Reading problems in childhood are associated with worse verbal memory in middle age, new research suggests.
Specifically, reading problems at age 11 are significantly associated with the recall of 5.65 fewer words on a 15-item word recall task during middle age.
In addition, childhood reading problems are significantly linked to an increased risk of cognitive impairment at age 69, an association mediated, in part, by education level.
“Our study showed that reading problems in childhood are associated with long-lasting negative effects on cognition over a period of up to six decades,” Amber John, PhD, research fellow at University College London in the United Kingdom, told Medscape Medical News.
The findings were published online July 6 in the Journal of Epidemiology & Community Health.
Previous research indicates that reading problems affect children’s cognitive functioning in various domains. Studies also show childhood reading problems are associated with poor outcomes in adulthood including lower income level, decreased self-esteem, and higher risk of psychiatric disorders.
“However, not much is known about whether childhood reading problems can have more long-term effects on cognitive health,” said John. “Additionally, previous studies have mainly looked at childhood cognition as a comprehensive measure, whereas this study focuses on one specific aspect of that, which is independent of general cognitive ability.”
For the study, investigators examined data from the Medical Research Council (MRC) National Survey of Health and Development (NSHD), which included 5362 individuals born in England, Scotland, and Wales during 1 week in 1946. At age 11 years, all participants underwent a reading test that the current researchers used to identify participants with reading problems.
At ages 43, 53, 60-64, and 69 years, participants underwent tests of verbal memory using a 15-item word recall task. They also performed a letter cancellation task that measured cognitive processing speed.
At age 69 years, participants underwent assessment with the Addenbrooke’s Cognitive Examination III (ACE-III). This measure evaluates attention, verbal fluency, memory, language, and visuospatial function. The score ranges from zero to 100, and the lower and upper thresholds for screening for clinically significant cognitive impairment are 82 and 88, respectively.
Risk of Cognitive Impairment
The final analysis included 1051 participants. After adjusting for covariates such as sex, education, and socioeconomic position, they found that reading problems at age 11 were significantly associated with poorer verbal memory (P < .001) during follow-up. However, reading problems were not associated with the rate of cognitive decline from age 43 years to 69 years (P = .22).
Reading problems also were not significantly associated with processing speed during follow-up visits (P = .65) or change in processing speed (P = .46). When the investigators included childhood cognition as a covariate, it did not significantly change the pattern of associations.
The proportion of participants with ACE-III scores lower than 82 was 32.95% among patients with childhood reading problems and 4.75% among participants without reading problems. Similarly, the proportion of patients with ACE-III scores lower than 88 was 61.36% among participants with childhood reading problems and 18.43% among those without childhood reading problems.
Childhood reading problems were significantly associated with a 5.14-point decrease in ACE-III total score at age 69 years (P < .001). They also were significantly associated with lower scores on all subdomains of ACE-III.
The associations between childhood reading problems and ACE-III score were partially mediated by education. When the investigators adjusted the data for cognitive ability in childhood, reading problems were significantly associated with poorer scores in verbal, but not nonverbal, cognitive functions in early old age.
Self-Esteem a Factor?
The findings indicate that the link between childhood reading problems and cognitive function in early old age is at least partly explained by education. “Children with reading problems may be less likely to obtain high levels of education which, in turn, may be linked with poorer cognitive health,” said John.
“Another mechanism which may play a role in the association between childhood reading problems and cognitive function may be reduced self-esteem,” she added. However, the study did not examine the potential effects of reduced self-esteem.
Clinicians should keep in mind that childhood reading problems can affect a patient’s cognitive function for six decades, said John. These problems may be associated with lower scores on commonly used dementia screening tools.
“When assessing cognitive function requiring written test material, clinicians must be aware of whether the patient has any difficulties reading this,” said John.
“It is advisable to improve reading skills for any reason, but our study suggests that this might also have positive implications for cognitive aging,” she added, while cautioning that the study cannot establish causality.
“This particular paper does not provide enough clear evidence to suggest reading skills in childhood are tied to cognitive decline later in life,” said Rebecca Edelmayer, PhD, senior director of scientific engagement for the Alzheimer’s Association, who commented on the findings for Medscape Medical News. “Much more longitudinal research is needed to draw any conclusions.”
Still, evidence increasingly suggests that some social determinants of health early in life, such as access to education resources and quality or duration of education, may influence a person’s risk for cognitive decline and dementia as he or she ages. “It’s important for the Alzheimer’s research field to continue to study the factors that drive dementia risk and how they may be modified to reduce risk,” said Edelmayer.
The study was supported by the Alzheimer’s Society and MRC. John and Edelmayer have reported no relevant financial relationships.
J Epidemiol Community Health. Published online July 6, 2021. Full text
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