A review of epidemiologic studies of the effects of hearing protection devices on cardiovascular responses to noise exposure.
Proceedings: 1992 hearing conservation conference, April 1-4, 1992. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, task order 91-37982, 1992 Apr; :111-118
Epidemiological studies on the effects of hearing protection devices (HPDs) on cardiovascular (CV) responses to noise exposure were reviewed. The role of the sympathetic nervous system, epinephrine, norepinephrine, adrenocorticotrophic hormone, and the renin angiotensin aldosterone system in the control of blood pressure was discussed. Many early studies suggesting adverse effects of high noise on the CV system lacked standardization of outcome measurements, did not consider confounders, and were poorly designed. Later studies while adjusting for these factors did not control for variables which had the greatest impact as risk factors such as alcohol consumption and family history. Four more recent studies in which rigorous study design was adopted failed to show association between prolonged noise exposure and hypertension. Two investigations in which noise was assessed as a stressor indicated noise as a significant predictor of diastolic blood pressure. Even though the ability of HPDs to mitigate the effects of prolonged noise exposure on hearing damage was known, no studies designed to specifically examine long term effects of HPD use on blood pressure were identified. One study found that workers using HPDs had mean blood pressure levels nearly equal to those who did not use them. Prevalence ratios for hypertension with noise induced hearing loss as exposure indicator, and tabulated from 12 studies showed little or no association. The poor methodological quality of these studies was addressed. The authors conclude that there is a need for properly designed studies on noise exposure effects on CV responses, and that the use of HPDs and perception of noise as a stressor needed to be treated as potential intervening variables.
Cardiovascular-function; Ear-protectors; Epidemiology; Hearing-disorders; Physiological-response; Noise-measurement; Noise-induced-hearing-loss; Sensory-disorders
Proceedings: 1992 hearing conservation conference, April 1-4, 1992