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小蝌蚪APP Researchers Find Link Between Air Pollution and Risk of Brain Bleed

Media Contact:

Julie Kiefer
Director, Research Communications, 小蝌蚪APP
Email: Julie.Kiefer@hsc.utah.edu

小蝌蚪APP researchers have linked particulate matter (PM2.5) air pollution with aneurysmal subarachnoid hemorrhage (aSAH)鈥攂leeding within the brain caused by a ruptured aneurysm. Although rare, when severe, these hemorrhagic strokes can damage brain tissue enough to leave patients paralyzed or in a coma, or cause death. 

The research findings came from a preliminary study recently published in . 

The American Lung Association鈥檚 2024 list of ranked the Salt Lake City-Provo-Orem area of Utah 25th in the U.S. for short-term PM2.5 pollution. PM2.5 particulates are tiny particles or droplets (30 times finer than human hair) that are easily inhaled and can be harmful, damaging lungs and even contributing to risk of ischemic strokes. 

Research led by neurosurgeon Robert Rennert, MD, links high levels of air pollution to an increased risk for bleeding in the brain, a serious but rare complication.
Research led by neurosurgeon Robert Rennert, MD, links high levels of air pollution to an increased risk for bleeding in the brain, a serious but rare complication.

The air quality along the Wasatch Front has long been considered poor, especially during the winter when inversions trap polluted air in the valleys, but researchers are still learning exactly how our health is affected by poor air quality. 

Neurosurgeon Robert Rennert, MD, led research efforts for a retrospective study of 70 patients seen at the University of Utah for aSAH. In the course of the study, Rennert and his team reviewed nearly 13,000 data points to determine PM2.5 levels in the days, weeks, and months leading up to the admissions of local patients treated for aSAH at the University of Utah Hospital over five years. The goal was to determine whether PM2.5 levels affected each patient鈥檚 risk of hemorrhage. 

鈥淎fter controlling for other variables, we expected to find that patients were more likely to be admitted for aSAH within a week of exposure to high PM2.5 levels,鈥 Rennert says. 鈥淚nstead, we found that these patients were experiencing higher rates of aneurysmal rupture 3-6 months after peaks in air pollution levels.鈥 

Circled area on the left shows an aneurysmal subarachnoid hemorrhage (aSAH), or bleeding within the brain. Credit: Robert Rennert.
Circle on the left shows an aneurysmal subarachnoid hemorrhage (aSAH), or bleeding within the brain. Credit: Robert Rennert.

This gap in time between when PM2.5 levels were highest and when an aSAH actually occurs makes studying the association between these events challenging. Nonetheless, 鈥渁SAH has a high risk of death and disability, so understanding the risk factors for rupture in patients with brain aneurysms is critically important from a public health perspective.鈥 

Rennert says this study is the beginning of the team鈥檚 efforts to understand the effects of PM2.5 on brain health, with additional studies planned to determine more definitively whether PM2.5  pollution can cause aSAH, including in regions beyond Utah's Wasatch Front, as well as further assess the mechanisms and risks of air pollution on cerebrovascular 小蝌蚪APP more broadly. 

鈥淲e鈥檙e hoping that our research helps alert people to the public health risks of air pollution, and encourages changes. Incentivizing public transportation use, applying stricter daily pollution quota regulations, and broadening research funding for environmental studies, will all help to lessen our exposure and have long-term benefits for collective health.鈥 

  • Written by Cortlynd Olsen, Marketing and Communications Specialist, Neurosurgery