Is Chronic Kidney Disease of Undetermined Causes the Canary in the Coal Mine for Rising Temperatures and Health Effects?

Workers in a sugar cane field in Nicaragua. (Photo: Oriana Ramirez)

In recent years, numerous cases of chronic kidney disease (CKD) have emerged among agricultural workers, as well as other manual workers in several tropical regions of the world (namely Mesoamerica, Sri Lanka and India). The disease does not appear to be due to the classic causes of kidney disease (e.g., diabetes, hypertension, and glomerular disease) and is taking a premature death toll in communities where affected people ­–usually young, poor and rural males– cannot access treatment (i.e. dialysis or kidney transplant). For example, the Nicaraguan neighborhood of Chichigalpa ­–a hotspot of the epidemic with up to 20% prevalence among males– is known as "Isla de las viudas".

The Nicaraguan neighborhood of Chichigalpa ­–a hotspot of the epidemic with up to 20% prevalence among males– is known as "Isla de las viudas"

The disease is strongly associated with working and living in a hot environment, but the exact cause (a toxin, an infectious agent, a heat-associated injury, or a combination of factors) is not yet known. Nevertheless, various authors have suggested that this could be a multifactorial disease where heat exposure and dehydration could aggravate the effect of any other nephrotoxic substance (such as pesticides, heavy metals or anti-inflammatory drugs NSAIDs). The effect of increasing temperatures on labour productivity of outdoor and agricultural workers has been a topic of concern for the 2018 “Lancet Countdown: tracking progress on health and climate change” report.

Heat exposure and dehydration could aggravate the effect of any other nephrotoxic substance

ISGlobal is contributing to generate knowledge in this regard. I have recently been named “Associate Researcher” in the Non-communicable Diseases and Environment research programme because of my work studying Mesoamerican Nephropathy in Nicaragua. Together with Cristina O’Callaghan, who has studied prevalence and factors associated with the disease in India, and leads a study to investigate if the environmental and occupational conditions to which agricultural workers are exposed in areas of Mediterranean climate are a risk for developing acute kidney injury ( LeRAGs study), we are currently constituting a small knowledge hub of young researchers on the topic, within ISGlobal.

Today we also celebrate that I have been awarded the 2019 Editors’ Choice Award by the American Journal of Kidney Disease, from among close to 100 original investigations.

Short term kidney injury is common in sugarcane workers and may progress to irreversible kidney damage

In this article, authors from Boston University CKD research team followed a group of over 300 Nicaraguan sugarcane workers with previously normal kidney function. We found that kidney function decreased to abnormal levels over the course of a sugarcane harvest season in about 10% of workers. Cane cutters, who perform a highly demanding physical task, were at highest risk for worsening kidney function compared to other job categories. At follow-up evaluations 6 and 12 months later, kidney function remained impaired in some of these workers and met the definition of chronic kidney disease, suggesting that short term kidney injury is common in sugarcane workers and may progress to irreversible kidney damage in some cases.