A simple, memorable model to help prevent Alzheimer’s disease and dementia

Toronto: Alzheimer’s disease (AD) is on track to become one of the defining public health challenges of our time. Every three seconds, somewhere in the world, someone is diagnosed with dementia, and it’s usually Alzheimer’s disease.

Currently, approximately 50 million people worldwide have AD. By 2050, this number will exceed 130 million.

The human health and socioeconomic consequences of this are going to be immense. But perhaps it doesn’t have to be this way.

Preventing Alzheimer’s disease

A 2024 report from the influential Lancet Commission suggests that up to one-third of AD cases could be prevented simply by avoiding certain risk factors. These 14 modifiable risk factors encompass: traumatic brain injury, hypertension, depression, diabetes, smoking, obesity, high cholesterol levels, low physical activity levels, too much alcohol consumption, too little education, vision loss, hearing loss, social isolation and air pollution.

SHIELD (Sleep, Head Injury prevention, Exercise, Learning and Diet) may fill that role. SHIELD brings together the most significant, overlapping dementia risk factors into five core pillars, offering a clear and effective strategy for prevention.

Sleep

Sleep is a foundational element of SHIELD. Maintaining healthy sleep habits is a key protective factor against dementia. Adequate sleep supports brain function, memory, mood and learning.

Insufficient (less than five hours per night) or poor-quality sleep (frequent awakenings), especially in midlife, increases the risk of cognitive decline and dementia.

Head injury

Head injury prevention is, rather surprisingly, often overlooked in conversations about dementia. There are strong links between traumatic brain injuries, including concussions, and higher AD risk. Such head injuries can occur in a wide variety of settings, not just professional sports.

Exercise

Exercise is perhaps the most powerful lifestyle habit for reducing the risk of AD. Exercise directly addresses multiple major risk factors, including obesity, high blood pressure, high cholesterol and depression.

Learning

Learning, both in and out of school, remains one of the strongest protective factors against dementia. Lower educational levels, such as not finishing secondary school, are linked to a significantly increased risk for dementia.

Learning contributes to the brain’s “cognitive reserve,” which is the brain’s ability to function well despite damage or disease.

Diet

Diet also plays a major role in brain health and dementia prevention. No single food prevents dementia. Rather, a combination of nutrient-rich foods supports overall brain health.

A healthy diet can lower dementia risk by emphasizing whole foods like fruits, vegetables, whole grains, nuts and fish, while restricting processed foods, red meat

and sweets.

Adhering to dietary patterns like the Mediterranean diet has shown promising results in protecting against cognitive decline.