Search

Introduction: Strong evidence suggests that olfactory dysfunction (OD) can predict additional neurocognitive decline in neurodegenerative conditions such as Alzheimer's and Parkinson's diseases. However, research exploring olfaction and cognition in younger populations is limited. The aim of this review is to evaluate cognitive changes among non-elderly adults with non-COVID-19-related OD. Methods: We performed a structured comprehensive literature search of PubMed, Ovid Embase, Web of Science, and Cochrane Library in developing this scoping review. The primary outcome of interest was the association between OD and cognitive functioning in adults less than 60 years of age. Results: We identified 2878 studies for title and abstract review, with 167 undergoing full text review, and 54 selected for data extraction. Of these, 34 studies reported on populations of individuals restricted to the ages of 18–60, whereas the remaining 20 studies included a more heterogeneous population with the majority of individuals in this target age range in addition to some above the age of 60. The etiologies for smell loss among the included studies were neuropsychiatric disorders (37%), idiopathic cause (25%), type 2 diabetes (7%), trauma (5%), infection (4%), intellectual disability (4%), and other (18%). Some studies reported numerous associations and at times mixed, resulting in a total number of associations greater than the included number of 54 studies. Overall, 21/54 studies demonstrated a positive association between olfaction and cognition, 7/54 demonstrated no association, 25/54 reported mixed results, and only 1/54 demonstrated a negative association. Conclusion: Most studies demonstrate a positive correlation between OD and cognition, but the data are mixed with associations less robust in this young adult population compared to elderly adults. Despite the heterogeneity in study populations and outcomes, this scoping review serves as a starting point for further investigation on this topic. Notably, as many studies in this review involved disorders that may have confounding effects on both olfaction and cognition, future research should control for these confounders and incorporate non-elderly individuals with non-psychiatric causes of smell loss. [ABSTRACT FROM AUTHOR]

Background: Nearly 40% of patients who experience smell loss during SARS-CoV-2 infection may develop qualitative olfactory dysfunction, most commonly parosmia. Our evidence-based review summarizes the evolving literature and offers recommendations for the clinician on the management of patients experiencing parosmia associated with COVID-19. Methods: We performed a systematic search using independent queries in PubMed, Embase, Ovid, and Cochrane databases, then categorized articles according to themes that emerged regarding epidemiology, effect on quality of life, disease progression, prognosis, pathophysiology, diagnosis, and treatment of parosmia. Results: We identified 123 unique references meeting eligibility and performed title and abstract review with 2 independent reviewers, with 74 articles undergoing full-text review. An inductive approach to thematic development provided 7 central themes regarding qualitative olfactory dysfunction following COVID-19. Conclusions: While other respiratory viruses are known to cause qualitative olfactory disturbances, the incidence of parosmia following COVID-19 is notable, and correlates negatively with age. The presence of parosmia predicts persistent quantitative olfactory dysfunction. Onset can occur months after infection, and symptoms may persist for well over 7 months. Affected patients report increased anxiety and decreased quality of life. Structured olfactory training with essential oils is the preferred treatment, where parosmia predicts recovery of aspects of quantitative smell loss when undergoing training. There is limited evidence that nasal corticosteroids may accelerate recovery of olfactory function. Patients should be prepared for the possibility that symptoms may persist for years, and providers should guide them to resources for coping with their psychosocial burden. [ABSTRACT FROM AUTHOR]

Introduction: Olfactory dysfunction (OD) is common among people with cystic fibrosis (PwCF). The Questionnaire of Olfactory Disorders (QOD) is a validated instrument that evaluates olfactory‐specific quality‐of‐life. The QOD minimal clinically important difference (MCID) and factors associated with olfactory improvement after elexacaftor/tezacaftor/ivacaftor have not been determined for PwCF. Methods: Prospective observational data were pooled from three studies that enrolled adult PwCF with chronic rhinosinusitis (CRS). QOD scores and disease characteristics were assessed. To evaluate internal consistency and calculate the QOD MCID, Cronbach's alpha and four distribution‐based methods were employed. For participants who enrolled prior to elexacaftor/tezacaftor/ivacaftor, QOD scores were obtained at baseline and after elexacaftor/tezacaftor/ivacaftor initiation. Multivariable regression was used to identify factors associated with QOD improvement. Results: Of 129 PwCF included, 65 had QOD scores before and 3–6 months after starting elexacaftor/tezacaftor/ivacaftor. Mean baseline QOD score was 6.5 ± 7.9. Mean Cronbach's alpha was ≥0.85. The MCID estimates were as follows: Cohen's effect size = 1.6, standard error of measurement = 2.5, ½ baseline standard deviation = 4.0, and minimal detectable change = 6.9. Mean MCID was 3.7. Of those with pre/post elexacaftor/tezacaftor/ivacaftor QOD scores, the mean change in QOD was −1.3 ± 5.4. After elexacaftor/tezacaftor/ivacaftor, QOD improvement surpassed the MCID in 22% of participants (14/65). Worse baseline QOD scores and nasal polyps were associated with improved QOD scores after elexacaftor/tezacaftor/ivacaftor (both p < 0.04). Conclusion: The QOD MCID in PwCF was estimated to be 3.7. Elexacaftor/tezacaftor/ivacaftor led to qualitative but not clinically meaningful improvements in QOD score for most PwCF; PwCF with worse baseline QOD scores and nasal polyps improved in a clinically significant manner. [ABSTRACT FROM AUTHOR]

Background: Social determinants of health (SDoH) are environmental conditions that influence health outcomes. As olfactory dysfunction (OD) in older individuals is associated with increased morbidity and mortality, we sought to investigate the impact of specific SDoH on olfactory function. Methods: A cross‐sectional analysis of the Health, Aging and Body Composition Study, a US population‐based epidemiologic cohort study, was performed. Olfactory function was assessed utilizing both a self‐report and a psychophysical olfactory test (CC‐SIT test). Multivariable logistic regressions were performed to examine associations between specific SDoH with self‐reported anosmia (sOD) and objective anosmia (oOD) as assessed by psychophysical testing. Differences in sensitivity and specificity were evaluated with sample tests for equality of proportions. Results: Of 2219 participants, 13% had oOD and 18% had objective hyposmia; only 10% had sOD. Individuals identifying as Black race had higher odds of oOD (odds ratio [OR]:1.41, 95% confidence interval [CI]:1.02‐1.95), while females and those reporting family incomes ≥$50,000 had lower odds of oOD (OR: 0.46, CI:0.34‐0.62; OR:0.52, CI:0.29‐0.93), adjusting for covariates. No specific SDoH was significantly associated with sOD. The sensitivity and specificity of sOD for oOD was 23.1% and 92.0%, respectively. sOD had greater sensitivity in females than males (30.8% vs. 18.8%, p = 0.030), while specificity varied significantly depending on family income (range: 90.0%‐94.8%, p = 0.033). Conclusions: Utilizing a large population‐based study, we find disparities in the prevalence and self‐recognition of OD among individuals of different gender, race, and income levels. Further effort is needed to evaluate factors propagating these disparities and to raise awareness of OD across all patient populations. [ABSTRACT FROM AUTHOR]

Background: The literature regarding clinical olfaction, olfactory loss, and olfactory dysfunction has expanded rapidly over the past two decades, with an exponential rise in the past year. There is substantial variability in the quality of this literature and a need to consolidate and critically review the evidence. It is with that aim that we have gathered experts from around the world to produce this International Consensus on Allergy and Rhinology: Olfaction (ICAR:O). Methods: Using previously described methodology, specific topics were developed relating to olfaction. Each topic was assigned a literature review, evidence‐based review, or evidence‐based review with recommendations format as dictated by available evidence and scope within the ICAR:O document. Following iterative reviews of each topic, the ICAR:O document was integrated and reviewed by all authors for final consensus. Results: The ICAR:O document reviews nearly 100 separate topics within the realm of olfaction, including diagnosis, epidemiology, disease burden, diagnosis, testing, etiology, treatment, and associated pathologies. Conclusion: This critical review of the existing clinical olfaction literature provides much needed insight and clarity into the evaluation, diagnosis, and treatment of patients with olfactory dysfunction, while also clearly delineating gaps in our knowledge and evidence base that we should investigate further. [ABSTRACT FROM AUTHOR]

Background: Social determinants of health (SDoH) include the socioeconomic, demographic, and social conditions that influence differences in health status among individuals and groups. The impact of these conditions on olfactory function remains poorly understood. In this scoping review, we systematically review the available literature to synthesize the association between SDoH and olfactory function. Methods: In accordance with the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses extension for Scoping Review (PRISMA‐ScR) guidelines, we performed systematic search queries in PubMed, Embase, and Ovid databases and categorized articles according to themes that emerged regarding SDoH. The primary outcomes included self‐reported and objective measurements of smell. Results: We identified 722 unique references that underwent title and abstract review by two independent reviewers, with 70 articles undergoing full‐text review and 57 relevant for data extraction. Six themes emerged in our review, under which we categorized the studies and synthesized respective associations with olfactory function. These include studies exploring socioeconomic status (n = 19, 33%), education status (n = 27, 47%), occupational exposures (n = 26, 46%), racial/ethnic disparities (n = 12, 21%), and lifestyle/behavioral factors (n = 33, 58%). Conclusions: Within the context of this scoping review, olfactory dysfunction is significantly more prevalent in patients with lower socioeconomic status, exposure to environmental and occupational toxins, and of minority race/ethnicity, whereas the associations between olfactory dysfunction and education level and lifestyle factors such as smoking and drinking seem to be much more elusive. This review highlights the importance of accounting for SDoH in observational studies examining olfactory outcomes. Given the increased awareness of olfactory loss, special consideration should be given to understanding olfactory dysfunction in the context of these factors. [ABSTRACT FROM AUTHOR]

Olfactory dysfunction (OD) commonly occurs in patients with sinonasal dysfunction, but the prevalence and severity of olfactory issues in adolescents with cystic fibrosis (AwCF) is unclear. OD may contribute to dietary deficiencies and exacerbate nutritional challenges. We sought to review literature on the effectiveness of medical and surgical management of sinonasal symptoms in AwCF and the associated impact on olfactory function. We performed a systematic literature search of PubMed, Embase, Web of Science, and Ebsco CINAHL from 1980 to 2022 per PRISMA-ScR protocols to conduct a scoping review in an effort to compile data on study design, patient demographics, clinical characteristics and outcomes, along with risk of bias. Of 368 abstracts, 3 articles exclusively evaluated AwCF for a total of 34 patients. Two studies evaluated endoscopic sinus surgery (ESS) and dornase alfa. An additional 6 articles were included for mixed pediatric and adult CF populations totaling 313 patients. Interventions included ESS, elexacaftor-tezacaftor-ivacaftor (ETI), ivacaftor, saline, dornase alfa, hyaluronic acid, and hyaluronic acid-tobramycin combination. Outcome measures included subjective assessment of OD using non-validated (4/9) and validated (4/9) surveys, and psychophysical (1/9) smell testing. Studies evaluating ESS, FESS, dornase alfa, ivacaftor, and both hypertonic and isotonic saline reported statistically significant improvement in OD, whereas ETI failed to improve OD despite improvement in other quality of life measures. There is limited data regarding the impact of medical and surgical interventions on olfaction for AwCF. Assessment of olfaction was often limited to subjective and qualitative self-report. We suggest that tracking of olfactory outcomes with psychophysical testing is critical in this population with dietary challenges and weight management issues. [ABSTRACT FROM AUTHOR]