Sugar Cane Worker Chronic Kidney Disease

An unknown medical condition has been killing male agricultural workers in central America. The illness is officially described as a 'Chronic Kidney Disease of non-Traditional causes (CKDnT)' and it is responsible for 75% of deaths of young and middle-aged men in Nicaragua and El Salvador. Workers in the sugarcane industry are worst affected and the disease has been destroying families and communities since it emerged in the late 1990s. Some researchers suspect that a virus might be to blame as the fields are heavily infested with rodents[1].

Patients experience fever, nausea and vomiting, joint pain, muscle pain, headache, neck and back pain, weakness, and itchiness at the onset of acute kidney disease.

However, further research has now indicated that the epidemic of kidney disease among young Central American males may be the result of continued heat stress and volume depletion[2].

In Nicaragua and El Salvador, age-adjusted mortality rates from kidney disease are among the highest in the world. According to researchers, in these countries, the prevalence of kidney disease (defined as eGFR <60 mL/min/1.73m²).

“Most researchers believe the causes are multifactorial, and it is at least in part related to occupation, given the severe toll that kidney disease is taking on heavy manual laborers in the region,” explained Rebecca Laws, lead author on the study.

For the study, researchers followed 284 sugarcane workers in seven different jobs from one company in Nicaragua. Blood and urine samples were collected before and near the end of the six-month harvest season. Those workers who had the most labor-intensive jobs, cane cutters, had increased urinary NGAL (Neutrophil Gelatinase Associated Lipocalin) and IL-18 (Interleukin-18), both biomarkers of kidney injury.

Researchers observed a protective effect of consuming an electrolyte solution among cane cutters and seed cutters. This indicates there are ways to prevent kidney injury among laborers in high-heat settings.

Global warming might further give rise to the number of cases. Climate change has led to a significant rise of 0.8°C–0.9°C in global mean temperature over the last century and has been linked with significant increases in the frequency and severity of heat waves (extreme heat events)[3].

[1] Murray et al: Mesoamerican nephropathy: a neglected tropical disease with an infectious etiology? in Microbes and Infection - 2015
[2] Laws et al: Biomarkers of Kidney Injury Among Nicaraguan Sugarcane Workers in American Journal of Kidney Diseases - 2015
[3] Glaser et al: Climate Change and the Emergent Epidemic of CKD from Heat Stress in Rural Communities: The Case for Heat Stress Nephropathy in Clinical Journal of the American Society of Nephrology - 2016