Can developing type 2 diabetes before age 50 raise dementia risk?

Scientists have linked an earlier diabetes diagnosis to increased dementia risk. 

Previous research shows that more adults are developing type 2 diabetes before the age of 45, and type 2 diabetes is a known risk factor for dementia.

Researchers have found that adults diagnosed with type 2 diabetes before the age of 50 have a higher chance of developing dementia than those who receive a type 2 diabetes diagnosis later in life.

Scientists also found that participants with obesity who received a type 2 diabetes diagnosis before age 50 had the highest dementia risk.

Although type 2 diabetes — a condition where the body is not able to properly use or produce insulin — is normally seen in adults ages 45 and older,Trusted Source research shows a higher rate of younger adults are now developing the condition earlier in life.

Past studies show that type 2 diabetes is a risk factor for developing dementia.

Now, researchers from the NYU Rory Meyers College of Nursing have found that adults diagnosed with type 2 diabetes before the age of 50 — especially those who also have obesity — have a higher chance of developing dementia than those who receive a type 2 diabetes diagnosis later in life.

The study was recently published in the journal PLOS ONETrusted Source.

The link between earlier-diagnosed diabetes and dementia

For this study, researchers analyzed data for about 1,200 U.S. adults ages 50 and over from the Health and Retirement StudyTrusted Source conducted by the University of Michigan Institute for Social Research.

At the time of the Health and Retirement Study, all participants had type 2 diabetes and no dementia diagnosis.

Type 2 diabetes ages for participants were grouped by before age 50, between ages 50-59, 60-69, and 70 years or above.

“While we’ve known that diabetes increases dementia risk, an emerging trend has caught our attention — type 2 diabetes is occurring at much younger ages than before,” Bei Wu, PhD, FAAN, FGSA, the Dean’s Professor in Global Health and vice dean for Research at NYU Rory Meyers College of Nursing and senior author told Medical News Today.

Wu said that globally, the number of people being diagnosed with diabetes before age 40 was rising.

“This shift raised an important question that hadn’t been fully addressed: Does developing diabetes earlier in life impact dementia risk differently than developing it later? Previous research has shown that people diagnosed with diabetes at younger ages often have worse health outcomes, including poorer blood sugar control and more cardiovascular problemsTrusted Source,” Wu continued.

“We hypothesized that a longer duration of exposure to diabetes-related complications might also increase dementia risk. What’s particularly concerning is that few studies have examined this relationship specifically among people with type 2 diabetes. Most previous research has compared individuals with diabetes to those without diabetes, but we wanted to understand the risk patterns within this group itself. Understanding this could help healthcare providers better identify high-risk individuals and develop more targeted prevention strategies,” he said.

Type 2 diabetes diagnosis before 50 increases dementia risk 1.9 times

After a follow-up of about 10 years, almost 18% of the study’s participants developed dementia.

Upon analysis, Wu and her team found that participants who received a type 2 diabetes diagnosis at younger ages increased their dementia risk, compared to those diagnosed at age 70 and older.

Participants diagnosed with type 2 diabetes before age 50 were 1.9 times more likely to develop dementia. Receiving a diagnosis between ages 50 to 59 increased dementia risk 1.72 times, and between ages 60 to 69 by 1.7 times.

“Most strikingly, we found that the earlier someone develops type 2 diabetes, the higher their dementia risk — with those diagnosed before age 50 having nearly twice the risk compared to those diagnosed at 70 or older,” Xiang Qi, PhD, RN, assistant professor at NYU Rory Meyers College of Nursing and first author told MNT. “This wasn’t just a slight increase; we saw a clear ‘dose-response’ pattern where younger age at diagnosis consistently linked to higher dementia risk.”

“What makes this particularly concerning is that we’re seeing a rapid rise in early-onset type 2 diabetes globally,” Qi continued. “Our findings suggest this trend could lead to a larger wave of dementia cases in the future, as these individuals age. This aligns with the 2024 Lancet CommissionTrusted Source‘s emphasis that ‘the earlier, the better’ for risk reduction.”

Highest dementia risk among people with obesity

The researchers also found that obesity seemed to play a role in the link between type 2 diabetes and dementia. They found that participants with obesity who received a type 2 diabetes diagnosis before age 50 had the highest dementia risk in the study.

“The findings become even more significant when we consider obesity,” Qi said. He said they discovered that individuals who had obesity and who were diagnosed with diabetes before age 50 had the highest dementia risk, which was equivalent to three times the risk of individuals who did not have obesity and were diagnosed with diabetes after age 50.

“This interaction between early diabetes and obesity suggests we have multiple intervention points for prevention. These results aren’t just academic — they have immediate clinical implications. They tell us we need to be especially vigilant about cognitive health in younger diabetes patients, particularly those with obesity,” Qi said.

“Our research has highlighted a particularly concerning trend: younger individuals developing type 2 diabetes face a significantly higher risk of dementia, especially if they are also living with obesity. This is troubling, as diabetes and obesity are both increasing at younger ages and affecting a growing number of individuals,” Wu added.

“The most important aspect of our findings is that the risk factors we identified — obesity and early-onset diabetes — are potentially modifiable. This means that there are steps individuals and healthcare providers can take to reduce dementia risk. The goal of our research goes beyond understanding the disease; it’s about finding practical ways to prevent it. Each new risk factor we uncover offers an opportunity to intervene early and potentially prevent cognitive declineTrusted Source, ultimately improving quality of life for millions of individuals and their families.” — Bei Wu, PhD, FAAN, FGSA

More research on type 2 diabetes and the brain needed

MNT also spoke with Clifford Segil, DO, neurologist at Providence Saint John’s Health Center in Santa Monica, CA, about this study.

“Increased blood sugars increase a person’s risk of having a heart attack or strokeTrusted Source, and therefore, increase the risk of type 2 diabetic patients having vascular dementia but not Alzheimer’s dementia. Vascular or multi-infarct dementia is a subcortical dementia in which people become slower (than) forgetful,” Segil said.

“Early onset diabetes (increases) cardiovascular risk with an increased risk for a heart attack and stroke. There are many diabetic patients who never get Alzheimer’s dementia or vascular dementia if they can control their blood sugars.” — Clifford Segil, DO

“I would like to see MRIs of these (study) participants’ brains and a screening cognitive test to determine if early diabetes causes worsening cognition in addition to the expected worsening brain chronic ischemic white matter disease,” Segil added.

https://www.medicalnewstoday.com/articles/can-developing-type-2-diabetes-before-age-50-raise-dementia-risk