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Abstract
Objective: To investigate olfaction in relation to incident Parkinson disease (PD) in US white and black older adults.
Methods: The study included 1,510 white (mean age 75.6 years) and 952 black (75.4 years) participants of the Health, Aging, and Body Composition study. We evaluated the olfaction of study participants with the Brief Smell Identification Test (BSIT) in 1999–2000. We retrospectively adjudicated PD cases identified through August 31, 2012, using multiple data sources. We used multivariable Cox models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).
Results: During an average of 9.8 years of follow-up, we identified a total of 42 incident PD cases, including 30 white and 12 black participants. Overall, poor sense of smell, as indicated by a lower BSIT score, was associated with higher risk of PD. Compared with the highest tertile of BSIT (t3), the HR was 1.3 (95% CI 0.5–3.6) for the second tertile (t2) and 4.8 (95% CI 2.0–11.2) for the lowest tertile (t1) (ptrend < 0.00001). Further analyses revealed significant associations for incident PD in both the first 5 years of follow-up (HRt1/[t2+t3] 4.2, 95% CI 1.7–10.8) and thereafter (HRt1/[t2+t3] 4.1, 95% CI 1.7–9.8). This association appeared to be stronger in white (HRt1/[t2+t3] 4.9, 95% CI 2.3–10.5) than in black participants (HRt1/[t2+t3] 2.5, 95% CI 0.8–8.1), and in men (HRt1/[t2+t3] 5.4, 95% CI 2.3–12.9) than in women (HRt1/[t2+t3] 2.9, 95% CI 1.1–7.8).
Conclusions: Poor olfaction predicts PD in short and intermediate terms; the possibility of stronger associations among men and white participants warrants further investigation.
GLOSSARY
- BSIT=
- Brief Smell Identification Test;
- CI=
- confidence interval;
- HAAS=
- Honolulu-Asia Aging Study;
- Health ABC=
- Health, Aging, and Body Composition;
- HR=
- hazard ratio;
- ICD-9-CM=
- International Classification of Diseases–9–Clinical Modification;
- PD=
- Parkinson disease;
- PRIPS=
- Prospective Evaluation of Risk Factors for Idiopathic Parkinson's Syndrome
Footnotes
Coinvestigators are listed at Neurology.org.
Go to Neurology.org for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.
Supplemental data at Neurology.org
Editorial, page 1432
- Received October 4, 2016.
- Accepted in final form April 20, 2017.
- © 2017 American Academy of Neurology
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