Comparison of the Standard Threshold Shift Criteria for Evaluating Hearing Conservation Programs / 대한산업의학회지

OBJECTIVES: Workers from a factory was selected to compare 8 standard threshold shift criteria with the Korean diagnostic criteria of noise-induced hearing loss for this cohort study. METHODS: From 1990 to 1999, 491 workers at a manufacturing company with complete record of the hearing test covering the range of 0.5~6 kHz for 10 consecutive years were finally selected. Eight standard threshold shift criteria (15 dB once, NIOSH (1972), 10 dB average 3~4 kHz, OSHA STS, AAOHNS, 15 dB twice, 15 dB 1~4 kHz, OSHA STS twice) along with the Korean standard for diagnosing the noise-induced hearing loss (the average hearing threshold at 0.5, 1 and 2 kHz) were compared to calculate the degree of the threshold shift and the minimum time required to detect the change. RESULTS: Those workers showing at least one positive shift in the 'once'criteria of NIOSH (1972) were 92.5%; the 'average'criteria of 10 dB average 3~4 kHz were 35.8%; 'twice'criteria of 15 dB twice were 44.4%. The duration from the baseline to the year showing the first positive shift was from 3.2 +/- 3.1 years (NIOSH, 1972) to 6.0 +/- 2.1 years (OSHA STS twice). The percentage of true positive shift ranging from 20.4% (AAO-HNS) to 69.8% (NIOSH, 1972). There were 10 (2%) which met the Korean diagnostic criteria of noise-induced hearing loss. CONCLUSIONS: Currently the concept of hearing threshold shift in diagnosing the hearing loss was adopted in Korea thus in this study we determined the validity and the effect of the various hearing threshold shift criteria and showed that NIOSH (1972) criteria was the best of all. In the future, hearing data from various manufacturing workers should be compared to thoroughly evaluate the threshold shift criteria and to establish adequate standard for Korean workers.

A study on the Frequency of Sister Chromatid Exchanges in Peripheral Lymphocytes among Painters / 대한산업의학회지

The author studied the frequencies of sister chromatid exchanges of cultured peripheral Iymphocytes from 51 chromium exposed workers and 29 controls in order to examine the inductivity of sister chromatid exchanges of cultured peripheral lymphocytes of chromium exposed workers, from June 1989 to March 1990. The results obtained were as follows; 1. Mean frequencies of sister chromatid exchanges of cultured peripheral lymphocytes were 9.33+/-2.57 from chromium exposed workers and 7.59+/-0.81 from control, respectively, and the former was significantly higher than the latter (p<0.01) . 2. The frequencies of sister chromatid exchanges of cultured peripheral lymphocytes by duration of employment from chromium exposed workers was increased in proportion to that, but there was no statistical significance. 3. The frequencies of sister chromatid exchanges of cultured peripheral lymphocytes by chromium concentration in blood and urine of chromium exposed workers were not significantly increased. 4. The frequencies of sister chromatid exchanges of cultured peripheral lymphocytes by levels of alcohol consumption in chromium exposed workers was inclined to increase in proportion to that. 5. The frequencies of sister chromatid exchanges of cultured peripheral lymphocytes by number of cigarettes smoked was significantly increased in proportion to that in both chromium exposed workers and controls (p<0.05) . 6. In drinkers of chromium exposed workers, the frequencies of sister chromatid exchanges of cultured peripheral lymphocytes in smokers was higher than non-smokers, but there was no statistical significance.