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

ObjectiveExposure to particulate matter of 10 mu m 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.MethodsAdults from Sao 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 (R)). 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.ResultsAcute exposures to PM10 were related to worse UPSIT (R) scores, including 30- (beta = - 0.94, 95% Confidence Interval [CI] - 0.98, - 0.89), 60- (beta = - 1.09, 95% CI = - 1.13, - 1.04) and 90-day intervals (beta = - 1.06, 95% CI - 1.10, - 1.02) (reference for beta: 1 mu m/m(3) increase in PM10 exposure per point decrease in UPSIT (R) score). Chronic exposures were also associated with worse olfaction for both 180- (beta = - 1.06, 95% CI - 1.10, - 1.03) and 364-day (beta = - 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.ConclusionAcute 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.