Higher optimism is associated with a lower risk of dementia

An analysis of Health and Retirement Study data found that higher optimism was associated with a somewhat lower risk of developing dementia over a study period of up to 14 years. The association remained even after the study authors accounted for health behaviors, controlled for possible reverse causation (the possibility that the early stages of dementia reduce optimism), and excluded individuals with the poorest mental health. The paper was published in the Journal of the American Geriatrics Society.

Optimism is the general tendency to expect favorable outcomes and believe that difficulties can be managed or overcome. It involves positive expectations about the future rather than simply feeling cheerful in the present.

Studies show that optimistic people are more likely to use active coping strategies, persist toward goals, and seek help when needed. Higher optimism is associated with better psychological well-being and lower levels of depression, anxiety, and perceived stress. It has also been linked to healthier behaviors, including greater physical activity, better diet, and stronger adherence to medical advice.

Some studies associate optimism with better cardiovascular health, stronger immune functioning, and a lower risk of premature death. These health benefits may partly arise because optimistic people cope more effectively with stress and maintain stronger social relationships. However, optimism does not guarantee good health, and many associations may also reflect personality, socioeconomic circumstances, or existing health differences.

Säde Stenlund, a researcher at the Harvard T.H. Chan School of Public Health, and colleagues noted that many previous studies have already linked higher optimism to better cognitive health, including some longitudinal studies. However, they pointed out that these studies usually have relatively shorter follow-up periods that do not fully account for the possibility of reverse causation between optimism and cognitive health.

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The researchers analyzed data from the Health and Retirement Study with the aim of exploring the longitudinal association between optimism and the risk of developing dementia over a longer period. The Health and Retirement Study is an ongoing, nationally representative cohort study in the U.S. that began in 1992 and has followed men and women aged 50 years and older through biennial in-person interviews, telephone, and mailed questionnaires.

For this analysis, study authors used data from participants who completed cognitive assessments and provided data in in-person or telephone interviews at the age of 70 or older. This information was needed for a dementia assessment algorithm to determine whether participants suffered from dementia. Optimism was measured through self-reports via the Life Orientation Test-Revised Scale.

In total, the analysis used data from 9,071 individuals who were dementia-free when enrolled in the study. Their average age at that time was 74 years. On average, they were followed for 6.7 years, with a maximum follow-up of 14 years. About 57% of participants were women.

Results showed that 3,027 participants developed dementia over the course of the study. Participants with higher optimism were less likely to develop dementia. More specifically, for each one standard deviation increase in optimism, the risk of developing dementia over the course of the study was 15% lower after taking into account age, sex, race, ethnicity, education, chronic health conditions, and probable depression.

Interestingly, adding health behaviors (like physical activity and smoking) did not qualitatively change the findings. The findings also held when study authors controlled for possible reverse causation by excluding individuals who developed dementia within the first two years of follow-up.

“Higher optimism was associated with a lower incidence of dementia,” the study authors concluded. “These findings suggest a potential value of optimism in supporting healthy aging, which could be considered in future research on dementia prevention initiatives.”

The study contributes to the scientific knowledge about dementia risk and protective factors. However, study authors note that a number of potentially eligible participants were excluded from analyses due to missing data. These individuals tended to be slightly younger, more often non-Hispanic White, had somewhat higher education, and were generally healthier. This could affect the generalizability of findings somewhat. Because the study was observational, the possibility of unmeasured confounding variables remains.

The paper, “The Bright Side of Life: Optimism and Risk of Dementia,” was authored by Säde Stenlund, Hayami K. Koga, Peter James, Justin Farmer, Colleen B. McGrath, Francine Grodstein, and Laura D. Kubzansky.