Water Quality and Kidney Disease in Sri Lanka
Chronic kidney disease of unknown etiology (CKDu) is a health problem of growing importance and prevalence worldwide. As indicated by the name, the causes of CKDu remain mysterious, but prior research has hypothesized a connection between the disease and contaminants in drinking water or in water used for agricultural production. This project started with an effort to sample and test for contaminants in drinking water sources from locations in Sri Lanka that varied according to the prevalence of CKDu. In addition, our team collected urine samples to test for the presence of nephrotoxic contaminants in individuals’ urine.
See this link for a CNN story featuring Tewodros Rango speaking about the issue.
Another aspect of this research involves systematically reviewing the global literature on CKDu research. Joseph Lunyera (MS in Global Health) helped to conduct a vote counting analysis from peer-reviewed publications seeking to establish associations between CKDu and environmental and non-environmental risk factors. He is now extending that work with a meta-analysis that adjusts for study quality.
Main research collaborators:
- Tewodros Rango (Duke)
- Herath Manthrilake, Peter McCornick (International Water Management Institute)
- Joseph Lunyera (Duke)
Publications:
Lunyera, J.; D. Mohottige; M. von Isenburg; M. Jeuland; U. Patel; and J. Stanifer (2015). “Chronic Kidney Disease of Uncertain Etiology: A Systematic Review.” Clinical Journal of the American Society of Nephrology (Accepted).
Background and objectives. Epidemics of CKDof uncertain etiology are emerging around the world. Highlighting common risk factors for CKD of uncertain etiology across various regions and populations may be important for health policy and public health responses.
Design, setting, participants, & measurements. We searched PubMed, Embase, Scopus and Web of Science databases to identify published studies on CKD of uncertain etiology. The search was generated in January of 2015; no language or date limits were used. We used a vote-counting method to evaluate exposures across all studies.
Results. We identified 1607 articles, of which 26 met inclusion criteria. Eighteen (69%) were conducted in known CKD of uncertain etiology–endemic countries: Sri Lanka (38%), Nicaragua (19%), and El Salvador (12%). The other studies were from India, Japan, Australia, Mexico, Sweden, Tunisia, Tanzania, and the United States. Heavy metals, heat stress, and dietary exposures were reported across all geographic regions. In South Asia, family history, agrochemical use, and heavy metal exposures were reported most frequently, whereas altitude and temperature were reported only in studies from Central America. Across all regions, CKD of uncertain etiology was most frequently associated with a family history of CKD of uncertain etiology, agricultural occupation, men, middle age, snake bite, and heavy metal exposure.
Conclusions. Studies examining etiologies of CKD of uncertain etiology have reported many exposures that are heterogeneous and vary by region. To identify etiologies of CKD of uncertain etiology, designing consistent and comparative multisite studies across high-risk populations may help elucidate the importance of region–specific versus global risk factors.
Rango, T.; M. Jeuland; H. Manthrithilake; P. McCornick (2014). (2015). “Nephrotoxic contaminants in drinking water and urine, and chronic kidney disease in rural Sri Lanka.” Science of the Total Environment 518-519: 574-585.
Abstract: Chronic kidney disease of unknown (“u”) cause (CKDu) is a growing public health concern in Sri Lanka. Prior research has hypothesized a link with drinking water quality, but rigorous studies are lacking. This study assesses the relationship between nephrotoxic elements (namely arsenic (As), cadmium (Cd), lead (Pb), and uranium (U)) in drinking water, and urine samples collected from individuals with and/or without CKDu in endemic areas, and from individuals without CKDu in nonendemic areas. All water samples – from a variety of source types (i.e. shallow and deep wells, springs, piped and surface water) – contained extremely low concentrations of nephrotoxic elements, and all were well below drinking water guideline values. Concentrations in individual urine samples were higher than, and uncorrelated with, those measured in drinking water, suggesting potential exposure from other sources. Mean urinary concentrations of these elements for individuals with clinically diagnosed CKDu were consistently lower than individualswithout CKDu both in endemic and nonendemic areas. This likely stems from the inability of the kidney to excrete these toxic elements via urine in CKDu patients. Urinary concentrations of individuals were also found to be within the range of reference values measured in urine of healthy unexposed individuals from international biomonitoring studies, though these reference levels may not be safe for the Sri Lankan population. The results suggest that CKDu cannot be clearly linked with the presence of these contaminants in drinking water. There remains a need to investigate potential interactions of low doses of these elements (particularly Cd and As) with other risk factors that appear linked to CKDu, prior to developing public health strategies to address this illness.