In the JournalsPerspective

Teenagers with cognitive disabilities may be at higher risk for Alzheimer’s disease

Adolescent girls with lower memory for words and adolescent boys with lower mechanical reasoning had higher odds of developing Alzheimer’s disease and related disorders, according to findings recently published in JAMA Network Open.

“Elucidating the specific early-life cognitive abilities that reliably correlate with dementia risk in later life can inform targeted focus areas for prevention and intervention efforts,” Alison R. Huang, MPH, from the American Institutes for Research in Washington, D.C., and colleagues wrote.

Researchers analyzed IQ, general cognitive ability, cognitive aptitude and general academic aptitude scores from 1960 in a cohort of 43,014 male adolescents and 42,749 female adolescents alongside these same patients’ 2012 and 2013 Medicare claims and expenditure data.

Huang and colleagues found that lower memory for words as a teenager was associated with increased odds of Alzheimer’s disease and related disorders in women (OR = 1.16; 95% CI, 1.05-1.28) and lower mechanical reasoning as a teenager was associated with increased odds of Alzheimer’s disease and related disorders in men (OR = 1.17; 95% CI, 1.05-1.29) after accounting for demographic characteristics, socioeconomic status as a teenager, regional effects and participant’s sex.

In addition, lower performance on several other mathematics, visualization, reasoning and language aptitude tests as teenagers showed prominent, but weaker, associations of the same link. In total, 1,416 women and 1,239 men developed Alzheimer’s disease and related disorders, according to researchers.

“The mechanism underlying the relationship between adolescent cognitive ability and [Alzheimer disease and related disorders] is still unclear; however, these results provide insight into the specific aspects of cognitive aptitude involved,” Huang and colleagues wrote, noting that many of their findings mirror previous studies that explored similar associations.

Teenagers Walking
Adolescent girls with lower memory for words and adolescent boys with lower mechanical reasoning had higher odds of developing Alzheimer’s disease and related disorders, according to findings recently published in JAMA Network Open.

Photo source:Shutterstock

“Our results ... bring forth the potential for specific measures of cognitive ability to assist in very early identification of subgroups at risk for [Alzheimer’s disease and related disorders],” they concluded.

Tom C. Russ, PhD, MRCPsych, of the Alzheimer Scotland Dementia Research Centre, in the United Kingdom, agreed that Huang and colleagues’ findings advance the understanding of cognitive ability as an adolescent with limited cognitive function ages.

“However, as with all observational research, there remains the need to clarify whether these associations are causal. ... we now need to consider interventional research,” he wrote, adding that researching both the modifiable and non-modifiable health factors that possibly impact cognitive reserve is an important next step.

“If, as a result, cognitive reserve could be modified before the clinical onset of dementia (even if Alzheimer’s disease were present in the brain), this may delay the onset of these clinical symptoms which would, in turn, reduce the number of people affected by dementia worldwide. Given the growing global public health burden of dementia, this is a vital question,” Russ wrote. – by Janel Miller

Disclosures : The authors report no relevant financial disclosures.

Adolescent girls with lower memory for words and adolescent boys with lower mechanical reasoning had higher odds of developing Alzheimer’s disease and related disorders, according to findings recently published in JAMA Network Open.

“Elucidating the specific early-life cognitive abilities that reliably correlate with dementia risk in later life can inform targeted focus areas for prevention and intervention efforts,” Alison R. Huang, MPH, from the American Institutes for Research in Washington, D.C., and colleagues wrote.

Researchers analyzed IQ, general cognitive ability, cognitive aptitude and general academic aptitude scores from 1960 in a cohort of 43,014 male adolescents and 42,749 female adolescents alongside these same patients’ 2012 and 2013 Medicare claims and expenditure data.

Huang and colleagues found that lower memory for words as a teenager was associated with increased odds of Alzheimer’s disease and related disorders in women (OR = 1.16; 95% CI, 1.05-1.28) and lower mechanical reasoning as a teenager was associated with increased odds of Alzheimer’s disease and related disorders in men (OR = 1.17; 95% CI, 1.05-1.29) after accounting for demographic characteristics, socioeconomic status as a teenager, regional effects and participant’s sex.

In addition, lower performance on several other mathematics, visualization, reasoning and language aptitude tests as teenagers showed prominent, but weaker, associations of the same link. In total, 1,416 women and 1,239 men developed Alzheimer’s disease and related disorders, according to researchers.

“The mechanism underlying the relationship between adolescent cognitive ability and [Alzheimer disease and related disorders] is still unclear; however, these results provide insight into the specific aspects of cognitive aptitude involved,” Huang and colleagues wrote, noting that many of their findings mirror previous studies that explored similar associations.

Teenagers Walking
Adolescent girls with lower memory for words and adolescent boys with lower mechanical reasoning had higher odds of developing Alzheimer’s disease and related disorders, according to findings recently published in JAMA Network Open.

Photo source:Shutterstock

“Our results ... bring forth the potential for specific measures of cognitive ability to assist in very early identification of subgroups at risk for [Alzheimer’s disease and related disorders],” they concluded.

Tom C. Russ, PhD, MRCPsych, of the Alzheimer Scotland Dementia Research Centre, in the United Kingdom, agreed that Huang and colleagues’ findings advance the understanding of cognitive ability as an adolescent with limited cognitive function ages.

“However, as with all observational research, there remains the need to clarify whether these associations are causal. ... we now need to consider interventional research,” he wrote, adding that researching both the modifiable and non-modifiable health factors that possibly impact cognitive reserve is an important next step.

“If, as a result, cognitive reserve could be modified before the clinical onset of dementia (even if Alzheimer’s disease were present in the brain), this may delay the onset of these clinical symptoms which would, in turn, reduce the number of people affected by dementia worldwide. Given the growing global public health burden of dementia, this is a vital question,” Russ wrote. – by Janel Miller

Disclosures : The authors report no relevant financial disclosures.

    Perspective
    Rebecca Edelmayer

    Rebecca Edelmayer

    The findings by Huang and colleagues suggest that education across the life course, particularly at a young age, may be helpful in decreasing the risk for Alzheimer’s and related diseases in the future.

    Though we do not know the best recipe yet for completely eliminating the risk for these diseases, research has shown that some risk for developing these disorders could be decreased across the life course. Engaging in multiple activities that promote well-being, such as continuing one’s education, eating healthy, exercising regularly and maintaining normal BP and BMI as early in life as possible may likely provide maximum benefits for the body and the brain. The Alzheimer’s Association publication 10 Ways to Love Your Brain provides more details on this.

    It is important to note that Huang and colleagues looked at tests that were designed and implemented in the 1960s, and then the actual diagnosis of dementia appearing on their Medicare record more than 50 years later. Consequently, it is difficult to pinpoint if the tests done in that earlier time are as relevant as we would want them to be today. Huang also makes the important observation that their research was limited in diversity with low African-American and Hispanic representation, which could change the impact of the results, as they may not be generalizable to current United States demographics. Furthermore, using Medicare records to diagnose Alzheimer’s and related diseases presents its own set of challenges, because physicians are not always having conversations about mild cognitive impairment and cognitive decline with their patients, and patients are also reluctant to have conversations with their health care professionals about Alzheimer’s and related diseases as well. 

    Thus, Huang and colleagues’ findings contribute to our understanding of early-life risk factors. However, additional studies in this area are needed to guide prevention and early intervention efforts. The Alzheimer’s Association is always advocating for more research that may prove (or disprove) a cause and effect, or an association, with cognitive decline and education.

    Reference:

    Alzheimer’s Association. 10 Ways to Love Your Brain. https://www.alz.org/help-support/brain_health/10_ways_to_love_your_brain. Accessed September 13, 2018.

    • Rebecca Edelmayer, PhD
    • Director of scientific engagement
      Alzheimer's Association

    Disclosures: Edelmayer reports no relevant financial disclosures.