Survival analysis of long-term exposure to different sizes of airborne particulate matter and risk of infant mortality using a birth cohort in Seoul, Korea

Ji Young Son, Michelle L. Bell, Jong-Tae Lee

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Background: Several studies suggest that airborne particulate matter (PM) is associated with infant mortality; however, most focused on short-term exposure to larger particles. Objectives: We evaluated associations between long-term exposure to different sizes of particles [total suspended particles (TSP), PM ≤ 10 μm in aerodynamic diameter (PM10), ≤ 10-2.5 μm (PM10-2.5), and ≤ 2.5 μm (PM2.5)] and infant mortality in a cohort in Seoul, Korea, 2004-2007. Methods: The study includes 359,459 births with 225 deaths. We applied extended Cox proportional hazards modeling with time-dependent covariates to three mortality categories: all causes, respiratory, and sudden infant death syndrome (SIDS). We calculated exposures from birth to death (or end of eligibility for outcome at 1 year of age) and pregnancy (gestation and each trimester) and treated exposures as time-dependent variables for subjects' exposure for each pollutant. We adjusted by sex, gestational length, season of birth, maternal age and educational level, and heat index. Each cause of death and exposure time frame was analyzed separately. Results: We found a relationship between gestational exposures to PM and infant mortality from all causes or respiratory causes for normal-birth-weight infants. For total mortality (all causes), risks were 1.44 (95% confidence interval, 1.06-1.97), 1.65 (1.18-2.31), 1.53 (1.22-1.90), and 1.19 (0.83-1.70) per interquartile range increase in TSP, PM10, PM2.5, and PM10-2.5, respectively; for respiratory mortality, risks were 3.78 (1.18-12.13), 6.20 (1.50-25.66), 3.15 (1.26-7.85), and 2.86 (0.76-10.85). For SIDS, risks were 0.92 (0.33-2.58), 1.15 (0.38-3.48), 1.42 (0.71-2.87), and 0.57 (0.16-1.96), respectively. Conclusions: Our findings provide supportive evidence of an association of long-term exposure to PM air pollution with infant mortality.

Original languageEnglish
Pages (from-to)725-730
Number of pages6
JournalEnvironmental Health Perspectives
Volume119
Issue number5
DOIs
Publication statusPublished - 2011 May 1

Fingerprint

Particulate Matter
Infant Mortality
Survival Analysis
Korea
Parturition
Sudden Infant Death
Mortality
Pregnancy
Air Pollution
Maternal Age
Particle Size
Birth Weight
Cause of Death
Hot Temperature
Confidence Intervals
Seoul

Keywords

  • Air pollution
  • Cox proportional hazards model
  • Infant mortality
  • Long-term effect
  • Particulate matter
  • PM
  • PM
  • PM
  • Survival analysis
  • Time dependent
  • TSP

ASJC Scopus subject areas

  • Health, Toxicology and Mutagenesis
  • Public Health, Environmental and Occupational Health

Cite this

@article{94e23d74bf3a49cf975bbbeb1652fcc3,
title = "Survival analysis of long-term exposure to different sizes of airborne particulate matter and risk of infant mortality using a birth cohort in Seoul, Korea",
abstract = "Background: Several studies suggest that airborne particulate matter (PM) is associated with infant mortality; however, most focused on short-term exposure to larger particles. Objectives: We evaluated associations between long-term exposure to different sizes of particles [total suspended particles (TSP), PM ≤ 10 μm in aerodynamic diameter (PM10), ≤ 10-2.5 μm (PM10-2.5), and ≤ 2.5 μm (PM2.5)] and infant mortality in a cohort in Seoul, Korea, 2004-2007. Methods: The study includes 359,459 births with 225 deaths. We applied extended Cox proportional hazards modeling with time-dependent covariates to three mortality categories: all causes, respiratory, and sudden infant death syndrome (SIDS). We calculated exposures from birth to death (or end of eligibility for outcome at 1 year of age) and pregnancy (gestation and each trimester) and treated exposures as time-dependent variables for subjects' exposure for each pollutant. We adjusted by sex, gestational length, season of birth, maternal age and educational level, and heat index. Each cause of death and exposure time frame was analyzed separately. Results: We found a relationship between gestational exposures to PM and infant mortality from all causes or respiratory causes for normal-birth-weight infants. For total mortality (all causes), risks were 1.44 (95{\%} confidence interval, 1.06-1.97), 1.65 (1.18-2.31), 1.53 (1.22-1.90), and 1.19 (0.83-1.70) per interquartile range increase in TSP, PM10, PM2.5, and PM10-2.5, respectively; for respiratory mortality, risks were 3.78 (1.18-12.13), 6.20 (1.50-25.66), 3.15 (1.26-7.85), and 2.86 (0.76-10.85). For SIDS, risks were 0.92 (0.33-2.58), 1.15 (0.38-3.48), 1.42 (0.71-2.87), and 0.57 (0.16-1.96), respectively. Conclusions: Our findings provide supportive evidence of an association of long-term exposure to PM air pollution with infant mortality.",
keywords = "Air pollution, Cox proportional hazards model, Infant mortality, Long-term effect, Particulate matter, PM, PM, PM, Survival analysis, Time dependent, TSP",
author = "Son, {Ji Young} and Bell, {Michelle L.} and Jong-Tae Lee",
year = "2011",
month = "5",
day = "1",
doi = "10.1289/ehp.1002364",
language = "English",
volume = "119",
pages = "725--730",
journal = "Environmental Health Perspectives",
issn = "0091-6765",
publisher = "Public Health Services, US Dept of Health and Human Services",
number = "5",

}

TY - JOUR

T1 - Survival analysis of long-term exposure to different sizes of airborne particulate matter and risk of infant mortality using a birth cohort in Seoul, Korea

AU - Son, Ji Young

AU - Bell, Michelle L.

AU - Lee, Jong-Tae

PY - 2011/5/1

Y1 - 2011/5/1

N2 - Background: Several studies suggest that airborne particulate matter (PM) is associated with infant mortality; however, most focused on short-term exposure to larger particles. Objectives: We evaluated associations between long-term exposure to different sizes of particles [total suspended particles (TSP), PM ≤ 10 μm in aerodynamic diameter (PM10), ≤ 10-2.5 μm (PM10-2.5), and ≤ 2.5 μm (PM2.5)] and infant mortality in a cohort in Seoul, Korea, 2004-2007. Methods: The study includes 359,459 births with 225 deaths. We applied extended Cox proportional hazards modeling with time-dependent covariates to three mortality categories: all causes, respiratory, and sudden infant death syndrome (SIDS). We calculated exposures from birth to death (or end of eligibility for outcome at 1 year of age) and pregnancy (gestation and each trimester) and treated exposures as time-dependent variables for subjects' exposure for each pollutant. We adjusted by sex, gestational length, season of birth, maternal age and educational level, and heat index. Each cause of death and exposure time frame was analyzed separately. Results: We found a relationship between gestational exposures to PM and infant mortality from all causes or respiratory causes for normal-birth-weight infants. For total mortality (all causes), risks were 1.44 (95% confidence interval, 1.06-1.97), 1.65 (1.18-2.31), 1.53 (1.22-1.90), and 1.19 (0.83-1.70) per interquartile range increase in TSP, PM10, PM2.5, and PM10-2.5, respectively; for respiratory mortality, risks were 3.78 (1.18-12.13), 6.20 (1.50-25.66), 3.15 (1.26-7.85), and 2.86 (0.76-10.85). For SIDS, risks were 0.92 (0.33-2.58), 1.15 (0.38-3.48), 1.42 (0.71-2.87), and 0.57 (0.16-1.96), respectively. Conclusions: Our findings provide supportive evidence of an association of long-term exposure to PM air pollution with infant mortality.

AB - Background: Several studies suggest that airborne particulate matter (PM) is associated with infant mortality; however, most focused on short-term exposure to larger particles. Objectives: We evaluated associations between long-term exposure to different sizes of particles [total suspended particles (TSP), PM ≤ 10 μm in aerodynamic diameter (PM10), ≤ 10-2.5 μm (PM10-2.5), and ≤ 2.5 μm (PM2.5)] and infant mortality in a cohort in Seoul, Korea, 2004-2007. Methods: The study includes 359,459 births with 225 deaths. We applied extended Cox proportional hazards modeling with time-dependent covariates to three mortality categories: all causes, respiratory, and sudden infant death syndrome (SIDS). We calculated exposures from birth to death (or end of eligibility for outcome at 1 year of age) and pregnancy (gestation and each trimester) and treated exposures as time-dependent variables for subjects' exposure for each pollutant. We adjusted by sex, gestational length, season of birth, maternal age and educational level, and heat index. Each cause of death and exposure time frame was analyzed separately. Results: We found a relationship between gestational exposures to PM and infant mortality from all causes or respiratory causes for normal-birth-weight infants. For total mortality (all causes), risks were 1.44 (95% confidence interval, 1.06-1.97), 1.65 (1.18-2.31), 1.53 (1.22-1.90), and 1.19 (0.83-1.70) per interquartile range increase in TSP, PM10, PM2.5, and PM10-2.5, respectively; for respiratory mortality, risks were 3.78 (1.18-12.13), 6.20 (1.50-25.66), 3.15 (1.26-7.85), and 2.86 (0.76-10.85). For SIDS, risks were 0.92 (0.33-2.58), 1.15 (0.38-3.48), 1.42 (0.71-2.87), and 0.57 (0.16-1.96), respectively. Conclusions: Our findings provide supportive evidence of an association of long-term exposure to PM air pollution with infant mortality.

KW - Air pollution

KW - Cox proportional hazards model

KW - Infant mortality

KW - Long-term effect

KW - Particulate matter

KW - PM

KW - PM

KW - PM

KW - Survival analysis

KW - Time dependent

KW - TSP

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U2 - 10.1289/ehp.1002364

DO - 10.1289/ehp.1002364

M3 - Article

VL - 119

SP - 725

EP - 730

JO - Environmental Health Perspectives

JF - Environmental Health Perspectives

SN - 0091-6765

IS - 5

ER -