Lifelong vibration energy exposure and smoking were strongly associated with the incidence of vibration white finger (VWF) in a cohort study of 52 Finnish forestry workers conducted over a 19 year period. The odds of smokers experiencing VWF was seven times greater than non-smokers. For each unit of lifelong vibration energy dose [106 (m2/s4)hd], the odds ratio of having VWF increased 3 percent. An association was found between lifelong vibration energy exposure and right rotator cuff syndrome however, no association was established with upper extremity numbness.
From 1976 to 1995, the subjects underwent medical examinations on eleven occasions that included a history, interview concentrating on the neck/upper extremity regions, testing procedures (for paresthesias, loss of strength, sensorimotor function) and other evaluation processes.
During the same time period, the vibration of several chain saws commonly used by these subjects was measured with accelerometers on the front and rear handles. Daily chain saw exposure was self-reported during the medical examinations. Findings over the years were:
- In the early 1970s, vibration level of 9.1 m/s2 for 2.5 hours/day
- In the early 1980s, vibration level of 2.2 m/s2 for 3.5 hours/day
- After the early 1980s, vibration level of 1.8 to 2.2 m/s2 for 4.5 to 5 hours /day
Lifetime vibration dose was calculated following a modified Bovenzi formula
This article originally appeared in The Ergonomics Report™ on 2006-12-13.