October 12, 2005 – Researchers at Columbia University's Mailman School of Public Health have been awarded a $10 million grant from National Cancer Institute (NCI) to conduct a chemoprevention trial of 4,500 adults in Bangladesh who were exposed to very high levels of arsenic in drinking water. The research will focus on reducing the high rates of skin cancer and other cancers in this population, which are believed to be a result of arsenic exposure.
The Mailman School is combining its research efforts with the International Center for Diarrheal Disease Research, Bangladesh, Centre for Health and Population Research, an internationally renowned public health research institution based in Bangladesh, to investigate whether vitamin E and/or selenium has a beneficial effect in reducing skin and other cancers.
The study led by Habibul Ahsan, MD, MMedSc, associate professor and director of the Center for Genetics in Epidemiology in the Department of Epidemiology at the Mailman School of Public Health, also will be coordinated by the Herbert Irving Comprehensive Cancer Center (HICCC) at Columbia University Medical Center and NewYork-Presbyterian Hospital. The HICCC is one of only three NIH-designated Comprehensive Cancer Centers in New York State.
Skin cancer is the most common arsenic-related cancer. Nearly 100 million people in the world are chronically exposed to arsenic and, therefore, are at increased risk of skin and other arsenic-induced cancers. Arsenic has been shown to produce mutations in cancer causing genes, but it is also believed that antioxidants, such as vitamin E and selenium, may impede the carcinogenic effects.
"If the research confirms that supplementing one's diet with vitamin E and/or selenium, has an impact on changes of pre-malignant skin lesions and its progression to skin cancer, the results could provide essential data on potential low-cost interventions for reducing the cancer risk among millions of arsenic exposed population in Bangladesh as well as other parts of the world," said Dr. Ahsan, principal investigator of the study.
The most common route of human exposure to arsenic is through ingesting drinking water that is naturally enriched with arsenic. With an estimated 57 million people in Bangladesh having been exposed to high levels of arsenic from drinking water, starting in the 1970s, UNICEF and the Bangladeshi government installed a large number of hand-pumped tube-wells to provide pathogen-free drinking water to the population of Bangladesh.
"Over the past several years, nationwide surveys have established that half of Bangladesh's 10+ million tube wells serving 95% of the population have been contaminated," said Dr. Ahsan. "Given that tens of millions of people have already accrued decades of chronic exposure, an epidemic of arsenic-induced cancers is thus almost inevitable in the Bangladesh population."
Long-term studies from Taiwan indicate that once chronically exposed, a population continues to experience elevated cancer risk for several decades. With very little currently known regarding cancer prevention for the millions of arsenic-exposed individuals, particularly those who have already developed pre-malignant skin lesions, evaluation of appropriate preventive measures using a well-designed trial is urgently needed, according to the team of researchers.
The Mailman School team of researchers also includes co-investigators Joseph Graziano, PhD, associate dean for research, professor of Pharmacology & Public Health, and professor of Environmental Health Sciences; Alfred Neugut, MD, PhD, MPH, professor of Medicine and Epidemiology, and co-director of cancer prevention and control for the Herbert Irving Comprehensive Cancer Center; Mary Gamble, PhD, assistant professor, Department of Environmental Health Sciences; Regina Santella, PhD, director of the Columbia Center for Environmental Health in Northern Manhattan and professor of Environmental Health Sciences; Wei-Yann Tsai, PhD, professor of Biostatistics; and Paul Brandt-Rauf, MD, DrPH, ScD, professor and chair of the Department of Environmental Health Sciences. Dr. John Baron, MD, a well-known chemoprevention expert from Dartmouth Medical School is also involved in this chemoprevention trial.
The NCI grant includes funding for patient recruitment, questionnaire, clinical data assessment, and follow-up of 4,500 patients for the five-year intervention period. The study builds on some of the activities developed in coordination with the NIEHS-funded Superfund Basic Research Program, led by Dr. Graziano, whose primary goal is to elucidate the health effects and geochemistry of arsenic. The work of the Superfund involves studies at four sites in the U.S., and also focuses on carcinogenic, reproductive, and childhood effects of arsenic exposure in drinking water in Bangladesh.
As part of this large program project, Dr. Ahsan and his colleagues have been following nearly 12,000 men and women since 1999 in Bangladesh for another epidemiologic study to investigate health effects of arsenic and this newly-funded NCI grant will start a new dimension to the ongoing Columbia University research activities in Bangladesh.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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