Metabolic Syndrome in Midlife Linked to Higher Dementia Risk

Summary: A large-scale study has found that having metabolic syndrome in midlife—marked by excess belly fat, high blood pressure, and abnormal cholesterol or blood sugar—is associated with a significantly higher risk of developing young-onset dementia before age 65. The analysis, based on nearly two million people, showed that the more components of metabolic syndrome a person had, the greater their dementia risk, with women and those in their 40s being most vulnerable.

While the study does not prove causation, it highlights the importance of managing cardiovascular and metabolic health during midlife. Preventive lifestyle changes could play a key role in reducing early cognitive decline.

Key Facts:

Alzheimer’s and Vascular Dementia: Metabolic syndrome was linked to both major dementia subtypes.

70% Risk Increase: People with all five components of metabolic syndrome had a 70% higher risk of young-onset dementia.

Sex and Age Disparity: Women and individuals in their 40s faced the highest increased risks.

Source: AAN

Having a larger waistline, high blood pressure and other risk factors that make up metabolic syndrome is associated with an increased risk of young-onset dementia, according to a study published on April 23, 2025, online in Neurology.

Young-onset dementia is diagnosed before the age of 65. The study does not prove that metabolic syndrome causes young-onset dementia, it only shows an association.

Metabolic syndrome is defined as having excess belly fat plus two or more of the following risk factors: high blood pressure, high blood sugar, higher than normal triglycerides, which are a type of fat found in the blood, and low high-density lipoprotein (HDL) cholesterol, or “good” cholesterol.

“While most dementia is diagnosed in older age, young-onset dementia occurs while a person is still working and perhaps raising a family,” said study author Minwoo Lee, MD, PhD, of Hallym University Sacred Heart Hospital in Anyang, South Korea.

“Our study found having metabolic syndrome in middle age is a risk factor for young-onset dementia.”

For the study, researchers reviewed national health insurance data in South Korea to identify nearly two million people between the ages of 40 and 60 who had a health check-up.

The check-up included measurements of waist circumference, blood pressure, blood sugar, triglyceride and cholesterol levels. Of all participants, 25% had metabolic syndrome.

Over an average follow-up period of eight years, 8,921 people, or 0.45% of all participants, developed dementia. For those with metabolic syndrome, the incidence rate was 0.86 cases per 1,000 person-years, compared to 0.49 cases for those without metabolic syndrome.

Person-years represent both the number of people in the study and the amount of time each person spends in the study.

After adjusting for age, education and health factors such as level of physical activity, depression and stroke, researchers found metabolic syndrome was associated with a 24% higher risk of dementia.

When looking at specific types of dementia, it was associated with a 12% increased risk of Alzheimer’s disease and a 21% increased risk of vascular dementia.

Researchers found female participants with metabolic syndrome had a 34% increased risk of dementia compared to male participants who had a 15% increased risk. People in their 40s had a greater risk than people in their 50s.

Researchers found each component of metabolic syndrome was associated with an increased risk of dementia, which was cumulative. People with all five components had a 70% increased risk of dementia.

“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,” said Lee.

“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.”

A limitation of the study was that researchers did not review genetic risk factors for Alzheimer’s disease.

Funding: The study was supported by the Korean National Research Foundation.