Association of Occupational and Non-occupational Risk Factors with the Prevalence of Work Related Carpal Tunnel Syndrome

PURPOSE: Several occupational and personal risk factors cause the development of carpal tunnel syndrome (CTS). The purpose of the study was to evaluate both non-occupational and occupational factors associated with CTS in industrial workers. METHODS: A cross sectional study was designed with 400 industrial workers (77% male, 23% female) randomly selected. Workers' upper extremities were examined and related signs and symptoms were assessed. Questionnaires about personal and occupational risk factors were completed and suspicious cases were referred for NCV (nerve conduction velocity) testing and documentation of diagnosis. RESULTS: About 395 workers from automobile industry factories in Iran were assessed by interview and electrodiagnostic studies. Among 395 workers, 47 met the definition of CTS to yield a prevalence of 11.9%. These 47 workers averaged 29.85 years of age (SD = 6.28), and the mean age of the healthy group was 27.95 (SD = 4.86). 395 workers included 91 women (23%) and 304 men (77%). Using multivariate logistic regression model the largest adjusted odds ratios of personal and occupational factors for CTS were: exertion of force over one kilogram 6.38 (1.91-2.02); bending/twisting of the hands/wrists > 30 degrees , 5.62 (0.56-55.6); history of cigarette smoking 4.68 (1.80-11.80); rapid movement of hands 4.44 (1.41-14.02); and use of vibrating tools 3.23 (1.46-7.15). CONCLUSION: Some occupational factors including force exertion, bending/twisting of the hands, rapid movement of the hands and vibration are associated with CTS.