Work-Related Risk Factors for Rotator Cuff Syndrome in a Prospective Study of Manufacturing and Healthcare Workers

Area of Science:

• Occupational health
• Musculoskeletal disorder research
• Biomechanics

Background:

• Work-related shoulder musculoskeletal disorders show slower decline rates compared to other musculoskeletal issues.
• Understanding specific biomechanical risk factors for rotator cuff syndrome (RCS) is crucial for targeted prevention.

Purpose of the Study:

• To assess the risk of developing rotator cuff syndrome (RCS) associated with specific combinations of biomechanical exposures.
• To control for individual confounders in the risk assessment of RCS.

Main Methods:

• Prospective study of 393 U.S. manufacturing and healthcare workers over 2 years.
• Annual assessments of covariates, exposures (forceful exertions, vibration, upper arm postures), and health outcomes.
• Cox proportional hazard models used to calculate hazard ratios (HRs).

Main Results:

• 39 incident RCS cases observed, with an incidence rate of 5.62 per 100 person-years.
• Increased RCS risk linked to forceful hand exertions combined with upper arm flexion ≥45° (HR=1.11) and abduction ≥30° (HR=1.18) or >60° (HR=1.16).
• No statistically significant risks found for separate biomechanical exposures or other interactions.

Conclusions:

• Assessing combined exposures to forceful repetition and upper arm elevation is critical for effective RCS prevention strategies.
• Interventions reducing forceful repetition, particularly when upper arm elevation is unavoidable, may lower RCS risk.