People who develop prediabetes when they are younger are likely to have a higher risk of dementia later in life, a new study finds.
Prediabetes is when the blood sugar level is higher than optimal, but not yet high enough for the patient to be medically diagnosed with diabetes. Unfortunately, millions of Americans under the age of 60 have prediabetes — and many aren’t even aware of it.
“Prediabetes is associated with the risk of dementia, but this risk is explained by the development of diabetes,” authors Elizabeth Selvin, a professor of epidemiology, and Jiaqi Hu, a doctoral student, said in a news statement. They both attend Johns Hopkins Bloomberg School of Public Health in Baltimore.
The study, published Wednesday in Diabetologia, analyzed data from the Atherosclerosis Risk in Communities study. It enrolled people between the ages of 45 and 64 in four U.S. counties: Forsyth County, North Carolina; Jackson, Mississippi; suburbs of Minneapolis; and Washington County, Maryland.
People in the study who developed type 2 diabetes before age 60 had a three times greater risk of dementia later in life compared to those who did not have type 2 diabetes before age 60, the study found. If prediabetes progressed to type 2 diabetes between ages 60 and 69, the risk dropped, but only by a few points.
“We all have transient spikes in our blood glucose. It goes up and then down again,” said Dr. Andrew Freeman, director of cardiovascular prevention and wellness at National Jewish Health in Denver. He was not involved in the investigation.
“But when you look at ‘glucose years’ to determine how high your glucose is and for how long, you start to see cumulative damage,” Freeman said. “And the sooner you’re exposed, the greater the cumulative damage.”
Until then, the study found that if type 2 diabetes was not diagnosed before the person was in their 70s, the risk of dementia fell to 23%. And if a person developed type 2 diabetes in their 80s or 90s, the risk was no greater than those without diabetes.
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Recognizing high blood sugar levels early may help prevent dementia in later years, one study says.
“There was a strong association between prediabetes and dementia, but this association was only present in people who developed diabetes,” Selvin told CNN in an email. “This finding suggests that preventing progression from prediabetes to diabetes may help prevent dementia in old age.”
Alzheimer’s disease researcher Dr. Richard Isaacson, a preventive neurologist at Florida’s Institute of Neurodegenerative Diseases, said the results weren’t shocking.
“I’ve been shouting this from the rooftops for over a decade,” Isaacson, who was not involved in the investigation, said via email. “If this study gets people to actually take action when a ‘borderline diabetes’ or prediabetes diagnosis is made, that will definitely improve brain health outcomes.”
More than 1 in 3 American adults have prediabetes, and 80% of them don’t even know it, according to the U.S. Centers for Disease Control and Prevention. Nearly a third of those are between the ages of 18 and 44 – quite young to develop a condition that puts them at extreme risk for type 2 diabetes, significant cardiovascular problems and vascular dementia as they age.
Even worse, nearly 1 in 5 adolescents ages 12 to 18 and 1 in 4 young adults ages 19 to 34 are living with prediabetes, according to the CDC.
The CDC estimates that about 5.8 million people in the United States have Alzheimer’s disease and related dementias. And according to research cited in a 2019 report from the Alzheimer’s Association, the lifetime risk for the most common form of dementia is about 1 in 10 (10%) for men aged 45 and 1 in 5 (20%) for women.
A 2013 meta-analysis found that type 2 diabetes is associated with a 60% higher risk of all-cause dementia. In addition, people with dementia who have type 2 diabetes have an increased risk of premature death.
While the exact link between diabetes and dementia is not known, there are several possible pathways, according to research.
“Diabetes increases the risk of heart disease and stroke, which damage the heart and blood vessels. Damaged blood vessels in the brain can contribute to cognitive decline,” according to the Alzheimer’s Association.
In addition, high blood sugar causes inflammation, which can damage brain cells, the association said. Even people in the early stages of type 2 diabetes show signs of dysfunction in the brain.
Research has shown that type 2 diabetes dramatically increases levels of beta-amyloid protein in the brain, a hallmark sign of Alzheimer’s disease, the association says.
This study is not the first to find a link between the earlier onset of diabetes and dementia. A 2021 study conducted in the UK found that developing diabetes more than 10 years earlier increased the risk of dementia by more than 18%.
Prediabetes is known as a silent predator, developing and progressing without obvious symptoms. However, there are risk factors.
You are at a higher risk of prediabetes if you are overweight, over age 44, exercise less than three times a week, have a parent or sibling with type 2 diabetes, had diabetes during pregnancy, or gave birth to a child over 9 years old. pounds (4 kilograms), according to the CDC.
Some groups are also at higher risk, including people who are black, Hispanic or Latino, American Indian, Alaska Native, Pacific Islander, or Asian American. You can screen for your personal risk by taking a test offered by the National Diabetes Prevention Program.
The US Preventive Services Task Force recommends that all adults ages 35 to 70 who are considered medically overweight or obese be screened for prediabetes or diabetes. If blood sugar is a concern, reducing weight, exercising, following a healthy diet, and avoiding processed and ultra-processed foods may reduce risk.