Association between Ambient Air Pollution Exposure and Dizziness

Abstract

Background/Aim: Exposure to environmental chemicals has been suggested to alter the physiologic state of the inner and middle ear. However, it is unknown if air pollutant exposure is associated with dizziness. Therefore, we evaluated the association between daily concentration of ambient air pollutants and the number of dizziness hospital visits using time series analysis. Methods: We used National Health Insurance Service-National Sample Cohort (NHS-NSC), which is nationally representative cohort of Korea. Among total NHS-NSC participants, we selected 210,000 Seoul residents and linked daily hospital use data to daily levels of air pollutants data [nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), ozone (O3), and particulate matter < 2.5μg/m3 (PM2.5)]. Time series analysis using the Poisson generalized additive model was applied in our analysis. Results: There were total 1,462 dizziness hospital visits during 4 year study periods (2007-2010). An interquartile range (IQR) increase of NO2 on lag day 0 and 1 was significantly associated with an increased risk of dizziness hospital visits [relative risk (RR), 95% confidence interval (CI): lag 0: l.06, 1.00-1.11; lag 1: 1.06, 1.00-1.11]. In a subgroup analysis by sex, we found significant association between an IQR increase of NO2 and dizziness hospital visits in both men and women [RR, 95% CI: men, lag 4: 1.12, 1.02-1.22; women, lag 0: 1.09, 1.03-1.16; lag 1: 1.10, 1.04-1.17]. In a subgroup analysis by age, an IQR increase in SO2 was significantly associated with dizziness hospital visits from elderly individuals in lag day 3 [RR, 95% CI: 1.09, 1.03-1.16]. In addition, NO2 was significantly associated with dizziness hospital visits from non-elderly individuals in lag day 0 [RR, 95% CI: 1.09, 1.03-1.16]. Additional case-crossover analyses showed similar results. Conclusions: Dizziness hospital visits were associated with ambient air pollution exposure. Among diverse air pollutants, NO2 was most significantly associated with dizziness hospital visits.