Jinks et al. BMC Public Health 2010, 10:148 http://www.biomedcentral.com/1471-2458/10/148 particular those intended to prevent ill-health, knee pain and disability - and the context which might shape their decisions. The rainbow model is particularly suited to the study of knee pain and disability for a number of reasons. Firstly, the main determinants of health it outlines (for example exercise, diet, education, health services) are also core treatments for the effective care and management of knee osteoarthritis (OA) [9]. However, there is evidence of the under use of exercise, weight loss and written information in knee pain patients [10]. Exploring these determinants may therefore shed light on reasons for this. Secondly, items on the rainbow (for example work conditions and diet) reflect opportunities for prevention activity that have been identified in epidemiological stu- dies and randomised clinical trials [e.g. [11,12]] but which have not been explored in detail at the individual level. Thirdly, the new Musculoskeletal Services Frame- work recommends integrated care pathways which focus efforts at self help and prevention [13]. Despite this, there is a lack of research into views of prevention for knee pain, and therefore a lack of knowledge on how such integrated pathways could be operationalised, or on what prevention activity would be acceptable or relevant to people in the context of their everyday lives. Methods There were three aims of this study. First, to investigate people’s perceptions of prevention of knee pain and dis- ability and the factors that enhance or restrict preven- tion activity. Second, to use Dahlgren and Whitehead’s rainbow model to explore in more detail a range of social determinants and how people make sense of these in relation to prevention of knee pain and disability and their health in general. Third, to consider the findings in terms of agency and structure. Semi-structured interviews were undertaken with peo- ple from an existing knee pain cohort (KNEST study) [14,15]. In 2000, a questionnaire was mailed to 8995 adults aged 50 and over registered with three GP prac- tices. 6792 people responded to the survey (77%) of which 5784 were still registered with the GP 3 years later when a follow up survey was administered. 58% of responders to the follow-up survey gave consent to further contact. Our sample was drawn from people who had given this consent. The interview started with exploring people’s general health, followed by a discussion of the influencing fac- tors using a pictorial representation of the rainbow model as a reference point. While the second part of the interviews centred around the model, the semi- structured format allowed people the freedom to discuss all or just a section of the model, and to elaborate as they saw fit. Page 3 of 9 A topic guide for the interviews was developed and discussed at a Knee Pain Forum [16]. This group con- tained patients, health and social care professionals and representatives from other community groups. The Forum guided the research team on if and how to use the rainbow picture within a qualitative interview and recommended a pilot study. We therefore undertook a small pilot study with eight people. The aim of the pilot study was to test out using the rainbow model in a qua- litative interview. The results of this are reported else- where [16]. The main study invited 180 people by letter to participate. The sample was selected purposively from the cohort study. We aimed to interview people with recent pain, resolved pain, or who were symptom free but who had at least two risk factors for knee pain (e.g. a previous knee injury, had a body mass index of 25 or over and classified as overweight or obese, or had a previous manual job). We also selected an equal num- ber or men and women and sampled to ensure people were invited from across three age groups (50-64 years, 65-74 years and 75 years and over). People could either return a reply slip or telephone the researchers if they wanted to take part. Twenty people volunteered to take part. This seems a low uptake, but part of the reason for this may have been that people who were pain free, or who had resolved pain did not feel that the study was relevant to them. This paper reports on the total sample of 28 patient interviews (pilot and main study). As the interview method did not significantly change for the main interviews we felt that it was appropriate to com- bine the pilot and main datasets, particularly as we had low uptake in the resolved and pain free groups. This final study sample included eight women and twenty men, aged between 53-86 years and is outlined in Table 1. Thirteen of the participants had current knee pain, two had resolved pain and thirteen were pain free. In relation to social class status [17] ten partici- pants were classified as being, or had been, in profes- sional or managerial occupations, eight intermediate and ten manual or routine occupations. Each interview lasted between 40 and 90 minutes (the majority were carried out by TO), were tape recorded and fully tran- scribed. Field notes were written after each interview. Common information and consent procedures were adopted in line with the approval by the Local Research Ethics Committee. The three researchers read the first three transcripts independently from each other and a coding framework was then developed through an iterative process and through discussion and comparison of data. Overall, there were few anomalies in interpretation when devis- ing the coding frame and this is probably due to the similar backgrounds of the three researchers. The fra- mework was used to code the remaining interviews.