Having a positive outlook on life could reduce the risk of developing dementia by at least 15 percent, according to new research from the Harvard T.H. Chan School of Public Health. The study, published on Wednesday, analysed data from more than 9,000 healthy adults aged 50 and older over 14 years.
Researchers measured participants' optimism using a six-point scale and found that each higher point was associated with a 15 percent lower risk of dementia, regardless of age, sex, race or other health factors. About a third of participants developed dementia during the study period, but those with higher optimism were least at risk.
The findings suggest that optimism may protect brain health by lowering levels of the stress hormone cortisol and reducing harmful inflammation, both linked to dementia. The researchers noted that optimistic individuals tended to be more educated, less likely to smoke, more physically active and had fewer health conditions.
With roughly 7.2 million Americans currently living with Alzheimer's disease—a figure expected to nearly double by 2050—the study highlights the potential value of optimism in supporting healthy ageing. The authors called for further research into how optimism could be incorporated into dementia prevention initiatives.
Previous studies have also linked optimism to longer lifespan and slower cognitive decline. Experts suggest that fostering a sense of purpose and self-efficacy can help older adults maintain a positive outlook, which may in turn reduce dementia risk.
