“Numerous studies have linked arsenic to many types of cancer including lung; and studies in Chile, Taiwan and Bangladesh, where high levels of arsenic in drinking water are common, have established a clear association between arsenic and lung cancer,” Dr. Guo said. “But until now little has been known about the effect chronic low-level arsenic exposure has on lung cancer incidence rates in this country.”
Another aspect of the WVU study was to better understand the effect of arsenic on lung cancer rates independent of and in conjunction with smoking – the leading cause of lung cancer in the U.S.
Researchers developed an epidemiology model based on national statistics on arsenic stream sediment and soil concentration, estimates on smoking prevalence and income levels in more than 700 counties in 12 states.
“Our findings revealed that exposure to arsenic likely contributed to significantly higher lung cancer incidence rates in the U.S. and may contribute to more than 5,000 lung cancer cases per year in the U.S,” Guo said.
The model also suggests that the higher lung cancer incidence rate in West Virginia and Kentucky is strongly associated with higher arsenic exposure and smoking prevalence as well as lower income in those states.
“These findings indicate that environmental exposure to arsenic may have a significantly larger effect on lung cancer incidence in the U.S. than previously thought. Even though the concentration of arsenic is lower here compared to some countries, it still is toxic and poses a significant health risk,” Guo said. “In addition, smoking prevalence appears to strengthen the effect that arsenic exposure has on lung cancer incidence, resulting in an excess of lung cancer cases in areas with high levels of arsenic exposure and smoking.”
Researchers are seeking federal funding to support their work on the effect of heavy metals on cancer. In the meantime they are looking at the mechanisms of heavy metal on carcinogenesis and hope to identify biomarkers for early detection of heavy metal induced lung cancer.
The study is published online at http://dx.plos.org/10.1371/journal.pone.0025886.
For more information: Amy Johns, HSC News Service, 304-293-7087