INTRODUCTION: Following animal experiments where correlations were observed between serum magnesium level and noise-induced permanent hearing threshold shifts (NIPTS), we tested the prophylactic effect of magnesium in human subjects exposed to hazardous noise. METHODS: Subjects were 300 young, healthy, and normal-hearing recruits who underwent 2 months of basic military training. This training necessarily included repeated exposures to high levels of impulse noises while using ear plugs. During this placebo-controlled, double-blind study, each subject received daily an additional drink containing either 6.7 mmol (167 mg) magnesium aspartate or a similar quantity of placebo (Na-aspartate). RESULTS: NIPTS was significantly more frequent and more severe in the placebo group than in the magnesium group, especially in bilateral damages. NIPTS was negatively correlated to the magnesium content of blood red cells but especially to the magnesium mononuclear cells. Long-term additional intake of a small dose of oral magnesium was not accompanied by any notable side effect. CONCLUSION: This study may introduce a significant natural agent for the reduction of hearing damages in noise-exposed population.

Administration, Oral↗

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Traffic noise and cardiovascular risk. The Caerphilly study, first phase. Outdoor noise levels and risk factors.

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.

Automobiles↗

PubMedDate not supplied

Traffic noise and cardiovascular risk: the Speedwell study, first phase. Outdoor noise levels and risk factors.

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.

Automobiles↗

PubMedDate not supplied

Traffic noise and cardiovascular risk: the Caerphilly and Speedwell studies, second phase. Risk estimation, prevalence, and incidence of ischemic heart disease.

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.

Aged↗