Association of air pollution with olfactory identification performance of São Paulo residents: a cross-sectional study.

OBJECTIVE: Exposure to particulate matter of 10 µm or less in diameter (PM10) has been implicated in pulmonary and cardiovascular diseases. However, the effect of PM10 on olfaction has not been well established. We estimated individual acute and chronic PM10 exposure levels in a large Brazilian cohort and related them to the ability to identify odors. METHODS: Adults from São Paulo (n = 1358) were recruited from areas with different levels of air pollution. To verify individual exposure to air pollution, the averages of 30, 60, 90, 180 and 364 days of PM10 were interpolated to subjects' zip codes using the kriging method. Olfactory identification performance was tested using the University of Pennsylvania Smell Identification Test (UPSIT®). Multiple linear regressions were used to calculate the effect of air pollution on olfactory identification performance, controlling for demographic and other variables that affect the sense of smell. RESULTS: Acute exposures to PM10 were related to worse UPSIT® scores, including 30- (ß = - 0.94, 95% Confidence Interval [CI] - 0.98, - 0.89), 60- (ß = - 1.09, 95% CI = - 1.13, - 1.04) and 90-day intervals (ß = - 1.06, 95% CI - 1.10, - 1.02) (reference for ß: 1 µm/m3 increase in PM10 exposure per point decrease in UPSIT® score). Chronic exposures were also associated with worse olfaction for both 180- (ß = - 1.06, 95% CI - 1.10, - 1.03) and 364-day (ß = - 0.87, 95% CI - 0.90, - 0.84) intervals. As in prior work, men, older, low-income, and low-schooling people demonstrated worse olfactory performance. CONCLUSION: Acute and chronic exposure to PM10 is strongly associated with olfactory identification performance in Brazilian adults. Understanding the mechanisms which underlie these relationships could help to improve chemosensory function with a large public health impact.

Chemosensory Dysfunction 3-Months After COVID-19, Medications and Factors Associated with Complete Recovery.

OBJECTIVES: To examine the longitudinal prevalence and recovery of olfactory, gustatory, and oral chemesthetic deficits in a sizable cohort of SARS-CoV-2 infected persons using quantitative testing. To determine whether demographic and clinical factors, mainly the medications used after the COVID-19 diagnosis, influence the test measures. METHODS: Prospective cohort in a hospital with primary, secondary, tertiary, and quaternary care. Patients with confirmed COVID-19 were tested during the acute infection phase (within 15 days of initial symptom, n = 187) and one (n = 113) and 3 months later (n = 73). The University of Pennsylvania Smell Identification Test, the Global Gustatory Test, and a novel test for chemesthesis were administered at all visits. RESULTS: During the acute phase, 93% were anosmic or microsmic and 29.4% were hypogeusic. No one was ageusic. A deficit in oral chemesthesis was present in 13.4%. By 3 months, taste and chemesthesis had largely recovered, however, some degree of olfactory dysfunction remained in 54.8%. Remarkably, patients who had been treated with anticoagulants tended to have more olfactory improvement. Recovery was greater in men than in women, but was unrelated to disease severity, smoking behavior, or the use of various medications prior to, or during, COVID-19 infection. CONCLUSIONS: When using quantitative testing, olfactory disturbances were found in nearly all SARS-CoV-2 infected patients during the acute infection phase. Taste or chemesthetic deficits were low. Olfactory impairment persisted to some degree in over half of the patients at the 3-month follow-up evaluation, being more common in women and less common in those who had been treated earlier with anticoagulants. LEVEL OF EVIDENCE: 3.