Background: Chronic pain is known to be very common in the community. Less is known about the epidemiology of more significant or severe chronic pain. The impact of chronic pain in the community, in terms of general health, employment and interference with daily activity, has not been quantified.

Objectives: The aim of this study was to describe the prevalence and distribution in the community of chronic pain defined as 'significant' and 'severe', and to explore the impact of chronic pain on health and activity.

Methods: A questionnaire survey was carried out of a sample drawn from the general population in the Grampian region of SCOTLAND: Questionnaires were sent to a random sample of 4611 individuals aged 25 years and over, stratified for age and gender, selected from the practice lists of 29 general practices (total practice population 136,383). The study instrument included a case definition questionnaire, from which were identified individuals with 'any chronic pain' (pain of at least 3 months duration). The instrument also included a level of expressed need questionnaire and the chronic pain grade questionnaire, from which were derived definitions for 'significant chronic pain' (based on the reported need for treatment and professional advice) and 'severe chronic pain' (based on reported intensity and pain-related disability). The SF-36 general health questionnaire and demographic questions were also included.

Results: Of the sample, 14.1% reported 'significant chronic pain', and this was more prevalent among women and older age groups. A total of 6.3% reported 'severe chronic pain', and this was more common in older age groups. On multiple logistic regression modelling, female gender, housing tenure, employment category and educational attainment were found to be independently associated with both 'significant' and 'severe' chronic pain. The presence of 'any', 'significant' and 'severe' chronic pain had progressively more marked adverse associations with employment, interference with daily activities and all measured dimensions of general health.

Conclusions: Comparison of the epidemiology of 'significant chronic pain' and 'severe chronic pain' with 'any chronic pain' allows an understanding of the more clinically important end of the chronic pain spectrum. These results support the suggestion that chronic pain is multidimensional, both in its aetiology and in its effects, particularly at this end of the spectrum. This must be addressed in management and in further research.