Nancy Gell

A longitudinal study of industrial and clerical workers: predictors of upper extremity tendonitis.

Upper extremity tendonitis (UET) associated with work activity is common but the true incidence and risk factors can best be determined by a prospective cohort study. This study followed a cohort of 501 active workers for an average of 5.4 years. Incident cases were defined as workers who were asymptomatic at baseline testing and had no prior history of UET and went on to be diagnosed with an UET during the follow-up period or at the follow-up evaluation. The incident cases were compared to the subset of the cohort who also had no history of an UET and did not develop tendonitis during the study. The cumulative incidence in this cohort was 24.3% or 4.5% annually. The factors found to have the highest predictive value for identifying a person who is likely to develop an UET in the near future included age over 40, a BMI over 30, a complaint at baseline of a shoulder or neck discomfort, a history of CTS and a job with a higher shoulder posture rating. The risk profile identifies both ergonomic and personal health factors as risks and both categories of factors may be amenable to prevention strategies.

A longitudinal study of industrial and clerical workers: incidence of carpal tunnel syndrome and assessment of risk factors.

This study followed workers over an extended period of time to identify factors which may influence the onset of Carpal Tunnel Syndrome (CTS). The purpose was to evaluate incidence of CTS and to create a predictive model of factors that play a role in the development of CTS. This prospective study followed 432 industrial and clerical workers over 5.4 years. Incident cases were defined as workers who had no prior history of CTS at baseline testing and were diagnosed with CTS during the follow-up period or at the follow-up screening. On the basis of logistic regression, significant predictors for CTS include baseline median-ulnar peak latency difference, a history of wrist/hand/finger tendonitis, a history of numbness, tingling, burning, and/or pain in the hand, and work above the action level of the peak force and hand activity level threshold limit value. This longitudinal study supports findings from previous cross-sectional studies identifying both work related ergonomic stressors and physical factors as independent risk factors for CTS.

Incidence of carpal tunnel syndrome among automobile assembly workers and assessment of risk factors.

Objectives: This study defined the incidence rate of carpal tunnel syndrome (CTS) among active assembly workers and evaluated risk factors. Methods: This study followed 189 automobile assembly workers over 1 year. Incident cases were defined as workers who had no current or prior history of CTS and were subsequently diagnosed with CTS by means of active surveillance during the study. Results: The estimated annual incidence rate ranged from 1% to 10%, depending on the case definition. Significant predictors for CTS include a higher baseline median-ulnar peak latency difference, history of wrist/hand/finger tendonitis, history of diabetes, nonneutral wrist and elbow postures, and a lower self-reported social support. Conclusions: This is similar to other prospective studies that demonstrate both ergonomic and medical history are independent risk factors for development of CTS.

Prolonged median sensory latency as a predictor of future carpal tunnel syndrome

The purpose of the study was to determine whether abnormal median sensory nerve conduction among asymptomatic workers was predictive of future symptoms suggestive of carpal tunnel syndrome (CTS). This was a prospective study involving 77 workers who were identified as asymptomatic cases with electrodiagnostic findings of median mononeuropathy compared to an age‐ and sex‐matched control group. Follow‐up was completed an average of 70 months later, and subjects who reported pain, numbness, tingling, or burning in the distribution of the median nerve, based upon a hand diagram, were classified as having CTS symptoms. The follow‐up participation rate was 70%. Among subjects with abnormal median sensory latencies, 23% went on to develop symptoms consistent with CTS within the follow‐up period, compared with 6% in the control group (P = .010). Age and hand repetition were also risk factors for CTS, but the majority of asymptomatic workers with a median mononeuropathy do not become symptomatic over an extended time.

Risk Factors for Plantar Fasciitis Among Assembly Plant Workers

The objective of this study was to determine the relative contributions of work activity (time spent standing, walking, or sitting), floor surface characteristics, weight, body mass index, age, foot biomechanics, and other demographic and medical history factors to the prevalence of plantar fasciitis.

Predictors of Persistent Elbow Tendonitis Among Auto Assembly Workers

Introduction: Lateral and medial epicondylitis associated with work activity is a common upper extremity musculoskeletal disorder with a prevalence of 4–30% depending upon the work setting and diagnostic criteria. The influence of treatment, ergonomic factors, medical history, psychosocial variables, and aging on the improvement of symptoms has not been well defined. Methods: This was a prospective cohort study of a cohort of 45 workers with active elbow tendonitis for an average of 13 months. Complete resolution of symptoms was the defined outcome measure. Results: The predictive factors for persistent elbow tendonitis included older age (OR = 1.1, 95% CI: 0.99, 1.33), higher hand repetition level for their job(s) (OR = 2.5, 95% CI: 1.00, 6.25), more deviation from a neutral wrist position during the work activity (OR = 2.0, 95% CI: 0.80, 5.56), and lower perceived decision authority on the job (OR = 0.9, 95% CI: 0.79, 0.98). Other ergonomic, psychosocial, and electrophysiologic measures were not predictive. The models had relatively high sensitivity and specificity. Treatment effects could not be evaluated due to incomplete data available. Conclusions: Older workers with jobs requiring more repetition and awkward wrist postures, and less decision authority were less likely to have resolution of their elbow tendonitis. Implications: Workers at highest risk for persistent elbow tendonitis should be placed at jobs with lower repetition levels and that use more neutral wrist postures. Effective interventions must address both the ergonomic and psychosocial risk factors in a multifaceted approach to this problem.

Predictors of Upper Extremity Discomfort: A Longitudinal Study of Industrial and Clerical Workers

Upper extremity discomfort associated with work activity is common with a prevalence of over 50% in many settings. This study followed a cohort of 501 active workers for an average of 5.4 years. Cases were defined as workers who were asymptomatic or had a low discomfort score of 1 or 2 at baseline testing and went on to report a discomfort score of 4 or above on a 10-point visual analog scale. This change is considered clinically significant. Controls had a low baseline discomfort score and continued to have a low discomfort rating throughout the study. The risk factors found to have the highest predictive value for identifying a person who is likely to develop a significant upper extremity discomfort rating included age over 40, a BMI over 28, a complaint of baseline discomfort, the severity of the baseline discomfort rating and a job that had a high hand activity level (based upon hand repetition and force). The risk profile identified both ergonomic and personal health factors as risks and both factors may be amenable to prevention strategies.

Risk factors for lower extremity fatigue among assembly plant workers

BACKGROUND Work-related fatigue of the lower extremities is a known cause of lost productivity and significant employer costs. Common workplace solutions to reduce fatigue levels include anti-fatigue matting, shoe orthoses, or sit/stand work stations. However, assessment of these anti-fatigue measures within the workplace has been limited. METHODS This was a cross sectional study in an automotive assembly plant on employees with at least 6 months tenure. Subject data were collected via questionnaires including Likert-scale questions to define fatigue severity. Jobs were evaluated for lower extremity ergonomic exposures via videotaping, pedometers, interviews, and industrial engineering records. RESULTS Lower extremity fatigue at the end of the work day was associated with a higher prevalence of smoking, rheumatoid arthritis, job dissatisfaction, use of shoes with firmer outsoles, and increased time on the job spent standing or walking. Supervisor support and increased time spent on carpet were protective. Lower extremity fatigue that interfered with activities outside of work had additional risk factors including higher BMI, prior diagnosis of osteoarthritis, and increased hours per week spent working. CONCLUSIONS While these results identify carpet as being protective against lower extremity fatigue, no similar relationship was identified for anti-fatigue mats. No adverse relationship was found between hard surfaces such as concrete and lower extremity fatigue. Given the high costs associated with work-related fatigue, future areas for potential intervention include smoking cessation, specific shoe recommendations, and enhancing psychosocial aspects of work such as supervisor support.

Inter-Worker Variability in Lower Body Postures During Assembly Line Work: Implications for Exposure Assessment

This study evaluated inter-worker variability in lower body posture and work activity during highly-structured assembly line work. Data were collected from 79 unique assembly line workstations in an engine manufacturing plant. Because the plant utilized work teams, 4–8 workers rotated through each workstation. At least 30 min of videotape was collected from at least three workers at each workstation. A computer-assisted work sampling procedure randomly selected 200 video “freeze-frames” for each worker. Lower body posture/movement (e.g., sit, stand, walk, etc.) was determined for each frame and used to estimate the percentage of time the worker spent in various postures and activities. Chi-square analyses were performed for each workstation to assess the significance of inter-worker differences. Due to variations in individual work methods, significant differences (p <.05) were found at 57 out of 79 workstations (72%). The greatest differences occurred when workers had the option to choose between standing and sitting (significant in 8 of 8 cases; in extreme examples, sit time ranged between 0–100% on one job, and 6.5–98% on another). Studying a single worker (or “proxy”) can contribute to substantial error when estimating exposures in workplace studies of ergonomic stressors, since the proxy may not be representative of all workers who perform the job. Individual measurements are preferable, particularly for jobs where workers have substantial latitude to develop individualized work methods.

Risk factors for foot and ankle disorders among assembly plant workers

BACKGROUND Jobs that necessitate prolonged standing and walking activities are commonly associated with workers complaints of foot and ankle pain. The objective of this study was to determine the relative contributions of work activity (time spent standing, walking, or sitting), floor surface characteristics, weight, BMI, age, foot biomechanics, and other demographic and medical history factors to the prevalence of foot and ankle disorders. METHODS A cross-sectional observational study design was used to evaluate employees of an engine manufacturing plant. The main outcome variable was foot or ankle disorders defined by pain and a positive physical examination. The independent variables included baseline demographics, medical history, ergonomic exposures, psychosocial factors, shoe characteristics and foot biomechanics. RESULTS Twenty-four percent of the cohort met the case definition of foot/ankle disorder with 10% defined as new cases. Fifty-two percent had symptoms of foot/ankle. An increased risk of presenting with foot/ankle disorders was associated with high metatarsal pressure on gait assessment, increased time spent walking, female gender, reported high job dissatisfaction, a history of rheumatoid arthritis, osteoporosis or vascular disorder. For the truck/forklift drivers, an increased number of times getting in and out of the vehicle was associated with a higher prevalence of ankle/foot problems. CONCLUSIONS An increased risk is associated with higher metatarsal pressure and increased time spent walking. These findings suggest several options for primary and secondary prevention strategies. The use of shoe orthoses with a medial longitudinal arch and metatarsal pad as well as including optional sit/stand workstations may be helpful.