Jolly et al. BMC Public Health 2010, 10:439 http://www.biomedcentral.com/1471-2458/10/439 for drop-out will be presented using descriptive statistics. To determine whether the service reaches those most in need, the age, gender, and deprivation score (derived from the postcode of residence) of those who were ran- domised will be compared to those who received the let- ter but did not respond or declined to be randomised. Responses to open-ended questions about experience of the service and reasons for dropping out of their allo- cated programme will be categorised and presented descriptively. Costs An NHS perspective will be taken in the cost analysis. The price to the PCT of each programme will be used. The cost of the call center which co-ordinated the ser- vice will be calculated as an average per person, based on the numbers of staff employed over a 12 month per- iod and clients who used the service over this time per- iod. The mean cost per kg of weight lost will be determined for each programme. Ethical approval Ethical approval was granted by South Birmingham Research Ethics Committee (08/H1207/331). Discussion A quarter of the UK population and a similar high pro- portion in other countries are obese. If primary care clinicians were to manage this disorder, it would poten- tially mean a large proportion of their time being devoted to it. Commercial weight loss organizations have a large network of treatment services that provide a cheaper alternative to primary care services. However, the comparative effectiveness and the cost-effectiveness is unknown. This trial aims to provide these data. One important aspect to this work is that it is a weight loss trial recruiting in primary care among those who have not specifically sought treatment. Many published weight loss intervention trials treat patients in specialist obesity clinics. These clinics pro- vide treatment for only a minority of all people who need it. In particular, in this study, we will be able to examine uptake of obesity management services in response to an invitation. We are not aware of any other study that has examined uptake in a defined population in this way. Robust clinical trial results are not available for all the commercial providers in this trial and for few primary care led programmes, so this research will extend knowledge about the efficacy of commercial and com- munity weight loss programmes. In addition our partici- pants were responders to an invitation from their general practitioner, whereas many other trials have Page 7 of 8 recruited volunteers, who are likely to be more moti- vated to lose weight. This trial will inform decisions about which weight loss programmes might make useful clinical contributions for patients with obesity and which might have useful contributions to reducing the public health toll of obesity. Abbreviations BMI: body mass index; GP: general practice; IPAQ: international physical activity Questionnaire; UK: United Kingdom. Acknowledgements The trial was funded by NHS South Birmingham. Author details 1School of Health & Population Sciences, University of Birmingham, Birmingham B15 2TT, UK. 2School of Sport and Exercise Sciences, University of Birmingham, Birmingham B15 2TT, UK. 3NHS South Birmingham, 6th Floor, Triplex House, Eckersall Road, Kings Norton, Birmingham B38 5SR, UK. Authors’ contributions KJ, AD, PA, JD, JB and PA designed the study and wrote the initial protocol. KJ, AL, AD, PA, JD, JB and PA are on the trial management committee. AL co-ordinated the study with supervision from KJ. KJ drafted the manuscript with contributions from the other authors. All authors read and approved the final manuscript. Competing interests The authors declare that they have no competing interests. Received: 30 June 2010 Accepted: 27 July 2010 Published: 27 July 2010 References 1. Butland B, Jebb S, Kopelman P, McPherson K, Thomas S, Mardell J, Parry V: Foresight. Tackling Obesities: Future Choices - Project report. [http:// www.foresight.gov.uk/OurWork/ActiveProjects/Obesity/KeyInfo/Index.asp]. 2. Kopelman P: Health Risks Associated with Overweight and Obesity. Short Science Review. Foresight Tackling Obesities: Future Choices. Obesity Reviews 2007, 8(s1):13-17. 3. Craig R, Mindell J, Hirani V: Health Survey for England 2008. Physical activity and fitness: summary of key findings. 2009 [http://www.ic.nhs.uk/ webfiles/publications/HSE/HSE08/HSE_08_Summary_of_key_findings.pdf]. 4. World Health Organisation: Obesity. [http://www.who.int/topics/obesity/en/]. 5. Diabetes Prevention Program Research Group: Reduction in the incidence if type 2 diabetes with lifestyle intervention or metformin. New Eng J Med 2002, 346:393-403. 6. Tuomilehto J, Lindström J, Eriksson JG, Valle TT, Hämäläinen H, Ilanne- Parikka P, Keinänen-Kiukaanniemi S, Laakso M, Louheranta A, Rastas M, Salminen V, Uusitupa M: Finnish Diabetes Prevention Study Group: Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med 2001, 344:1343-1350. 7. Douketis JD, Macie C, Thabane L, Williamson DF: Systematic review of long-term weight loss studies in obese adults: clinical significance and applicability to clinical practice. Int J Obes 2005, 29:1153-1167. 8. Shaw KA, Gennat HC, O’Rourke P, Del Mar C: Exercise for overweight or obesity. Cochrane Database of Systematic Reviews 2006, , 4: CD003817. 9. Curioni CC, Lourenco PM: Long-term weight loss after diet and exercise: a systematic review. Int J Obesity 2005, 29:1168-1174. 10. Gilden A, Wadden TA: Systematic review: an evaluation of major commercial weight loss programs in the United States. Ann Intern Med 2005, 142:56-66. 11. Truby H, deLooy A, Fox KR, Livingstone MBE, Logan CM, Macdonald IA, Morgan LM, Taylor MA, Millward DJ: Randomised controlled trial of four commercial weight loss programmes in the UK: initial findings from the BBC “diet trials”. BMJ 2006, 332:1309-1314. 12. Department of Health: Choosing Health: white paper. London: The Stationary Office 2004.