Summary: New research reveals that individuals diagnosed with type 2 diabetes at a younger age face a higher risk of developing dementia, particularly those with obesity. The study found that for each year earlier type 2 diabetes is diagnosed, dementia risk increases by 1.9%.
Obesity further amplifies this risk, with the highest dementia rates observed in individuals diagnosed with diabetes before age 50. These findings highlight the need for targeted interventions addressing both diabetes and obesity to prevent cognitive decline.
Key Facts:
- Adults diagnosed with type 2 diabetes before age 50 are nearly twice as likely to develop dementia as those diagnosed at 70 or older.
- Obesity significantly elevates dementia risk in younger individuals with diabetes.
- For each year earlier type 2 diabetes is diagnosed, dementia risk rises by 1.9%.
Source: NYU
People diagnosed with type 2 diabetes at a younger age are at a higher risk for developing dementia than those diagnosed later in life, according to a study led by researchers at the NYU Rory Meyers College of Nursing.
The findings, published in PLOS ONE, show that the increased risk is especially pronounced among adults with obesity.
“Our study suggests that there may be cognitive consequences to earlier onset type 2 diabetes, and it points to the need for strategies to prevent dementia that consider both diabetes and obesity,” said Xiang Qi, assistant professor at NYU Meyers and the study’s first author.
Type 2 diabetes is a known risk factor for dementia. Although the underlying mechanisms are not fully understood, scientists think that some of the hallmarks of diabetes—such as high blood sugar, insulin resistance, and inflammation—may encourage the development of dementia in the brain.
While type 2 diabetes was once a disease of older adults, it is increasingly prevalent among younger individuals: one in five people with type 2 diabetes worldwide is under 40 years old.
To understand how the timing of a type 2 diabetes diagnosis relates to dementia risk, the research team analyzed data from 2002 to 2016 in the Health and Retirement Study, a longitudinal study conducted by the University of Michigan Institute for Social Research.
The PLOS ONE study included 1,213 U.S. adults aged 50 and over with type 2 diabetes confirmed by blood tests—and no dementia upon joining the study. Following participants for up to 14 years, 216 (17.8%) developed dementia based on follow-up telephone interviews.
The researchers found that adults diagnosed with type 2 diabetes at younger ages were at increased risk for developing dementia, compared to those diagnosed at 70 years or older.
Adults diagnosed with diabetes before age 50 were 1.9 times as likely to develop dementia as those diagnosed at 70 and older, while those diagnosed between 50-59 years were 1.72 times as likely and those diagnosed between 60-69 years were 1.7 times as likely.
Using linear trend tests, the researchers found a graded association between age at diagnosis and dementia risk: for each year younger a person is at the time of their type 2 diabetes diagnosis, their risk for developing dementia increases by 1.9%.
“While we do not know for sure why an earlier diabetes diagnosis would increase the risk for dementia, prior studies show that people diagnosed with type 2 diabetes in mid-life may experience more vascular complications, poor blood sugar control, and insulin resistance—all of which are known risk factors for cognitive impairment,” said Bei Wu, the Dean’s Professor in Global Health and vice dean for research at NYU Meyers and the study’s senior author.
In addition, obesity appeared to influence the relationship between type 2 diabetes and dementia. Individuals with obesity who were diagnosed with type 2 diabetes before age 50 had the highest dementia risk in the study.
The researchers note that this greater understanding of the connection between diabetes onset, obesity, and dementia may help inform targeted interventions to prevent dementia.
“Our study highlights the importance of one’s age at diabetes diagnosis and suggests that specifically targeting obesity—whether through diet and exercise or perhaps medication—may play a role in staving off dementia in younger adults with diabetes,” said Wu.
In addition to Qi and Wu, study authors include Zheng Zhu of NYU Meyers, Huabin Luo of East Carolina University, and Mark D. Schwartz of NYU Grossman School of Medicine.
Funding: The research was supported in part by the National Institute of Aging (P30AG083257, R56AG067619) and National Institute of Minority Health and Health Disparities (P50MD017356).
About this dementia and diabetes research news
Author: Rachel Harrison
Source: NYU
Contact: Rachel Harrison – NYU
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Age at diagnosis of diabetes, obesity, and the risk of dementia among adult patients with type 2 diabetes” by Xiang Qi et al. PLOS One
Abstract
Age at diagnosis of diabetes, obesity, and the risk of dementia among adult patients with type 2 diabetes
Background
While Type 2 Diabetes Mellitus (T2DM) prevalence is increasing among younger individuals, few studies have examined how age at T2DM diagnosis relates to dementia risk in diabetic populations. We aimed to investigate the association between age at T2DM diagnosis and subsequent dementia risk, and to determine whether obesity moderates this relationship.
Methods
We conducted a prospective cohort study using data from the Health and Retirement Study (2002–2016) matched with its 2003 Diabetes Mail-Out Survey. The study included 1,213 dementia-free adults aged ≥50 with diagnosed T2DM. Primary exposures were age at T2DM diagnosis (categorized as <50, 50–59, 60–69, and ≥70 years) and obesity status (BMI ≥30 kg/m2).
The outcome was incident dementia, assessed using the Telephone Interview for Cognitive Status. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), adjusting for sociodemographic factors, health behaviors, health status, and diabetes medication use.
Results
Over a median follow-up of 10 (interquartile range, 6–14) years, 216 (17.8%) participants developed dementia. Compared to participants diagnosed with T2DM at age ≥70 years, those diagnosed at younger ages had increased dementia risk: HR 1.70 (95% CI, 1.03–2.80) for 60–69 years, 1.72 (95% CI, 1.06–2.79) for 50–59 years, and 1.90 (95% CI, 1.14–3.18) for <50 years.
Obesity significantly moderated this relationship, with obese individuals diagnosed with T2DM before age 50 showing the highest dementia risk (HR 3.05; 95% CI 1.23–7.56) compared to non-obese individuals diagnosed at ≥50 years.
Conclusions
Younger age at diagnosis of T2DM was significantly associated with a higher risk of dementia, particularly among individuals with obesity. Interventions specifically targeting obesity may be more effective in preventing dementia for adults with a younger onset of T2DM.
