Heavy metals exposure and chronic kidney disease among agricultural workers in Nicaragua: Understanding a mysterious epidemic

Background

Chronic Kidney Disease (CKD) has emerged as a devastating epidemic in northwest Nicaragua, with a prevalence of moderate to severe CKD (glomerular filtration rates (eGFR) <60mL/min/1.73m2) as high as 31% in some populations. Whereas CKD is typically linked to hypertension and diabetes, this epidemic affects young, otherwise healthy males with an employment history on sugar cane plantations; previous studies report odds ratios as high as 12 compared to individuals in different occupations. We hypothesize this epidemic may be linked to exposure to heavy metals, which are frequently present in fertilizers and have been associated with CKD in other populations. Methods

This study builds on a previously conducted survey and biological sampling protocol using a nested case-control design. Banked blood and urine from 41 cases (males with eGFR < 60) and 38 controls (males with eGFR > 90) is available for analysis of exposure to cadmium, mercury, lead, and arsenic. Data will be analyzed using multiple regression, controlling for medical, demographic, and lifestyle covariates.

Results

Metals analysis is in process; we anticipate a positive association between heavy metal exposure and CKD. A negative association will help us target other exposures, particularly pesticides and dehydration, as etiological factors.

Conclusions

This study is part of a larger community based project exploring additional potential mechanisms and modifiable risk factors for CKD in northwest Nicaragua. Findings addressing the association between heavy metals and CKD will help inform the etiologic investigation of this epidemic, as well as similar epidemics in other Central American agricultural communities.