Cognitive decline can begin years before signs of dementia appear, which for some can begin as early as age 30, a condition known as dementia praecox. Globally, nearly 4 million people aged 30 to 64 are estimated to be living with the condition, according to a 2021 study, and the number of cases is increasing.
The main risk factors for dementia later in life and Alzheimer’s disease are well known: older age and biological sex at birth (women are more likely to get Alzheimer’s disease). Genetics also determine risk: People who inherit one or more copies of the APOE4 gene are at greater risk of developing Alzheimer’s disease, although many never develop the disease. Although these risks are not modifiable, other risk factors exist, including smoking, prediabetes and diabetes, obesity, high blood pressure, depression, social isolation, and hearing loss.
Young-onset dementia is thought to be primarily driven by the APOE4 gene, with little research into other causal factors. However, a new study has found that many of the same risk factors may contribute to the early onset of dementia, offering new hope for slowing or preventing the disease.
“This changes our understanding of young-onset dementia, challenging the idea that genetics is the sole cause of the disease and highlighting that a range of risk factors may be important,” said the lead author. of the study, Stevie Hendriks, postdoctoral researcher in psychiatry and neuropsychology at Maastricht University in the Netherlands.
“In addition to physical factors, mental health also plays an important role, including avoiding chronic stress, loneliness and depression,” Hendriks said in an email. “The fact that this was also evident in early-onset dementia surprised us, and it could also provide opportunities to reduce risk in this group.”
The findings echo clinical work done with patients trying to combat advancing dementia, said Dr. Richard Isaacson, director of research at the Florida Institute for Neurodegenerative Diseases, who was not involved in the study.
“Based on my observations over more than a decade of seeing at-risk patients, I strongly disagree that people are powerless in the fight against early cognitive decline,” Isaacson said in an email. “On the contrary, my clinical experience is much more consistent with the results of this new study, which is that it really is possible to take the bull by the horns and be proactive about certain lifestyle and other health factors, in order to reduce the risks.”
Staying active, being socially connected and eating a healthy diet are all ways to reduce the risk of cognitive decline, experts say.
In the study, published Tuesday in the journal JAMA Neurology, researchers followed 356,000 men and women enrolled at age 40 in a longitudinal health study called the UK Biobank. Blood, urine and saliva levels, as well as weight and other health measures were collected, and researchers compared the levels between the groups who developed and those who did not develop dementia. early.
The analysis found many similarities between the risk of late-onset and early-onset dementia, such as alcohol abuse, diabetes, depression, heart disease and stroke, both linked to high blood pressure. .
Given the young age of the participants, other risk factors were more surprising. According to the study, being socially isolated, living with hearing loss and low vitamin D levels were key risk factors for developing early-onset dementia.
“Social isolation is linked to depression, but depression did not mediate the association of social isolation with YOD (young-onset dementia) in our analyses, suggesting that both directly contribute to dementia risk “, notes the study.
Higher levels of C-reactive protein, which indicates infection or inflammation in the body, were also associated with a higher risk of early-onset dementia, but only in women, the study found.
Orthostatic hypotension, a condition in which dizziness occurs when blood pressure drops when a person stands, was also a factor.
“Hazard ratios of orthostatic hypotension and depression were highest, meaning that the risk of developing early dementia is higher in people with orthostatic hypotension or depression than in people without these factors,” Hendriks said. “However, the risks were still very low and the majority of people with orthostatic hypotension or depression will not develop dementia in the early stages.”
Having two copies of APOE4, a key genetic marker for Alzheimer’s disease, was also a factor, as was a person’s socioeconomic status and ability to obtain higher education. Diabetes played a role that differed by sex at birth: Diabetic men had a higher risk than nondiabetic men, but there was no association with diabetes in women, the study found.
There are a number of steps people can take to reduce their risk of early dementia, Hendriks said, including not smoking and maintaining a healthy diet.
“Be curious: learn new things, make time for a hobby, stay engaged and socially active by visiting friends and family or attending social gatherings,” she said. “Exercise regularly: keep moving, all levels of exercise from walking to vigorous exercise, find something that works for you.”
Overall, people should feel empowered by the results of this study, Isaacson said.
“While additional research is needed to prove more definitively which factors may be most protective in various individuals, I urge those at risk not to wait,” he said.
“Check in with your primary care physician regularly and know your numbers: ask about vitamin D levels, track blood pressure goals, cholesterol results, and blood sugar readings. Have your hearing checked and seek treatment with a hearing aid if necessary.
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