A new study concludes that being more optimistic is associated with longer life expectancy and the likelihood of high longevity.
Previous studies have already shown that optimism is associated with a reduced risk of premature death and longer life expectancy.
The novelty of the study lies in focusing on high longevity. Thus, greater optimism is associated with the probability of reaching the age of 85, at least.
Genetics, psychosocial factors, and health
Longevity research has focused on identifying biological factors – especially genetic variants – associated with increased survival. However, as we discussed , growing evidence suggests that non-genetic factors are more important.
Thus, recent epidemiological studies have identified psychosocial characteristics – among which is being optimistic – as a potential predictor of a longer life. In this sense, a strong relationship is observed between a high level of optimism and a reduced risk of developing chronic diseases, including a lower risk of cardiovascular events, metabolic diseases, a decline in lung function, and, ultimately, a decrease in premature mortality.
Study characteristics
The new study carried out by researchers at Harvard University in the US and recently published in the journal PNAS, was based on the hypothesis that a higher degree of optimism was associated with longer life expectancy and longer longevity (over 85 years).
This association was replicated in two independent cohorts, one of the women and the other of men, after adjusting for confounding factors and related variables.
Study participants
NSH participants have been followed up since 1976 with biennial questionnaires, and optimism assessment in 2004, and mortality follow-up until 2014. NAS participants have been followed since 1961, with an evaluation of the degree of optimism in 1986 and a follow-up of mortality until 2016.
Qualitatively, the women evaluated with higher levels of optimism had a higher degree of education and were less likely to suffer from depression and type 2 diabetes.
Likewise, they were less likely to have depressive symptoms and type 2 diabetes and reported lower alcohol consumption and lower BMI.
In both women and men, greater optimism meant a greater degree of physical activity.
During the 10 and 30 years of NHS and NAS follow-up, respectively, mortality reached 13% of women and 71% of men.
Study results
The results of the study suggest that optimism is presented as a psychological aspect that promotes health and longevity. Thus, optimism would be a valuable independent goal for health promotion.
Women
In the model adjusted according to demographic and health conditions at the beginning of the study, women with greater optimism had a life expectancy 15% greater than those less optimistic (95% CI: 11.9-18.0%).
To contextualize the magnitude of these estimates, not having type 2 diabetes was associated with a 17.0% greater life expectancy and never having suffered a myocardial infarction, 18.0% greater.
After further adjustment of health habits, the association between optimism and life expectancy attenuated but remained statistically significant. Thus, the most optimistic women had a life expectancy 8.7% higher than the pessimistic ones (95% CI: 5.8-11.6%).
Men
In the case of men, higher optimism at the beginning and after adjusting for sociodemographic variables, health conditions and depression, was associated with a life expectancy 10.0% greater than in the less optimistic (95% CI: 1.3-21.5%).
In this case, not suffering from type 2 diabetes was associated with a 13.1% greater life expectancy and not suffering from coronary disease, with a 16.6% greater life expectancy (95% CI: 10.4-22,4%).
As in women, the adjustment according to health habits determined a life expectancy of 9.8% higher for the most optimistic vs. the least (95% CI: 0.3-20.3%).
High longevity
In the NHS, of the 13,045 women born early enough to reach at least 85 years, 86% survived to that age. Greater optimism was associated with a greater likelihood of achieving that high longevity.
Thus, after adjusting for demographic factors, health conditions and depression, the probability of achieving high longevity was 50% higher in the most optimistic (OR: 1.5; 95% CI: 1.2-1, 7).
In the NAS, of the 1,117 eligible men, 56% were over the age of 85. The Odds Ratio or probability of reaching high longevity for the most optimistic men was 1.7 (95% CI: 1.1-2.6), that is, a 70% more probability of reaching 85 years.
Optimism, goals, and life expectancy
Optimistic people often have vital goals and greater availability and determination to achieve them. Optimism can also provide greater effectiveness in solving problems and the ability to readjust initial goals when they become unattainable.
On the other hand, the association between life expectancy and optimism remains after adjusting for numerous health conditions, including high cholesterol, hypertension, type 2 diabetes, heart disease, stroke, and cancer.
Be optimistic: optimism is learned!
Researchers have speculated that optimism may facilitate healthier behaviors and longer longevity since optimism contributes to how goals translate into behaviors.
Some estimates indicate that being optimistic can be a condition of heritable character in 25%, but it is also influenced by environmental, social, and structural factors that determine the possibility of their learning.
In this sense, some studies have shown that relatively brief interventions can increase optimism in the short term.
Grade of evidence and recommendation
To begin with, it must be made clear that since it is an observational study, conclusions of cause and effect cannot be drawn.
An important strength of the study is the inclusion of a large sample of participants and the consideration of a wide set of variables that could influence the association between optimism, life expectancy, and longevity.
Some limitations of the study are that both cohorts mostly include white people with high socioeconomic status. In this sense, other studies have found that higher education, income level, and occupational status can determine higher levels of optimism in individuals. On the other hand, ethnic differences are less clear.
One of the uncertain factors is how early life circumstances shape the level of optimism and the likelihood of achieving high longevity. However, optimism seems highly stable in adulthood.
Finally, reverse causality cannot be ruled out, that is, individuals with less health or who are already ill are less optimistic and therefore less likely to achieve high longevity.
Therefore, we are at a secondary level of evidence that allows recommendation level B. In any case, it is not going to hurt anyone – especially those around you – to be advised to be a little more optimistic.
