Temperature modifies the association between particulate air pollution and mortality: A multi-city study in South Korea.
Substantial epidemiologic literature has demonstrated the effects of air pollution and temperature on mortality. However, there is inconsistent evidence regarding the temperature modification effect on acute mortality due to air pollution. Herein, we investigated the effects of temperature on the relationship between air pollution and mortality due to non-accidental, cardiovascular, and respiratory death in seven cities in South Korea. We applied stratified time-series models to the data sets in order to examine whether the effects of particulate matter <10 μm (PM10) on mortality were modified by temperature. The effect of PM10 on daily mortality was first quantified within different ranges of temperatures at each location using a time-series model, and then the estimates were pooled through a random-effects meta-analysis using the maximum likelihood method. From all the data sets, 828,787 non-accidental deaths were registered from 2000-2009. The highest overall risk between PM10 and non-accidental or cardiovascular mortality was observed on extremely hot days (daily mean temperature: >99th percentile) in individuals aged <65 years. In those aged ≥65 years, the highest overall risk between PM10 and non-accidental or cardiovascular mortality was observed on very hot days and not on extremely hot days (daily mean temperature: 95-99th percentile). There were strong harmful effects from PM10 on non-accidental mortality with the highest temperature range (>99th percentile) in men, with a very high temperature range (95-99th percentile) in women. Our findings showed that temperature can affect the relationship between the PM10 levels and cause-specific mortality. Moreover, the differences were apparent after considering the age and sex groups.
Department of Biostatistics and Epidemiology, Graduate School of Public Health, Seoul National University, Seoul, Republic of Korea; Institute of Health and Environment, Seoul National University, Seoul, Republic of Korea.
Satbyul Estella
SE
Kim
Institute of Environmental Medicine, Seoul National University of Medical Research Center, Seoul, Republic of Korea; Environmental Health Center, Seoul National University College of Medicine, Seoul, Republic of Korea.
Youn-Hee
YH
Lim
Department of Biostatistics and Epidemiology, Graduate School of Public Health, Seoul National University, Seoul, Republic of Korea; Institute of Health and Environment, Seoul National University, Seoul, Republic of Korea. Electronic address: hokim@snu.ac.kr.
Ho
H
Kim
D000328:Adult; D000368:Aged; D000393:Air Pollutants; D000397:Air Pollution / Q000706:statistics & numerical data*; D002318:Cardiovascular Diseases / Q000401:mortality*; D002947:Cities; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D052638:Particulate Matter / Q000032:analysis*; D056910:Republic of Korea / Q000453:epidemiology; D012140:Respiratory Tract Diseases / Q000453:epidemiology; D013696:Temperature; D055815:Young Adult
D000393:Air Pollutants; D052638:Particulate Matter
Air pollution; Effect modification; Mortality; Particulate matter; Temperature; Time-series studies