Risk factors of atherosclerosis and shoulder pain--is there an association? A systematic review.

Background: Shoulder pain is prevalent and a common cause of disability at work and daily activities. Some studies suggest an association between risk factors of atherosclerosis and shoulder pain and disorders.

Aim: To assess associations between risk factors of atherosclerosis and shoulder pain or disorders and to discuss possible pathophysiological pathways for found associations.

Methods: A systematic review was conducted searching Medline until June 2006. Two authors extracted data and assessed quality independently using the Cochrane criteria for the assessment of quality in non-experimental studies with slight modifications. Due to heterogeneity of studies, meta-analysis was not possible. Results were summarized and discussed paying attention to study design and quality.

Results: Fifteen papers from 14 studies were included in the review. Diabetes was consistently associated with clinically defined shoulder disorders in population studies. Overweight or obesity was associated with the incidence of shoulder symptoms in three studies and with clinically defined shoulder disorders in one case control study. A few studies showed a preventive effect of physical exercise. Associations between smoking and shoulder disorders were seen only in studies on occupational populations.

Conclusions: A consistent association between diabetes and shoulder disorders, some associations for weight-related factors as well as a possible preventive effect from physical exercise and sports suggest a metabolic pathophysiological process in shoulder disorders. More prospective studies using appropriate analytical methods are needed.