Objectives: Hand-arm vibration syndrome (HAVS) consists of vascular and neurological component. Musculoskeletal component has not been delineated yet. In the present follow-up study, we evaluated the prevalence of HAVS and the cumulative exposure to vibration among a cohort of forestry workers. Special interest was given to numbness and musculoskeletal disorders of upper extremity and neck in forestry workers.
Methods: A follow-up study starting from 1976 was conducted among forestry workers in Suomussalmi in Finland. Total exposure of hand-arm vibration was recorded during 11 cross-sectional surveys. The last study was carried out in 1995. The lifetime dose of vibration energy was calculated. A cohort of 52 forest workers participated to all 11 cross-sectional surveys 1976-1995. HAVS and musculoskeletal disorders were evaluated.
Results: The prevalence of active vibration white finger (VWF) decreased from 13 to 4% in the cross-sectional study. In the cohort VWF decreased from 17 to 8% and numbness increased from 23 to 40%. Rotator cuff syndrome (P=0.034) and epicondylitis (P=0.004) associated with numbness. Regional neck pain was diagnosed in 38% of workers and associated with low back pain. In modeling VWF, the lifelong vibration energy (OR 1.03, CI 1.01-1.05), and smoking (OR 7.36, CI 1.07-50.76) were significant. Numbness was modeled by pain in upper extremities (OR 12.43, CI 2.42-63.80) and neck pain (5.97, CI 1.25-28.39), not by lifelong vibration energy. Right rotator cuff syndrome was modeled by age (OR 2.58, CI 1.04-6.41) and lifelong vibration energy (OR 1.04, CI 1.00-1.07).
Conclusions: The prevalence of VWF constantly decreased. Numbness did not follow the vibration exposure profile. Numbness also associated with upper extremity musculoskeletal disorders. Hand-arm vibration associated with the right rotator cuff syndrome in forestry workers.