Recovery From COVID-19-Related Olfactory Disorders and Quality of Life: Insights From an Observational Online Study.

Although olfactory disorders (OD) are among the most significant symptoms of COVID-19, recovery time from COVID-19-related OD and their consequences on the quality of life remain poorly documented. We investigated the characteristics and behavioral consequences of COVID-19-related OD using a large-scale study involving 3111 French respondents (78% women) to an online questionnaire over a period of 9 months covering different epidemic waves (from 8 April 2020 to 13 January 2021). In the patients who subjectively recovered from COVID-19-related OD (N = 609), recovery occurred on average after 16 days and most of the time within 1 month ("normal" recovery range); 49 subjectively recovered in 1-2.5 months, and several cases took up to 6.5 months. Among the patients with ongoing OD (N = 2502), 974 were outside the "normal" recovery range (persistent OD) and reported OD for 1-10 months. Developing a persistent OD was more likely with increasing age and in women and was more often associated with parosmia and phantosmia. The deleterious impact of COVID-19-related OD on the quality of life was significantly aggravated by OD duration and was more pronounced in women. Because persistent OD is not infrequent after COVID-19, has deleterious consequences on the quality of life, and receives few solutions from the health practitioners, it would be beneficial to implement screening and treatment programs to minimize the long-term behavioral consequences of COVID-19-related OD.

Association of Lewy Bodies With Age-Related Clinical Characteristics in Black and White Decedents.

OBJECTIVE: The associations of Lewy bodies (LBs) with olfactory dysfunction, parkinsonism, and higher odds of dementia were assessed in Black and White community-dwelling elders and racial differences in these associations were tested. METHODS: Black decedents (n = 81) were matched 2-to-1 by age, sex, years of education, and follow-up time in the study with White decedents (n = 154) from 4 longitudinal studies of dementia and aging. Participants underwent uniform clinical examination and cognitive, motor, and olfactory testing. LBs were detected in 7 brain regions by α-synuclein immunohistochemistry and racial differences in their association with olfaction, parkinsonism, and odds of dementia were determined using regression analyses. RESULTS: The mean scores of the odor test, global parkinsonism signs, and global cognition were lower in Black than White decedents; the frequency of dementia was similar in both groups. The frequency of LBs was similar in Black and White decedents (∼25%), as was the frequency of LBs in individual brain regions, while the mean LB counts/mm2 were similar in all regions except the cingulate cortex, which showed higher mean LB counts in Black decedents. In regression analyses, LBs were associated with impaired olfaction (-2.23, 95% confidence interval [CI] -3.45 to -1.01) and higher odds of dementia (odds ratio 3.0, 95% CI 1.10-8.17) in both racial groups; an association with parkinsonism was stronger in Black than White decedents. CONCLUSIONS: The frequency, distribution, and clinical manifestations of LBs are similar in Black and White elders.

Prevalence of Chemosensory Dysfunction in COVID-19 Patients: A Systematic Review and Meta-analysis Reveals Significant Ethnic Differences.

A significant proportion of people who test positive for COVID-19 have chemosensory deficits. However, the reported prevalence of these deficits in smell and taste varies widely, and the reason for the differences between studies is unclear. We determined the pooled prevalence of such chemosensory deficits in a systematic review and meta-analysis. We searched the COVID-19 portfolio of the National Institutes of Health for studies that reported the prevalence of smell or taste deficits or both in patients diagnosed with COVID-19. One-hundred-four studies reporting on 38 198 patients qualified and were subjected to a systematic review and meta-analysis. Estimated random prevalence of olfactory dysfunction was 43.0%, that of taste dysfunction was 44.6%, and that of overall chemosensory dysfunction was 47.4%. We examined the effects of age, gender, disease severity, and ethnicity on chemosensory dysfunction. Prevalence of smell or taste dysfunction or both decreased with older age, male gender, and disease severity. Ethnicity was highly significant: Caucasians had a three times higher prevalence of chemosensory dysfunctions (54.8%) than Asians (17.7%). The finding of geographic differences points to two causes that are not mutually exclusive. A virus mutation (D614G) may cause differing infectivity, while at the host level genetic, ethnicity-specific variants of the virus-binding entry proteins may facilitate virus entry in the olfactory epithelium and taste buds. Both explanations have major implications for infectivity, diagnosis, and management of the COVID-19 pandemic.

The Prevalence of Anosmia and Associated Factors Among U.S. Black and White Older Adults.

BACKGROUND: Olfactory impairment is common among older adults; however, data are largely limited to whites. METHODS: We conducted pooled analyses of two community-based studies: the Atherosclerosis Risk in Communities study (ARIC, 1,398 blacks and 4,665 whites), and the Health, Aging, and Body Composition study (Health ABC, 958 blacks and 1,536 whites) to determine the prevalence of anosmia and associated factors for black and white older adults in the United States. RESULTS: The overall prevalence of anosmia was 22.3% among blacks and 10.4% among whites. Blacks had a markedly higher odds of anosmia compared to whites in age and sex adjusted analyses (odds ratio [OR] 2.96, 95% confidence interval [CI] = 2.59-3.38). In both blacks and whites, higher anosmia prevalence was associated with older age and male sex. The highest prevalence was found in black men 85 years or older (58.3%), and the lowest in white women aged 65-69 years (2.4%). Higher education level, lower cognitive score, ApoE ε4, daytime sleepiness, poorer general health status, lower body mass index, and Parkinson disease were associated with higher prevalence of anosmia in one or both races. However, the racial difference in anosmia remained statistically significant after adjusting for these factors (fully adjusted OR = 1.76, 95%CI: 1.50-2.07). Results were comparable between the two cohorts. DISCUSSION: Anosmia is common in older adults, particularly among blacks. Further studies are needed to identify risk factors for anosmia and to investigate racial disparities in this sensory deficit.

Olfaction and risk of dementia in a biracial cohort of older adults.

OBJECTIVE: Prior studies indicate that olfactory function may be an early marker for cognitive impairment, but the body of evidence has been largely restricted to white populations. METHODS: We studied 2,428 community-dwelling black and white older adults (baseline age 70-79 years) without dementia enrolled in the Health, Aging, and Body Composition (Health ABC) study. Olfaction was measured as odor identification (OI) with the 12-item Cross Cultural Smell Identification Test in year 3. We defined incident dementia over 12 years on the basis of hospitalization records, prescription for dementia medication, or 1.5-SD decline in race-stratified global cognition score. We assessed dementia risk associated with OI score (by tertile) using Cox proportional hazards models. All analyses were stratified by race. RESULTS: Poorer OI in older adults without dementia was associated with increased risk of dementia. After adjustment for demographics, medical comorbidities, and lifestyle characteristics, white participants in the poor or moderate OI tertile had greater risk of dementia (adjusted hazard ratio [HR] 3.34, 95% confidence interval [CI] 2.45-4.54; and HR 1.84, 95% CI 1.33-2.54, respectively) compared to those in the good tertile of function. Among blacks, worse OI was associated with an increased risk of dementia, but the magnitude of the effect was weaker (p for interaction = 0.04) for the poor OI tertile (adjusted HR 2.03, 95% CI 1.44-2.84) and for the moderate tertile (adjusted HR 1.42, 95% CI 0.97-2.10). There was no interaction between OI and APOE ε4 and risk of dementia. CONCLUSIONS: While the magnitude of the association was stronger in whites, we found that poor OI was associated with increased risk of dementia among both black and white older adults.

Reliability and validity of the Chinese version of the questionnaire of olfactory disorders (QOD) when used with patients having olfactory dysfunction.

To cross-culturally adapt the Questionnaire of olfactory disorders (QOD) into a Chinese version, and then evaluate its reliability and validity for testing patients with olfactory dysfunction. A Chinese version of the QOD was evaluated for test-retest reliability, split-half reliability, and internal consistency. The validity analysis included components of content validity and criterion-related validity, as well as comparisons between The Medical Outcomes Study's36-Item ShortForm Health Survey(SF-36)questionnaire and the WHO Quality of Life-BREF (WHOQOL-BREF)questionnaire. A total of 125 patients with olfactory dysfunction were tested, and 104 patients completed three different surveys (QOD, SF-36, and WHOQOL-BREF). The test-retest reliabilities of the QOD-Parosmia statements (QOD-P), QOD-Quality of life (QOD-QoL), and QOD-Visual simulation (QOD-VAS)sections were 0.802 (P < 0.001), 0.797 (P < 0.001), and 0.468 (P < 0.001), respectively, and the Cronbach's α coefficients of internal consistency were 0.473, 0.814, and 0.882, respectively. The split-half reliability was 0.70. No correlation was found between the QOD-P section and the SF-36; however, there were statistically significant correlations between the QOD-QoL andQOD-VAS sections and the SF-36. The same results were observed for correlations between the QOD and WHOQOL-BREF. The Chinese version of the QOD was proven to be a generally reliable and valid questionnaire for use in evaluating mainland Chinese patients suspected of having olfactory dysfunction. However, the QOD-P section requires further modifications to properly evaluate patients with a Chinese cultural background and type of cognition.

Prevalence of subjective olfactory dysfunction and its risk factors: korean national health and nutrition examination survey.

BACKGROUND: Population-based studies for olfactory dysfunction are lacking. The aim of this study is to evaluate the prevalence of subjective olfactory dysfunction and its risk factors in the Korean general population. METHODS: The data were obtained from the 2009 Korea National Health and Nutrition Examination Survey (KNHANES), which was a cross-sectional survey of non-institutionalized population all around the country (n = 10,533). All interviewees underwent medical interviews, physical examinations, endoscopic examination and blood/urine tests. Whether sense of smell has been normal or abnormal during the last 3 months was asked. Complete olfaction data were obtained from 7,306 participants and the participants were divided into normosmic and hyposmic group. Multivariate logistic regression analyses were performed to identify its risk factors. RESULTS: The weighted prevalence of subjective olfactory dysfunction was 4.5%. Its increased prevalence was significantly associated with the increasing age for both men and women. In the multivariate analyses, low income (adjusted odds ratio [OR] = 1.43, 95% Confidence Interval [CI] = 1.01-2.03), habitual exposure to air pollutants (adjusted OR = 2.18, CI = 1.33-3.55), a history of hepatitis B (adjusted OR = 3.10, CI = 1.25-7.68), rhinitis (adjusted OR = 1.78, CI = 1.26-2.51) and chronic sinusitis (adjusted OR = 14.55, CI = 10.06-21.05) were risk factors of olfactory dysfunction. CONCLUSION: Our population-based study showed that olfactory dysfunction was quite prevalent and several risk factors were associated with impaired sense of smell. Given its prevalence, further researches for its prevention and management are required.

The odor stick identification test for Japanese differentiates Parkinson's disease from multiple system atrophy and progressive supra nuclear palsy.

BACKGROUND: Progressive supranuclear palsy (PSP) and parkinsonian variant of multiple system atrophy (MSA-P) are clinically difficult to differentiate from idiopathic Parkinson's disease (PD), particularly in the early stages of the disease. Previous reports indicated that the olfactory function is relatively intact or slightly reduced in patients with PSP and MSA-P, suggesting that the odor stick identification test for Japanese (OSIT-J), which is a short and simple noninvasive test that is potentially useful clinically for detecting early-stage PD in Japan, may be useful in the differential diagnosis of early-stage PD from MSA-P and PSP. There is no information on the sensitivity and specificity of OSIT-J in the diagnosis of parkinsonian syndromes such as PSP and MSA-P. METHODS: We assessed the olfactory function using the OSIT-J test in 94 Japanese patients with idiopathic PD, 15 with MSA-P, 7 with PSP, and 29 age-matched control subjects. RESULTS: The mean ± SD score of OSIT-J in patients with PD (4.4 ± 2.9) was significantly lower than in patients with MSA-P (8.7 ± 2.2, P < 0.0001), PSP (7.6 ± 2.2, P < 0.0057), and control subjects (10.5 ± 1.3, P < 0.0001). The area under the curve (AUC) of receiver operating characteristic (ROC) to discriminate PD from normal control using OSIT-J scores was 0.97 (95% confidence interval, 0.95-1.00), from MSA-P 0.87 (0.80-0.95), and from PSP 0.81 (0.66-0.96). CONCLUSION: The OSIT-J is a potentially useful clinical test not only for detection of olfactory deficit in PD but also for differentiating PD from MSA-P and PSP.

Olfactory identification deficits and MCI in a multi-ethnic elderly community sample.

Odor identification deficits occur in Alzheimer's disease (AD) and mild cognitive impairment (MCI), and predict clinical conversion from MCI to AD. In an epidemiologic study conducted in a multi-ethnic community elderly sample (average 80 years old), the University of Pennsylvania Smell Identification Test (UPSIT, range 0-40) was administered to 1092 non-demented subjects. Women (mean 26.6, S.D. 6.6) scored higher than men (mean 24.4, S.D. 7.4, p<.02), and ethnic differences were not significant after controlling for age and education. UPSIT scores correlated inversely with age (r=-0.24, p<.0001) and positively with Selective Reminding Test immediate recall (r=0.33), delayed recall (r=0.28), category fluency (r=0.28) and the 15-item Boston Naming Test (r=0.23), all ps<.0001. In a sub-sample in which MRI was done, UPSIT scores showed a significant correlation with hippocampal volume (n=571, r=0.16, p<.001) but not entorhinal cortex volume nor total number of white matter hyperintensities. In ANOVA, UPSIT scores differed (p<.0001) as a function of MCI classification: no MCI (mean 26.6, S.D. 6.8), non-amnestic MCI (mean 24.4, S.D. 7.2), and amnestic MCI (mean 23.5, S.D. 6.7). The difference between amnestic MCI and no MCI remained significant after controlling for relevant covariates. These findings indicate that the predictive utility of olfactory identification deficits for decline from no MCI to MCI and AD needs to be assessed in longitudinal studies of elderly community samples.

The standard clinical smell testing protocol of the National Center for Diabetes, Endocrinology and Genetics in Amman, Jordan: JOR test.

OBJECTIVE: The aim of this study was the development of a simple clinical smell test that can be applied in Jordan and its validation against one of the standard tests, the University of Pennsylvania Smell Test (UPSIT, Sensonics Inc, Haddon Heights, NJ). DESIGN: A prospective validation study of a locally designed smell test was done. SETTING: The study was conducted at the National Center for Diabetes, Endocrinology and Metabolism in Amman, Jordan. PARTICIPANTS: Fifty subjects were recruited to participate in this study. Twenty-five were normal healthy individuals, and 25 were patients with Kallmann syndrome. INTERVENTION AND MAIN OUTCOME MEASURES: All 50 participants underwent 2 tests, the UPSIT and the locally designed test (JOR test). The scores of all patients in both tests were compared. Test-retest reliability was determined in the same 50 subjects. All patients completed the study. RESULTS: Subjects who scored within normal limits on the UPSIT scored 8 to 10 on the JOR test, and people who were abnormal on the UPSIT scored between 0 and 5 on the JOR test. The correlation between the scores of both tests was almost perfect (r = 0.984, P = .000). When both tests were classified as normal and abnormal, there was a complete agreement (kappa statistic = 1). Both sensitivity and specificity were 100%. CONCLUSION: Given its highly significant correspondence to the UPSIT and the odor thresholds of Jordanians, our test proved valid and useful as a cross-cultural clinical test of olfactory function. In addition, it is an inexpensive, rapid test. Unfortunately, the data lacked persons with moderate impairment of smell. Therefore, the new test may not be used to assess this category of patients.

Usefulness of the odor stick identification test for Japanese patients with olfactory dysfunction.

The odor stick identification test (OSIT) is a new test of olfactory function recently developed for Japanese people. The purpose of the present study was to evaluate this test in relation to T&T olfactometry and the cross-cultural smell identification test (CC-SIT) by applying to 110 Japanese patients with olfactory disturbance. The averaged recognition thresholds for five odorants in T&T olfactometry, the number of correct answers in the CC-SIT and the rates of identification of 13 odorants in the OSIT were compared. The visual analogue scale (VAS) was also used to evaluate symptoms. The rate of identification of OSIT showed high and significant correlation coefficients with the averaged recognition thresholds of T&T olfactometry (-0.766, P < 0.001), with the number of correct answers in CC-SIT (0.754, P < 0.001) and with the VAS score (0.591, P < 0.001). In addition, on the identification performance measured by OSIT, we found significant differences between all pairs of four degrees of olfactory dysfunction except for one pair. Thus, we conclude that OSIT is useful for evaluating olfactory dysfunction in Japanese people.