Table 2. Poorer olfactory identification is associated with higher odds of psychotic symptoms and abnormal performance on tests of verbal memory or executive function.

Odds ratios and p-values of having an abnormal score on the indicated tests after adjustment for age, sex, disease severity, duration and medication status. Backward logistic regression was performed with an abnormal score on the indicated test as the dependent variable and UPSIT performance (top or bottom half) together with the indicated covariates as independent variables. Age-specific standardized scores were available for the Stroop, Tower of London and Hopkins Verbal Learning Test, so age was not included as a covariate in the regression models for those tests. Covariates remaining significant at the p=0.05 level in the last iteration of the regression model are listed in the far-right column. UPSIT, University of Pennsylvania Smell Identification Test. LEDD, levodopa equivalent daily dose.

	Adjusted OR (95% CI) for UPSIT performance	p	Significant covariates at final iteration
Psychiatric
Geriatric Depression Scalea	1.2 (0.70–2.3)	0.42	Hoehn/Yahr
Inventory of Depressive Symptomatologya	1.5 (0.86–2.7)	0.15	Hoehn/Yahr, sex
State Anxiety Inventorya	0.97 (0.47–2.0)	0.94	Hoehn/Yahr, age
Apathy Scale a	1.1 (0.61–1.9)	0.77	Hoehn/Yahr
Psychosisa	2.1 (1.0–4.3)	0.05	UPSIT, age, LEDD
Cognitive
Mini Mental State Examinationa	1.0 (0.47–2.1)	0.99	Hoehn/Yahr, age, sex
Digit Spana	1.0 (0.52–2.1)	0.90	Hoehn/Yahr, age
Stroop Color Word Testb	1.3 (0.50–3.2)	0.61	Hoehn/Yahr, sex, PD duration
Tower of London-DXb	3.1 (1.5–6.2)	0.001	UPSIT, Hoehn/Yahr
Hopkins Verbal Learning Test-Revisedb	1.8 (1.1–3.7)	0.04	UPSIT, Hoehn/Yahr, duration

^aInitial covariates in the regression model: UPSIT performance, age, sex, PD duration, Hoehn and Yahr stage, LEDD

^bInitial covariates in the regression model: UPSIT performance, sex, PD duration, Hoehn and Yahr stage, LEDD.