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Olfactory Dysfunction and Metabolic Syndrome Components: A Systematic Review and Meta-Analysis
Neeti Gandra1,2, Kaitlyn A Roberts1,3, Shaun A Nguyen1
1Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina, USA.
The Laryngoscope
|June 5, 2026
Summary
Olfactory dysfunction (OD) is linked to higher risks of metabolic syndrome components like diabetes and heart issues. Metabolic disorders also correlate with poorer olfactory function, suggesting a two-way relationship.
Area of Science:
- Metabolic health and sensory science.
- Clinical research and epidemiology.
Background:
- Olfactory dysfunction (OD) is increasingly recognized as a potential indicator of systemic health.
- Metabolic syndrome is a cluster of conditions that increase the risk of heart disease, stroke, and diabetes.
Purpose of the Study:
- To investigate the association between olfactory dysfunction and the components of metabolic syndrome.
- To explore the bidirectional relationship between impaired sense of smell and metabolic dysregulation.
Main Methods:
- A systematic review and meta-analysis of studies from PubMed, Scopus, CINAHL Complete, and Cochrane Library databases.
- Included studies were analyzed for associations between olfactory dysfunction and metabolic parameters like BMI, cholesterol, blood pressure, and glucose levels.
- Risk of bias was assessed using the Joanna Briggs Institute (JBI) tool.
Main Results:
- 47 studies involving 4045 participants were analyzed.
- Olfactory dysfunction was associated with increased odds of smoking, antihypertensive medication use, atrial fibrillation, heart failure, and diabetes.
- Individuals with OD had higher fasting glucose and lower total and HDL cholesterol levels.
- Diabetes and elevated BMI were linked to significantly lower olfactory test scores (TDI composite scores).
Conclusions:
- Olfactory dysfunction is associated with a higher prevalence of conditions that constitute or contribute to metabolic syndrome.
- Metabolic disorders are linked to reduced olfactory function, indicating a bidirectional relationship between olfactory impairment and metabolic dysregulation.
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