Cumulative Trauma Disorders among Telephone Directory Assistance Operators

Cheong, Hae Kwan; Choi, Byung Soon; Kim, Ji Yong; Yu, Sun Hee; Lim, Hyun Sul; Kim, Yong Min; Uh, Kyung Yun; Kwon, Yong Wook

Abstract

To evaluate the prevalence of cumulative trauma disorders in relation to ergonomic evaluation of their work, 260 female directory assistance operators employed in three branch facilities of the nation-wide telecommunication company. Ergonomic evaluation of the work status was done by two industrial hygienists through inspection. Workers were surveyed with standardized self-administered questionnaire and examined by family physicians and an orthopaedician for cumulative trauma disorders. Laboratory examination of serum aspartate aminotransferase(AST), creatinine phosphokinase(CPK), aldolase and rheumatoid factor was done and X-ray of cervical spine and both shoulders was taken from all subjects and nerve conduction velocity test was done on 57 subjects with suspected nerve entrapment cases. Cumulative trauma disorders were categorized into 3 category according to work-relatedness of the disorders. On ergonomic evaluation of the working posture and work environment, improvement of work posture revealed inappropriate postures and devices. Mean age of the subjects were 39 years old and more than 80% graduated high school or above. Ninety-eight percent of the workers employed in the company for more than 15 years and 74.6% of the workers worked at the VDT job for more than 4 years. Mean daily work hours was 8.0 hours per day and mean break hours was 90.5 minutes per day with mean extra work hours of 10.7 hours per month. Mean daily calls were 1128.6 calls in maximum and 864.8 calls in minimum. On laboratory examination, 13 (5.0%) workers had abnormal AST, 53(20.4%) had abnormal CPK, and 1 (0.4%) had abnormal aldolase level. On x-ray examination of cervical spine, 111 (42.7%) had loss of or reversed normal cervical lordosis, 10(3.8%) had narrowing of intervertebral space. Nerve conduction velocity test was abnormal in 11 (19.2%) among 57 workers. Among disorders categorized as work-related, 131 (50.4%) were diagnosed to have fatigue myalgia of levator scapulae, 108 (41.5%) had cervical strain or sprain, 47 (18.1%) had fatigue arthralgia of phalangeal joints, and 47 (18.1%) had probable carpal tunnel syndrome, in 10 (3.8%) of those diagnosis was confirmed electrophysiologically. Age, seniority, work duration at present job, workload nor location of facilities were associated with the prevalence of symptoms nor specific diagnoses on simple statistical analysis and multiple logistic regression, which deems to be due to highly selected and homogeneous characteristics of the study subjects. Above results shows that cumulative trauma disorders are very prevalent among directory assistance operators and elaborate effort is needed to reduce the cumulative trauma disorders among the operators.