Dementia’s roots trace all the way back to childhood, experts find

Dementia is often associated with older people, but it doesn’t just appear out of nowhere.

Some risk factors may begin before we are born, while others appear as we grow from childhood to adulthood.

According to research, that may be the best time to start an intervention.

Previous studies have identified various modifiable risk factors for dementia, but modifying them once neurodegeneration has set in doesn’t do much, encouraging researchers to look to the early moments of life for actions that could one day make a difference.

Related: Dementia in young people is often overlooked. Here are 5 major reasons.

A 2023 study by researchers in Sweden and the Czech Republic identified a handful of birth factors associated with a slightly increased risk of dementia later in life.

While some, such as sharing a womb with twins, is beyond anyone’s control, others – such as short spacing between births, and being pregnant over the age of 35 – can weigh on parents’ decisions.

You can watch a video summary of some of the research in this article here:

Another study published in late 2024 looked at risk factors for young adults ages 18 to 39. A team led by Ireland’s Global Brain Health Institute (GBHI) brought together a group of experts from 15 countries around the world to help develop a lifelong plan to promote brain health.

“Young adulthood represents a critical window for intervention that can significantly reduce the risk of dementia in later life,” said GBHI neuroscientist Francesca Farina.

“To secure healthy brain outcomes, young adults must be included as key partners in research, education, and policymaking efforts.”

Some of the risk factors identified by the researchers are related to lifestyle, including excessive alcohol consumption, smoking, physical inactivity and social isolation.

Others are environmental, such as pollution exposure, traumatic brain injury, hearing or vision loss, or low levels of education. And others, such as obesity, diabetes, high blood pressure, LDL cholesterol, and depression, are health problems that can arise from lifestyle choices.

Ultimately, the researchers suggest that there are steps we can take to help reduce the risk of developing dementia, which begins much earlier in our lives than most people realize.

“Can dementia have its roots in infancy or childhood? Growing evidence suggests yes, and exposure to risk factors in the first decade of life (or even during pregnancy) can have lifelong implications for dementia risk,” the team explained in an article in Conversations published earlier this year.

“Most dementia research focuses on associative changes [age-related cognitive] decline in later life. But there is evidence that many of the differences in brain structure and function associated with dementia in older adults may date back, at least in part, to childhood.”

According to the team, there are many examples of this.

“In longitudinal studies where people have tracked their cognitive ability throughout their lives, one of the most important factors explaining someone’s cognitive ability at age 70 is their cognitive ability when they were 11 years old,” the study authors explained.

“That is, older adults with poorer cognitive skills often have these reduced skills from childhood, rather than differences simply due to rapid decline in old age.”

Another possible indication is evidence of brain injury or abnormalities later in life that may be related to events or behaviors in youth.

“While looking for evidence of dementia-related damage in brain scans, similar patterns were seen, with some changes appearing to be more closely related to risk factor exposure in early life than current unhealthy lifestyles,” the authors explained.

“Taken together, perhaps it’s time to think of dementia prevention as a lifelong goal rather than focusing on aging.”

In their 2024 study, some of the identified risk factors became apparent. Drinking and smoking, for example, are generally considered bad for health, and are a direct risk for dementia after brain injury.

But others take a more circuitous route – hearing or sight loss, for example, is also linked to dementia, possibly due to brain degeneration or social isolation.

Knowing the risks is one thing, but mitigating them is difficult. The researchers suggest that the problem can best be addressed by identifying factors at the individual, community and national levels.

Helping people on a personal level involves raising awareness about the importance of brain health and risks, the team says.

This can be done with public health campaigns and school education, and can be funded through taxes on substances that negatively affect brain health, such as alcohol or cigarettes.

At the community level, the team recommends developing an advisory council of diverse young adults to “act as a liaison with local governments to provide relevant knowledge about brain health in the community.”

And at the national level, the panel recommends creating and committing to a Brain Health Charter to keep people on track for good brain health throughout their lives.

“Young adults have a real hunger to learn more about their brain health – they are very aware of cognitive and neurodiversity, many can be identified with a diagnosis such as ADHD or autism,” said GBHI social gerontologist Laura Bui.

“This awareness drives their strong interest in understanding and improving their brain health.”

The identified factors are also not constant. The team says that emerging factors including ultra-processed foods, drug use, screen time, stress, and microplastic exposure require further study.

The research was published in 2015 Lancet: Healthy Longevity.

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