Diet, sleep, activity, and optimism linked to lower dementia risk — studies

04.09.2026. According to SigmaLive and the ΑΠΕ-ΜΠΕ agency, several international studies published in the Journal of the American Geriatrics Society, the American Academy of Neurology's journal Neurology, and the open-access journal PLOS One have shown a link between lifestyle and dementia risk.

One study analyzed data from 9,071 cognitively healthy participants in the American Health and Retirement Study, followed for up to 14 years. Higher-than-average optimism was associated with a 15% lower risk of developing dementia after adjusting for age, sex, background, education, depression, and serious illnesses.

A study published in Neurology covered 92,849 people (average age 59) and showed that adhering to a high-quality plant-based diet—prioritizing whole grains, fruits, vegetables, plant oils, nuts, and legumes—is associated with a lower risk of Alzheimer's disease and other forms of dementia. Conversely, a "low-quality" plant-based diet with an excess of added sugars, refined grains, and potatoes as part of processed meals or fast food was linked to a higher risk. The authors emphasize that this refers to correlation, not a proven causal link.

A meta-analysis of 69 studies showed that regular physical activity and 7–8 hours of night sleep are associated with a lower risk of dementia: activity was associated with an average 25% reduction in risk. Sleeping less than 7 hours and more than 8 hours was linked to an 18% and 28% increased risk, respectively; a sedentary lifestyle for more than 8 hours a day was linked to a 27% increased risk. The authors note significant heterogeneity in the data.

For residents in Cyprus, these results mean: prioritizing high-quality plant-based foods, maintaining regular physical activity, aiming for 7–8 hours of sleep, and reducing prolonged sitting, keeping in mind that the conclusions are based on observational data.