Forceful motion a key risk factor for carpal tunnel syndrome: PREMUS keynote

June 20, 2016 (Toronto, Ontario)—Workers who often use their hands in forceful gripping and pinching motion face a higher risk of developing carpal tunnel syndrome, a painful condition that causes tingling, numbness and weakness in the hand and sometimes requires surgery.

Low-force repetitive hand motion and wrist posture, widely thought of as key risk factors, appear in these findings to be of lower importance than forceful pinch and grip among workers doing hand-intensive tasks such as food processing and manufacturing work. That was a key message in Dr. Bradley Evanoff’s keynote address this morning at the 9th International Scientific Conference on the Prevention of Work-Related Musculoskeletal Disorders (PREMUS), taking place today through Thursday June 23. While the results of this study do not directly address the risk factors for carpal tunnel syndrome in office and computer work, workers in these jobs have much lower rates of this condition than those in more physically demanding occupations.

Dr. Evanoff shared the findings of a large-scale research project involving more than 4,300 workers at more than 50 workplaces, a project conducted by six major research centres in the United States and led by the U.S. Centers for Disease Control and Prevention’s National Institute for Occupational Safety and Health (NIOSH). The data pooled from the six centres have made it possible to explore the role of work-related and personal risk factors for carpal tunnel syndrome, as well as to measure the level of exposure that would result in the condition.

“Recent results from our study and others suggest that the frequency and duration of forceful grip and pinch are the major work-related predictors of carpal tunnel syndrome,” said Dr. Evanoff, Richard A. and Elizabeth Henby Sutter Professor of Occupational and Environmental Medicine at Washington University School of Medicine in St. Louis. “Low-force repetitive movements such as computer use do not seem to be a major risk factor.”

Findings from this pooled data also reveal the psychosocial factors at play. For example, high job demand and low job control increase the risk of carpal tunnel syndrome among those already using forceful motion at work. Having greater say on how to do one’s work decreases the risk, but only for those working with low levels of hand force. The data also show the risk of carpal tunnel syndrome, which is 30 per cent higher among women, also increases with age and body mass index.  

“There has been the long-standing question of the relative importance of work factors as compared to the personal factors in the development of carpal tunnel syndrome,” said Dr. Evanoff. “It has been demonstrated in this study that work factors are strong independent risk factors, even after controlling for obesity, diabetes, age and gender.”

PREMUS, held every three years since 1992, is the primary conference of the Musculoskeletal Disorders Scientific Community of the International Commission of Occupational Health (ICOH). PREMUS 2016 takes place from June 20 to 23, 2016, at Toronto’s Allstream Centre, is hosted by the Institute for Work & Health.