title: The epidemiology of regional and widespread pain syndromes
Creators: name: MacFarlane, Gary J
Publisher: name: University of Glasgow
Year: 2001
Subjects: subject: Epidemiology.

description: Background: Pain is common in the general population. Approximately 50% of adults will report pain during the past month which has lasted at least 1 day. The most common sites for pain to occur are the lower back and upper limbs (particularly the shoulder), but chronic widespread body pain is also reported by around 10% of the general population. The majority of pain reported in a population would be considered to be of musculoskeletal origin. Even if one restricts attention to pain which results in some limitation of activities - the prevalence is still high. What is the aetiology of these common conditions. Aims: This thesis, using published work explores the aetiology of regional and widespread body pain syndromes. They consider both the outcome and onset of symptoms in addition to some methodological issues arising from the work. Methods: All the studies included are population-based. There were four studies conducted: The Stockport Shoulder Study, The North Cheshire Pain Study, The South Manchester Low Back Pain Study and The Altrincham Pain study. All were conducted on random samples of the adult population aged 18-65 years who were followed prospectively either to determine the onset or outcome of pain symptoms. These were then related to risk factor information, collected around the time of recruitment. The risk factor information included: a) individual (constitutional) factors such as age, gender, anthropometry, b) work-related mechanical (injury) factors c) psychological distress and d) psychosocial factors usually measured in the workplace and including measurements of demands, support available and autonomy. In addition, participants in two of the surveys were flagged at the Office for National Statistics and information on their vital status collected for up to ten years after participating in the original pain study. Their pain status on survey was then related to long-term mortality experience. Results: The studies find that adverse psychological and psychosocial factors are strong predictors of onset and outcome of both regional and widespread pain syndromes. Mechanical factors are also important in the onset of regional pain syndromes, although the precise risk factor (load, posture, repetitive movements) varies between individual sites. There is little evidence for considering widespread body pain as a distinct entity from regional pain syndromes - instead it is more appropriate to think of it as one end of the pain spectrum. Persons reporting widespread pain in population surveys were also demonstrated to have increased mortality, principally a doubling of the risk of cancel- death, over the subsequent decade. These remained true after removing those subjects who already had a diagnosis of cancer at the time of reporting widespread pain. Conclusions: The papers included in the thesis have demonstrated that both mechanical (injury) factors, and psychological/psychosocial factors have an important influence on the onset of pain, and that both clinical and psychological/psychosocial factors are strongly related to outcome. The results provide some insight in to interventions that may be successful with respect to possible primary (in high risk occupational groups) and secondary prevention of some of these episodes. The finding that widespread pain is associated with an increased risk of cancer death in the long-term requires confirmation.