Padilla Article on Pollutants Causing Weight Gain Wins International Award
By Jim Raper
Miguel A. Padilla, assistant professor of quantitative psychology and mathematics and statistics at Old Dominion, is an author of a research article on the connection between environmental pollutants and weight gain in humans that has won an international best paper award.
Mai A. Elobeid, David B. Allison and David W. Brock of the University of Alabama at Birmingham, and Douglas M. Ruden of Wayne State University, are also authors of the paper titled "Endocrine Disruptors and Obesity: An Examination of Selected Persistent Organic Pollutants in the NHANES 1999-2002 Data."
The researchers' work received the top prize in the "articles" category of the International Journal of Environmental Research and Public Health (IJERPH) Best Paper Award 2014. The journal is published online monthly by the Multidisciplinary Digital Publishing Institute, an open-access publisher headquartered in Basel, Switzerland.
The award-winning article investigates the association among body mass index (BMI), waist circumference (WC) and selected persistent organic pollutants (POPs) via multiple linear regressions, using data from the National Health and Nutrition Examination Survey (NHANES) between 1999-2002.
Judges praised the article as an "innovative approach to highlight the role played by human exposure to endocrine-disrupting chemicals on the etiology and prevalence of obesity."
Articles that appeared in IJERPH between 2010 and early this year were eligible for the 2014 Best Paper Award. The winning paper by Padilla and colleagues appeared in the journal in 2010. See the article at http://www.mdpi.com/1660-4601/7/7/2988.
Padilla directs The Omega Laboratory at ODU, an all-purpose quantitative methodology lab working in the development, exploration and application of general quantitative methods for the sciences. Because of the adaptability of quantitative methodology, the lab operates at the intersection of many fields - psychology, psychometrics, sociology, education, program evaluation, medicine and others.
Quantitative analysis of NHANES data - including general-population body weight and serum tests for POPs - gave Padilla and the co-authors some of the clearest evidence yet that environmental pollutants are endocrine-disrupting chemicals in humans that can cause perturbations in endogenous hormonal regulation affecting weight gain.
These persistent pollutants in the environment include dioxins from the burning of waste and various pesticides. The POPs evaluated by the researchers were present in 80 percent of the NHANES subjects.
From their research and from other studies, the authors conclude: "Persistent organic pollutants, synthetic and industrial chemicals, appear to cause weight gain by interfering with most of the different elements that comprise the human weight control system. In particular, these chemicals have been shown to disrupt major weight controlling hormones, such as thyroid hormones, estrogens, testosterone, corticosteroids, insulin, growth hormone, and leptin and to alter levels of, and sensitivity to, neurotransmitters (in particular dopamine, noradrenaline, and serotonin). They interfere with many metabolic processes and cause widespread damage to body tissues and cardiovascular disease. This interference may result in changes in appetite, in food efficiency, and in fat, carbohydrate, and protein metabolism. The desire, and ability, to exercise also may be affected. These changes have been thought to be responsible for increases in body weight."
They added: "To the extent that our associations can be speculated to represent causation, on average, one of the toxic effects of these chemicals appears to be weight gain. Unlike the well-known weight loss resulting from high exposure to POPs, this weight gain may occur at much lower levels of exposure, levels which fail to make animals or humans obviously ill."
Interestingly, one pesticide, oxychlordane, was found to be associated with BMI increases in males but BMI decreases in females. Conversely, another pesticide, DTT, was associated with WC decreases in males but WC increases in females. "A speculation, which needs further validation, is that this might have to do with hormonally-directed differences in fat storage in men versus women. Men tend to be 'apples' and store their fat in the waist, whereas females tend to be 'pears' and store their fat in their hips. POPs might be affecting this process," the paper states.
Padilla, who received a Ph.D. in research and evaluation methodology from the University of Florida in 2005, completed a postdoctoral fellowship in biostatistics at the University of Alabama in Birmingham before joining ODU in 2008.