Summary: Your personality traits as a teen may predict your risk of developing dementia 50 years later. Teens who were more energetic and those who were calm had a lower risk of being diagnosed with dementia later in life.
For the first time, a study has shown that personality traits as a teenager may predict dementia risk over 50 years later. The study, led by researchers at the University of Rochester, was published in JAMA Psychiatry.
Previous studies have shown a link between early thinking abilities and later dementia. Other studies have also shown personality changes around the time when brain abnormalities can first be detected, but before thinking and memory are impaired. The current study, which was funded by NIA, set out to examine the effects of personality traits measured many decades before dementia begins to develop and long before it can be diagnosed.
The researchers obtained data from 1960 for Project TALENT, the largest national sample of high school students. At baseline, when the tests for 10 personality traits were administered, the average age of each participant was about 16. After examining Medicare records for more than 82,000 people who had participated decades earlier in Project TALENT, the researchers found that 2,543 met criteria for dementia by an average age of about 70.
The analysis showed that the relative risk of being diagnosed with dementia in later life was lower for teens who had higher levels of vigor, which was linked to having an energetic disposition, vitality and a high level of physical activity. The traits of calmness and maturity were also associated with a lower risk of dementia later. Not associated with a dementia diagnosis were personality traits like social sensitivity, sociability and leadership.
The researchers also evaluated the influence of socioeconomic status on the students’ personality test results. Socioeconomic status did not influence the results observed for vigor. But for higher levels of socioeconomic status, the protection from dementia from calmness and maturity increased. At lower socioeconomic status, these two personality traits did not reduce risk for a dementia diagnosis. The authors noted that this finding suggests that lower socioeconomic status is linked to higher chronic stress, which could eliminate the benefits of traits like being calm and mature.
As these older adults continue to age and even more of them develop dementia, additional studies can be conducted to examine the risk for dementia from having certain personality traits at age 16. Additional and stronger evidence for vigor, calmness and maturity as protective personality traits could provide the basis for behavioral modification prevention studies.
Funding: This research was funded by NIA grant R01AG053155.
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Original Research: Open access
“Association between high school personality phenotype and dementia 54 Years later in results from a national US sample”. Chapman BP, et al.
JAMA Psychiatry doi:10.1001/jamapsychiatry.2019.3120.
Association between high school personality phenotype and dementia 54 Years later in results from a national US sample
Personality phenotype has been associated with subsequent dementia in studies of older adults. However, neuropathologic changes often precede cognitive symptoms by many years and may affect personality itself. Therefore, it is unclear whether supposed dementia-prone personality profiles (high neuroticism and low conscientiousness) are true risk factors or merely reflections of preexisting disease.
To examine whether personality during adolescence—a time when preclinical dementia pathology is unlikely to be present—confers risk of dementia in later life and to test whether associations could be accounted for by health factors in adolescence or differed across socioeconomic status (SES).
Design, Setting, and Participants
Cohort study in the United States. Participants were members of Project Talent, a national sample of high school students in 1960. Individuals were identified who received a dementia-associated International Classification of Diseases, Ninth Revision (ICD-9) diagnosis code during any year between 2011 and 2013. The dates of our analysis were March 2018 to May 2019.
Ten personality traits were measured by the 150-item Project Talent Personality Inventory. Socioeconomic status was measured by a composite based on parental educational level, income, occupation, and property ownership. Participants were also surveyed on demographic factors and height and weight.
Main Outcomes and Measures
Medicare records were collected, with dementia diagnoses in the period of 2011 to 2013 classified according to the US Centers for Medicare & Medicaid Services ICD-9–based algorithm. Cox proportional hazards regression models estimated the relative risk of dementia based on the 10 personality traits, testing interactions with SES and adjusting for demographic confounders.
The sample of 82 232 participants was 50.1% female, with a mean (SD) age of 15.8 (1.7) years at baseline and 69.5 (1.2) years at follow-up. Lower risk of dementia was associated with higher levels of vigor (hazard ratio for 1 SD, 0.93; 95% CI, 0.90-0.97; P < .001). Calm and maturity showed protective associations with later dementia that increased with SES. At 1 SD of SES, calm showed a hazard ratio of 0.89 (95% CI, 0.84-0.95; P < .001 for the interaction) and maturity showed a hazard ratio of 0.90 (95% CI, 0.85-0.96; P = .001 for the interaction).
Conclusions and Relevance
This study’s findings suggest that the adolescent personality traits associated with later-life dementia are similar to those observed in studies of older persons. Moreover, the reduction in dementia risk associated with a calm and mature adolescent phenotype may be greater at higher levels of SES. Personality phenotype may be a true independent risk factor for dementia by age 70 years, preceding it by almost 5 decades and interacting with adolescent socioeconomic conditions.