Objective:

To investigate the relationship between metabolic health status and dementia risk, independent of obesity status.

Approach:

• Study Design: A prospective cohort study analyzing data from 11,482 patients in the US Health and Retirement Study and 13,068 patients in the Swedish Twin Registry, all free of dementia at baseline.
• Classification: Patients were classified into four groups based on metabolic health and obesity status: metabolically healthy without obesity, metabolically healthy with obesity, metabolically unhealthy without obesity, and metabolically unhealthy with obesity.
• Dementia Risk Evaluation: Cox proportional hazards models were used to evaluate dementia risk, adjusted for age, sex, smoking status, and education level, with follow-up ranging from 8 to 17 years.

Key Findings:

• Metabolically unhealthy status without obesity was associated with a 62% higher adjusted hazard of dementia in midlife among women in the Health and Retirement Study.
• In the Swedish Twin Registry, metabolically unhealthy status without obesity in late life was linked to a 13% higher adjusted hazard of dementia.
• Metabolically healthy obesity was not associated with increased dementia risk in either age group.
• Findings for metabolically unhealthy obesity were inconsistent across cohorts, particularly in late life.

Interpretation:

Limitations:

• Dementia ascertainment methods differed between cohorts, potentially affecting results.
• The study assessed all-cause dementia and could not evaluate dementia subtypes.
• Follow-up duration may have been insufficient to capture the long preclinical phase of dementia.
• The observational design limits conclusions about causality.

Conclusion:

Sources:

• BMC Medicine