Is Metabolic Syndrome Tied to a Higher Risk for Young-Onset Dementia?

Young-onset dementia (YOD) is associated with metabolic syndrome and its components, according to the findings of a study published in Neurology.

Risk for dementia onset before age 65 is associated with unique features, some of which may be modifiable.

Researchers from Soonchunhyang University Seoul Hospital and Hallym University Sacred Heart Hospital in South Korea sourced data for this study from the Korean National Health Insurance Service Database (K-NHID). Adults (N=1,979,509) aged 40 to 60 years who underwent a health screening in 2009 were evaluated for YOD through 2020 on the basis of metabolic syndrome, defined by the American Heart Association and National Heart, Lung, and Blood Institute.

The table below presents a comparison of adults with and without metabolic syndrome.

Variable	With Metabolic Syndrome	Without Metabolic Syndrome	P-value
Mean age (years)	50.72	48.49	<.0001
Men (%)	62.17%	47.61%	<.0001
BMI (kg/m2)	25.98	23.26	<.0001
Diabetes prevalence (%)	24.09%	3.74%	<.0001

During an average follow-up of 7.8 years, 0.45% of individuals were diagnosed with YOD.

Risk for YOD was significantly related with metabolic syndrome (adjusted hazard ratio [aHR], 1.240; 95% CI, 1.186-1.296).

Stratified by metabolic syndrome components, YOD was associated with:

• elevated blood pressure (aHR, 1.320; 95% CI, 1.264-1.378),
• glucose (aHR, 1.208; 95% CI, 1.157-1.261),
• triglycerides (aHR, 1.166; 95% CI, 1.117-1.217),
• waist circumference (aHR, 1.111; 95% CI, 1.058-1.166), and
• low high-density lipoprotein cholesterol (aHR, 1.128; 95% CI, 1.079-1.179).

The risk of young-onset dementia (YOD) increased with the number of metabolic syndrome components present. The highest risk was observed in individuals meeting all 5 Metabolic syndrome criteria (aHR, 1.696; 95% CI, 1.511–1.904), followed by those with 4 (aHR, 1.595; 95% CI, 1.469–1.732), 3 (aHR, 1.444; 95% CI, 1.342–1.555), 2 (aHR, 1.411; 95% CI, 1.317–1.512), and 1 (aHR, 1.196; 95% CI, 1.116–1.282) component.

Stratified by type of YOD, metabolic syndrome was associated with vascular dementia (aHR range, 1.209-1.700), all-cause dementia (aHR range, 1.153-1.341), and Alzheimer dementia (aHR range, 1.124-1.264) among both men and women.

Among women, all 5 components of metabolic syndrome were significantly associated with every type of YOD. In contrast, among men, high waist circumference was not linked to any form of YOD; high triglycerides were not associated with vascular or Alzheimer dementia; and low HDL-C was not associated with vascular dementia.

Risk for all types of YOD increased with the number of metabolic syndrome components among men whereas having only 1 metabolic syndrome component was not associated with risk for all-cause dementia or Alzheimer dementia among women.

In the subgroup analysis, significant interactions were observed for age, gender, alcohol consumption, obesity status, and depression groups.

This study may have been limited by not having access to data about dementia risk factors, such as education, genetic markers, and family history.

“MetS [metabolic syndrome], its individual components, and the cumulative presence of these components were significantly associated with an increased risk of all-cause YOD. These findings suggest that interventions targeting MetS may help mitigate YOD risk,” the researchers concluded.