Kidney Disease in Nicaragua Linked to Adolescents and Young Women, and Those Without Occupational Heat Exposure.
Kidney Disease in Nicaragua Linked to Adolescents and Young Women, and Those Without Occupational Heat Exposure
In a Nicaraguan region marked by a high burden of chronic kidney disease of unknown origin (CKDu) among young males working in heat-intensive labor, a new study not only shows evidence of CKDu among males, but also metabolic-associated kidney disease among young girls and women and those with and without occupational heat exposure. This insight suggests there are early-life risk factors and multiple contributors to kidney dysfunction.
Chronic kidney disease of unknown origin (CKDu) is an ongoing global health concern and public health challenge often described as a silent health threat, as it progresses without the classic metabolic symptoms of kidney disease—such as obesity and diabetes—and is not typically diagnosed until it reaches an advanced stage. While the progression of this disease remains poorly understood, CKDu to date has been linked primarily to young adult males who engage in heat-intensive manual labor in equatorial agricultural communities.
Now, a new study led by Boston University School of Public Health researchers indicates that other populations in these regions also face a greater risk of kidney dysfunction, and at younger ages.
Published in the journal BMC Nephrology, the study found that young adults and adolescents in Nicaragua had an elevated risk of developing both metabolic and non-metabolic (CKDu) kidney disease, compared to similar populations in the United States.
Notably, the findings showed a greater prevalence of poor kidney health among young girls and women than previously known, as this population is usually excluded from CKDu research because they are rarely diagnosed with CKDu in clinics. Their elevated risk was also strongly associated with high body mass index (BMI) levels. While the researchers did identify CKDu among heat-exposed young males working in sugarcane fields, the majority of participants who exhibited higher risks for both metabolic and non-metabolic kidney disease did not work in heat-intensive environments. Both of these findings were unexpected.
“We were surprised to see that there appears to be multiple pathways to kidney disease in this region among young people and that exposure to extreme heat, while important, is not the sole driver of poor kidney health here,” says study senior and corresponding author Jessica Leibler, associate professor of environmental health. “We were also surprised especially to see how prevalent poor kidney health was among girls and young women. We believe we identified early and important signals of kidney disease risk that allow for early interventions.”
For the study, a team of SPH researchers collaborated closely with Nicaraguan-based colleagues to analyze survey and biospecimen data from adolescents and young adults living in five regions of Nicaragua in 2023. Measuring participants’ estimated glomerular filtration rate, they distinguished between non-metabolic characteristics associated with CKDu (referred to as Mesoamerican Nephropathy in Nicaragua) risk and metabolic kidney disease risk, assessing participants’ history of high BMI, diabetes, and hypertension, as well as employment, sociodemographic, and environmental exposures.
While the researchers did not observe significant links between poor kidney health and drinking water, low socioeconomic status, or non-sugarcane, heat-intensive work, the patterns they did observe suggest that risk factors for moderate and severe kidney disease are present at younger ages, with environmental and social factors likely determining individuals’ disease progression.
“Our findings suggest that there may be non-occupational factors affecting kidney health in this region, such as genetic susceptibilities or environmental exposures, and that young people—including girls and women—should be involved in surveillance efforts,” says co-lead author Selene Vences Brown, a PhD student in environmental health. “ To date, these efforts are limited to men working in sugarcane production.”
CKDu primarily occurs in Central America and South Asia, but there are other hotspots in rural agricultural communities across the globe, from Africa to Thailand, and also Texas.
“One of the main challenges in understanding CKDu is that CKDu patients lack risk factors, so they don’t have hypertension and aren’t overweight, and are usually not diagnosed until they reach end-stage renal failure,” says co-lead author Yiron Yuan, a PhD student in biostatistics. “Beyond these devastating health impacts, this disease also inflicts social and economic consequences, as the loss of young adult males can lead to financial instability for families and contribute to intergenerational poverty.”
The team is continuing to study early-life, metabolic, and occupational risk factors among young people in Nicaragua, and is currently analyzing longitudinal kidney health data to identify patterns and trajectories in kidney health among these populations.
“We are also focused on understanding dysuria, or painful urination, which is a symptom commonly reported by our participants, but superficially understood,” Vences Brown says. “We are evaluating the urinary microbiome and other urinalysis data to help us understand this problem more comprehensively and consider how it may be related to risk of kidney disease.”
This work is a testament to cross-collaboration across research disciplines, she adds.
“I’d love for this collaborative approach to become more commonplace for doctoral studies, as it reflects real-world sharing of expertise that is vital for impactful public health research,” says Vences Brown. “The team is also grateful to our Nicaragua-based colleagues, whose dedication and commitment to this research were critical to the project’s success and findings.”