Self-Reported Versus Objectively Assessed Olfaction and Parkinson's Disease Risk

Area of Science:

• Neurology
• Gerontology
• Epidemiology

Background:

• Olfactory dysfunction is an early indicator of Parkinson's disease (PD).
• Self-reported sense of smell is often disregarded due to perceived unreliability.

Purpose of the Study:

• To evaluate the predictive value of self-reported and objectively assessed sense of smell for future PD risk.
• To determine if combining both assessment methods improves PD risk prediction.

Main Methods:

• Prospective analysis of 2,424 older adults (ages 71-82) from the Health, Aging, and Body Composition study.
• Assessed self-reported smell/taste and objective smell function using the Brief Smell Identification Test.
• Incident PD was analyzed using Cox proportional hazard models over approximately 10 years.

Main Results:

• Both self-reported and objectively tested poor smell were independently linked to increased PD risk (HRs 2.8 and 4.0, respectively).
• Participants with both self-reported and tested poor smell had the highest PD risk (HR 7.8).
• No significant interaction was found between self-reported and objective smell tests in PD prediction.

Conclusions:

• Self-reported sense of smell is a valuable, non-dismissible predictor of future Parkinson's disease risk.
• Combined self-reported and objective smell assessments enhance PD risk prediction.
• Further research into structured questionnaires for smell assessment is warranted.