Study Links Low-level Toxicants to Liver Disease
A new study is the first to show that there is a previously unrecognized role for environmental pollution in liver disease in the general U.S. adult population. This work builds upon the groups' previous research demonstrating liver disease in highly-exposed chemical workers.
The study was presented during Digestive Disease Week® 2009, the largest international gathering of physicians and researchers in the fields of gastroenterology, hepatology, endoscopy, and gastrointestinal surgery.
"Our study found that greater than one in three U.S. adults had liver disease, even after excluding those with traditional risk factors such as alcoholism and viral hepatitis," said Matthew Cave, M.D., assistant professor, department of medicine, division of gastroenterology and hepatology at the University of Louisville. "Our study shows that some of these cases may be attributable to environmental pollution, even after adjusting for obesity, which is another major risk factor for liver disease."
Using the 2003-2004 National Health and Nutrition Examination Survey (NHANES), researchers from the University of Louisville study examined chronic low-level exposure to 111 common pollutants including lead, mercury, polychlorinated biphenyls, and pesticides and their association with otherwise unexplained liver disease in adults. The specific pollutants included were detectable in 60 percent or more of the 4,500 study subjects.
Cave added that this analysis used only the ALT liver enzyme as a marker of liver injury and cautioned that this associative study does not prove causality. However, he added that previous animal studies do suggest causality for many of these chemicals. Dr. Cave and his co-authors also plan to examine the additive effects of environmental pollutants on liver disease in children and adults with risk factors including obesity, viral hepatitis, and alcoholism in the NHANES population.