There is an epidemic of chronic kidney disease of unknown etiology, also referred to as Mesoamerican Nephropathy (MeN), in Central America. Researchers studying this epidemic believe the disease etiology likely has an occupational component, with a growing body of evidence to support the hypothesis that heat stress and dehydration play an important role. Previous research has focused extensively on sugarcane workers, but there are limited data describing the heat strain experienced at work for these and other workers. There are no established early indicators of disease onset and the role of other exposures in the disease’s etiology are still uncertain. This dissertation aims to address some of these gaps using data from two occupational cohort studies in Central America.
The first is a cohort of Nicaraguan sugarcane workers who were monitored across the 2010-2011 harvest season. The second is the MesoAmerican Nephropathy Occupational Study (MANOS)—a cohort of 569 workers in El Salvador and Nicaragua from the sugarcane, corn, plantain, brick manufacturing, and construction industries.
We found that dipstick leukocyte esterase at the end of the harvest, which was relatively common among cane cutters (33%), seed cutters (22%), and seeders/reseeders (21%), was associated with a 12.9 ml/min per 1.73 m2 (95% CI: −18.7 to −7.0) lower mean eGFR and 2.8 times (95% CI: 1.8 to 4.3) higher mean neutrophil gelatinase-associated lipocalin (NGAL). We also found that workers who reported symptoms (e.g., flank pain, fever/chills, and dysuria) had higher mean kidney injury biomarker levels.
Among MANOS participants, we found that sugarcane workers, especially cane cutters and Nicaraguan agrichemical applicators, had the highest estimated work rates, core temperatures (Tc), and heart rates (HR), but workers in other industries occasionally reached high Tc (> 39°C) as well. We found that workers with low eGFR had higher average Tc and HR values and that spending more time on break was associated with lower average HR. We report a higher incidence of cross-shift, serum creatinine-defined kidney injury among sugarcane workers, particularly at one Nicaraguan company, and found evidence that core body temperature and work rate were risk factors for this outcome. / 2023-03-21T00:00:00Z
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/44065 |
| Date | 21 March 2022 |
| Creators | Petropoulos, Zoe Elyse |
| Contributors | Scammell, Madeleine K. |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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