Posts Tagged ‘statistics’

Research

September 26th, 2009

                                                                                                                                                                                                                                                                              

Research is fundamental to understanding, preventing and treating obesity. And yet research reports are often not accepted by the public or policy-makers. One reason is that almost every adult is their own self-study of weight control. A study might have the most precise protocol, a powerful sample size and control for a variety of factors but if it does not comport with what “I” experience, I am not likely to believe it. But research itself in obesity is not without its difficulties. Many studies are ‘underpowered”, i.e. they have too few subjects to draw a conclusion from. That is why many preliminary studies do not pan out in larger tests. Also, in many cases, especially in drug trials, researchers try to remove “confounders” from the test subjects so they can see if there is an effect of the drug. That means that many patients who are sick, smoke, take other drugs, etc. are excluded from the trial. When the drug, for example, gets used by a more ‘real-world’ sample, the effects sometimes vanish. Studies that rely on self-reported weights or dietary recall or physical activity diaries are sometimes less reliable than studies where a more objective measurement is needed. Self-reported weight and height — Rowland 52 (6): 1125 — American Journal of Clinical Nutrition and COMPARISON OF SELF-REPORTED AND MEASURED HEIGHT AND WEIGHT — PALTA et al. 115 (2): 223 — American Journal of Epidemiology

There also may be a bias from the funding source (See Conflict of Interest in Medical Research, Education, and Practice – Institute of Medicine, Relationship between funding source and conclusion…[PLoS Med. 2007] – PubMed Result, Scope and impact of financial conflicts of interes…[JAMA. 2003 Jan 22-29] – PubMed Result) or a selection of participants which may skew the results one way or another. Currently, there is a lot of concern about ghost written scientific articles. Ghostwriting Widespread in Medical Journals, Study Says – NYTimes.com

What’s a reader to do? The first is to read skeptically. The second is to go to several different papers or research articles. If different authors appear to agree upon key points, chances are that they are on to something. Remember, extraordinary claims require extraordinary evidence. Research is a communications process among researchers and it should be thought of as a dialogue to which we can all listen.

Many readers may find useful this site, The Little Handbook of Statistical Practice. It is a handy guide to understanding some of the statistical issues involved…like association is not causation.

Research is key. If you are interested in furthering research, you should look into participating in a clinical research activity. To see what clinical trials are underway in obesity research, see www.ClinicalTrials.gov/Search of: Open Studies | “Obesity” – List Results – ClinicalTrials.gov

A major NIH initiative is support for Obesity and Nutrition Research Centers. In addition to the research they carry out, these centers are critical training facilities for new investigators exploring obesity. Most have their own websites which can provide additional, valuable information. Their sites may provide you with helpful information. Also included are their annual reports.

  1. University of Alabama Nutrition & Obesity Research Center | Nutrition & Obesity Research Center Annual report at http://www2.niddk.nih.gov/NR/rdonlyres/E6AE7940-23AC-402E-BCAC-D4F11A9213B0/0/Alabama.pdf
  2. University of Colorado at Denver and Health Science Center. No website. Annual report at http://www2.niddk.nih.gov/NR/rdonlyres/061BCC83-261E-4B39-95CC-226C97B03ED2/0/Colorado.pdf
  3. Pennington Biomedical Research Center PBRC – Nutrition Obesity Research Center. Annual report at: http://www2.niddk.nih.gov/NR/rdonlyres/841B5FA5-7AC1-4DDB-AD3F-300B94468560/0/Pennington.pdf
  4. University of Maryland, http://medschool.umaryland.edu/cnru/index.asp. Annual report at http://www2.niddk.nih.gov/NR/rdonlyres/BF6E7D31-948E-450A-AFF5-B863FF427B24/0/Maryland.pdf
  5. Boston, MA  Boston Obesity Nutrition Research Center Annual report at: http://www2.niddk.nih.gov/NR/rdonlyres/83F114DD-E707-4623-BA20-BCE02C33ADF6/0/Boston.pdf
  6. Harvard,MA,  no website. Annual report at: http://www2.niddk.nih.gov/NR/rdonlyres/9AFA2465-42C0-40CB-87DB-35813E80A978/0/Harvard.pdf
  7. University of Minnesota. Minnesota Obesity Center | College of Food, Agricultural and Natural Resource Sciences | University of Minnesota Annual Report at http://www2.niddk.nih.gov/NR/rdonlyres/78A3842A-030C-45F7-856E-5C27BE202C15/0/Minnesota.pdf
  8. Washington University, Missouri http://www2.niddk.nih.gov/NR/rdonlyres/BB5BBA2D-AA63-4B73-99D6-56741BB220B3/0/WashingtonUniversity.pdf
  9. Columbia/Cornell, New York, NY http://www.nyorc.org/favicon.ico Annual Report at: http://www2.niddk.nih.gov/NR/rdonlyres/28E027FF-5212-4F15-960B-4E5C84FF952A/0/NewYork.pdf
  10. University of North Carolina at Chapel Hill. No website. Annual report at: http://www2.niddk.nih.gov/NR/rdonlyres/8836D29C-0AF8-4C6A-914E-9D12828A1A82/0/NorthCarolina.pdf
  11. University of Pittsburgh. No web site. Annual Report at: http://www2.niddk.nih.gov/NR/rdonlyres/C8B65B24-EE7A-495C-B441-05EAD3372283/0/Pittsburgh.pdf
  12. University of Washington. http://depts.washington.edu/favicon.ico. Annual Report at: http://www2.niddk.nih.gov/NR/rdonlyres/739D3F88-98FE-4733-9D31-6BB81A1DA915/0/Washington.pdf

 

New Studies , updated October 16, 2009

Obesity driven GERD drives up health care visits Trends in Gastroesophageal Reflux Disease as Measu…[Dig Dis Sci. 2009] – PubMed Result

Psychiatrists survey on attitudes to obese patients Psychiatrists’ perceptions and practices in treati…[Acad Psychiatry. 2009 Sep-Oct] – PubMed Result

More evidence for role of FTO gene in obesity via loss of control and selecting diet high in fat The FTO gene rs9939609 obesity-risk allele and los…[Am J Clin Nutr. 2009] – PubMed Result

AHRQ summarizes evidence on breast-feeding, finds reduced risk of obesity, type 2 diabetes A Summary of the Agency for Healthcare Research an…[Breastfeed Med. 2009] – PubMed Result

Weight loss after bariatric surgery may be explained by changes in gut hormones controlling appetite. The Gut Hormone Response Following Roux-en-Y Gastr…[Obes Surg. 2009] – PubMed Result