Occupational class, physical workload, and musculoskeletal morbidity in the engineering industry

Area of Science:

• Occupational Health
• Epidemiology
• Musculoskeletal Disorders

Background:

• Musculoskeletal disorders (MSDs) are a significant occupational health concern.
• Previous studies suggest a link between physical workload and MSDs, particularly in blue-collar occupations.

Purpose of the Study:

• To investigate the relationship between physical workload and musculoskeletal disorders in metal industry workers.
• To examine changes in MSDs over a five-year follow-up period.
• To explore individual-level associations within blue-collar occupations.

Main Methods:

• A cohort of 502 metal industry employees was assessed for physical workload and MSDs in 1973.
• Workload was measured using indices of physical strain, load, static phases, and stereotypy via interviews and observations.
• Participants underwent a follow-up examination five years later (88% participation rate).

Main Results:

• Blue-collar workers exhibited higher physical workload indices and greater prevalence of rheumatic symptoms and chronic MSDs compared to white-collar workers.
• The incidence of MSDs increased more in blue-collar groups during the follow-up period.
• Individual-level associations between workload indices and MSDs were weak, confounded by selective job mobility and early retirement.

Conclusions:

• While group-level data indicate higher MSD risk for blue-collar workers due to physical demands, individual-level associations are complex.
• Job mobility and premature retirement among workers with MSDs attenuate the observed relationship between physical workload and morbidity.
• Further research is needed to understand the interplay of occupational factors and individual responses in MSD development.