Chronic kidney diseases of uncertain etiology (CKDue) in Sri Lanka: geographic distribution and environmental implications

Abstract

The increase in the number of chronic kidney disease (CKD) patients from the north central region of Sri Lanka has become a environmental health issue of national concern. Unlike in other countries where long-standing diabetes and hypertension are the leading causes of renal diseases, the majority of CKD patients from this part of Sri Lanka do not show any identifiable cause. As the disease is restricted to a remarkably specific geographical terrain, particularly in the north central dry zone of the country, multidisciplinary in-depth research studies are required to identify possible etiologies and risk factors. During this study, population screening in the prevalent region and outside the region, analysis of geoenvironmental and biochemical samples were carried out. Population screening that was carried out using a multistage sampling technique indicated that the point prevalence of CKD with uncertain etiology is about 2-3% among those above 18 years of age. Drinking water collected from high-prevalent and non-endemic regions was analyzed for their trace and ultratrace element contents, including the nephrotoxic heavy metals Cd and U using ICP-MS. The results indicate that the affected regions contain moderate to high levels of fluoride. The Cd contents in drinking water, rice from affected regions and urine from symptomatic and non-symptomatic patients were much lower indicating that Cd is not a contributing factor for CKD with uncertain etiology in Sri Lanka. Although no single geochemical parameter could be clearly and directly related to the CKD etiology on the basis of the elements determined during this study, it is very likely that the unique hydrogeochemistry of the drinking water is closely associated with the incidence of the disease.

Escalating chronic kidney diseases of multi-factorial origin in Sri Lanka: causes, solutions, and recommendations

“…When one considers males who are older than 20 years, the prevalence of CKD-mfo is approximately 10 %. However, the final WHO report based on random sampling estimated an overall prevalence of CKD-mfo of more than 16 % in the region [3], whereas others reported a prevalence of less than 3 % [2]. It is difficult to explain this major discrepancy.…”

“…As with other CKDue affected countries, the disease in Sri Lanka is restricted to specific geographical terrains, in the drier zones (regions that receive precipitations during one monsoon period and drier conditions prevail rest of the year), including the NCP [2]. The CKD-affected areas cover approximately 24,000 km 2 and include a population of approximately 3.0 million [1].…”

“…Taking into account the mosaic pattern of geographical distribution [2], an adverse soil-water, occupational environment exposure is likely to play a role in the CKD-mfo epidemic in Sri Lanka and other CKDuo affected counters. It is common to see villages with a high prevalence of CKD located within a few kilometres of villages without a high prevalence of the disease.…”

“…The assorted patterns of the disease distribution strongly indicate that the environment and the geochemistry has an important impact on this condition [2,30]. Nevertheless, based on the demarcated geographical distribution of people with renal failure and CKD-associated deaths [5], groundwater testing data, and local farming habits [2], do not support any of the currently postulated components alone is likely to be the cause of the CKD-mfo in Sri Lanka.…”

“…Approximately 100,000 people are currently affected, with 5,000 deaths occurring each year, attributed to an unusual form of CKD of unknown aetiology (CKDue), with an approximate 5 % death rate per year amongst the affected individuals [1]. Most of these deaths occur in villages in the NCP and other drier regions, but the disease is spreading to other areas distant from this region [2]. In certain villages, more than 10 % of the adult population has this terminal illness [3].…”