“This study underscores the importance of looking at asthma as a potential source of cognitive difficulty in children. We are becoming increasingly aware that chronic diseases, not only asthma but also diabetes, heart disease and others may place children at increased risk of cognitive difficulties,” said lead author Simona Ghetti, a professor of psychology in the UC Davis Center for Mind and Brain in the College of Letters and Science. “We need to understand the factors that might exacerbate or protect against the risks.”

Connecting asthma to memory in children

Asthma is a chronic condition that affects the lungs. Attacks are triggered when inflammation causes the airways to tighten, making it hard to breathe. Asthma affects about 260 million people worldwide. In the United States, roughly 4.6 million children have asthma.

“Childhood is a period of rapid improvement in memory and, more generally, cognition. In children with asthma that improvement may be slower,” said Nicholas Christopher-Hayes, a Ph.D. candidate in psychology at UC Davis and the study’s first author.

This study included data from 2,062 children 9 to 10 years old with asthma to test how the condition might affect episodic memory and other cognitive measures. Episodic memory is a specific type of memory that makes up the stories of our lives. It’s how we remember experiences and emotions, like events and the people and objects that were there.

The analysis found that children with asthma had lower scores on the episodic memory task than children without the lung condition. In a smaller sample of 473 children who were followed for two years, the research team found that children with an earlier asthma onset, who had the disease for a longer period of time, also had a slower development of memory over time.

The data from this study came from the National Institutes of Health and were collected beginning in 2015 as part of the large and ongoing Adolescent Brain Cognitive Development study of 11,800 children. The analysis compared children who shared similar characteristics and backgrounds to ascertain that the differences in memory and other outcomes were linked to asthma itself.

Avoiding long-term consequences of asthma

These memory deficits may have longer-term consequences, the researchers said. In prior studies with older adults and with animals, asthma was associated with a greater risk of dementia and Alzheimer’s disease, both of which affect memory.

“Asthma might set children on a trajectory that could increase their risk to later develop something more serious like dementia as adults,” said Christopher-Hayes.

While the study did not assess the mechanism responsible for memory difficulties associated with asthma, the research team cited various potential factors, such as prolonged inflammation from asthma or repeated disruptions in oxygen supply to the brain due to asthma attacks.

Research with rodents has also found that common asthma medications have a measurable effect on the hippocampus, a structure in the brain that plays a fundamental role in episodic memory for both rodents and humans.

Additional authors on this study are Sarah C. Haynes, Nicholas J. Kenyon and Julie B. Schweitzer, UC Davis School of Medicine; and Vidya Merchant, UC Davis. The study was supported by the Memory and Plasticity Program at UC Davis and by a Learning, Memory, and Plasticity Training Program Fellowship from the National Institutes of Health.