News
Study throws light on NCP farmers’ kidney ailment
Thousands, mostly farmers, in the North Central Province have been stricken with a mysterious chronic kidney disease that has baffled doctors and scientists for over a decade, but now a national study has found that the cause may be a combination of factors including the ingestion of a ‘low concentration of heavy metals’ over a long period of time.
Both Health Ministry and World Health Organization (WHO) officials are confident that the National Research Project, with its systematic work, may be able to zero-in on the ‘unknown cause’ of this disease, which is sending a large number of farmers to an early grave.
While the prevalence of chronic kidney disease of unknown origin (CKDu) has been established beyond doubt and also the prevalence areas identified, the mystery, however, has deepened with regard to the cause.
The prevalence has been established at 15 out of 100 people (15%) among farmers in the age-group 15-70 years, Prof. Shanthi Mendis, who handles non-communicable diseases (NCDs) at the WHO headquarters in Geneva, told the Sunday Times. Prof. Mendis is heavily involved in Sri Lanka’s National Research Project on CKDu, providing major technical support.
While both men and women are affected, overall, men have a more severe form of the disease. The average age of those struck down is 39 years but those older had a higher tendency to be affected, the Sunday Times learns.
The urine and fingernail specimens analysed in efforts to find the cause indicate long-term exposure to low levels of heavy metals, Prof. Mendis said.
But how are the heavy metals getting ingested in the farmers’ system – is it through the water that they drink or in the food that they eat?
The heavy metals are not in the water samples collected from all sources that the farmers drink from, stressed Prof. Mendis, explaining that 260 water samples were tested at internationally-accredited laboratories. Five to six water samples were even tested twice.
But the bearing on the human body of other factors linked to water such as hardness and fluoride and the intake of water by the farmers have to be checked out, it is learnt.
There are many heavy metals around but international research over the years has effectively found that three — cadmium, arsenic and lead — cause CKDu, according to Prof. Mendis. After closely studying scientific literature, it was, therefore, decided that in the Sri Lankan research with regard to the NCP, the association of these three heavy metals would be studied first, she says, adding that water was also tested for uranium.If the heavy metals found in urine and nail specimens are not from the water the farmers drink, is it from the food would be the next obvious question.
The food chain may get heavy metals from the soil and a range of foods that the farmers eat, from rice to pulses, vegetables to tank fish and even the nelum ala have been tested and found to contain heavy metals, says Prof. Mendis, hastening to point out though, that “it was not at dangerous levels”.There was also no pointer that certain foods should not be eaten, the Sunday Times understands.
Prof. Mendis, however, urges that the immediate need is to stop the levels of heavy metals in food going up.
Referring to how heavy metals could contaminate the soil, Prof. Mendis explains that it could either be from the fertilizer, pesticides and weedicides sprayed on crops or through air pollution. Air pollution, in turn, could have many sources including vehicle fumes or tobacco use. While the tobacco plant captures cadmium easily, smoking could release this heavy metal into the air as well as get ingested in the body if tobacco leaves are chewed.
Fertilizer, pesticide and weedicide samples from the NCP, meanwhile, have been tested for heavy metals, says Prof. Mendis, adding that in a small percentage of samples the presence of heavy metals was found to be raised above the reference value.
Quality controls are of importance, stresses Prof. Mendis, underlining the fact that while strengthening the quality control methods, the indiscriminate use of fertilizer, pesticides and weedicides should also be prevented. “For, fertilizer, pesticides and weedicides by nature have a nephrotoxic effect,” she said.
This is also why it is vital to use them safely, with protective measures in place and not over-use them, she warns.
No research has yet been carried out with regard to air pollution’s impact on the soil, Prof. Mendis said, so all sources from which the soil could get contaminated with heavy metals have not been looked at. While the National Research Project is making a concerted effort to find the cause of CKDu, Prof. Mendis has a clear message: Sri Lanka needs to take urgent action to stop the low levels of heavy metals present in food from rising and strengthen quality controls on fertilizer, pesticides and weedicides, while not over-using them in our fields.
WHO commends research on CKDu
With the scientific paper on the current findings expected in August, Sri Lanka’s National Research Project on CKDu was commended by WHO Representative Dr. Firdosi Rustom Mehta at a media briefing last Monday.
The Health Ministry lead in initiating this multi-pronged, multi-disciplinary effort to place a solution before the nation is commendable, said Dr. Mehta, pointing out that soon the disease would not be of unknown origin, with light being cast on it by the National Research Project.
Health Ministry Additional Secretary Dr. Palitha Mahipala is the Chair of the Scientific Committee – CKDu of the National Research Project supported by the WHO and launched in late 2009. The research effort has drawn together a diverse group from the Health Ministry, the provincial and regional health authorities; universities and research institutes, clinicians, nephrologists and pathologists, public health and community physicians, the National Science Foundation, the National Water Supply and Drainage Board and the Office of the Registrar of Pesticides.
With about 2,000 new patients seeking treatment for end-stage kidney disease in the Anuradhapura and Polonnaruwa areas, the authorities felt the need for this project as the origin of the disease was unknown. Usually, the common causes of CKD are diabetes and hypertension.
The Sunday Times as far back as December 8, 2002, raised concerns whether CKDu is linked to pesticides, in an article headlined, ‘Deadly drink?’
The National Research Project is built around a population-prevalence study; a hospital-based CKD registry; an environmental study of high and low prevalence areas; a post-mortem study of cases and controls – specimens including kidney, liver and bone etc; a case control study to analyse urine for metals; a case control study to analyse nails and hair for arsenic; a study of nephrotoxic herbal remedies; a socio-economic and productivity impact study; and a randomized clinical trial to check efficacy of a medication.
No danger to food
Food had no dangerous levels of heavy metals and the levels were well within international specification, Health Ministry Additional Secretary and CKDu Scientific Committee Chair, Dr. Palitha Mahipala reiterated.
Stressing that it is a complex issue, he assured that the Registrar of Pesticides was implementing a very strict system of quality control.
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