Dementia Risk May Be Linked to One’s Outlook, Study Suggests

People with a sunnier outlook had less dementia risk, a study of nearly 9,100 people suggested.

Over up to 14 years, each standard deviation increase in optimism was tied to a 15% lower risk of developing dementia (HR 0.85, 95% CI 0.82-0.88), after adjusting for age, sex, race and ethnicity, education, depression, and major health conditions, reported Säde Stenlund, MD, PhD, of the Harvard T. H. Chan School of Public Health in Boston, and colleagues.

Associations were similar in both white and Black subgroups, Stenlund and colleagues wrote in the Journal of the American Geriatrics Society. The relationships didn’t change substantially when researchers adjusted for health behaviors, removed the first 2 years of follow-up to reduce risks of reverse causation, or excluded people with the poorest mental health.

The findings “highlight that our personal emotional and social resources — like how hopeful and positive we feel about the future — may be related to keeping our brains healthy as we age,” Stenlund said.

“Our study points to promising new directions for preventing dementia. It suggests that psychological factors such as optimism could eventually be part of strategies to reduce dementia risk,” she told MedPage Today.

“Since optimism may be increased through relatively simple, low-intensity programs, it is helpful to understand how it is related to health in aging,” Stenlund continued. “What we do not yet know is whether boosting optimism in this way is strong enough to actually change a person’s long-term dementia risk. Future research, such as randomized trials, need to test this directly, but our work is important in terms of building an evidence base for these studies.”

Earlier research supports the idea that optimism is associated with healthy aging. For example, in a meta-analysis of 15 studies and 230,000 people, optimism was linked to a reduced risk of cardiovascular events, while pessimism was tied to greater cardiovascular event risk. The pooled association was similar to that of other well-established cardiac risk factors.

In 2022, a study of 159,000 participants from the Women’s Health Initiative showed that higher optimism correlated with a longer lifespan and a greater likelihood of surviving to age 90 or longer. That same year, data from 7,200 postmenopausal women found that less pessimism — but not more optimism — was associated with a lower risk of mild cognitive impairment and dementia.

Stenlund and colleagues evaluated data from 9,071 cognitively healthy individuals in the Health and Retirement Study (HRS) to assess whether optimism was linked with a lower risk of developing dementia and whether associations remained after accounting for initial health status and other potential confounders.

Optimism was measured using the Life Orientation Test-Revised, a six-item scale measuring dispositional optimism, within 2 years of obtaining each person’s first measure of cognitive function. Cognitive assessments were conducted at each of eight waves of data collection from 2006 to 2020. Dementia status was derived using an algorithm specifically developed in the HRS to account for racial and ethnic differences more accurately than other algorithms.

On average, participants were 74 years old at baseline. Follow-up ranged from 2 to 14 years, with a mean of 6.7 years. During this time, 3,027 individuals developed dementia.

The association between higher optimism and lower dementia risk seen in this analysis aligned with previous HRS studies with shorter follow-up times, Stenlund and colleagues observed.

“Our study is the first to directly address concerns about reverse causation, a significant issue as psychological symptoms, such as low mood, have been observed to represent early symptoms of dementia,” they wrote.

However, reverse causation was still a possibility, the researchers acknowledged. “As with any observational study, the possibility of residual or unmeasured confounding remains,” they added.