Air Pollution Linked to Accelerated Kidney Function Decline, Reveals Large-Scale Study

Chronic kidney disease (CKD) is a growing global public health challenge, and while traditional risk factors like hypertension and diabetes are well-known, environmental factors such as air pollution are gaining attention as contributors to kidney damage. This study aimed to investigate whether air pollution exposure could hasten kidney function decline, defined by reductions of 30% or more, or 40% or more, in estimated glomerular filtration rate (eGFR).

Researchers utilized a nested case-control design drawing on data from Taiwan Adult Preventive Healthcare Services and National Health Insurance claims, covering the period from 2016 to 2021. The study analysed a large cohort of over 871,000 adults who had participated in routine health checkups. Cases were the individuals whose eGFR declined by ≥30% or ≥40% from baseline. They were matched with control participants based on age, sex, initial kidney function, and follow-up duration.

The team evaluated participants' exposure to six major air pollutants—PM2.5, PM10, nitrogen dioxide (NO₂), sulfur dioxide (SO₂), carbon monoxide (CO), and ozone (O₃)—over varying periods (1, 2, 3, and 5 years) before the recorded kidney function decline. These exposure levels were estimated using land-use regression models combined with machine learning techniques to ensure precise data mapping.

The following were the notable findings of the study:

• The study analyzed 61,239 cases with a decline in eGFR of 30% or greater and 23,330 cases with a decline of 40% or greater.
• Increased exposure to air pollutants was significantly associated with worsening kidney function.
• Carbon monoxide (CO) and fine particulate matter (PM2.5) showed the strongest links to kidney function decline.
• An increase in the interquartile range (IQR) of CO levels was associated with a 2.78-fold higher risk of a ≥30% decline in eGFR.
• PM2.5 exposure was linked to a 2.60-fold increased risk of a ≥30% eGFR decline.
• For a ≥40% decline in eGFR, CO exposure was associated with a 2.46-fold increase in risk.
• PM2.5 exposure in this group was linked to a 2.36-fold higher risk.
• The risk of kidney function decline was more pronounced with short-term (1–2 year) exposure to pollutants than with longer-term exposures.
• Recent air pollution exposure had a more acute impact on kidney health than longer durations.

The researchers concluded that ambient air pollution—especially CO and PM2.5—may play a critical role in accelerating kidney damage. These findings emphasize the urgent need for environmental health interventions and policy measures aimed at reducing pollutant levels to help curb the growing burden of chronic kidney disease.

Reference:

Wu, J., Chang, Y., Lee, P., Cheng, Y., Yu, T., Wong, P., Da Wu, C., Chen, P., & Li, C. Association between exposure to air pollution and kidney function decline. Nephrology Dialysis Transplantation. https://doi.org/10.1093/ndt/gfaf143