7578409638

Fig. 1. Mean hearing loss levełs in the right ear for workers in the noisy plant (exposed workers).

TABLE 1

Distribution of Age among Ret«c<l AssemWy WockefS in Piltsfourgh. Pa

1986-1987

Blood Pressure

Age Group. _No    %    Diastolic    Systolic

y    __ _

Mcan SO Mean SO

56-59	39	15.9	83.6	9 62	135.6	13.3
60-63	93	38 0	82.5	932	138.7	17.3
64-68	113	46.1	83.4	11.01	143.4	19.4
Totai	245	1000	835	10.24	140.3	17.9

• Mean age (SO) 62.9 (3.2).

The majority of workers attained a high school di-ptoma. Ninety percent were currently marricd. Neither educalion or marital status was related to blood pres-sure in this sample. Eighty-ninc percent had served in the military, especially World War II and the Korean conflict. In addition, 61% of the participants roportcd participation in hobbies, the majority of which would be construcd as noisy, such as woodworking, hunting, and target shooting. These noise insults might produce a cumulative effect on the acoustic mechanism and might affect our exposure marker, noise-related hcaring loss. The majority (80%) of the men worked in arcas meas-ured as noisy (steel Stores, press, machinę shop, press pit, or metal assembly).

Hypertension Risk Factors

The prevalence of hypertension is defined as >: 90 mm Hg diastolic or currently taking blood pressure medi-cations. Workers who reported currently taking blood pressure medications exhibited higher systolic and diastolic blood pressure than those not reporting such usage (mean BP 85.9 mm Hg diastolic, 146.4 mm Hg systolic and 81.8 mm Hg diastolic, 137.1 mm Hg systolic, respectively). This may reflect poor compliance or poor hypertension control in this population. In contrast, those workers reporting a history of heart discase had stightly lower diastolic blood pressures than workers reporting no history of hypertension (mean BP 81.6 mm Hg diastolic and 146.4 mm Hg systolic, v 83.5 mm Hg diastolic and 140.0 mm Hg diastolic, respectively). A history of hypertension in the immediate family was noted for 35.1% of the participants. Those reporting a family history of hypertension also exhibited higher systolic and diastolic blood pressure.

Body mass index was directly related to blood pressure. For both 56 to 63-year-old and the 64 to 68-year-old groups, systolic and diastolic blood pressures signif-icantly inereased as body mass inereased (P < .01). Alcohol consumption patterns were detailed by a self-report of the type, quantity, freąuency, and variability of alcohol use.^16-19 There was a significant relationship between alcohol intake and systolic and diastolic blood pressure in the younger (P< -05), but not in the older age group. Although 75.9% of the participants reported ever smoking cigarettes, only 26.5% reported being current cigarette smokers.

Hearing Levels

Mean hcaring levcls across various freąuoncics are shown in Figs. 1 and 2 for both the right and the lcft ear for all ages combincd. It can be seen that there is significant hearing loss in this population, particularly in the high froqucncics, with average deeibel loss at 53.7, 60.3, and 60.5 dBA at 3, 4, and 6 kHz, respectively. There is some mild recovcry cvidenced at 6000 and 8000 Hz. The mean thrcshold levels for the right and left ears of all 245 participants indicate differences between ears no greater than 2.5 dBA at all frequencies from 0.25 kHz to 6.0 kHz. The combincd results of our sub-jects demonstrate hcaring within normal limits through

1.0    kHz, followed by a progression of hcaring loss that begins with a decline of 12 dBA between 1.0 kHz and

2.0    kHz, a much steeper decline (30 dBA/octave) be-twecn 2.0 and 3.0 kHz, a rather uniform loss between

3.0    and 6.0 kHz, and. finally, a mild rocovery at 8000 kHz. The audiogram was consistent with noiso-induced hearing loss (Figs. 1 and 2).

Severe noise-induced hearing loss was defined as a threshold greater than or equai to 65 decibels, at 3, 4, or 6 kHz within 20 dBA in the contralateral ear. Fifty-six percent of the men aged 56 to 63 years and 68.1% of the older men (64 to 68 years) had severe noise-induced hearing loss. Average speech reception threshold scorcs (an index of hearing impairment at lower speech frequencics), monosyllabic word discrimination test scores (a measure of speech distortion), and mean hearing thresholds for the two age groups according to severe noise-induced hearing loss categories were also determined (Table 2). There were elear differonces between the high frequency ranges 3, 4, and 6 kHz according to severe noise-induced hearing loss cate-

“dB —i— SD* (high)    SD* (Iow)

692

Noise-induced Hearing Loss and High Blood Pressure/Talbott et al