Many of the biggest dementia risk factors are preventable

A new study of more than 13,000 adults in the United States links household income to several health risks. Many of those risks feed into dementia, a condition that damages memory, thinking, and daily independence.

In the data, the heaviest burden of dementia- related risks fell on people with the lowest incomes. Those at the very bottom of the income scale often had several of these risks stacked together in late life.

Everyday risk factors for dementia

Dementia risk does not depend only on genes or age; it also reflects everyday risk factors. Income shapes many of these conditions, from the food people can afford to the health care they can access.

The work was led by Dr. Eric L. Stulberg at Thomas Jefferson University Sidney Kimmel Medical College in Philadelphia (TJU). His research focuses on how social and economic conditions influence brain health and dementia risk in everyday communities.

Dr. Stulberg and colleagues examined national health survey data to see how often certain dementia risks appeared at different income levels. 

Many of these risks were modifiable, changeable through treatment or lifestyle choices, which means they might be lowered with the right support.

Income makes a difference

The team drew on data from a large U.S. health survey that regularly checks how common major conditions and behaviors are across the country. 

They focused on 13 dementia-linked risks, including smoking, untreated hearing loss, vision loss, high blood pressure, depression, and social isolation, having very few regular social contacts.

The researchers grouped people by income, from households below the poverty line to those far above it.

With each step up the income ladder, adults in midlife were about 9 percent less likely to carry an additional dementia risk.

Vision loss and social isolation

The researchers then asked how many dementia cases might, in theory, be delayed or prevented if each risk factor could be removed.

Among older adults living below the federal poverty line, they estimated that vision loss and social isolation could each be linked to about one in five dementia cases.

The analysis separated adults into early life, midlife, and late life groups to see when each risk factor mattered most.

That life course view helps explain why education and smoking stand out earlier on, while sensory problems and loneliness become important as people age.

Poverty can amplify other issues

Outside this new analysis, other research has shown that older adults with both hearing and vision problems face higher chances of developing dementia.

Individuals with sensory impairment, serious trouble with both hearing and vision, had more than double the risk of dementia.

Researchers report that older adults with vision loss are about 50 percent more likely to develop dementia than people with normal sight.

Trouble seeing can make it harder to move around, read, or recognize faces, which often shrinks social life and daily activity levels.

In another U.S. study, socially isolated older adults had a 27 percent higher risk of developing dementia over nine years than connected peers. 

The new income analysis fits into this picture, suggesting that poverty can amplify the damage from losing sight or from being cut off socially.

Income, identity, and unequal risk

Not every dementia-related risk dropped as income rose. Obesity, high LDL cholesterol, and past head injuries stayed common even in the top income group, pointing to different causes and habits.

Even after accounting for income, historically underrepresented groups in research had more diabetes, obesity, physical inactivity, and vision loss than white adults.

The authors stressed that race and ethnicity are social constructs, categories shaped by society not biology, so gaps reflect inequities in health services.

A commission on dementia prevention has estimated that tackling 12 modifiable risks could delay or prevent about 40 percent of dementia cases worldwide.

Dr. Stulberg’s research suggests that without addressing income and structural inequities, global prevention goals may leave many high-risk communities behind.

Turning dementia risk factors into action

The income results do not mean dementia is inevitable for people with low incomes, but highlight where prevention efforts could have more impact.

Treating hearing and vision problems, controlling high blood pressure and diabetes, and creating chances for regular social contact are all practical targets.

Dr. Stulberg noted that some groups may bear a higher burden of many modifiable dementia risk factors.

He also suggested that improving access to vision care and reducing social isolation among older adults could potentially have a major impact. 

The study is published in the journal Neurology

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