Objective testing identifies higher prevalence of olfactory dysfunction in Primary Ciliary Dyskinesia than patient reportsMore people with Primary Ciliary Dyskinesia have smell loss than expected

medRxiv Published August 23, 2026 Study authors: Zubair, A.; Whitcroft, K.; Khong, G.; Bhargava, E. DOI ↗ Editorial oversight: Dr. Lars van Dijk, PhD · Surgical, Procedural & Diagnostic

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Key Takeaway

Note that objective testing identifies significantly higher rates of olfactory dysfunction in PCD than patient reports.

This meta-analysis evaluates the prevalence and associated factors of olfactory dysfunction in 865 patients with confirmed Primary Ciliary Dyskinesia (PCD). The analysis synthesizes data regarding both subjective patient perceptions and objective psychophysical testing to determine the scope of olfactory impairment in this population.

The study reports an overall pooled prevalence of olfactory dysfunction at 43.4% (95% CI 25.2-62.5%). Notably, a significant discrepancy exists between assessment methods: objective psychophysical testing revealed a prevalence of 66.1% (95% CI 55.5-76.0%), while patient-reported outcome measures showed a lower prevalence of 30.5% (95% CI 11.4-54.0%). The authors note that age, sinonasal disease burden, and ciliary ultrastructural defects are associated with worse olfactory function.

A primary limitation identified is the discordance between objective dysfunction and subjective awareness among patients. These findings suggest that patient-reported measures may underestimate the extent of olfactory impairment. Consequently, integrating routine objective olfactory screening into multidisciplinary PCD care may improve clinical management.

Living with Primary Ciliary Dyskinesia (PCD) can be challenging for the senses. New research into olfactory function, which is the ability to smell, shows a significant gap between how patients feel and what tests actually reveal. While many people with PCD might not realize their sense of smell is impaired, objective testing shows that more than half of those tested had some form of dysfunction.

The study looked at 865 patients with confirmed PCD. Researchers found that while only about 30% of patients reported having trouble smelling, actual tests showed a much higher rate of nearly 66%. This means many people are living with an impaired sense of smell without realizing it because their own reports do not match the results of objective testing.

Several factors were linked to worse smell, including the age of the patient and the amount of sinonasal disease they have. Because patients often under-report their issues, experts suggest that doctors should include regular, objective smell tests as part of standard care for those with PCD.

What this means for you:

Objective testing reveals much higher rates of smell loss in people with Primary Ciliary Dyskinesia than self-reporting.

Common questions

How common is smell loss in people with Primary Ciliary Dyskinesia?

The overall prevalence of olfactory dysfunction in this group was found to be 43.4%. However, when using objective tests rather than patient reports, the rate of dysfunction jumped to 66.1%.

Why do some patients not report having a loss of smell?

There is a notable difference between how patients feel and what tests show. Only 30.5% of patients reported issues with their sense of smell, while objective testing showed much higher rates of dysfunction.

What factors make smell loss worse for these patients?

The study found that age, the burden of sinonasal disease, and specific defects in cilia (the tiny hairs in the nose and airways) were all linked to worse olfactory function.

Study Details

Study typeMeta analysis

Sample sizen = 865

EvidenceLevel 1

PublishedAug 2026

View Original Abstract ↓

Background: Olfactory dysfunction is a recognised but poorly characterised comorbidity of Primary Ciliary Dyskinesia (PCD). No prior systematic review has synthesised its prevalence or clinical correlates. Methodology: A PRISMA compliant systematic review and meta-analysis was conducted. Five databases were searched to February 2026. Observational studies reporting olfactory function in confirmed PCD were included. Risk of Bias was assessed using the Newcastle-Ottawa Scale. A random-effects meta-analysis using the Freeman-Tukey double arcsine transformation was performed to calculate pooled prevalence with 95% confidence intervals (CI) and prediction intervals (PI). Results: Twelve studies (n=865) were included. Overall pooled prevalence of olfactory dysfunction was 43.4% (95% CI 25.2-62.5%; 95% PI 0.1-99.0%). Objective psychophysical testing yielded a significantly higher pooled prevalence of 66.1% (95% CI 55.5-76.0%; 95% PI 38.4-88.9%) compared to patient-reported outcome measures (30.5%; 95% CI 11.4-54.0%). Older age, greater sinonasal disease burden, and specific ciliary ultrastructural defects were associated with worse olfactory function. A striking discordance between objective dysfunction and subjective awareness was observed across multiple studies. Conclusions: Olfactory dysfunction is highly prevalent in PCD and substantially under-recognised by patients. Routine objective olfactory screening should be integrated into standard multidisciplinary PCD care.

Objective testing identifies higher prevalence of olfactory dysfunction in Primary Ciliary Dyskinesia than patient reportsMore people with Primary Ciliary Dyskinesia have smell loss than expected

Common questions

Study Details

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Objective testing identifies higher prevalence of olfactory dysfunction in Primary Ciliary Dyskinesia than patient reportsMore people with Primary Ciliary Dyskinesia have smell loss than expected

Common questions

Study Details

Global GJB2 mutation prevalence in nonsyndromic hearing impairment

One in four people with hearing loss carries a specific gene mutation

Clinical research that matters. Delivered to your inbox.

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