Yoko Komura

Prevalence of Raynaud's phenomenon in different groups of workers operating hand-held vibrating tools

In eight groups of subjects operating various hand-held vibrating tools and aged from 30 to 59 years, the prevalence rates of vibration-induced white finger (VWF) and numbness, pain, or stiffness in the upper and lower extremities were investigated. Hand-transmitted vibration levels (HTVLs) were measured on the back of the hand, by means of unidirectional (x-axis) vibration dosimeters, and the frequency-weighted acceleration levels [(Lh,w)eq,t] were determined as the vibration levels. The prevalence rates of VWF and numbness of the hands in these subjects were compared to the prevalence rates of Raynauds phenomenon (RP) and numbness of the hands in 1027 males and 1301 females not occupationally exposed to vibration (age range: 30–59 years). It was observed that in subjects exposed to HTVLs of between 1.1 and 2.5 m/s2, the prevalence of VWF was between 0.0% and 4.8%. The prevalence of VWF reached 9.6% in a group of workers exposed to HTVLs of 2.7–5.1 tn/s2. The latter group showed a significant difference (P < 0.05) in the prevalence of VWF compared to the 2.7% prevalence of RP in male subjects of the general population. The prevalence of VWF in female subjects exposed to vibration (4.3%) was not significantly different from the prevalence of RP in females of the general population (3.4%). The prevalence rates of numbness of the hands were in the range of 6.5%–30.4% in the exposed groups and in the range of 13.4%–29.5% in the general population. Among the subjective symptoms, only VWF showed a significant positive correlation with HTVLs (R2 = 0.5, P < 0.05). It was concluded that in decisions concerning quantitative recommendations for vibration exposure, the prevalence of VWF should be employed. With a view to decreasing the risk of developing VWF, estimated vibration safety values for 4 h and 2 h daily exposures are discussed.

Cutaneous signs (Raynaud's phenomenon, sclerodactylia, and efladema of the hands) and hand-arm vibration exposure

SummaryDermatological tests and examinations of the hand(s) were carried out in vibration-exposed and un exposed males. The subjects were 179 chain-saw workers in private forestry companies and 205 local inhabitants who had never used vibrating tools. The prevalences of Raynauds phenomenon (RP), sclerodactylia, and edema of the hands were estimated in both groups, and associations between these cutaneous signs and vibration exposure were evaluated. The prevalences of RP and edema in the exposed group were 9.5% and 1.7%, respectively, and in the unexposed group, 2.9% and 1.5%, respectively. Sclerodactylia was seen in 31.8% of the chain-saw workers but in only 6.4% of the unexposed individuals. In statistical analyses based on unconditional logistic regression models with adjustment for age, RP was associated with long-term (≥ 20 years) vibration exposure [odds ratio (OR) = 7.06; 95% confidence interval (CI) = 2.51−19.87]. Sclerodactylia was associated with both short- and long-term vibration exposure (OR = 6.54, Cl = 3.30-13.36; OR = 7.05; CI = 3.41-14.60, respectively). There were significant dose-response relationships between RP and duration of exposure and between sclerodactylia and duration of exposure. Results of function tests indicated a longer recovery time and a higher vibration threshold for the workers with RP. The presence of sclerodactylia, however, did not have any significant influence on function test results. It is possible to conclude that not only RP but also sclerodactylia could be induced by vibration exposure. However, most cases of sclerodactylia were not so serious as to involve disturbances of peripheral circulatory and nerve function.

PREVALENCE OF RAYNAUD'S PHENOMENON AND SPECIFIC CLINICAL SIGNS RELATED TO PROGRESSIVE SYSTEMIC SCLEROSIS IN THE GENERAL POPULATION OF JAPAN

Background. In order to evaluate the prevalence rates of Raynauds phenomenon (RP) and specific clinical signs related to progressive systemic sclerosis (PSS) in the general population of Japan, inquiries were made concerning RP in the hands and dermatologic examinations were also conducted.