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 and is often fatal. While the progression of this disease remains poorly understood, CKDu to date has primarily affected young adult males working in heat-intensive manual labor in equatorial agricultural communities.
Now, a new study led by researchers at Boston University School of Public Health (BUSPH) 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 often excluded from CKDu research because they are rarely diagnosed with CKDu. Their elevated risk was also strongly associated with high body mass index (BMI) levels, indicating elevated risk of metabolic kidney disease. While the researchers did identify poor kidney health among heat-exposed young males working in sugarcane fields, the majority of participants who exhibited higher poor kidney health 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 at BUSPH. "We were also interested 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 may allow for early interventions in this region."
For the study, a team of BUSPH 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 (also 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 kidney disease are present at younger ages.
"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 at BUSPH. " To date, kidney disease screening is focused on 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 .
The disease can have meaningful impacts on families and communities, says co-lead author Yirong Yuan, a PhD student in Biostatistics at BUSPH. "CKDu also inflicts social and economic consequences, leading to financial instability for families and contributing to intergenerational poverty."
The team is continuing to study early-life, metabolic, and occupational risk factors among young people in Nicaragua. Yuan is currently analyzing longitudinal kidney health data to identify patterns and trajectories in kidney health among these populations.
This work is a testament to cross-collaboration across research disciplines with doctoral students in Environmental Health and Biostatistics co-leading the manuscript, Dr. Leibler says. "I'd love for this collaborative approach to become more commonplace for doctoral studies, as it reflects sharing of expertise that is vital for impactful public health research," she says.
Vences Brown also reflects on the value of local engagement throughout the project: "We are very grateful to our Nicaragua-based colleagues, whose dedication and commitment to this research were critical to the project's success."
**
About Boston University School of Public Health
Founded in 1976, Boston University School of Public Health is one of the top ten ranked schools of public health in the world. It offers master's- and doctoral-level education in public health. The faculty in six departments conduct policy-changing public health research around the world, with the mission of improving the health of populations—especially the disadvantaged, underserved, and vulnerable—locally and globally.
