Media & Publications
Barry Braun, Associate Professor of Kinesiology, and colleagues recently reported unexpected results in a study suggesting that exercise and one of the most commonly prescribed drugs for diabetes, metformin, each improves insulin resistance when used alone...but when used together, metformin actually blunted the full effect of a 12-week exercise program in pre-diabetic men and women.
Insulin resistance is the root problem in pre-diabetes, a condition that often leads to Type 2 diabetes, the increasingly common disease in which the natural hormone, insulin, becomes less effective at lowering blood sugar, leading to a range of adverse health effects such as eye and nerve damage. An estimated 26 million Americans have diabetes and 69 million are pre-diabetic.
In studies funded by the American Diabetes Association and the National Institutes of Health, Dr. Braun expected to show that combining drug treatment and exercise would help to regulate blood sugar better than either treatment alone. However, the surprising result was that "exercise combined with metformin was not better than exercise alone and it might even be worse," says Dr. Braun. "We're now trying to understand the mechanisms to explain this." Findings appear in a recent issue of Diabetes Care.
Dr. Braun, with his former doctoral student Steven Malin, and colleagues recruited 32 men and women with pre-diabetes and assigned them to one of four groups, 8 per group, and asked them to follow a 12-week course of exercise, exercise plus the drug metformin, metformin alone, or no treatment. The researchers measured insulin sensitivity at baseline and again after the 12-week treatment period in the double-blind study. Exercise training consisted of 60- to 75-minutes of aerobic exercise and resistance training three times per week.
All treatment groups had improved insulin sensitivity but only the two metformin groups lost weight after 12 weeks of exercise training, metformin alone or the two combined. But as noted, adding metformin to exercise did not enhance the effects of exercise training. Rather, adding metformin seems to have blunted the positive effect of exercise by 25 to 30 percent. This is probably enough to have clinical relevance, the researchers point out.
Dr. Braun and colleagues speculate that differences in outcome for the exercise-only and the exercise-plus-metformin group may be related to differences in how muscles, the liver and the insulin-producing cells of the pancreas adapt to exercise training when metformin is present. They are now turning their attention to investigate an exercise/medication combination that more effectively targets the liver and the pancreas in the hope of creating a more effective exercise drug to prevent the transition from pre-diabetes to Type 2 diabetes.
It's high time for industry and governments to improve the way nuclear health risks are estimated using more evidence-based risk assessment, according to Edward Calabrese, Professor of Environmental Health Sciences.
From the Chernobyl nuclear accident in 1986 to this year's incident at Fukushima, says Dr. Calabrese, governments and the nuclear industry have failed to address serious data gaps and untested assumptions guiding exposure limits to Cesium (Cs)-137 released.
Dr. Calabrese's commentary, "Improving the scientific foundations for estimating health risks from the Fukushima incident," is included in a Nov. 21, 2011 special issue of Proceedings of the National Academy of Sciences devoted to documenting the estimated release magnitude and distribution of Cs-137 from the nuclear incident in Japan after the March earthquake and tsunami.
"It is also critical that the linear, no-threshold (LNT) model and the alternative models, such as the threshold and hormesis models, be objectively assessed so that society can be guided by scientific data and validated models rather than ideological perspectives that stealthily infected the risk assessment process for ionizing radiation and carcinogenic chemicals," he states.
After his career-long study of hormesis persuaded Dr. Calabrese that low doses of some chemicals and radiation are benign to humans or even helpful, he says a "comprehensive reappraisal" of the LNT model for cancer risk assessment is urgently needed. He argues that the LNT model was incorporated into U.S. regulatory policy in the 1950s based on faulty assumptions. Its use has become codified in regulatory agencies despite its "questionable scientific foundations," he says.
In addition to over-reliance on the LNT, Dr. Calabrese contends, regulators also place too much weight on assumptions about the ingestion of contaminants in soil by children, in particular dioxin, which date from the 1980s at Times Beach, Mo. "Subsequent soil ingestion studies in children would prove this default exposure assumption represented a massive overestimation, being too high by 200-fold," he points out. Without follow-up studies to provide more accurate data, "costs of clean up at Times Beach alone would have been many billions of dollars more," he adds, illustrating that non-validated assumptions can markedly affect the risk assessment outcome.
Dr. Calabrese also criticizes expert advisory groups and government agencies for rendering exposure guidance "based on hypothetical risks of Cs-137" and using highly precise estimates that give "a false impression of considerable accuracy." In fact, he says, acceptable levels of Cs-137 exposure in Japan are more than three times higher than levels permitted in the Ukraine, while both are probably based on "little independent analysis."
Overall, precautionary urges that pressure regulators to rely on the most conservative option have a downside, in Dr. Calabrese's opinion. They lead to multiplicative protective factors that can add substantially to remediation costs "without validated assurances of accompanying benefit."
Lower is not always better when it comes to enhancing public health, he says. "It is time for the responsible governmental and industrial organizations to develop a practical plan to fill important data gaps."
Dominique Williams, MD, a graduate student in the online MPH in Nutrition program, recently published "Obesity in Children and Adolescents: Identifying Eating Disorders" - the feature article in the December 2011 issue of Consultant for Pediatricians. Dr. Williams is an assistant professor of pediatrics at Eastern Virginia Medical School, fellow of the American Academy of Pediatrics, and medical director of the Healthy You for Life Program at Children's Hospital of The King's Daughters in Norfolk, VA. The journal can be found online at http://www.pediatricsconsultant360.com/.
Fellow online MPH in Nutrition student Joan Temmerman, MD, also published this year. Her article titled "Vitamin D and Cardiovascular Disease" appeared in the Journal of the American College of Nutrition this past June. (Click here to view the abstract.) The article was a direct result of an assignment for her Nutritional Assessment course. Dr. Temmerman credits her instructor, Dr. Nancy Munoz, for her encouragement to submit the article for publication, as well as online MPH in Nutrition program coordinator Patricia Beffa-Negrini for her support. Dr. Temmerman is a physician in the Division of Gastroenterology and Hepatology, Department of Medicine at the Indiana University School of Medicine.
William H. Wiist, clinical professor in the online MPH in Public Health Practice program, has authored a chapter in the new global chronic disease book Sick Societies: Responding to the global challenge of chronic disease, edited by David Stuckler and Karen Siegler. The book, published by Oxford University Press, examines the prevention and control of chronic diseases from epidemiologic, economic, prevention/management, and governance perspectives and covers both the developing and the developed world.
Wiist contributed a chapter titled “The corporate play book, health, and democracy: The snack food and beverage industry’s tactics in context.” The chapter is juxtaposed with the chapter written by employees of PepsiCo.
For more information, visit the Oxford University Press website.
Dr. Marya Zilberberg, adjunct Associate Professor of Epidemiology, discusses in a recent Reuters article that an increasing number of elderly dementia patients are being hospitalized, putting a strain on both the health care system and the patients themselves.
To read the article, click here.
Reed Mangels, Lecturer in the Department of Nutrition, has authored The Everything Vegan Pregnancy Book. The book "answers any question that a pregnant woman and her family could possibly have."
A review of the book appears here.
Richard Peltier, Assistant Professor of Environmental Health Sciences, joined Anika James, environmental advocate for Environmental Massachusetts, on The Bill Newman Show on WHMP radio to talk about the smog problem in Springfield, deemed the smoggiest metropolitan area in Massachusetts.
To listen to the full podcast of the interview, click here.
Barry Braun, Associate Professor of Kinesiology, is quoted in the October 2011 issue of Self magazine. In an article titled "The Truth About Exercise and Appetite," he describes how physical activity may increase appetite-stimulating hormones, especially among women.
The article can be read in full here.
Ivan Oransky, co-instructor in the online MPH in PHP program, discusses Retraction Watch, the blog he co-founded with Adam Marcus, on NPR's "On the Media."
The segment can be heard in full at the NPR website.