LA Wildfires Linked to Spike in Heart Attacks, Lung Issues & Illness: New Study

The January 2025 wildfires that swept through Los Angeles County weren’t just a disaster for homes and businesses; they triggered a significant, though previously unquantified, surge in health problems in the months that followed. A new study from Cedars-Sinai Medical Center reveals a marked increase in emergency room visits for heart attacks, respiratory illnesses, and general ailments within 90 days of the fires, adding to a growing body of evidence linking wildfire exposure to acute health impacts.

Wildfire Smoke and the Cardiovascular System

Researchers, led by Dr. Susan Cheng, director of Public Health Research at Cedars-Sinai’s Smidt Heart Institute, analyzed emergency department data from January 7 to April 7, 2025, comparing it to records from the same period in the previous seven years (2018-2024). Even as the overall number of ER visits remained consistent, specific conditions showed alarming increases. Heart attack-related visits rose by 46%, while those for pulmonary illness increased by 24%, and general illness by a striking 118%. The study, published in the Journal of the American College of Cardiology, focused on the impact of the Eaton and Pacific Palisades fires, with Cedars-Sinai located approximately 10-20 miles from the largest ignition points.

“Wildfires that spread into urban areas have proven to be extremely dangerous because of how quickly they move and what they burn and release into the environment,” Dr. Cheng explained. The findings underscore the immediate and widespread health consequences of wildfires, even for those not directly in the path of the flames. The researchers emphasize that the fine particulate matter released during wildfires can penetrate deep into the lungs and bloodstream, causing inflammation and injury, particularly to the cardiovascular and respiratory systems. Previous research has established a link between air pollution and increased cardiovascular risk, and this study provides further evidence of that connection in the context of wildfire events.

Beyond the Lungs and Heart: Unexpected Blood Test Anomalies

Perhaps the most surprising finding of the Cedars-Sinai study was the doubling of abnormal blood test results associated with general illness during the 90-day period following the fires. This is a previously unreported consequence of major wildfire events. Dr. Joseph Ebinger, associate professor in the Department of Cardiology and first author of the study, suggested that these abnormalities could indicate the body’s response to toxins in the air. “Abnormal blood test results could indicate that the body is responding to an external stressor such as toxins in the air,” he stated. Patients presenting with symptoms like coughs or dizziness often had normal chest x-rays and hydration levels, suggesting a more subtle, systemic effect of wildfire exposure.

Study Design and Limitations

The Cedars-Sinai study employed a retrospective analysis of existing emergency department data, a robust method for identifying trends in healthcare utilization. However, it’s important to acknowledge the study’s limitations. The data are specific to a single hospital system in Los Angeles County, which may not be fully representative of the broader population. The study establishes a correlation between wildfire exposure and increased illness, but it cannot prove causation. Other factors, such as seasonal variations in respiratory illnesses or concurrent public health events, could have contributed to the observed increases. The researchers controlled for these factors as much as possible, but residual confounding remains a possibility.

Understanding Relative vs. Absolute Risk

While a 46% increase in heart attack-related ER visits sounds alarming, it’s crucial to understand the context. This is a relative increase, meaning it’s a 46% increase *compared to the baseline rate* observed in previous years. The absolute risk of experiencing a heart attack remains relatively low, even with the increase. However, even a small increase in risk can translate to a significant number of additional cases, particularly in a large population like Los Angeles County. As reported by Powers Health, the study highlights the potential for wildfires to exacerbate existing health conditions and trigger acute events.

The Broader LA Fire HEALTH Study and Future Research

This research is part of the larger LA Fire HEALTH Study, a collaborative effort involving multiple universities and research institutions, including Harvard, USC, Stanford, UCLA, and UC Davis. The study aims to track the long-term health consequences of the January 2025 wildfires over the next decade. Researchers plan to investigate the specific components of wildfire smoke that are most harmful to human health, identify vulnerable populations, and develop strategies to mitigate the health impacts of future wildfires. ABC7 News reported on the study’s findings, emphasizing the novelty of the blood test anomaly discovery.

Ongoing Surveillance and Public Health Response

Public health agencies are increasingly recognizing the importance of wildfire smoke monitoring and public health messaging. The Environmental Protection Agency (EPA) provides real-time air quality data through its AirNow website, and local health departments issue advisories when air quality reaches unhealthy levels. Individuals with pre-existing respiratory or cardiovascular conditions are advised to take extra precautions during wildfire events, such as staying indoors, using air purifiers, and avoiding strenuous activity. The findings from the LA Fire HEALTH Study will inform future public health guidance and interventions aimed at protecting communities from the health impacts of wildfires.

What to expect in the coming months: Researchers will continue to analyze data from the LA Fire HEALTH Study, focusing on identifying specific biomarkers of wildfire exposure and assessing the long-term health outcomes of affected populations. The study’s findings will be used to refine risk assessments and develop targeted interventions to protect vulnerable communities during future wildfire events. Ongoing surveillance of emergency department visits and air quality data will be crucial for monitoring the health impacts of wildfires and informing public health responses.