Metabolic syndrome linked to increased risk for young-onset dementia in South Korea

Key takeaways:

• Metabolic syndrome included elevated waist circumference, blood pressure, blood sugar, triglyceride and cholesterol.
• Future research that uses brain scans is needed to confirm and expand upon the findings.

Metabolic syndrome was a risk factor for developing young-onset dementia, along with Alzheimer’s disease and vascular dementia, among individuals in South Korea, according to data published in Neurology.

“[Young-onset dementia] is typically defined as dementia with onset before the

age of 65,” Jeong-Yoon Lee, a doctoral student in the department of neurology at Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine in South Korea, and colleagues wrote.

“Globally, the age-standardized prevalence of [young-onset dementia (YOD)] is approximately 119.0 per 100,000 individuals aged 30 to 64, affecting more than 3.9 million people,” they continued.

Although prior research has established that metabolic syndrome (MetS) is a significant risk factor for cardiovascular disease and stroke, associations between the condition and YOD are less established, Lee and colleagues wrote.

They sought to determine whether MetS and its individual factors, including larger waist circumference and elevated blood pressure, blood sugar, triglyceride and cholesterol, increase the risk for YOD as well as all-cause dementia, AD, and vascular dementia (VaD).

The researchers conducted a population-based cohort study utilizing data from the Korean National Insurance Service to yield more than 4.2 million individuals who underwent a health screening in 2009. From this cohort, eligibility criteria such as prior dementia diagnosis left 1.98 million individuals (mean age, 49 years; 51.3% men; 50.7% with MetS) available for the study.

Eligible individuals were followed until Dec. 31 of the year they turned 64 years, or Dec. 31, 2020 for those who did not reach 64 years, whichever came first. The study’s primary outcome was incident YOD, defined as a diagnosis before a participant’s 65th birthday, while secondary outcomes included risk for young-onset AD and VaD with MetS.

Lee and colleagues used covariates for statistical analysis including age, sex, BMI and obesity, income level, alcohol and tobacco use, along with comorbidities such as hypertension, diabetes, dyslipidemia and depression.

Over an average follow-up of 7.75 years, 8,921 individuals (0.45%) developed YOD, with a risk for all-cause YOD 1.77 times higher among those with MetS compared with those who did not have MetS.

Lee and colleagues also reported MetS was associated with a 24% higher risk of all-cause YOD (adjusted HR = 1.24; 95% CI: 1.19–1.3), a 12.4% increased risk of AD (HR = 1.12; 95% CI: 1.03–1.22), and a 20.9% increased risk of VaD (HR = 1.21; 95% CI: 1.08–1.35).

All the components of MetS were associated with an increased risk of YOD.

Data further revealed that risk for YOD increased by the number of MetS components, remaining statistically significant when fewer than three components required for a MetS diagnosis were present. Also, risk for dementia increased by 70% for patients with all five components of MetS examined.

The researchers further noted that women with metabolic syndrome had a 34% increased risk for dementia compared with 15% increased risk in men, while individuals in their 40s logged a greater risk than those in their 50s, as well as those who consumed alcohol, or had a diagnosis of obesity or depression.

“Our findings suggest that lifestyle changes to reduce the risk of metabolic syndrome, such as eating a healthy diet, exercising regularly, maintaining a healthy weight, quitting smoking and reducing stress, may help reduce the risk of young-onset dementia,” Minwoo Lee, MD, PhD, of Hallym University Sacred Heart Hospital in Anyang, South Korea, said in the release. “Future research that follows people over longer periods of time and uses brain scans to look for biomarkers of dementia is needed to confirm and expand upon our findings.”

Reference:

Metabolic syndrome linked to increased risk of young-onset dementia. https://www.aan.com/PressRoom/Home/PressRelease/5255. Published April 23, 2025. Accessed April 25, 2025.