Olfactory dysfunction occurrence, undetected hazards, and relationships in Parkinson’s disease: a multicentre study

Abstract Background The study sought to quantify and stratify olfactory dysfunction (OD) in Parkinson's disease (PD) using a brief multi-item tool and to explore demographic and clinical patterns in a broad cohort from Egypt. We conducted a multicentre cross-sectional study across neurology clinics. OD was assessed using Vernetti’s Hyposmia Rating Scale, which was translated into Egyptian, integrated into the study survey, piloted, and psychometrically tested. Analyses included multivariable adjusted models. Results We enrolled 434 patients with PD. Median age at diagnosis was 55 years (IQR 45 to 62), and two thirds were diagnosed within 1 year of motor symptom onset. Family history of PD (20%) was associated with motor symptoms appearing years earlier. Smoking, however, was associated with a later age. More than half of all patients had OD (58.5%), which was typically gradual and either persistent or worsening. The six-item scale identified 34.3% of OD cases that a single global question would have missed ( p < 0.001). In adjusted models, OD showed only a small association with education. A quarter of patients reported never detecting nearby gas leaks even when alerted. Loss of food-smell distinction closely tracked OD status ( p < 0.001). Most had at least one other non-motor symptom (NMS). Conclusions A majority of patients had OD. It was the prevailing NMS and correlated with overall burden. PD patients in this cohort had a younger age at disease onset and a high rate of family history linked to an even earlier onset. The interval from initial motor complaints to diagnosis appeared comparable to that reported in advanced healthcare settings worldwide. For hyposmia assessment, the brief scale improved identification and flagged safety risks and quality-of-life implications. The hyposmia-related hazards warrant further investigation to objectively test hazard detection and risk-reduction measures.

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Publication Details

Journal
The Egyptian Journal of Neurology Psychiatry and Neurosurgery
Published
2026-06-09
DOI
https://doi.org/10.1186/s41983-026-01175-4
Primary Topic
Olfactory and Sensory Function Studies
Type
article
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article

Olfactory dysfunction occurrence, undetected hazards, and relationships in Parkinson’s disease: a multicentre study

Mahmoud Samir, Ahmad Farag Ibrahim El-Adawy, Ahmed Elhussieny, Osama Yacoub et al.
The Egyptian Journal of Neurology Psychiatry and Neurosurgery
Olfactory and Sensory Function Studies
article

Olfactory dysfunction occurrence, undetected hazards, and relationships in Parkinson’s disease: a multicentre study

Mahmoud Samir, Ahmad Farag Ibrahim El-Adawy, Ahmed Elhussieny, Osama Yacoub, Ahmed Ramzi, Nadeen Balousha, Mostafa Ramzi Shiha, Ghalia Aljarrah, Nesreen Abdelwahhab, Ahmed Samir, Subhia Maya, George Hanen, Pacinthe Ayman, Israa Ahmed Qutob, Rovan Ahmed Rouby, Dalia Gamal Elnady, Ibrahim Moqbel, Mufreh Amin, Yousuf Abuelkhair, Ahmed Kertam, Hanan Amer, Jaidaa Mekky, T I Ghanm, Sohaila Mohamed Mohamed Abdelbar, Mustafa Mahmoud, Amin Mefreh Amin Elkhayat, Mostafa Meshref, Rasha Elkabany, Mazen Mohammed Alhammamy, Samer Mohammed Ali Hussein, Mohammed Abdelshafey, ODOUR-PD Study Group, Shaimaa Ahmed Mustafa El-Naggar, Marwa Yassin Badr, Mohammed Yasser, Mohammed Tamimy, Tasneem Mohamed Osama Desouky, Esraa Elsaeed Elnawagy, Esraa Maharem, Mohamed Srour, Rami Ismail Mahmoud
article en

Abstract

Abstract Background The study sought to quantify and stratify olfactory dysfunction (OD) in Parkinson's disease (PD) using a brief multi-item tool and to explore demographic and clinical patterns in a broad cohort from Egypt. We conducted a multicentre cross-sectional study across neurology clinics. OD was assessed using Vernetti’s Hyposmia Rating Scale, which was translated into Egyptian, integrated into the study survey, piloted, and psychometrically tested. Analyses included multivariable adjusted models. Results We enrolled 434 patients with PD. Median age at diagnosis was 55 years (IQR 45 to 62), and two thirds were diagnosed within 1 year of motor symptom onset. Family history of PD (20%) was associated with motor symptoms appearing years earlier. Smoking, however, was associated with a later age. More than half of all patients had OD (58.5%), which was typically gradual and either persistent or worsening. The six-item scale identified 34.3% of OD cases that a single global question would have missed ( p < 0.001). In adjusted models, OD showed only a small association with education. A quarter of patients reported never detecting nearby gas leaks even when alerted. Loss of food-smell distinction closely tracked OD status ( p < 0.001). Most had at least one other non-motor symptom (NMS). Conclusions A majority of patients had OD. It was the prevailing NMS and correlated with overall burden. PD patients in this cohort had a younger age at disease onset and a high rate of family history linked to an even earlier onset. The interval from initial motor complaints to diagnosis appeared comparable to that reported in advanced healthcare settings worldwide. For hyposmia assessment, the brief scale improved identification and flagged safety risks and quality-of-life implications. The hyposmia-related hazards warrant further investigation to objectively test hazard detection and risk-reduction measures.

The Egyptian Journal of Neurology Psychiatry and NeurosurgeryVol. 62(1)
Ain Shams University (EG), Beni-Suef University (EG), Damietta University (EG), Cairo University (EG), Misr University for Science and Technology (EG), Mansoura University (EG), Al-Azhar University (EG), United Arab Emirates University (AE), Tanta University (EG), Al-Balqa Applied University (JO), Menoufia University (EG), Fayoum University (EG), Alexandria University (EG), Damascus University (SY), Minia University (EG)
Good health and well-being
Openalex Percentile: Top 7%
Olfactory and Sensory Function Studies
DOIOpen Access PDFOpenAlex
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