The prevalence of osteoarthritic changes in the lumbar spine (disc space narrowing and spinal osteophytes) is significantly greater in those whose occupations require heavy and repetitive lifting compared with age-matched controls whose occupations are more sedentary. Despite these radiographical differences, most of the studies show little or no difference in the prevalence of low back pain or sciatica between those with radiological changes of osteoarthritis and those with no radiological changes. Based on the current evidence, modification of the lifting can reduce symptoms and complaints. Specific successful strategies, which include ergonomic interventions (such as the use of lift tables and other devices and matching the worker's capacity to the lifting tasks), administrative controls (such as job rotation), and team lifting, appear successful. Despite enthusiasm for their use, there is marginal or conflicting evidence about lifting belts and educational programs in reducing low back pain in the population with heavy lifting requirements. Some examples of positive interventions include:
Truck drivers—Vibration exposure is thought to be the dominant cause for the increased risk for low back pain and lumbar disc herniation. There are some data to support the efficacy of vibrational dampening seating devices.
Hand-held tool operators—Occupations that involve the use of hand-held tools, particularly those with vibration, are associated with the general complaints of hand pain, a greater risk of carpal tunnel syndrome, and some tenosynovitis. Redesign of tools is associated with reduced risks.
Food processing—Food processing, e.g., meat cutting, is associated with a greater risk of shoulder and elbow complaints. Job redesign appears to reduce this risk, but this information is largely based on best practices and case reports.
7. What scientific questions remain unanswered, and may require further research, to determine which occupational activities in which specific industries cause or contribute to work-related musculoskeletal disorders?
The panel's recommended research agenda is provided in Chapter 12 of the report.