Reducing amounts of arsenic in drinking water can lower long-term deaths from cardiovascular disease and cancer, a new study shows.
Researchers at NYU Langone Health, Columbia University, and the University of Chicago say their landmark analysis is important for public health because groundwater contamination from naturally occurring arsenic remains a serious issue worldwide. In the United States, more than 100 million people rely on potentially contaminated groundwater sources, especially private wells, for their drinking water. Arsenic is among the most common chemical pollutants.
During the study, the drinking water and health records of 10,977 men and women in Bangladesh were monitored from 2002 to 2022. Results showed that efforts over the 20 years to reduce arsenic in drinking water led to a 70% decrease in levels of the chemical, which in turn halved arsenic levels in tested urine from study participants.
Publishing in the Journal of the American Medical Association (JAMA) online Nov. 17, the researchers compared study participants whose arsenic exposure changed from high to low to those whose arsenic exposure remained high. Results showed that those whose arsenic levels dropped had a 54% reduced risk of death from any chronic disease. Similar decreases were observed specifically for heart diseases (57%) and cancer (49%).
"Our study provides the strongest evidence to date that lowering arsenic in drinking water can lower death rates from chronic disease," said study co-lead investigator Fen Wu, PhD, a senior research scientist at the NYU Grossman School of Medicine. "Elevated arsenic levels in drinking water remains a pervasive public health issue because arsenic naturally accumulates in groundwater and has no taste or odor, so people can unknowingly consume unsafe levels for years."
"Our research supports switching to safer water sources as a strategy to improve long-term health around the world," said study senior investigator Yu Chen, PhD, MPH, a professor in the Department of Population Health at the NYU Grossman School of Medicine. "Improved access to low-arsenic water, periodic testing, and clear signage to mark safer from higher-arsenic water — are useful tools to accomplish this goal."
Chen says previous research in regions of Taiwan and Chile with high arsenic levels (at greater than 600 micrograms per liter), tied trends of decreasing heart disease and cancer death rates to reducing arsenic levels in drinking water. However, she says her team's study is the first to offer direct evidence by examining arsenic levels and mortality in each participant over two decades and in a region with moderate arsenic exposure (less than 200 micrograms per liter).
As part of the study, researchers monitored more than 10,000 wells in and around the district of Araihazar, Bangladesh, where arsenic mitigation efforts started in 2000. Wells are labeled to indicate if arsenic levels are high or low, community educators encourage people to switch to safer wells, and new wells are being drilled with lower concentrations of arsenic.
During the investigation, study participants volunteered to have their urine tested six times, periodically allowing researchers to track changes in arsenic exposure over time. Meanwhile, the research team recorded 1,401 deaths among the study participants from chronic disease, including 730 from cardiovascular disease and 256 from cancer.
Bangladesh as a whole has one of the world's most serious challenges with drinking water contaminated by arsenic. More than 50 million people are exposed to arsenic levels above the World Health Organization standard of 10 micrograms per liter.
Funding support for this study was provided by National Institutes of Health grants R01ES035219, P42ES010349, and P4242ES033719.
Besides Chen and Wu, Mengling Liu, PhD, is a study co-investigator from NYU Langone. Also involved in the study are co-lead investigator Alexander van Geen, PhD, and co-investigators Joseph Graziano, PhD, Vesna Slakovich, MS, Tyler Ellis, MS, and Ana Navas-Acien, PhD, at Columbia University in New York City; co-senior investigator Habibul Ahsan, MD, and co-investigators Muhammad Kibriya, MD, PhD, Farzana Jasmine, PhD, and Mohammad Hasan Shahriar, MD, at the University of Chicago; Kazi Matin Ahmed, PhD, and Imtiaz Choudury, MS, at the University of Dhaka in Bangladesh; Maria Argos, PhD, at Boston University in Massachusetts; and Tariqul Islam, MBBS, Alauddin Ahmed, MBBS, Rabiul Hasan, MA, Salma Akter Shima, MS, and Golam Sarwar, BS, at the University of Chicago and Columbia University Project Office in Dhaka.
