Endocrinological and immunological variables sensitive to psychosocial factors of possible relevance to work-related musculoskeletal disorders

Research has indicated that energy mobilization in the body is associated with lowered anabolism, which promotes the repair and restoration of damaged or worn out tissues. Problems may arise when adversity requires energy mobilization for a long period of time. Increased tissue vulnerability can be anticipated. There is evidence that growth hormone has anabolic activity, as do the male and female hormones testosterone and oestradiol and a precursor of both these anabolic steroids, dehydroepiandrosterone sulphate (DHEA-s). The levels of these in serum/plasma may be lowered during periods of adversity. It can therefore be hypothesized that due to the lowering of anabolic activity, tissues are at risk during periods of stress (part of the 'anabolic hypothesis') and that this will be reflected in musculoskeletal symptoms. Furthermore, low anabolic activity predicts more long-lasting illness/disability. In the present study, blood samples were drawn from representative groups of men and women with musculoskeletal disorders. The participants, who were engaged in various occupations in the Norrtalje area of Stockholm, Sweden, were followed up at 3 and 6 months, and development with regard to disability and pain was related to the hormone levels at the acute phase. Results indicated that a low level of DHEA-s was associated with persistent disability in women with acute low-back pain, which partially supports the hypothesis that low anabolic activity predicts more long-lasting illness (the second part of the 'anabolic hypothesis'). Also, a low concentration of beta endorphin, which indicates activity of the pain regulation system, was found to be associated with long-lasting disability in this group.