Asthma is linked to memory issues in children – and the condition appearing early may make memory difficulties worse, new research suggests.

The study found that children with asthma performed worse in memory tasks than children without the lung condition.

According to the researchers, memory deficits may have longer-term consequences, and may even increase the risk of developing conditions like dementia.

In a sample of 473 children who were followed for two years, the scientists found that those with an earlier asthma onset – who had the disease for a longer period of time – also had a slower development of memory over time.

Lead author Simona Ghetti, a professor of psychology in the University of California, Davis – centre for mind and brain in the college of letters and science, said: “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.

“We need to understand the factors that might exacerbate or protect against the risks.”

Past studies with older adults and with animals, found that asthma was associated with a greater risk of dementia and Alzheimer’s disease, both of which affect memory.

Nicholas Christopher-Hayes, a PhD candidate in psychology at UC Davis and the study’s first author, said: “Asthma might set children on a trajectory that could increase their risk to later develop something more serious like dementia as adults.”

Although the study did not look at the mechanism responsible for memory difficulties associated with asthma, the researchers cite potential factors, such as prolonged inflammation from asthma or repeated disruptions in oxygen supply to the brain due to asthma attacks.

The study included data from 2,062 children nine to 10 years old with asthma to test how the condition might affect episodic memory and other cognitive measures.

Episodic memory is how people remember experiences and emotions, like events and the people and objects that were there.

The smaller sample that followed the children for two years included 473 children.

The data from this study, published in Jama Network Open, came from America’s 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.