Changes in personality often become apparent just before dementia arises, but could certain traits in early life associate with dementia risk decades later? Yes, according to a study published October 16 in JAMA Psychiatry. Researchers led by Benjamin Chapman of the University of Rochester Medical Center in New York and Susan Lapham of the American Institutes for Research in Washington, D.C., cross-referenced scores from personality tests taken by thousands of high school students in 1960 with their current medical records. They reported that teens with higher levels of certain adaptive traits—vigor, calmness, and maturity—were less likely to have developed dementia by age 70. How these agreeable personality traits would protect against dementia remains unclear, but the results suggest that personality may be an independent risk factor for dementia, rather than merely a consequence of neurodegenerative pathology.
- Project Talent measured personality traits in teens in 1960.
- Higher “vigor” in high school lowered dementia risk.
- Calm or mature adolescents were also protected, but not those whose socioeconomic status was low.
Certain undesirable personality traits—such as neuroticism, impulsivity, and lack of conscientiousness—can appear in the years preceding a dementia diagnosis, but those attributes can also intensify during the symptomatic stages of the disease (Yoneda et al., 2016; Tautvydaité et al., 2017; Terracciano et al., 2019). This complicates efforts to understand whether personality quirks arise as a consequence of neurodegeneration, or are independent risk factors for those diseases.
To address this question, the researchers accessed personality data gathered from Project Talent—a massive study of high school students in the United States in 1960. At the time, more than 377,000 students participated in two days of tests and questionnaires, including a 150-item personality test that quantified 10 personality traits, such as sociability, impulsivity, leadership, vigor, calm, maturity, and self-confidence. More than 82,000 of those participants were recently identified in the Medicare claims database, allowing researchers to link their attributes in 1960 to their current health. Previously, the researchers tied adolescent personality traits in this cohort to all-cause mortality, and linked some teenage cognitive aptitudes to dementia risk (Oct 2018 news on Huang et al., 2018).
For this study, they asked whether adolescent personality traits associated with dementia diagnosis. Of the 82,232 participants, 2,543 (3.1 percent) met the criteria for dementia between 2011 and 2013, when they averaged 69 years of age. Each of the 10 personality traits was recorded as a range, allowing the researchers to correlate dementia risk with each standard deviation from the mean of that trait. A 7 percent lower risk of dementia for each standard deviation above the mean popped up for “vigor.”
What was 1960s vigor, a reader may ask? The measure comprised vitality, energy, and general activity level. It offered protection independently of socioeconomic status, which was defined by the education, income, and property ownership of each participant’s parents in 1960. Two other personality traits—calm and maturity—afforded about a 10 percent protection from dementia, but only for those with above-average socioeconomic status.
The researchers also found that people who possessed a combination of positive traits—social sensitivity, calm, tidiness, culture, and maturity—had a lower dementia risk. Protection afforded by this so-called “general personality factor” increased with higher socioeconomic status. A calm personality—also described as low neuroticism score—might reflect healthier physiological responses to chronic stress. Low socioeconomic status can cause chronic stress, and even a calm personality may be unable to offset a high degree of strain that comes with poverty, the researchers speculated.
The findings cast certain adolescent personality traits as risk factors for dementia by age 70. The authors speculated that vigor could be a proxy for physical activity and enthusiastic engagement with life. If these characteristics continue throughout life, they could hedge dementia risk, they proposed. “While social class may shape the specific type or content of one’s life activities, the beneficial nature of energetic enthusiasm appears to be constant across the socioeconomic spectrum,” they wrote.
“These results are certainly consistent with the current literature linking personality as a behavioral/lifestyle indicator of dementia risk in older adults,” commented Janet Duchek of Washington University in St. Louis. “This study provides further evidence that these personality traits may serve as important proxies for various protective lifestyle and health behaviors over the course of the lifespan, such as engagement in physical, cognitive, and social activities.”—Jessica Shugart
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