Three of La Isla Foundation’s (LIF) research partners recently published a comprehensive review of the possible causes of the epidemic of Chronic Kidney Disease of non-traditional causes (CKDnT) in Central America.

The article, co-authored by Dr. Ricardo Correa-Rotter, Dr. Richard Johnson and Dr. Catharina Wesseling, appears in the March 2014 issue of the American Journal of Kidney Disease (available online; subscription required). It is the latest review to draw together and discuss all of the evidence describing the epidemic to date. The authors analyze this evidence to provide suggestions for future research and preventive measures.

The following chart summarizes the authors’ survey of potential causes of CKDnT and their recommendations for research priorities:

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(Click image to enlarge.) 

The review concludes that while no single risk factor has emerged as the cause of CKDnT, several factors likely interact to play a role in the disease.

Recurrent dehydration as a result of strenuous work in high temperatures in the sugarcane fields and other agricultural settings is considered to be the most likely primary cause of CKDnT. The effect of dehydration on the kidneys may then be made worse by a number of secondary causes including sugar consumption, the use of certain pain relief medications like ibuprofen and aspirin, or exposure to other yet-undetermined factors.

There is less evidence that genetics; infections; or exposure to pesticides, or heavy metals such as arsenic and cadmium; cause CKDnT in Central America, although they should not yet be ruled out completely. Finally, the authors suggest that alcohol consumption is an unlikely cause and should be a low priority for further study.

At the root of all of these causes, however, is the poverty and harsh labor conditions experienced in the communities most affected by the disease. The authors emphasize that social determinants of health should be taken into consideration in further research towards determining its cause.

PREVENTION

The key to solving the CKDnT epidemic, according to the authors, is to learn how to prevent new cases, especially given how difficult and expensive it is to treat the disease in Central America. Based on what is known so far, they recommend the following preventive measures:

– Provide agricultural workers frequent rest breaks with access to clean drinking water and shade in order to decrease heat exposure and dehydration.

– Discourage the use of kidney-damaging medications such as ibuprofen and aspirin.

– Switch to the use of non-toxic pest control methods in place of potentially hazardous pesticides.

– Promote healthy lifestyle habits among at-risk individuals.

These findings support LIF’s position that labor conditions in the sugarcane fields are the main driver of CKDnT in northwest Nicaragua.

To improve these conditions, LIF is working in disease-affected communities to document the conditions for sugarcane workers, and to empower community members to find other work by providing alternative education and skills.

La Isla Foundation is also planning an intervention pilot study to determine whether workers who have access to adequate rest, water, and shade suffer from less kidney damage. We are confident that through our efforts and collaborations with academic and industry partners, we will be able to address the underlying causes of this epidemic.

Ricardo Correa-Rotter, M.D., is a nephrologist and clinical scientist at the National Institute of Medical Sciences and Nutrition Salvador Zubirán in Mexico City. He was also the recipient of the 2013 International Distinguished Medical from the National Kidney Foundation. Richard Johnson, M.D., is a nephrologist and researcher at the University of Colorado in Denver. Catharina Wesseling, M.D., Ph.D., is a physician and epidemiologist at the Central American Institute for Studies on Toxic Substances at the National University of Costa Rica. All three are internationally renowned experts on CKDnT and valued LIF partners.