BACKGROUND: Exposure to environmental chemicals has been suggested to alter the physiologic state of the inner and middle ear. However, it is unknown if particulate matter exposure is associated with acute vestibular dysfunction.

OBJECTIVES: To estimate the effects of particulate matter exposure on the number of hospital visits related to three major diseases of vestibular dysfunction, Meniere's disease (MD), benign paroxysmal positional vertigo (BPPV), and vestibular neuronitis (VN).

METHODS: Our study subject is from Korean National Health Insurance Service-National Sample Cohort, which is dynamic cohort consist of 1 million participants representing the Korean population. Among total cohort participants, we used the hospital visit data of 210,000 individuals who resided in Seoul from 2007 to 2010. Time series analysis using the Poisson generalized additive model and case-crossover analysis using conditional logistic regression were used to investigate the association between daily particulate matter levels (PM2.5, particulate matter <2.5μg/m3; PM10, particulate matter <10μg/m3; PM10-2.5, PM10- PM2.5) and number of MD, BPPV, and VN hospital visits.

RESULTS: Time series analysis showed that an interquartile range (IQR) increase in PM10 and PM10-2.5 on lag day 1 was associated with an increased risk of MD hospital visits [relative risk (RR), 95% confidence interval (CI), PM10: 1.09 (1.02-1.15); PM10-2.5: 1.06 (1.02-1.10)]. In addition, elderly individuals (≥60 years old) showed an increased risk of MD hospital visits after particulate matter exposure when compared to younger individuals. An IQR increase in particulate matter on lag day 1 was associated with a marginally significant increase in VN hospital visits [RR (95%CI), PM2.5: 1.11 (0.98-1.25); PM10: 1.07 (0.99-1.15); PM10-2.5: 1.04 (0.99-1.09)]. However, no association between particulate matter exposure and BPPV hospital visits was noted. Case-crossover analyses showed similar results to the time-series analysis across all three diseases.

CONCLUSION: MD hospital visits were associated with ambient particulate matter exposure. Elderly individuals, in particular, were more susceptible to particulate matter exposure than younger individuals.