Association between hand-arm vibration syndrome and vibrotactile perception thresholds among power tool users in an automobile industry, Malaysia

A cross sectional study was conducted to determine the prevalence of hand-arm vibration syndrome (HAVS) and also ascertain the relationship between HAVS and the increase in threshold level of vibrotactile perception threshold (VPT) among workers using vibration hand-held tools in an automobile industry. The study was designed using structured questionnaire and non invasive measurement of VPT at the fingertips and was conducted in one of the automobile company in Klang Valley. A total of 109 assembly line workers with at least one year of job tenure participated in this study. The mean age was 32.9±6.82 years. The mean daily vibration exposure for 8-hours was 1.41±0.878 m/s2. There was 11% of the tools measured were above the Action Level recommended by European Union Directive 2002. The overall prevalence of HAVS based on the reported symptoms through questionnaires was 27.5%. None of the respondents reported any whiteness on their fingers due to the exposure of the vibrations. However, 36.7% of the respondents were reportedly to experience a tingling sensation, 57.8 % reported of having the feeling of numbness on their hands and 10.1% claim that the symptoms were persistent. This study was done among exposed workers without a control group; the thresholds were measured by comparing the observed vibrotactile perception threshold with the vibrotactile perception threshold of healthy population provided by ISO 13091-2. The result showed that 98.2% of the respondents in this study were having a positive threshold which indicates the percentage of respondents that having deterioration on finger tactile perception. The positive threshold from comparison above showed that the respondents of this study were affected by the vibration exposure. The value proven that the exposure has caused the deterioration of tactile sensitivity in 98.2% of the respondents in this study which showed by having positive threshold compared to the healthy population. The results also showed that there was a significant correlation between daily vibration exposure A(8) and vibrotactile perception threshold at both frequency tested which was 31.5Hz (r = 0.417, p=0.002) and 125Hz (r = 0.480, p =0.001). In conclusion, even though the mean daily vibration exposure for 8-hours was low and below the action level, the correlation was observed between exposure to vibration and vibrotactile perception threshold. However, results show that there is no significant relationship between vibrotactile perception threshold and reported symptoms of hand-arm vibration syndrome (p>0.05)