Hand-arm symptoms related to impact and nonimpact hand-held power tools.

Hand and arm symptoms among workers using impact and non-impact hand-held power tools were investigated in a cross-sectional study and a 5-year follow-up study. The study population consisted of concrete workers (n = 103), truck assemblers (n = 234), electricians (n = 101), platers (n = 140) and lumberjacks (n = 102). Of the original 680 subjects, we followed up 312 after 5 years. A questionnaire concerning ongoing hand and arm symptoms, daily exposure to hand-held power tools, type of tool used, and individual factors was administered. More workers using low-frequency impact tools than workers using non-impact tools reported symptoms in the elbows and shoulders. Elbow symptoms were accentuated in the cross-sectional study, while shoulder symptoms were accentuated in the follow-up study. Wrist symptoms were reported by more of those working with high-frequency impact tools than of those using only non-impact tools when the analyses were controlled for age, years in the occupation and smoking habits. A possible explanation of the results found in this study is that low-frequency impact vibration is transmitted to the upper arm, and thus the elbow and shoulder are at risk, while high-frequency impact vibration is attenuated in the hand and wrist and may predominantly cause symptoms there.