Metabolic Syndrome Linked to Risk of Young Onset Dementia

People with metabolic syndrome (MetS) face a significantly increased risk of developing dementia before age 65, according to a large population-based study from South Korea. The condition was associated with an adjusted 24% higher risk of all-cause young-onset dementia over nearly 8 years of follow-up.

Minwoo Lee, MD, PhD
Courtesy of Hallym University Sacred Heart Hospital

The nationwide study, published in Neurology, analyzed health data from nearly 2 million adults (mean age 49 years) in the Korean National Insurance Service database. Researchers led by Minwoo Lee, MD, PhD, of Hallym University Sacred Heart Hospital, found that MetS was also tied to a 20.9% greater risk of vascular dementia (95% CI 1.08-1.35) and a 12.4% increased risk of Alzheimer disease (95% CI 1.03-1.22) in younger adults.

Overall the authors found that risk was more pronounced among women with MetS (34%) vs men (15%), non-obese individuals, people aged 40–49 vs those aged 50 to 59 years, those with depression, and non-drinkers.

The association showed a dose-response relationship with each component of MetS associated with increased risk of dementia, which was cumulative. Individuals in their 40s with all 5 MetS components had a 77% increased risk of dementia.

Young-onset dementia, which affects an estimated 3.9 million people ages 30 to 64 globally, is increasingly recognized as a public health concern. "While most dementia is diagnosed in older adults, young-onset dementia occurs while a person is still working and perhaps raising a family," Lee said in a statement.

The researchers followed 1,979,509 adults aged 40–60 years for a mean of 7.75 years. The cohort comprised 51.3% men . At baseline, 25.2% had metabolic syndrome, which was defined by standard clinical criteria including elevated waist circumference, blood pressure, fasting glucose, triglycerides, and low HDL cholesterol.

The association showed a dose-response relationship with each component of MetS associated with increased risk of dementia, which was cumulative. Individuals in their 40s with all 5 MetS components had a 77% increased risk of dementia.

The primary outcome of interest was an all-cause dementia diagnosis before age 65 years. Over the study period, 0.45% of participants were diagnosed with young-onset dementia. Univariable analysis showed a 77% increased risk in those with metabolic syndrome, which remained significant after adjusting for age, sex, income, lifestyle factors, depression, atrial fibrillation, and stroke.

"Each component of [MetS]— hypertension, obesity, diabetes, and dyslipidemia — has been associated with increased dementia risk," the authors noted. Their original hypothesis, that MetS could play a significant role in early onset dementia was confirmed.

The study underscores the importance of modifiable risk factors in preventing early cognitive decline. “Our findings suggest that lifestyle changes to reduce the risk of [MetS ], 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,” Lee said in the statement.

Among the study’s limitations the authors note reliance on ICD codes for diagnosis and the resulting lack of data on genetic risk for dementia, parental history of dementia, education level, head injury history, and other variables. Further, the findings may not generalize beyond the Korean population.

Lee and colleagues called for future studies using biomarkers and brain imaging, as well as longer follow-up, to validate and expand upon their results.

References

Association between metabolic syndrome and young-onset dementia: a nationwide population-based study. Neurology. 2025;104(10). /doi/10.1212/WNL.0000000000213599

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