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investigation as W-22 MAX, it represents the ability to differentiato a word list presonted on an audiotape with a background of noiso for both the left and right ear. The score or percent of a word list correctly identified in the better ear is then taken as the W-22 MAX score for speech discrimination. The W-22 MAX measure of speech discrimination (<60% v >60%) was a predictor of inereased prevalcncc of hypertension in both age groups. This indicates that W-22 MAX may be a morę sensitive index of both the psychosocial and biologie components of noise-induced hcaring loss. The hallmark of loss in the speech rangę was found in the frcąuencies of 1000 to 2000 kHz. Ciinically, a person who is above a 35-dBA threshold for these frequencies may beadversely affectcd with regard to his or her speech discrimination score. He or she may also be at risk for the hypertensive effects of chronic noise exposurc.

Our previous noise and blood pressure study also noted a significant relationship betwcen noise-induced hearing loss and blood pressure, with the effect in older men bcing morę pronounced.¹¹ The sample population drawn from the plant for the present study were older retired men who had not participated in the earlier investigation. They represent_T therefore, a cohort that in the earlier study were aged 56 to 63 years, but were now part of the 63 to 66-year-old group. It is interesting to notę that once again this group may represent the most noise-exposed cohort. These results suggest that there may be a threshold of occupational noise exposure that must be reached before the relationship between noise-induced hearing loss and hypertension is exhib-ited. W-22 MAX appears to be a uniąue measure of both noise-related damage to the cochlea as well as a determinant of communic&tion handicap. Further work with speech discrimination testing in other noise exposed populations is needed.

A variable not addrcssed by the current study is the effect of lipoprotein levels and noise exposure on hearing. Noise-induced hearing loss is a well-documented efTect of prolonged exposure in a noisy eimronment.*³ Several investigators, however, have reported a corre-lation between hearing loss, particularly at high fre--ąucncies, and high serum cholesterol leyels.²³'³¹ Epidemiologie studies have suggested that elevated blood lipids, which are known to lead to atherosclerosis, may cause damage to the vascular system of the inner ear. This may result in an inereased susceptibility to noise-induced hearing loss.³³* Animal experimentation invołv-ing exposurc to both an atherogenic diet and high levels of noise has yielded similar results.”³⁴ Although the pathogenesis of the relationship between abnormal blood lipids and noise-induced hearing loss is not fully under-stood, a model for the modę of interaction has been proposed by Axelsson and Lindgren.*⁶ Futurę work in the area of noise-induced hearing loss and blood pressure should inelude lipid measurements as well as better measures of speech discrimination.

Acknowledgment

We thank Commandcr James Ilolmkamp. PhD. for revtowlii£ this momiscript. This is conlracl no. 5- KOI -OH00042-03 from The Center* for DisesM Contro!/National InsUlute for Occupational 8afetjr and Health.

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