Preliminary evaluation of dose-effect relationships for vibration induced white finger in Japan

Abstract

Habitual use of many vibrating tools has been found to be connected with the appearance of various disorders affecting the blood vessels, nerves, bones, joints, muscles or connective tissues of the hand and forearm. The vibration exposures required to cause these diseases are not known exactly, either with respect to vibration intensity and the vibration frequency spectrum, or with respect to daily exposure time and total exposure period. The purpose of this study is to investigate available data on the physical conditions in Japan that have caused vibration induced white finger (VWF) and attempt to establish approximate relationships between vibration conditions and prevalence of VWF. The vibration conditions were evaluated using the method of vibration assessment recommended by the International Standardized Organization, which uses the weighted vibration level of the frequency weighted, dominant, single axis component of vibration directed into the hand. A clear correlation between level, prevalence of VWF and exposure period can be found. The results also suggest the relationship between the weighted levels and latent intervals. These dose-effect relationships enable the prediction of the average latent interval for a population group and the range of progression of the disorders--all from a measurement of the vibration entering the hands. In Japanese cases, 4, 8, and 15% of VWF prevalence correspond with 10, 20, and 40% of VWF prevalence in the Draft International Standard ISO/DIS 5349 (1982) within the weighted vibration level range of 2 to 50m X s-2.

Exposure-response relationship in the hand-arm vibration syndrome: an overview of current epidemiology research

“…Both overestimation and underestimation of the risk for VWF have been reported by investigators [16,21,24,60]. Risk overestimation has mainly been found in worker groups using tools with a predominantly lowfrequency percussive action, such as road breakers, rock drills, and stone hammers [4,6,21,56].…”

Frequency Weighting for Vibration-induced White Finger Compatible with Exposure-response Models

“…Finally, "typical" daily vibration exposures are constructed from the frequencyweighted accelerations (either single axis component accelerations or the vibration total value) and exposure durations. Studies of the prevalence or latency of VWF (i.e., time of exposure prior to the onset of white fingers) have reported agreement with the prediction of the health risk as well as overestimation and underestimation of the risk 18,19) . The health risk appears to be overestimated for power tools such as rock drills, pavement breakers, sand rammers and impact wrenches, (e.g., see references 2,4,[20][21][22][23] , and underestimated for riveting tools and some grinders and chain saws (e.g., see references [24][25][26] .…”

Effect of vibration magnitude and repetitive exposure on finger blood flow in healthy subjects

“…The magnitude of vibration is considered to be one of the principal physical variables in¯uencing the severity of handtransmitted vibration [9]. Epidemiological studies have shown that the prevalence of VWF among workers using hand-held tools depends on the magnitude of the vibrations to which they are exposed: increasing magnitude of vibration is associated with higher prevalence of VWF [3,7]. It is hence presumed that more intense vibration may aect peripheral ®nger circulation more severely.…”