COVID-19 Induced Taste Dysfunction and Recovery: Association with Smell Dysfunction and Oral Health Behaviour

Insights into salt perception and cognitive impairment among middle-aged and older adults: a scoping review

BACKGROUND

A decline in taste sensitivity from aging leads people with a higher salt threshold to frequently add more salt to their food, which attributed to decreased cognitive efficiency. This scoping review aimed to gather the latest evidence on the relationship between salt perception and cognitive impairment which is essential in the development of new intervention and prevention strategies.

METHODS

Studies published between January 2014 and March 2024 were searched across four databases: PubMed, the Cochrane Library, Scopus, and EBSCO. Data extraction involved gathering details on the study design, participant demographics, methods for assessing cognitive function and salt perception, considering confounding factors, and synthesizing the primary outcomes.

RESULTS

Six studies were included in the analysis, five cross-sectional studies and a longitudinal study. These studies revealed various associations between salt perception and cognitive impairment. Specifically, findings from a three-year longitudinal study suggested that lower salt sensitivity was associated with poorer cognitive scores, which is consistent with the results of two other studies. However, the remaining three studies did not find significant differences (p > 0.05) in salt taste perception related to cognitive status. Furthermore, a study identified executive function as another significant factor influencing salt taste perception.

CONCLUSION

These findings highlight the link between cognitive decline in salt perception, which provide an indication of salt intake and related health risks. There is a need to explore the mechanisms of salt taste sensitivity and its impact on cognitive health should be encouraged.

Association of self-reported periodontal disease and inequities with long haul COVID-19

In 2000, the Surgeon General's report highlighted that the mouth is a mirror for overall health of an individual and that disparities in oral health are directly proportionate to general health inequities. Among patients hospitalized due to COVID-19, diabetes and cardiovascular disease are the most common comorbidities; several studies support the association of these conditions with periodontal disease. This study's main aim is to assess the disproportionate impact of the COVID-19 pandemic on populations from lower socioeconomic statuses. The study also aims to assess the association of self-reported periodontal disease with COVID-19 disease course and severity. A sample population of Indiana residents with positive diagnosis of SARS-CoV-2 were recruited. A validated survey tool was sent to this cohort inquiring about sociodemographic distribution; co-morbid conditions, current symptoms of "long haul COVID," course of their COVID-19 infection; history of periodontal disease, existing periodontal disease symptoms, and oral hygiene habits. 209 individuals with a history of positive COVID test were returned to the survey, and association of participant characteristics and periodontal disease-related survey items with COVID-related survey items were evaluated using chi-square tests. Lower sense of smell ratings was associated with less education (p = 0.021), being unemployed/disabled (p = 0.008), worse health status (p<0.001), more frequent bleeding gums (p = 0.031), more frequent toothache (p<0.001), lower oral health rating (p = 0.002), and vaccine status (p = 0.011). Lower sense of taste ratings were associated with older age (p = 0.018), worse health (p<0.001), more frequent bleeding gums (p<0.001), more frequent mobile or loose tooth (p = 0.010), presence of gum disease (p<0.001), more frequent loss of teeth (p = 0.013), more frequent toothache (p<0.001), worse oral health (p = 0.001), teeth lost due to gum disease (p = 0.006), and vaccine status (p = 0.001). History of hospitalization due to COVID-19 was found to be associated with a history of gum disease within the past 12 months.

Treatment of Olfactory Disorders After SARS - CoViD 2 Virus Infection

OBJECTIVE

The benefit of a nasal corticosteroid in the treatment of persistent post-infectious smell disorders is not as clear in previous studies as is assumed for olfactory training. This study would therefore like to describe the treatment strategies using the example of a persistent olfactory dysfunction as a result of a proven infection with SARS-CoViD-2-virus.

METHODS

Twenty patients (average age of 33.9 ± 11.9 years) with hyposmia were included in this study from December 2020 to July 2021. Every second patient received additionally a nasal corticosteroid. The two resulting randomized groups of equal size were screened with the TDI test, a 20-item taste powder test for the assessment of retronasal olfaction and otorhinolaryngological examination. The patients were asked to train twice daily using a standardized odor training kit and followed up after 2 months and 3 months, respectively.

RESULTS

We documented a significant overall improvement in olfactory ability over the investigation period in both groups. While the TDI score steadily increased on average under the combination therapy, the rise under olfactory training alone was initially steeper. This short-term interaction effect over mean two months was not statistically significant. According to Cohen, however, a moderate effect (eta2 = 0.055, Cohen`s d = 0.5) can still be assumed. This effect could be explained by a possibly higher compliance at the beginning of the sole olfactory training due to the lack of further drug treatment offers. When the training intensity decreases, the recovery of the sense of smell stagnates. Adjunctive therapy ultimately outweighs this short-term benefit.

CONCLUSIONS

The results reinforce the recommendation of early and consistent olfactory training on patients with dysosmia due to COVID-19. For continuous improvement of the sense of smell, an accompanying topical treatment seems at least to be worth consideration. The results should be optimized with larger cohorts and using new objective olfactometric methods.

Treatments of COVID-19-Associated Taste and Saliva Secretory Disorders

Since the worldwide spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, treating taste and saliva secretory disorders associated with coronavirus disease 2019 (COVID-19) has become a critical issue. The aim of the present study was to update information on treatments applicable to such oral symptoms and discuss their pathogenic mechanisms. The literature search indicated that different treatments using tetracycline, corticosteroids, zinc, stellate ganglion block, phytochemical curcumin, traditional herbal medicine, nutraceutical vitamin D, photobiomodulation, antiviral drugs, malic acid sialagogue, chewing gum, acupuncture, and/or moxibustion have potential effects on COVID-19-associated ageusia/dysgeusia/hypogeusia and xerostomia/dry mouth/hyposalivation. These treatments have multiple modes of action on viral cellular entry and replication, cell proliferation and differentiation, immunity, and/or SARS-CoV-2 infection-induced pathological conditions such as inflammation, cytokine storm, pyroptosis, neuropathy, zinc dyshomeostasis, and dysautonomia. An understanding of currently available treatment options is required for dental professionals because they may treat patients who were infected with SARS-CoV-2 or who recovered from COVID-19, and become aware of their abnormal taste and salivary secretion. By doing so, dentists and dental hygienists could play a crucial role in managing COVID-19 oral symptoms and contribute to improving the oral health-related quality of life of the relevant patients.

Olfactory and taste dysfunction in COVID-19-incidence and recovery

Background

Olfactory and taste dysfunctions have been identified as prominent signs of COVID-19 infection. The data on its prevalence, time of onset, and recovery is highly variable.

Objective

The study was aimed at establishing the incidence of and the factors influencing smell and taste disorders in COVID-19-affected patients.

Methodology

Telephonic interviews were used to collect data on the symptoms of COVID-19-positive patients, with an emphasis on smell and taste disorders. Patients have severe disease and a history of illnesses that may affect olfaction or taste, and those unwilling to participate were excluded.

Results

A total of 1488 COVID-19-positive patients were identified. A total of 772 were included and interviewed, and their data were analysed. A total of 242 (31.3%) patients developed symptoms related to smell and/or taste. Anosmia (149) and ageusia (152) were the most common. Younger patients were more commonly affected (p = 0.0016). The presence and degree of smell symptoms and taste symptoms showed a small positive correlation (r = .234, p < .001). A strong relationship was seen with fever (r = .825, p < .001) and a significantly moderate relationship with breathing difficulty. There was no significant difference based on age or sex for the recovery of smell or taste sensations. There was a significant correlation between taste recovery and smell recovery times (p < 0.00001).

Conclusion

Smell and taste disorders, as early clinical symptoms of COVID-19, may have a diagnostic as well as a prognostic value. Treatment protocols for these patients are yet to be defined. A positive association between these symptoms and breathing difficulty was found, and we recommend COVID-19 testing and monitoring of symptoms for all patients with new-onset OTD symptoms. A combination of active enquiry about these symptoms, along with objective testing when the patients present with COVID-19 symptoms may help in better understanding of the pathophysiology and timely initiation of treatment.