In the pediatric population, exposure to recent ambient temperatures and fine particulate matter (PM2.5) is associated with alterations in urinary and renal biomarkers that could reflect subclinical glomerular or tubular injury, according to a new study.
Research examining environmental effects on kidney disease often employs hospital admission data where individuals may have preexisting or ongoing conditions, the authors wrote. This work aimed to follow a cohort of healthy individuals.
Air pollution is considered one of the major health problems following rapid industrial development. It is classified as a significant contributor to the global disease burden, as it has been linked to respiratory, cardiovascular, reproductive, neurologic, and neoplastic conditions.
The prevalence of chronic kidney disease worldwide is estimated to range between 11% and 15%, making it a critical concern for global public health. In addition to traditional risk factors such as age and metabolic diseases, recent research suggests that increasing temperatures due to global warming, as well as exposure to environmental pollutants, contribute to the disease’s developmental process.
Researchers from the Department of Environmental Medicine and Public Health at the Icahn School of Medicine at Mount Sinai, New York City, collaborated with the National Institute of Public Health and the National Institute of Perinatology in Mexico City for the study, which was published in Science of the Total Environment.
Long-Term Follow-Up
The research group previously reported that in utero exposure to PM2.5 is associated with a higher estimated glomerular filtration rate and elevated blood pressure in preadolescents in Mexico City. Therefore, to complement previous studies, the aim of this study was to evaluate the association of short-term ambient temperature and PM2.5 exposure with the estimated glomerular filtration rate and soluble renal damage biomarkers in healthy preadolescents in Mexico City.
Data were obtained from the Programming Research in Obesity, Growth, Environment, and Social Stress Factors study, which recruited pregnant women in the second trimester through the Mexican Institute of Social Security between July 2007 and February 2011. Women aged at least 18 years who were less than 20 weeks pregnant with no medical history of kidney or heart disease, no alcohol consumption, and no use of steroids or epilepsy drugs were included.
Of the 948 women who gave birth to a live child, only 571 brought their newborns to the 8- to 12-year-old visit, resulting in a population of 437 healthy infants with no kidney or cardiovascular disease and complete data.
Study author María José Rosa, DrPH, an environmental epidemiologist at the Icahn School of Medicine, noted that the major challenge faced during this research was achieving long-term follow-up. “We have been monitoring participants for 15 years now, so following the original recruitment up to this age to link data to outcomes is the biggest challenge in conducting this type of research,” she told the Medscape Spanish edition.
Urine and fasting blood samples were taken from each participant. Urine was tested for nine proteins, including glomerular and tubular, while serum cystatin C was quantified from blood samples. The average age was 9.6 years, and the men and women were equally distributed.
Satellite models were used to estimate participants’ exposure to temperature and PM2.5 according to their place of residence. The average temperature in the 7 days before sample collection was 16.2 °C, ranging from 10.8 °C to 21.8 °C. The average PM2.5 exposure was 18.7 μg/m3, ranging from 7.5 to 557 μg/m3.
Environmental Effects
No evidence of association between ambient temperature and renal damage biomarkers was found. A relationship was observed, however, between high ambient temperatures and decreased cystatin C.
Exposure to PM2.5 was associated with increases in albumin, cystatin C, KIM-1, alpha-1 microglobulin, osteopontin, and glutathione S-transferase. It also was associated with a decrease in uromodulin.
“As this is a new research area, we had no expectations, but we hoped that some proteins would be higher rather than decreasing. This was unexpected, but we trust that understanding some findings after follow-up will be possible,” said Rosa.
Both short-term and long-term exposure (30 days) were related to an increase in the estimated glomerular filtration rate.
Ximena Cortés, MD, pediatric nephrologist at the National Institute of Pediatrics in Mexico City, emphasized that the importance of the research is that it suggests new factors that affect renal damage biomarkers. “There is no detailed information on the current environmental impact on the glomerulus, which gives rise to considering situations that also cause kidney damage and that must be considered when evaluating kidney function,” she said. Cortés did not participate in the study.
She added that participant follow-up can provide clearer information. “Comparing glomerular filtration rates in areas with extreme heat vs areas with freezing temperatures and assessing if this is significant can add more to the research, as well as following study individuals for longer to analyze if the renal damage caused is acute or establishes chronic damage.”
Rosa mentioned that cohort follow-up continues with the intention of assessing long-term effects. “We have been following participants since they were 8-12 years old,” she said. “Now we are working to see them in the next 5 years. We have air pollution data from before they were born, so we want to analyze if long-term exposure leads to the development of kidney disease in any of them or understand the exposure trajectory that may lead to it.”
This work was funded by the National Institute of Environmental Health Sciences (NIEHS) and the National Institutes of Health. Rosa disclosed NIEHS funding as a potential conflict of interest. Cortés declared having no relevant financial conflicts of interest.
This story was translated from the Medscape Spanish edition using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.
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