HMN 2024: Can I Prevent Dementia? |

Older adult with walker.

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Aging is associated with reduced performance in multiple domains of cognition: memory, executive functions (planning, inhibition, manipulating information in one’s mind), language, processing speed, and visuospatial abilities. If there is an ongoing neurodegenerative disease within an individual, then cognitive decline will be accelerated. Yet, not all individuals experience age-related decline at the same rate: individual differences play an important role in the maintenance of cognitive function and dementia risk. For instance, in my work with Ohio Senior Olympians over the years, I have seen septuagenarians run 1500 meters (nearly a mile) in under 6 min 15 sec—a time that very few of the twenty-something-year-old undergraduate students in my Psychology classes at Ohio State could match. Septuagenarians at the other end of the fitness and mobility spectrum require a walker to ambulate across a room. These individual differences, not only in fitness and mobility, may impact brain health and dementia risk.

Individual differences in modifiable risk factors can prevent or delay dementia

Modifiable dementia risk factors include physical inactivity, obesity, and excessive alcohol consumption.

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In 2017, a highly cited study by Livingston et al. published in the Lancet identified nine modifiable variables that could reduce dementia risk. With additional scientific evidence accumulating over the last few years, the list of modifiable variables that reduce dementia risk has grown to 14 variables, as highlighted in follow-up work by Livingston et al. (2020; 2024) and published in The Lancet. Together, these variables account for roughly 45% of dementia cases. This work has highlighted a shift in the field of aging and neurodegenerative disease. Due to the continued absence of effective, accessible, and practical pharmacological interventions to treat neurodegenerative diseases that cause dementia, a lifespan approach aimed at preventing or delaying dementia onset has become more central to the field. This approach acknowledges that neurodegenerative disease and neuropathology accumulate over the course of years and that lifestyle changes throughout the lifespan can mitigate dementia risk. For instance, Alzheimer’s disease-related neuropathology can be found in middle-aged adults, decades before the onset of cognitive symptoms.

The initial report in The Lancet, 2017, highlighted 9 risk factors for dementia:

In the 2020 and 2024 Lancet Commission reports on dementia, the list was updated with the following risk factors:

Importantly, this series of studies highlights the opportunities available for individuals to reduce their dementia risk. Certainly, the list highlights a theme of implementing healthy behaviors to reduce dementia risk. This includes limiting alcohol intake and smoking, as well as exercising and healthy eating and/or medication adherence to reduce hypertension, high LDL cholesterol, diabetes, and obesity.

Air pollution at a car factory.

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Other risk factors may be modifiable but less amenable to change at the individual level. For instance, one may have economic, occupational, family, or social constraints that prevent them from moving away from an area with high air pollution or that had prevented them from pursuing more education during their childhood. Intervention for these risk factors would be more amenable to community-level interventions, such as regulations that reduce air pollution or enhancing resources for children and young adults to pursue higher levels of education. Importantly, addressing many of these risk factors would benefit from community-level efforts. Examples include programs to increase education surrounding traumatic brain injury and making helmets available to children and bike riders, or infrastructure to make communities more walkable and bikeable to encourage physical activity and reduce air pollution.

Importantly, the list of modifiable variables will likely continue to grow. For instance, there are other variables, such as sleep, nutrition, and dental disease, that may be added to the list in the future. Although there are some studies indicating these factors are associated with cognition, the evidence to date was considered insufficient to formally include them as a risk factor.

The bottom line from this series of studies: To most effectively reduce dementia risk, address as many of these modifiable variables as possible. The more years that you can limit these risk factors (e.g., smoking, excessive drinking, physical inactivity), the more you will likely reduce your risk for dementia.