Every other agri worker with chronic kidney disease has it due to unknown cause, study finds

New Delhi, Nov 1 (PTI) One in every 20 agricultural workers in Tamil Nadu could be having chronic kidney disease (CKD), with every other affected individual possibly having CKDu (chronic kidney disease with an unknown cause) -- a type known to affect mainly agricultural workers, a study published in The Lancet Regional Health Southeast Asia journal has estimated.

The study points to factors associated with chronic kidney disease, including an increased age, diabetes, hypertension, anaemia and duration in a week spent working outdoors.

Researchers, including those from Madras Medical College, said CKDu -- linked to heat stress due to working outdoors and exposure to agricultural chemicals and environmental toxins -- has been reported in "hotspots" around the world, including India, Sri Lanka and Central America.

More than 3,300 farm workers underwent a clinical evaluation and lab testing under phase-1 of the study.

After three months, participants having an 'eGFR', a measure of kidney function, under 60 millilitres per minute per 1.73 square metres (indicating a loss of kidney function) were counted.

Of the total, 584 and 178 participants at the end of phase 1 and phase 2, respectively, were found to have an eGFR value indicating a loss in kidney function and chronic kidney disease.

The remaining 406 having an unhealthy eGFR during phase 1 had a normal value when re-measured during phase-2, the authors said.

Episodes of transient subclinical acute kidney injury -- early damage to kidney not presenting symptoms -- could potentially contribute to chronic kidney disease, they added.

"The prevalence of CKD among agricultural workers in Tamil Nadu is 5.31 per cent, with about half of these due to CKDu," the authors wrote.

How transient subclinical acute kidney injury can contribute to advancing of chronic kidney disease needs to be studied, the team said.

The researchers said that previous studies looking at chronic kidney disease of unknown cause conducted in agricultural communities consist of small cohort sizes.

Research also tends to be confined to geographic hotspots and therefore, could be limited in providing a true estimate of prevalence, they said.

The study is the first conducted across varying agro-climatic zones in Tamil Nadu with a robust sampling technique, the team said.

Asymptomatic transient acute kidney injury was seen in 17.4 per cent of the study group, which the researchers said was three times the prevalence of chronic kidney disease and possibly have a high risk of developing the disease in the future.

The team also quantified how weekly work hours are linked with normal kidney function, chronic kidney disease and chronic kidney disease with an unknown cause. PTI KRS KRS MAH MAH