Sunday, February 14, 2010

News Briefs: February 14, 2010

No Conclusion Reached on Insulin’s Relation with Cancer Risk

Priya Larson

If you are diabetic and take insulin, you might be concerned about recent reports linking insulin use with cancer. However, you should know that such reports contain limitations. No existing study has proven whether the intake of insulin, or insulin analogs, reduces increases or has no effect on cancer risk.

Diabetes alone is a risk factor for cancer, so it is difficult isolate insulin as cancer’s cause. However, in patients with insulin resistance, taking the hormone can feed pre-existing cancerous cells. Insulin lowers glucose levels in blood by binding to receptors on the cell membrane, which are abundant on cancer cells, promoting tumor growth. However, no evidence shows that insulin use causes the establishment of new cancer cells. Literature also suggests that insulin can actually lower cancer risk, because when it decreases glucose levels, cell glycolysis cannot occur. Cancer cells depend on the glycolytic pathway to generate energy (ATP) and cell reproduction materials (amino acids, nucleotides, and lipids). With insulin, there is less glucose and less hospitable conditions for cancer cells.

There is literature claiming insulin both heightens and reduces the risk of incident cancer. Furthermore, some studies even show no conclusive relationship. Multiple factors, such as dysglycemia, obesity, and insulin intolerance, might promote cancer growth. Thus, we cannot accept any hypothesis that insists on a unidirectional relationship between insulin use and cancer risk.

Reference: JAMA.2010; 303: 446-447.

Image: Insulin Syringes. Available here.

Questioning the Benefits of Vertebroplasty

Yang (Karen) Chen

Vertebroplasty, a minimally-invasive procedure that prevents spine repair patients from depending on intravenous narcotics and bed rest, has previously been thought to have largely beneficial effects. However, two recently published, randomized control studies published in the New England Journal of Medicine (NEJM) report evidence against these preconceptions and have brought on a heated debate among physicians. The studies found that vertebroplasty for osteoporotic vertebral compression fractures did not yield significantly better results in terms of disability or short-term pain relief than sham procedures. Many physicians, particularly radiologists, are skeptical about the new findings. One of the radiologists’ main concerns is that insurance companies will use the trials to justify ending coverage of vertebroplasy for osteoporotic spinal fractures. Their reactions are not surprising, as radiologists are vested in this procedure and make a living performing them. Spine physicians including Drs. J. Kevin McGraw and Christopher Bono insist that the studies are too flawed to serve as the evidence base for clinical practice. Critics like them argue that the two studies had too few patients, failed to meet enrollment, and included patients with milder degrees of pain and disability than those usually treated. Although the NEJM studies have an effect in promoting more research by increasing the level of uncertainty about vertebroplasty, it is doubtful that they alone will make any formal changes.

Reference: Gever, John . (2010, February 4). Fractured Evidence: Spine Repair Debate Heats Up. MedPage Today. Retrieved February 7, 2010 from

Reevaluating the Mental State of ‘Vegetative’ Patients

Soumil Mhaskar

States of persistent unconsciousness have always been a mystery for the medical community. However, new findings at a clinic in Liège, Belgium may shed some light on this medical enigma. One of the clinic’s patients has showed traces of brain activity in response to questions by doctors. The ‘vegetative’ patient was able to show thought traces that indicated “yes” or “no” answers. This startling discovery may have broad implications and could possibly raise several ethical issues.

Scientific experts have swiftly responded to this report. The New England Journal of medicine posted online that they believe this finding does not suggest that unresponsive patients will get better and be able to communicate. Moreover, they believe that this ability to respond to doctor’s commands is rare within ‘vegetative patients.’ Furthermore, this does not apply to oxygen-deprived patients, such as Terri Schiavo, who was the center of the highly publicized battle over patients’ rights.

This is not to say that this finding is not important. Many experts believe that this has exposed the current flaws in diagnosing the mental states of patients. As stated by Dr. James L. Bernat, a professor of neurology at Dartmouth Medical School, “I’m convinced as an observer that in these few cases, the M.R.I. technique, in these researchers’ hands, gives us a window into human consciousness that we have not had and that potentially adds to the clinical exam we currently use.”

This discovery corroborates recent research where ‘vegetative’ patients showed increased brain activity in the corresponding regions of the brain when asked to think about motor movement and spatial recognition. Adrian M. Owen, a neuroscientist at the Medical Research Council in Cambridge, England, who co-authored the paper, said that the patient was able to respond “yes” or “no” to biographical questions. This ability to answer polar questions such as these raises the possibility of asking the patient whether he or she wants to live. Experts are not sure what the long-term consequences of this might be, but some are saying that a simple “yes” or “no” is not sufficient. Thus, further research is needed on this matter before concrete conclusions can be reached.

Reference: Carey, Benedict. (2010, February 3). Trace of Thought Is Found in ‘Vegetative’ Patient. The New York Times. Retrieved February 7, 2010 from

Post-Polio Syndrome: The Irony Afflicting Survivors

Lori Fingerhut

With the introduction of the polio vaccine in the 1950s, the polio virus no longer presents a threat to the health and welfare of Americans. However, for those who fell victim to the disease’s crippling effects the memory is still alive and well. A year ago, Becky Lloyd, a researcher at the University of Utah’s American West Center, took on the challenge of compiling an oral history of those who suffered from polio. What she found is that polio still affects these individuals physically thirty to more than fifty years after most had the disease. After suffering polio, the body’s muscles and nerves are forced to compensate for the breakdown that occurred while the virus was active. Known as post-polio syndrome, the bodies of polio survivors are wearing out more quickly than those who did not suffer from polio as a child. In an unfortunate irony, those who worked the hardest to hide their polio and look normal are those who have shown the more dramatic cases of post-polio syndrome.

With the passing of time has also come the passing of many polio survivors. Money for post-polio research, and doctors who have experienced polio themselves, are becoming less and less. Remembering their experiences, such as through the Utah project, has allowed many polio survivors to find inner strength and to accept the effects of post-polio syndrome.

Reference: Johnson, Kirk. (2010, February 2). For Some Survivors, Polio Won’t Fade Into the Past. The New York Times. Retrieved February 7, 2010 from

Studies Report Conflicting Results in Reducing Dietary Sodium

Virginia Saurman

Michael H. Alderman, MD argues that recommendations on reduced daily sodium intake ought to be reevaluated before being pursued with vigor. While those in favor of its reduction point to clear evidence of lowered blood pressure, which can prevent stroke and heart attacks.

However, Randomized Clinical Trials with morbidity and mortality due to heart failure are the only such tests available to analyze the effects of different sodium intakes. Restricted sodium intake of 1840 mg /day significantly increased mortality and hospitalization compared with those with 2760 mg/day. The US average is 2921 mg/day. However, since the study dealt only with heart failure patients, the data is irrelevant for public health purposes.

At least thirteen observational studies have yielded conflicting results. Additionally, given the different populations, diets, and data collection methods and conflicting results, there are multiple hypotheses available. Further observational studies and debate are unlikely to clarify the issue any further. However, the real issue is the limitations of observational studies for dietary questions such as sodium intake and observational studies have no way of determining the effects of a change in diet; what is needed is a randomized clinical trial.

Given the current dilemma, there are two ways of dealing with the recommendation for sodium reduction: cut all sodium levels in prepared foods, or large-scale, rigorous, population-based, clinical trials. Advocates of sodium reduction in prepared foods argue that despite the heterogeneity of blood pressure response to lowered sodium, the benefits outweigh the risks. The clinical trial route would take longer and require thousands of patients, but results in more precision and scientific credibility to help answer the question of sodium levels. Additionally, the human and material risks would be vastly smaller than an across the board sodium reduction. Both methods are experimental given the lack of definitive evidence. Regardless of the route taken, caution is a necessity.

Reference: JAMA.2010; 303: 448-449.

Eriene-Heidi Sidhom is the 2009 - 2010 News and Analysis Editor.
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