort of men who were followed for 6 y (i.e., from phase 2 to phase 3) and for whom room orientation and window-opening habits could be considered. Furthermore, the relative risk increased to 1.6 (95% confidence interval = 0.9, 3.0) in the subsample of men who had lived at least 15 y in their present homes at the time of recruitment. Living adjacent to streets with high traffic noise levels was associated with an adjusted (for covariates) increase in relative risk of 1.01-1.02/y in residence--a result that was only borderline significant (p < .10).
In recent years, the measurement of stress hormones including adrenaline, noradrenaline and cortisol has been widely used to study the possible increase in cardiovascular risk of noise exposed subjects. Since endocrine changes manifesting in physiological disorders come first in the chain of cause-effect for perceived noise stress, noise effects in stress hormones may therefore be detected in populations after relatively short periods of noise exposure. This makes stress hormones a useful stress indicator, but regarding a risk assessment, the interpretation of endocrine noise effects is often a qualitative one rather than a quantitative one. Stress hormones can be used in noise studies to study mechanisms of physiological reactions to noise and to identify vulnerable groups. A review is given about findings in stress hormones from laboratory, occupational and environmental studies.
The WHO definition of "health" is critically discussed in its broad context. Decision making in noise policy has to be made in the evaluation range between social and physical well-being. The term "adverse" is a crucial one in the process of risk characterization. In toxicological terms it refers to the single event itself; in psychosocial terms it refers to the relative number of people affected. The evidence of the association between community noise and cardiovascular outcomes is evaluated. The results of epidemiological studies in this field can be used for decision making when assessing maximum acceptable noise levels in the community. Since dose response relationships were mostly studied with respect to road traffic noise, inferences have to be made with respect to aircraft noise. Issues of statistical inferring are discussed.