1st place, PREMUS best paper competition: workplace and individual factors in wrist tendinosis among blue-collar workers − the San Francisco study

Abstract

Objective Workplace studies have linked hand/wrist tendinosis to forceful and repetitive hand exertions, but the associations are not consistent. We report findings from a prospective study of right wrist tendinosis among blue-collar workers. Methods Workers (N=413) at four industries were followed for 28 months with questionnaires and physical examinations every 4 months to identify incident cases of right wrist tendinosis. Exposure assessment of force and repetition were based on field measurements and video analysis to determine repetition rate and the percent time (% time) in heavy pinch (>1 kg-force) or power grip (>4 kg-force). All exposure variables were measured at the level of the individual and task. For workers responsible for >1 task, a time-weighted average exposure was calculated based on task hours per week. A proportional hazards model was used to assess the relationship between exposures and incidence of wrist tendinosis. Results During the 481 person-years of follow-up, there were 26 incident cases of right wrist tendinosis [incidence rate (IR) 5.40 cases per 100 person-years]. Adjusting for age, gender, and repetition, wrist tendinosis was associated with % time spent in heavy pinch [hazard ratio (HR) 5.01, 95% CI 1.27–19.79]. Composite exposure measure American Conference of Industrial Hygienists Threshold Limit Value (ACGIH-TLV) for hand activity level (HR 3.95, 95% CI 1.52–10.26) was also associated with the outcome for the medium-exposure group using video-based total repetition rate. Conclusions The workplace factors predicting wrist tendinosis were time-weighted average values of % time spent in heavy pinch and the ACGIH-TLV for Hand Activity Level. The % time spent in power grip was not a significant predictor, nor were any measures of repetition. An exposure–response relationship was observed for the % time spent in heavy pinch. These findings may improve programs for preventing occupational wrist tendinosis.

Pooling job physical exposure data from multiple independent studies in a consortium study of carpal tunnel syndrome

“…For example, do the force ratings from workers predict risk of CTS better than the analysts’ force ratings? Similarly, does HAL calculated using frequency and duration of exertion provide a better estimate of repetition than HAL rated using the verbal anchor scale (Harris et al 2011)? These are important issues for providing recommendations for future job analyses as different estimates of force and repetition are expected to have an effect on whether a job is classified as ‘safe’ or ‘unsafe’ (Garg and Kapellusch 2011).…”

“…Using standard industrial classification divisions, a majority of workers ( n = 2870) were employed in manufacturing or assembling of products, such as automobiles and automobile parts, electric motors, household appliances, furniture, artificial stone, metal and plastic products, commercial lighting, woodworking, books, textiles, glass and window manufacturing, and dairy and food processing to name a few. Other notable groups were services ( n = 775, mostly in healthcare, technical professions and general service work), construction ( n = 385), agriculture ( n = 172), wholesale trade ( n = 59) and retail trade ( n = 53) (Bao et al 2006; Armstrong et al 2008; Dale et al 2008, 2011; Dartt et al 2009; Gardner et al 2010; Burt et al 2011; Harris et al 2011; Garg, Hegmann, et al 2012; Garg, Kapellusch, et al 2012). …”

“…Models such as the rapid upper limb assessment (RULA, McAtamney and Corlett 1993), threshold limit value (TLV) for HAL (ACGIH 2002), the strain index (SI, Moore and Garg 1995) and occupational repetitive actions (OCRA, Occhipinti 1998) have been developed for field use, and each provides a single index for estimating biomechanical stresses from multiple physical exposure variables interacting with each other. However, there are only limited studies on the efficacy of these models in determining risk of DUE MSDs (Franzblau et al 2005; Gell et al 2005; Werner et al 2005; Occhipinti and Colombini 2007; Violante et al 2007; Harris et al 2011; Bonfiglioli et al 2012; Garg, Kapellusch, et al 2012). …”

1631c Recent changes to the acgih hand activity level tlv

“…Recent large, longitudinal studies, provide strong evidence that repetitive forceful hand exertions increase risk for occupational wrist tendinosis and carpal tunnel syndrome. 1,2,3 In the Harris-Adamson study, 3 forceful hand exertions (e.g., >9N pinch or >45N power grip force) and the%time performing forceful hand work increased risk. Based on these and psychophysics studies, 4 hand exertions should be considered in risk assessment models if they are above 10% of posture specific strength.…”

Return to work and job retention – increasingly important outcomes in occupational health research

“…The paper that won the first prize in the competition is the first report on risk factors for the incidence of tendon disorders of the wrist from the large collaborative project on work-related upper-extremity disorders carried out by several universities and research institutes in the United States (2). The paper deals with work-related and individual risk factors for wrist tendinosis based on a prospective study with a follow-up time of 28 months.…”