Mortality and Hospital Emergency Room Visit of Older Adults by Exposure to Fine Particulate Matter and Ozone

Abstract

The effects on particulate matter and ozone on health are being reported by a number of studies. The effects of these air pollutants are likely to be stronger in older adults, but studies in this regard are scarce. The purpose of this study was to study the effects of particulate matter ≤2.5 μm and ozone on acute health effects of older adults. In order to analyze the health status of older adults, NHIS (National Health Insurance System)-Senior Cohort data and National Statistical Office Mortality records were used. In this study, who were 60 years or older in Seoul, number of ER visit and number of deaths between 2002-2013 were calculated. The current study analyzed each disorder separately and the lag effect. Particulate matter and ozone were analyzed using the single exposure model, as well as the adjusted multi exposure model. In the single exposure analysis with PM2.5 as the exposure variable, with the increase of 10μg/m3, the number of ER (Emergency Room) visit increased by 1.0062 times, and in the multi exposure model adjusting for meterological factors, the number of ER visit increased by 1.0074 times. There was 1day lag effect and 1.0066 times increase between PM2.5 and ER visit in the multi exposure model, and 1.0057 times when adjusting for ozone (p value <0.10). There was 1day lag effect in all multi exposure models with ozone as the main variable, and when the particulate matter was adjusted, there was a 1day delay and 1.0143 times increase in ER visit. In the single exposure analysis with PM2.5 as the exposure variable, with the increase of 10μg/m3, the number of deaths increased by 1.0059 times, and vascular disease 1.0088 times. In the multi exposure model adjusting for ozone, the number of overall deaths increased by 1.0039 times, and vascular disease 1.0060 times. In the multiple exposure analysis adjusted meterological factors with ozone as the exposure variable, with the increase of 10 ppb, the number of overall deaths increased by 1.0021 times (p value <0.10). There were a 5-day lag effects between PM2.5 and deaths in the multi exposure model, and 1.0032 times when adjusted for ozone. These results differed depending on the season. Considering the warm and cold period separately, in the multiple exposure model adjusting for ozone, the number of ER visit increased by 1.0210 times were significant in the warm-period due to PM2.5, and in the multiple exposure model adjusting for meterological factors, 1.0323 times were significant in the warm-period due to ozone. In the single exposure model, the overall mortality rate increased by 1.0106 times and mortality due to diabetes increased by 1.0483 times were significant in the warm-period but there were no significant results in the cold-period due to ozone. In association with particulate matters, overall mortality increased by 1.0043 times and mortality due to vascular disease by 1.0063 times in the multiple exposure model adjusted ozone during the cold-period and during the warm-period, the overall mortality increased by 1.0066 times in the single exposure model. In this study, an increase in the number of ER visit, and deaths of older adults in accordance with the increase in the PM2.5 and ozone was found. Because the results differed according to warm- and cold- periods, it could be assumed that the period changes the effects of the PM2.5 and ozone on health on older adults. The association found in this study could also influence socioeconomic burden. Future studies need to be performed in regards to younger population, as well as other air pollutants.