Role of mechanical and psychosocial factors in the onset of forearm pain: prospective population based study

Objective To deter-mine the aetiology of forearm pain. In particular to determine the relative contribution of (a) psychological factors, features of somatisation, and health anxiety and behaviour, (b) work related mechanical factors, and (c) work related psychosocial factors in the onset of forearm pain. Design 2 year prospective population based cohort study, with retrospective assessment of exposures at work. Setting Altrincham, Greater Manchester. Participants 1953 individuals aged 18-65 years. Outcome measures Forearm pain of new onset. Results At follow up, 105 (8.3%) participants reported forearm pain of new onset lasting at least one day in the past month. Among these, 67% also reported shoulder pain, 65% back pain, and 45% chronic widespread pain. Increased risks of onset were associated with high levels of psychological distress (relative risk 2.4, 95% confidence interval 1.5 to 3.8), reporting at least two other somatic symptoms (1.7, 0.95 to 3.0), and high scores on the illness behaviour subscale of the illness attitude scales. The two work related mechanical exposures associated with the highest risk of forearm pain in the future were repetitive movements of the arm (4.1, 1.7 to 10) or wrists (3.4, 1.3 to 8.7), whereas the strongest work related psychosocial risk was dissatisfaction with support from colleagues or supervisors (4.7, 2.2 to 10). Conclusions Psychological distress, aspects of illness behaviour, and other somatic symptoms are important predictors of onset of forearm pain in addition to work related psychosocial and mechanical factors. Misleading terms such as "cumulative trauma disorder" or "repetitive strain injury," implying a single uniform aetiology, should be avoided.