Asthma Tied to Memory Difficulties in Kids

Childhood asthma was associated with difficulties with memory and other cognitive functions, according to an observational cohort study.

In a longitudinal analysis, children with earlier onset of asthma had lower rates of memory improvements as measured by the Picture Sequence Memory Test compared with those without asthma (β = -0.17, 95% CI -0.28 to -0.05, P=0.01), reported Nicholas J. Kenyon, MD, MAS, of the University of California Davis School of Medicine in Sacramento, and colleagues.

When children with later-onset asthma were compared with the kids without asthma, no such difference was observed, they noted in JAMA Network Open.

Meanwhile, in a cross-sectional analysis, children with asthma showed lower scores on episodic memory (β = -0.09, 95% CI -0.18 to -0.01, P=0.04), processing speed (β = -0.13, 95% CI -0.22 to -0.03, P=0.01), and inhibition and attention (β = -0.11, 95% CI -0.21 to -0.02, P=0.02).

“The current study provides novel evidence that children with asthma exhibit altered memory functioning during development, in addition to consequences extending to other cognitive domains,” the authors wrote. “These results accentuate the need to examine this population more closely to understand the full extent to which asthma influences neurodevelopment.”

According to Kenyon and team, the exact pathophysiology of asthma is still unclear, but rodent models have shown that asthma results in neural injury in the hippocampus. A previous study showed that children treated with high doses of corticosteroids for asthma had reduced verbal memory compared with those on lower doses. Others reported an association between asthma and cognitive performance difficulties, but did not account for confounding socioeconomic factors that could affect both the chances of developing asthma and cognitive abilities and lead to asthma disparities.

The current findings aligned with this research, the authors noted. Developing asthma as a younger child “may be particularly likely to perturb neurodevelopment, especially in brain regions that demonstrate ongoing plasticity and vulnerability to environmental input (e.g., the hippocampus),” they wrote.

Because children with earlier asthma onset also experience asthma for longer, “prolonged inflammation due to longer duration may result in detrimental neuroinflammatory responses, which may in turn disrupt neural processing and manifest in the form of cognitive dysfunction,” they added.

Farzin Irani, PhD, of AAA Neuropsychology in Malvern, Pennsylvania, told MedPage Today that this study’s findings were “consistent with [her group’s] meta-analysis, which was the first to show the presence of small to medium-sized effects for global cognitive impairment.” However, Irani noted that asthma severity, which they found to be the strongest moderator in the asthma-cognition relationship, was not accounted for in the present study, nor was the role of asthma control.

“This is important because asthma control tends to be poorer in younger children anyway,” she noted. “This is also an area of potential intervention for healthcare providers, i.e., working with parents to increase the control of asthma.”

For this study, the researchers used data collected from the long-term Adolescent Brain Cognitive Development (ABCD) Study. Children were included based on parent reports of asthma or asthma-related medical treatment. Participants were selected based on exposures described subsequently to determine longitudinal and cross-sectional associations between asthma and memory.

For the longitudinal analysis, the earlier-onset group included children whose parents reported asthma indicators at both baseline and at 2-year follow-up, while the later-onset group reported asthma indicators at 2-year follow-up only. The cross-sectional analysis included children whose parents reported asthma at any time point. A comparison group included children with no reports of asthma who were matched by age, sex, combined parental income, and other health indicators like allergies and bronchitis.

In total, 474 children were included in the longitudinal analysis. Mean age for all three subgroups (earlier onset, later onset, and comparison) was about 10; 56% of the earlier-onset group were boys, and 53% of the later-onset group were girls. All three subgroups had a distribution of race that reflected the racial disparities in asthma (48-63% white, 15-28% Black, and 19-21% Hispanic or Latino).

In the cross-sectional analysis of 2,062 children, mean age was 12, 57% of those with asthma were boys compared with 46% in the comparison group, and 54-59% were white, 21-27% were Black, and 18-23% were Hispanic or Latino.

Secondary outcomes were assessed using the Pattern Comparison Processing Speed Test and the Flanker Inhibitory Control and Attention Test.

The study authors were unable to assess asthma severity or its exact onset and duration, which was a limitation to the study. In addition, the ABCD Study analyzed neurocognitive development in children, and was not designed to find associations between asthma and cognition.

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