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J Occup Health year 1999 volume 41 number 4 page 232 - 237
Classification Original
Title Correlation between Vibration Induced White Finger and Hearing Loss in Miners
Author Csaba SZANTO and Stoica LIGIA
Organization Institute of Public Health Cluj-Napoca, Romania
Keywords Vibration exposure, VWF, Hearing loss, Correlation
Correspondence
Abstract Correlation between Vibration Induced White Finger and Hearing Loss in Miners: Szanto Cs., et al. Institute of Public Health Cluj-Napoca, Romania-In the present investigation age and duration of exposure to vibration and noise were matched with the intention to confirm the earlier reported difference in hearing threshold loss in miners with vibration-induced white finger (VWF) and those without VWF. The case-referent study comprised 264 miners without VWF and 84 miners with VWF. Out of the two groups were selected 65 pairs, having the same duration of exposure to vibration and noise (in years) and a maximal difference in age of 2 yr. The diagnosis of VWF was made after cold provocation at 10degree for 10 min, when the clinical sign appeared: whitening of the fingers. The values for acceleration of vibration and noise intensity exceeded the permissible level, when taking measurements for P-90 type pneumatic hammers used in miners. The mean hearing threshold level (HTL) was typical for hearing loss induced by noise, reaching the highest value at 6 kHz both in the case- and in the reference group. The HTL were lower in those suffering from VWF than without VWF, for all the frequencies, but significant differences exist only for 4, 6 and 8 kHz. The mean recovery rate (RR) for the skin temperature tested at the fingertips after 5, 10 and 15 min indicated significantly high values in the reference versus cases. The subjects were divided into three groups by RR of skin temperature 5 min after cold provocation. The miners having a smaller RR (<0.25) had the lowest HTL; but the subjects with a prompt RR (>0.90) had hearing thresholds significantly better at 4, 6 and 8 kHz. For the group with VWF a medium range correlation between HTL loss and duration of exposure to vibration at all frequencies was found. The same calculations for the reference group did not indicate a significant correlation. The effects of vibration in miners can appear in the hearing organ, far from the part of the body through which this risk factor enters (the hand/arm). The correlation between VWF and hearing loss is directly related to the duration of exposure.