Extreme heat can exacerbate the impacts of some toxins on the kidneys, according to a University of Arizona study published this month in the journal Environmental Research.
The team of researchers from the U of A Mel and Enid Zuckerman College of Public Health followed 77 farmworkers in Sonora, Mexico for several months, regularly testing the workers' blood and urine. The average age of the workers was 29 years old.
The farmworkers were exposed to several types of metals and chemicals on the job — some naturally occurring in the soil and others from agricultural products such as pesticides. Postdoctoral fellow Rietta Wagoner, lead author on the paper, said hot weather made those exposures more dangerous.
"For arsenic, cadmium, chromium and uranium, when those were combined with heat – so when the workers' bodies were heated up – we saw worse effects on the kidneys," Wagoner said.
Wagoner said there are several ways the heat changes the body's response to chemicals.
"You can absorb more things because you're breathing more heavily, your skin becomes more permeable, and your heart starts beating quite a bit, and so the way chemicals and different elements are broken down in the body even changes and how they're excreted can change as well," Wagoner said.
Chronic kidney disease typically occurs in older adults with risk factors like diabetes or hypertension. But Wagoner said around the world, certain populations of outdoor workers have been developing kidney disease at much younger ages than doctors would expect.
Wagoner said more research on the subject is needed, but she said rising temperatures are likely playing a role.
"It's a pretty debilitating disease, and we're seeing around the globe levels of chronic kidney disease are going up," Wagoner said. "The farmworkers seem to be the canary in the coal mine."
Wagoner said the findings of the new study point to a need for heat mitigation policies on outdoor job sites.
"Mandatory and paid breaks that include water, electrolytes, nearby restrooms so that workers aren't keeping themselves from staying hydrated if they have to travel a long way to the bathroom," Wagoner said.
She said new hires should also be given plenty of time to adjust to hot climates before working full shifts in the heat.
"When it comes to heat, prevention is key, and really aggressive prevention," Wagoner said.
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