Asthma in children linked to memory difficulties, study suggests

A recent study published in JAMA Network Open showed that asthma is associated with poorer memory, particularly in those who developed the disease early. 

The researchers found that children with asthma performed worse in memory tasks and executive functions than children without asthma, with those who developed the disease early scoring lower on memory tests. 

Episodic memory, the ability to remember past events with specific details, requires hippocampal integrity, as the hippocampus is where new connections are continuously formed under the influence of the environment. This type of memory involves remembering specific details about past events, such as when and where they occurred, who was present, and the emotions and thoughts that were present at that moment.

According to the researchers, memory deficits in children with asthma may have longer-term consequences, including an increased risk of developing conditions like dementia. Past studies with older adults and 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".

Simona Ghetti, a professor of psychology at the University of California, Davis, said: "This study underscores the importance of looking at asthma as a potential source of cognitive difficulty in children". She also stated: "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".

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. Rodent models have shown that asthma causes neural injuries in the hippocampus, a part of the brain highly sensitive to neuroinflammatory responses. Breathing difficulties may lead to episodes of oxygen deprivation in the brain, which can result in damage to the hippocampus.

Other studies have indicated difficulties in attention, executive functions, visual memory, and working memory among children with asthma, and children with asthma had more difficulty concentrating. Previous studies have shown that children with asthma who receive high doses of corticosteroids suffer from verbal memory deficits compared to children receiving lower doses.

In the cross-sectional analysis, the study included 2,062 children, of whom 1,031 had asthma with an average age of 11.99 years. The data were collected beginning in 2015 as part of the large and ongoing Adolescent Brain Cognitive Development study of 11,800 children. The smaller sample that followed the children for two years included 473 children, divided into two groups according to the age of onset of asthma in childhood. The first group included 135 children with early-onset asthma, of whom 56% were male. The racial distribution of the first group included 28% Black children, 21% Latino or Hispanic children, and 48% White children. The second group, which had relatively later onset of asthma symptoms, included 102 children with an average age of 9.88 years, of whom 53% were female. The racial distribution of the second group included 17% Black children, 19% Latino or Hispanic children, and 63% White children. The two groups were compared with a third group of 237 non-asthmatic children, with an average age of 9.89 years. The racial distribution of the third group included 15% Black children, 20% Latino or Hispanic children, and 62% White children.

In a sample of 473 children followed for two years, scientists found that those with earlier asthma onset—who had the disease for a longer period—had slower development of memory over time. The memory development of children who had asthma from a young age made less progress than that of children who developed asthma later or did not have asthma at all. Nicholas Christopher-Hayes stated: "Childhood is a period of rapid improvement in memory and, generally, in cognition. In children with asthma, that improvement may be slower".

The results of the cross-sectional analysis showed that children with asthma scored lower in tests of episodic memory, processing speed, and executive functions such as attention, and they also needed more time on average to answer questions (Asharq News). These results suggest that asthma may negatively affect memory, processing speed, and executive functions in children. This negative impact may affect children's academic performance and their ability to concentrate.

The researchers have unanswered questions, such as how often and how severely these children experienced asthma attacks and how that affects their development. They could not determine whether the use of inhalers with corticosteroids had an impact on the children's brains. They also want to understand how much the children's background influences their cognitive development. The study cannot prove that asthma is the cause of poorer cognitive development.

According to the researchers, factors such as prolonged inflammation or repeated disruptions in oxygen supply to the brain due to asthma attacks may contribute to cognitive difficulties. The duration of the disease may also play an important role, as the duration of asthma is associated with changes in brain structure and function in adults.

Research on other medical conditions, such as type 1 diabetes, has shown that children with complications at an early age may be particularly prone to cognitive difficulties. Such relationships between asthma and cognitive difficulties had already been found in adults.

Sources: NRC Handelsblad, The Independent, Yahoo News, The Guardian, expressandstar.com, La Razon, Asharq News.

This article was written in collaboration with generative AI company Alchemiq