Air pollution linked to worsening sleep apnea symptoms across European cities

Researchers studying sleep apnea across Europe have found evidence that the quality of the air people breathe at night may be making their condition worse. The discovery emerged from a large multinational study presented at the European Respiratory Society Congress in Amsterdam, drawing on medical records and pollution data from nearly 20,000 patients spread across 25 cities in 14 countries.

Obstructive sleep apnea is a condition in which a person's airway repeatedly closes during sleep, causing breathing to stop and start throughout the night. The result is loud snoring, frequent waking, and a persistent sense of exhaustion during waking hours. Beyond the fatigue, the condition carries serious health consequences: people with untreated sleep apnea face elevated risks of high blood pressure, stroke, heart disease, and type 2 diabetes. It is common enough that many people live with it without realizing what is happening to them.

Martino Pengo, an associate professor at the University of Milano-Bicocca and clinician in Milan, led the research. His team combined detailed sleep study data from the European Sleep Apnoea Database—which included information on patients' age, weight, smoking status, and precise measurements of breathing interruptions and oxygen drops during sleep—with air quality records from across Europe. Specifically, they looked at PM10 concentrations, a measure of tiny particles 10 micrometers or smaller that come from vehicle exhaust and industrial sources.

The pattern that emerged was consistent: as air pollution levels rose, so did the severity of patients' sleep apnea. Among patients with mild apnea, the average PM10 concentration in their neighborhoods was around 16 micrograms per cubic meter. For those with more severe apnea, it climbed to about 19 micrograms per cubic meter. When researchers controlled for other known risk factors—age, weight, smoking—they found that each unit increase in PM10 corresponded to an average increase of 0.41 additional breathing events per hour of sleep. Pengo emphasized that while this sounds modest for any single person, the effect compounds across entire populations, pushing many people into higher-severity categories and creating a meaningful public health concern.

What surprised the researchers was that the pollution-apnea connection was not uniform across Europe. In cities like Lisbon, Paris, and Athens, the link was particularly strong. In others, it was weaker or barely detectable. The team suspects that local climate, the specific composition of pollution in different regions, or variations in how healthcare systems diagnose sleep apnea might explain these differences. They are now investigating whether some people are inherently more vulnerable to pollution's effects and whether improving air quality could actually reverse or reduce sleep apnea symptoms.

Sophia Schiza, head of the European Respiratory Society's expert group on sleep disorders and based at the University of Crete, called the findings important for both patients and physicians. For people living with sleep apnea in polluted cities, the research suggests an environmental dimension to their suffering that had not been clearly established before. For doctors, it signals the need to think beyond the usual suspects—age, weight, smoking—and consider the air quality of a patient's home and neighborhood as part of the clinical picture. The study, she noted, underscores a broader truth: cleaning the air is not only an environmental imperative but a medical one.