Original Article

International Journal of Obesity (2008) 32, 1531–1536; doi:10.1038/ijo.2008.137; published online 19 August 2008

Industry funding and the reporting quality of large long-term weight loss trials

O Thomas1,2, L Thabane3,4, J Douketis5,6, R Chu7, A O Westfall8 and D B Allison2,8,9

  1. 1Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, AL, USA
  2. 2Clinical Nutrition Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
  3. 3Centre for Evaluation of Medicines, St Joseph's Healthcare, Hamilton, ON, Canada
  4. 4Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON, Canada
  5. 5St Joseph's Healthcare, Hamilton, ON, Canada
  6. 6Department of Medicine, McMaster University, Hamilton, ON, Canada
  7. 7Department of Health Care and Epidemiology, University of British Columbia, Vancouver, BC, Canada
  8. 8Department of Biostatistics, University of Alabama at Birmingham, Birmingham, AL, USA
  9. 9Department of Nutrition Sciences. University of Alabama at Birmingham, Birmingham, AL, USA

Correspondence: Dr DB Allison, Section on Statistical Genetics, Department of Biostatistics, Ryals Public Health Building, Suite 414, University of Alabama at Birmingham, 1665 University Boulevard, Birmingham, Alabama, USA. E-mail: dallison@uab.edu

Received 16 April 2008; Revised 29 June 2008; Accepted 2 July 2008; Published online 19 August 2008.





Quality of reporting (QR) in industry-funded research is a concern of the scientific community. Greater scrutiny of industry-sponsored research reporting has been suggested, although differences in QR by sponsorship type have not been evaluated in weight loss interventions.



To evaluate the association of funding source and QR of long-term obesity randomized clinical trials (RCT).



We analysed papers that reported long-term weight loss trials. Articles were obtained through searches of Medline, HealthStar, and the Cochrane Controlled Trials Register between the years 1966 and 2003. QR scores were determined for each study based upon expanded criteria from the Consolidated Standards for Reporting Trials (CONSORT) checklist for a maximum score of 44 points. Studies were coded by category of industry support (0=no industry support, 1=industry support, 2=in kind contribution from industry and 3=duality of interest reported). Individual CONSORT reporting criteria were tabulated by funding type. An independent samples t-test compared the differences in QR scores by funding source and the Wilcox–Mann–Whitney test and generalised estimating equations (GEE) were used for sensitivity analyses.



Of the 63 RCTs evaluated, 67% were industry-supported trials. Industry funding was associated with higher QR score in long-term weight loss trials compared with nonindustry-funded studies (mean QR (s.d.): industry=27.9 (4.1), nonindustry=23.4 (4.1); P<0.0005). The Wilcox–Mann–Whitney test confirmed this result (P<0.0005). Controlling for the year of publication and whether the paper was published before the CONSORT statement was released in the GEE regression analysis, the direction and magnitude of effect were similar and statistically significant (P=0.035). Of the individual criteria that prior research has associated with biases, industry funding was associated with greater reporting of intent-to-treat analysis (P=0.0158), but was not different from nonindustry studies in reporting of treatment allocation and blinding.



Our findings suggest that the efforts to improve reporting quality be directed to all obesity RCTs, irrespective of funding source.


randomized clinical trials, CONSORT, reporting quality, weight loss, industry funding



Research studies in biomedical journals are increasingly scrutinised, not only for their scientific findings and clinical and public health implications, but also because of … concerns about misleading reporting of industry-sponsored research.1

The above quotation, the opening line in an editorial in the Journal of the American Medical Association (JAMA), evinces strong concern regarding potential influence of industry sponsorship in the literature. The editors of JAMA, in reaction to the concern, suggested policies of extra scrutiny for industry-funded research. In response, an editorial in BMJ decried this as unfair and absurd.2

For the scientific community and society at large, to benefit maximally from biomedical research, the quality and integrity of each step in the research process must be maximised. Such steps include (1) selection of relevant questions; (2) design of research suitable to address those questions; (3) rigorous execution of the design; (4) faithful recording of the data; (5) appropriate statistical analysis of the data; (6) a decision to publish a report of study; (7) clear, accurate and thorough reporting of the study and (8) reasonable ‘second-level’ dissemination and interpretation of the findings in press releases, mass media coverage, scholarly reviews, expert testimony, blue ribbon panels and other venues. In each of these steps, there is an opportunity for some factors to inappropriately exert influence.

One such factor that is frequently discussed is financial duality (a.k.a ‘conflict’) of interest (DOI).3 Indeed, at least three papers4, 5, 6 suggest that in nutrition and obesity research, published papers in which authors were funded by or had other financial ties to industry were more likely than were other papers to contain results or interpretations that favor the industry or company producing the product or service under study. Similar findings have been observed on multiple occasions in other areas of biomedical research.7, 8 The reasons for and appropriate interpretation of these findings remain open to question.9 Nevertheless, concern about inappropriate influences (be they from financial or other DOIs) remains. The most common suggestion for dealing with the potential for inappropriate influence because of financial DOIs is disclosure of the DOI. However, disclosure is likely to be at best ineffectual5 and at worst antithetical to focusing on scientific method,10 derogatory toward industry-funded authors,11 and possibly productive of exactly the biases it is intended to diminish.12

Hence, we believe it will be more fruitful to identify factors that lead to better or poorer performance in each of the stages listed above hopeing that identification of such factors may lead to ideas about policies and practices that can minimise inappropriate influences and maximise performance. If we are to maintain the public trust, crucial for many reasons,13 we must investigate this area.

In this paper we focus on step 7 of the list of research steps presented above and ask whether industry funding leads to better or worse reporting of large, long-term randomized clinical trials (RCTs). We focus on RCTs for obesity treatment. This is an especially important area. Obesity is quite prevalent and causes a number of ill effects including earlier mortality.14 New and better obesity treatments are needed and, as NIDDK wrote, ‘Well conducted clinical trials are the fastest and safest way to find improved treatments and preventions.’15



Reports evaluated

The database16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78 of the papers evaluated has been described earlier.79 In brief, studies were selected by searching Medline (from 1966 to September 2003), HealthStar (from 1975 to September 2003) and the Cochrane Controlled Trials Register (from 1990 to September 2003). Inclusion criteria were (a) a randomized controlled trial; (b) a sample consisting of overweight or obese adults with a mean body mass index greater than or equal to25kg/m2; (c) investigation of a weight loss intervention and (d) duration of patient follow-up greater than or equal to1 year. Exclusion criteria were (a) patients were required to attain a weight loss target to qualify for study enrollment; (b) the weight loss intervention was not approved for clinical use and (c) the weight loss intervention was approved only for short-term use.79

Primary outcome measure

The primary outcome measure was quality of reporting (QR). QR was independently determined by two reviewers and summarized earlier by Thabane et al.79 Briefly, the authors used the CONSORT statement80, 81 to assess QR. For each trial, through an independent double review, the authors determined whether each of 44 detailed CONSORT reporting criteria contained within the checklist were satisfied. Eight of the 44 CONSORT criteria associated with methodologic quality from the Results and Methods sections were examined. The CONSORT statement is considered as the medical industry standard of reporting and contains elements that have been used to evaluate methodologic quality of RCTs.82, 83 Face and content validity have been evaluated for the CONSORT statement, which has been endorsed by numerous peer-reviewed journals and scientific organizations.83

Assessment of industry support

A full copy of each paper was independently reviewed by each of two authors and placed into one of the four categories defined in Table 1. The two reviewers then compared their codings of funding source, which was determined from financial information disclosed in each publication and an agreement of more than 89% (56 of 63 publications) was obtained. The remaining seven publications were reexamined and consensus was reached between the two reviewers. In all but two cases, the discrepancies were the result of a transcription error or oversight on the part of one coder and were corrected. In the last two cases, the disagreement entailed a question regarding ‘whether funding from a for-profit foundation established by, but independent of, a for-profit pharmaceutical company constituted industry support’. Owing to the difficulty in reaching a definitive decision on this and because there were only two such studies, we ran all analyses twice, first with these coded as nonindustry and then in a sensitivity analysis coding these studies as industry-funded.

Statistical analysis

Descriptive statistics (mean and s.d.) are tabulated (Table 2). The primary inferential analysis consisted of a simple independent samples t-test on the QR scores comparing category 0 (no industry funding) with category 1 (industry funded). Subsequently, a number of sensitivity and secondary analyses were conducted including (1) repeating the primary analysis with a nonparametric Wilcox–Mann–Whitney test; (2) repeating the primary analysis using generalised estimating equations (GEE)84 to account for possible clustering within journals to allow for possible correlation in the residuals by journal; (3) using the GEE regression to control for both, whether the paper was published after the 1996 publication of the CONSORT guidelines80, 81 on reporting of RCTs and year of publication; (4) repeating all analyses using only nondrug studies (there were no drug studies in category 0); (5) repeating all analyses after recoding studies in categories 2 and 3 as in category 0 (i.e., nonindustry funded); (6) repeating all analyses after excluding four nonindustry studies where funding source was not specified. The criterion for statistical significance was set at a two-tailed α of 0.05. All analyses were done using SPSS (version 15.0).



Table 2 contains descriptive statistics. As can be seen, the majority (close to 2/3) of long-term weight loss studies are industry-funded. The variances in QR scores are almost identical for industry- and nonindustry-funded studies, but QR scores tend to be higher (i.e., better reporting) for industry-funded studies. QR scores for industry-funded drug studies tended to be higher than industry-funded nondrug studies.

The t-test strongly indicated that the average QR was significantly higher for industry-funded than nonindustry-funded studies (t=4.02; P<0.0005; df=57), with no evidence of heteroscedasticity by Levene's test (P=0.640). This was confirmed by the Wilcox–Mann–Whitney test (P<0.0005) and the GEE analysis (P<0.0005). In a GEE regression analysis conditioning on year of publication and an indicator variable for whether the paper was published after the 1996 CONSORT statement was released, the result was in the same direction and remained statistically significant (P=0.0354). When examining only nondrug studies, the statistical significance was diminished with the much smaller sample size, but again, results were in the same direction (see Table 3). In addition, all analyses were repeated recoding the two aforementioned studies supported by for-profit foundations established by pharmaceutical companies as being industry supported. Finally, all analyses were repeated after excluding four nonindustry studies, where the funding source was unspecified. Results from the final two analyses were virtually identical to those of other analysis strategies (data not shown).



The results of this study show that industry funded studies are associated with higher QR on average. In this relatively small sample of weight loss studies restricted to both those that were relatively large and long-term, it was difficult to disentangle the independent effects or association of industry funding from that of whether the study was a drug study, both associated with better reporting.79 Nevertheless, even when examining only nondrug studies, the numerically superior QR was found for industry-funded research, though the statistical significance was diminished. Future research should evaluate whether such associations exist for shorter-term studies and smaller studies.

For the scientific process to proceed effectively, it is important that all studies, both industry-funded and not, be reported with the highest quality possible. This is because it is through the comprehension of published research reports that the scientific community at large can judge the merits and import of the findings.10 If industry-funded reporting was of lower quality than nonindustry-funded reporting, this would exacerbate existing concerns about potential biases being created by industry funding.5 In contrast, our results suggest that, if anything, industry funding is associated with higher reporting quality. This suggests that, while continued efforts to improve reporting quality are warranted, such efforts should be directed at nonindustry-funded research at least as much as at industry-funded research. A benefit of the greater funding offered by industry, the greater scrutiny of industry, or perhaps greater concern or training of industry personnel for rigorous reporting may be an enhancement of the overall reporting quality in the literature, at least for long-term weight loss studies.



Competing interests

LT is the clinical trials mentor for the Canadian Institutes of Health Research. DBA has received grants, honoraria, consulting fees and donations from numerous food, pharmaceutical and other companies as well as nonprofit organizations and government agencies with interests in obesity-related issues. Ethical approval is not required.



  1. Fontanarosa PB, Flanagin A, DeAngelis CD. Reporting conflicts of interest, financial aspects of research, and role of sponsors in funded studies. JAMA 2005; 294: 110–111. | Article | PubMed | ChemPort |
  2. Rothman KJ, Evans S. Extra scrutiny for industry funded trials. BMJ 2005; 331: 1350–1351. | Article | PubMed |
  3. Nestle M. Food company sponsorship of nutrition research and professional activities: a conflict of interest? Public Health Nutr 2001; 4: 1015–1022. | Article | PubMed | ChemPort |
  4. Lesser LI, Ebbeling CB, Goozner M, Wypij D, Ludwig DS. Relationship between funding source and conclusion among nutrition-related scientific articles. PLoS Med 2007; 4: e5. | Article | PubMed |
  5. Levine J, Gussow JD, Hastings D, Eccher A. Authors' financial relationships with the food and beverage industry and their published positions on the fat substitute olestra. Am J Public Health 2003; 93: 664–669. | PubMed |
  6. Vartanian LR, Schwartz MB, Brownell KD. Effects of soft drink consumption on nutrition and health: a systematic review and meta-analysis. Am J Public Health 2007; 97: 667–675. | Article | PubMed |
  7. Reynolds T. Industry-funded versus publicly funded trials: are the standards the same? J Natl Cancer Inst 2001; 93: 1590–1592. | PubMed | ChemPort |
  8. Gardner A. Industry-funded breast cancer trials show more positive results. Int J Health Serv 2007; 37: 591–593. | Article | PubMed |
  9. Katan MB. Does industry sponsorship undermine the integrity of nutrition research? PLoS Med 2007; 4: e6. | Article | PubMed |
  10. Borgert CJ. Conflict of interest or contravention of science? Regul Toxicol Pharmacol 2007; 48: 4–5. | Article | PubMed |
  11. Rothman KJ. Conflict of interest. The new McCarthyism in science. JAMA 1993; 269: 2782–2784. | Article | PubMed | ChemPort |
  12. Cain DM, Loewenstein G, Moore DA. The dirt on coming clean: perverse effects of disclosing conflicts of interest. Journal of Legal Studies 2005; 34: 1–25. | Article |
  13. Bleich S, Blendon R, Adams A. Trust in scientific experts on obesity: implications for awareness and behavior change. Obesity 2007; 15: 2145–2156. | Article | PubMed |
  14. Klein S, Burke LE, Bray GA, Blair S, Allison DB, Pi-Sunyer X et al. Clinical implications of obesity with specific focus on cardiovascular disease; a statement for professionals from the American Heart Association Council on Nutrition, Physical Activity, and Metabolism: endorsed by the American College of Cardiology Foundation. Circulation 2004; 110: 2952–2967. | Article | PubMed | ISI |
  15. National Institute of Diabetes Digestive Kidney Disease. Obesity Clinical Research 2004, www.niddk.nih.gov/patient/patientobesity.htm.
  16. Lechner GW, Elliott DW. Comparison of weight loss after gastric exclusion and partitioning. Arch Surg 1983; 118: 685–692. | PubMed | ChemPort |
  17. Stamler R, Stamler J, Grimm R, Gosch FC, Elmer P, Dyer A et al. Nutritional therapy for high blood pressure. Final report of a four-year randomized controlled trial—the hypertension control program. JAMA 1987; 257: 1484–1491. | Article | PubMed | ChemPort |
  18. Fortmann SP, Haskell WL, Wood PD. Effects of weight loss on clinic and ambulatory blood pressure in normotensive men. Am J Cardiol 1988; 62: 89–93. | Article | PubMed | ChemPort |
  19. Perri MG, McAllister DA, Gange JJ, Jordan RC, McAdoo G, Nezu AM. Effects of four maintenance programs on the long-term management of obesity. J Consult Clin Psychol 1988; 56: 529–534. | Article | PubMed | ISI | ChemPort |
  20. King AC, Frey-Hewitt B, Dreon DM, Wood PD. Diet vs exercise in weight maintenance. The effects of minimal intervention strategies on long-term outcomes in men. Arch Intern Med 1989; 149: 2741–2746. | Article | PubMed | ChemPort |
  21. Hall JC, Watts JM, O'Brien PE, Dunstan RE, Walsh JF, Slavotinek AH et al. Gastric surgery for morbid obesity. The Adelaide study. Ann Surg 1990; 211: 419–427. | Article | PubMed | ChemPort |
  22. Eriksson KF, Lindgarde F. Prevention of type 2 (non-insulin-dependent) diabetes mellitus by diet and physical exercise. The 6-year Malmo feasibility study. Diabetologia 1991; 34: 891–898. | Article | PubMed | ISI | ChemPort |
  23. Jalkanen L. The effect of a weight reduction program on cardiovascular risk factors among overweight hypertensives in primary health care. Scand J Soc Med 1991; 19: 66–71. | PubMed | ChemPort |
  24. Sheppard L, Kristal AR, Kushi LH. Weight loss in women participating in a randomized trial of low-fat diets. Am J Clin Nutr 1991; 54: 821–828. | PubMed | ISI | ChemPort |
  25. Foreyt J, Goodrick G, Reeves R, Raynaud A. Response of free-living adults to behavioral treatment of obesity: attrition and compliance to exercise. Behav Ther 1993; 24: 659–669. | Article |
  26. Hakala P, Karvetti RL, Ronnemaa T. Group vs individual weight reduction programmes in the treatment of severe obesity—a five year follow-up study. Int J Obes Relat Metab Disord 1993; 17: 97–102. | PubMed | ChemPort |
  27. Hakala P. Weight reduction programmes at a rehabilitation centre and a health centre based on group counselling and individual support: short- and long-term follow-up study. Int J Obes Relat Metab Disord 1994; 18: 483–489. | PubMed | ChemPort |
  28. Wadden TA, Foster GD, Letizia KA. One-year behavioral treatment of obesity: comparison of moderate and severe caloric restriction and the effects of weight maintenance therapy. J Consult Clin Psychol 1994; 62: 165–171. | Article | PubMed | ChemPort |
  29. Wing RR, Blair E, Marcus M, Epstein LH, Harvey J. Year-long weight loss treatment for obese patients with type II diabetes: does including an intermittent very-low-calorie diet improve outcome? Am J Med 1994; 97: 354–362. | Article | PubMed | ChemPort |
  30. Jeffery RW, Hellerstedt WL, French SA, Baxter JE. A randomized trial of counseling for fat restriction versus calorie restriction in the treatment of obesity. Int J Obes Relat Metab Disord 1995; 19: 132–137. | PubMed | ChemPort |
  31. Manning RM, Jung RT, Leese GP, Newton RW. The comparison of four weight reduction strategies aimed at overweight diabetic patients. Diabet Med 1995; 12: 409–415. | PubMed | ChemPort |
  32. Pascale RW, Wing RR, Butler BA, Mullen M, Bononi P. Effects of a behavioral weight loss program stressing calorie restriction versus calorie plus fat restriction in obese individuals with NIDDM or a family history of diabetes. Diabetes Care 1995; 18: 1241–1248. | Article | PubMed | ChemPort |
  33. Fontbonne A, Charles MA, Juhan-Vague I, Bard JM, André P, Isnard F et al. The effect of metformin on the metabolic abnormalities associated with upper-body fat distribution. BIGPRO Study Group. Diabetes Care 1996; 19: 920–926. | Article | PubMed | ISI | ChemPort |
  34. Skender ML, Goodrick GK, Del Junco DJ, Reeves RS, Darnell L, Gotto AM et al. Comparison of 2-year weight loss trends in behavioral treatments of obesity: diet, exercise, and combination interventions. J Am Diet Assoc 1996; 96: 342–346. | Article | PubMed | ChemPort |
  35. Pasman WJ, Westerterp-Plantenga MS, Muls E, Vansant G, van Ree J, Saris WH. The effectiveness of long-term fibre supplementation on weight maintenance in weight-reduced women. Int J Obes Relat Metab Disord 1997; 21: 548–555. | Article | PubMed | ChemPort |
  36. Rossner S, Flaten H. VLCD versus LCD in long-term treatment of obesity. Int J Obes Relat Metab Disord 1997; 21: 22–26. | Article | PubMed | ChemPort |
  37. Ryttig KR, Flaten H, Rossner S. Long-term effects of a very low calorie diet (Nutrilett) in obesity treatment. A prospective, randomized, comparison between VLCD and a hypocaloric diet+behavior modification and their combination. Int J Obes Relat Metab Disord 1997; 21: 574–579. | Article | PubMed | ChemPort |
  38. Torgerson JS, Lissner L, Lindroos AK, Kruijer H, Sjostrom L. VLCD plus dietary and behavioural support versus support alone in the treatment of severe obesity. A randomised two-year clinical trial. Int J Obes Relat Metab Disord 1997; 21: 987–994. | Article | PubMed | ChemPort |
  39. Charles MA, Morange P, Eschwege E, Andre P, Vague P, Juhan-Vague I. Effect of weight change and metformin on fibrinolysis and the von Willebrand factor in obese nondiabetic subjects: the BIGPRO1 study. Biguanides and the prevention of the risk of obesity. Diabetes Care 1998; 21: 1967–1972. | Article | PubMed | ChemPort |
  40. Hollander PA, Elbein SC, Hirsch IB, Kelley D, McGill J, Taylor T et al. Role of orlistat in the treatment of obese patients with type 2 diabetes. A 1-year randomized double-blind study. Diabetes Care 1998; 21: 1288–1294. | Article | PubMed | ISI | ChemPort |
  41. Sjostrom L, Rissanen A, Andersen T, Boldrin M, Golay A, Koppeschaar HP et al. Randomised placebo-controlled trial of orlistat for weight loss and prevention of weight regain in obese patients. European Multicentre Orlistat Study Group. Lancet 1998; 352: 167–172. | Article | PubMed | ISI | ChemPort |
  42. Wing RR, Venditti E, Jakicic JM, Polley BA, Lang W. Lifestyle intervention in overweight individuals with a family history of diabetes. Diabetes Care 1998; 21: 350–359. | Article | PubMed | ChemPort |
  43. Andersen RE, Wadden TA, Bartlett SJ, Zemel B, Verde TJ, Franckowiak SC. Effects of lifestyle activity vs structured aerobic exercise in obese women: a randomized trial. JAMA 1999; 281: 335–340. | Article | PubMed | ChemPort |
  44. Davidson MH, Hauptman J, DiGirolamo M, Foreyt JP, Halsted CH, Heber D et al. Weight control and risk factor reduction in obese subjects treated for 2 years with orlistat: a randomized controlled trial. JAMA 1999; 281: 235–242. | Article | PubMed | ISI | ChemPort |
  45. Davidson MH, Hauptman J, DiGirolamo M, Foreyt JP, Halsted CH, Heber D et al. Weight control and risk factor reduction in obese subjects treated for 2 years with orlistat: a randomized controlled trial. JAMA 1999; 281: 235–242. | Article | PubMed | ISI | ChemPort |
  46. Ditschuneit HH, Flechtner-Mors M, Johnson TD, Adler G. Metabolic and weight-loss effects of a long-term dietary intervention in obese patients. Am J Clin Nutr 1999; 69: 198–204. | PubMed | ChemPort |
  47. Hill JO, Hauptman J, Anderson JW, Fujioka K, O'Neil PM, Smith DK et al. Orlistat, a lipase inhibitor, for weight maintenance after conventional dieting: a 1-y study. Am J Clin Nutr 1999; 69: 1108–1116. | PubMed | ISI | ChemPort |
  48. Jakicic JM, Winters C, Lang W, Wing RR. Effects of intermittent exercise and use of home exercise equipment on adherence, weight loss, and fitness in overweight women: a randomized trial. JAMA 1999; 282: 1554–1560. | Article | PubMed | ISI | ChemPort |
  49. Jones DW, Miller ME, Wofford MR, Anderson Jr DC, Cameron ME, Willoughby DL et al. The effect of weight loss intervention on antihypertensive medication requirements in the hypertension optimal treatment (HOT) study. Am J Hypertens 1999; 12: 1175–1180. | Article | PubMed | ChemPort |
  50. Torgerson JS, Agren L, Sjostrom L. Effects on body weight of strict or liberal adherence to an initial period of VLCD treatment. A randomised, one-year clinical trial of obese subjects. Int J Obes Relat Metab Disord 1999; 23: 190–197. | Article | PubMed | ChemPort |
  51. Donnelly JE, Jacobsen DJ, Heelan KS, Seip R, Smith S. The effects of 18 months of intermittent vs continuous exercise on aerobic capacity, body weight and composition, and metabolic fitness in previously sedentary, moderately obese females. Int J Obes Relat Metab Disord 2000; 24: 566–572. | Article | PubMed | ChemPort |
  52. Finer N, James WP, Kopelman PG, Lean ME, Williams G. One-year treatment of obesity: a randomized, double-blind, placebo-controlled, multicentre study of orlistat, a gastrointestinal lipase inhibitor. Int J Obes Relat Metab Disord 2000; 24: 306–313. | Article | PubMed | ChemPort |
  53. Flechtner-Mors M, Ditschuneit HH, Johnson TD, Suchard MA, Adler G. Metabolic and weight loss effects of long-term dietary intervention in obese patients: four-year results. Obes Res 2000; 8: 399–402. | Article | PubMed | ChemPort |
  54. Hauptman J, Lucas C, Boldrin MN, Collins H, Segal KR. Orlistat in the long-term treatment of obesity in primary care settings. Arch Fam Med 2000; 9: 160–167. | Article | PubMed | ChemPort |
  55. He J, Whelton PK, Appel LJ, Charleston J, Klag MJ. Long-term effects of weight loss and dietary sodium reduction on incidence of hypertension. Hypertension 2000; 35: 544–549. | PubMed | ISI | ChemPort |
  56. James WP, Astrup A, Finer N, Hilsted J, Kopelman P, Rössner S et al. Effect of sibutramine on weight maintenance after weight loss: a randomised trial. STORM study group. Sibutramine trial of obesity reduction and maintenance. Lancet 2000; 356: 2119–2125. | Article | PubMed | ISI | ChemPort |
  57. Lindgarde F. The effect of orlistat on body weight and coronary heart disease risk profile in obese patients: the Swedish Multimorbidity Study. J Intern Med 2000; 248: 245–254. | Article | PubMed | ChemPort |
  58. McMahon FG, Fujioka K, Singh BN, Mendel CM, Rowe E, Rolston K et al. Efficacy and safety of sibutramine in obese white and African American patients with hypertension: a 1-year, double-blind, placebo-controlled, multicenter trial. Arch Intern Med 2000; 160: 2185–2191. | Article | PubMed | ISI | ChemPort |
  59. Metz JA, Stern JS, Kris-Etherton P, Reusser ME, Morris CD, Hatton DC et al. A randomized trial of improved weight loss with a prepared meal plan in overweight and obese patients: impact on cardiovascular risk reduction. Arch Intern Med 2000; 160: 2150–2158. | Article | PubMed | ChemPort |
  60. Rossner S, Sjostrom L, Noack R, Meinders AE, Noseda G. Weight loss, weight maintenance, and improved cardiovascular risk factors after 2 years treatment with orlistat for obesity. European Orlistat Obesity Study Group. Obes Res 2000; 8: 49–61. | Article | PubMed | ChemPort |
  61. Ashley JM, St Jeor ST, Schrage JP, Perumean-Chaney SE, Gilbertson MC, McCall NL et al. Weight control in the physician's office. Arch Intern Med 2001; 161: 1599–1604. | Article | PubMed | ChemPort |
  62. Ditschuneit HH, Flechtner-Mors M. Value of structured meals for weight management: risk factors and long-term weight maintenance. Obes Res 2001; 9 (Suppl 4): 284S–289S. | Article | PubMed |
  63. McManus K, Antinoro L, Sacks F. A randomized controlled trial of a moderate-fat, low-energy diet compared with a low fat, low-energy diet for weight loss in overweight adults. Int J Obes Relat Metab Disord 2001; 25: 1503–1511. | Article | PubMed | ChemPort |
  64. Rothacker DQ, Staniszewski BA, Ellis PK. Liquid meal replacement vs traditional food: a potential model for women who cannot maintain eating habit change. J Am Diet Assoc 2001; 101: 345–347. | Article | PubMed | ChemPort |
  65. Smith IG, Goulder MA. Randomized placebo-controlled trial of long-term treatment with sibutramine in mild to moderate obesity. J Fam Pract 2001; 50: 505–512. | PubMed | ISI | ChemPort |
  66. Tuomilehto J, Lindstrom J, Eriksson JG, Valle TT, Hämäläinen H, Ilanne-Parikka P et al. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med 2001; 344: 1343–1350. | Article | PubMed | ISI | ChemPort |
  67. Bakris G, Calhoun D, Egan B, Hellmann C, Dolker M, Kingma I. Orlistat improves blood pressure control in obese subjects with treated but inadequately controlled hypertension. J Hypertens 2002; 20: 2257–2267. | Article | PubMed | ChemPort |
  68. Broom I, Wilding J, Stott P, Myers N. Randomised trial of the effect of orlistat on body weight and cardiovascular disease risk profile in obese patients: UK Multimorbidity Study. Int J Clin Pract 2002; 56: 494–499. | PubMed | ChemPort |
  69. Ditschuneit HH, Frier HI, Flechtner-Mors M. Lipoprotein responses to weight loss and weight maintenance in high-risk obese subjects. Eur J Clin Nutr 2002; 56: 264–270. | Article | PubMed | ChemPort |
  70. Hanefeld M, Sachse G. The effects of orlistat on body weight and glycaemic control in overweight patients with type 2 diabetes: a randomized, placebo-controlled trial. Diabetes Obes Metab 2002; 4: 415–423. | Article | PubMed | ISI | ChemPort |
  71. Kelley DE, Bray GA, Pi-Sunyer FX, Klein S, Hill J, Miles J et al. Clinical efficacy of orlistat therapy in overweight and obese patients with insulin-treated type 2 diabetes: a 1-year randomized controlled trial. Diabetes Care 2002; 25: 1033–1041. | Article | PubMed | ChemPort |
  72. Knowler WC, Barrett-Connor E, Fowler SE, Hamman RF, Lachin JM, Walker EA et al. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med 2002; 346: 393–403. | Article | PubMed | ISI | ChemPort |
  73. McMahon FG, Weinstein SP, Rowe E, Ernst KR, Johnson F, Fujioka K. Sibutramine is safe and effective for weight loss in obese patients whose hypertension is well controlled with angiotensin-converting enzyme inhibitors. J Hum Hypertens 2002; 16: 5–11. | Article | PubMed | ChemPort |
  74. Miles JM, Leiter L, Hollander P, Wadden T, Anderson JW, Doyle M et al. Effect of orlistat in overweight and obese patients with type 2 diabetes treated with metformin. Diabetes Care 2002; 25: 1123–1128. | Article | PubMed | ChemPort |
  75. Donnelly JE, Hill JO, Jacobsen DJ, Potteiger J, Sullivan DK, Johnson SL et al. Effects of a 16-month randomized controlled exercise trial on body weight and composition in young, overweight men and women: the Midwest Exercise Trial. Arch Intern Med 2003; 163: 1343–1350. | Article | PubMed | ISI |
  76. Irwin ML, Yasui Y, Ulrich CM, Bowen D, Rudolph RE, Schwartz RS et al. Effect of exercise on total and intra-abdominal body fat in postmenopausal women: a randomized controlled trial. JAMA 2003; 289: 323–330. | Article | PubMed | ISI |
  77. Torgerson JS, Hauptman J, Boldrin MN, Sjostrom L. XENical in the prevention of diabetes in obese subjects (XENDOS) study: a randomized study of orlistat as an adjunct to lifestyle changes for the prevention of type 2 diabetes in obese patients. Diabetes Care 2004; 27: 155–161. | Article | PubMed | ISI | ChemPort |
  78. Nicklas BJ, Ambrosius W, Messier SP, Miller GD, Penninx BW, Loeser RF et al. Diet-induced weight loss, exercise, and chronic inflammation in older, obese adults: a randomized controlled clinical trial. Am J Clin Nutr 2004; 79: 544–551. | PubMed | ChemPort |
  79. Thabane L, Chu R, Cuddy K, Douketis J. What is the quality of reporting in weight loss intervention studies? A systematic review of randomized controlled trials. Int J Obes 2007; 31: 1554–1559. | Article | ChemPort |
  80. Altman DG, Schulz KF, Moher D, Egger M, Davidoff F, Elbourne D et al., for the CONSORT group. The revised CONSORT statement for reporting randomized trials: explanation and elaboration. Ann Intern Med 2001; 134: 663–694. | PubMed | ISI | ChemPort |
  81. Consolidated Standards of Reporting. CONSORT: transparent reporting of trials, 2008, www.consort-statement.org.
  82. Huwiler-Müntener K, Jüni P, Junker C, Egger M. Quality of reporting of randomized trials as a measure of methodologic quality. JAMA 2002; 278: 2801–2804. | Article |
  83. Olivo SA, Macedo LG, Gadotti IC, Fuentes J, Stanton T, Magee DJ. Scales to assess the quality of randomized controlled trials: a systematic review. Phys Ther 2008; 88: 1–20.
  84. Hanley JA, Negassa A, Edwardes MD, Forrester JE. Statistical analysis of correlated data using generalized estimating equations: an orientation. Am J Epidemiol 2003; 157: 364–375. | Article | PubMed |


We are grateful to Dr Stacey Cofield for her helpful comments on the statistical analysis. OT participated in the coding of the data, helped to interpret the results, and participated in drafting the paper. LT, JD and RC collected the initial sample of studies, coded the QR scores, advised on the conduct of analyses, and edited the paper. AW participated in the data analysis and interpretation of results.DBA conceived the project, participated in the coding of the data, analysed the data and led the writing of the paper. This research was supported in part by NIH grant P30DK056336.

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