Different effects of PM10 exposure on preterm birth by gestational period estimated from time-dependent survival analyses

• Published in: International archives of occupational and environmental health Vol. 82; no. 5; pp. 613 - 621
• Main Authors: Suh, Young Ju, Kim, Ho, Seo, Ju Hee, Park, Hyesook, Kim, Young Ju, Hong, Yun Chul, Ha, Eun Hee
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.04.2009; Springer; Springer Nature B.V
• Subjects: Adult; Air; Air - analysis; Air Pollutants - adverse effects; Air pollution; Biological and medical sciences; Cities; Diseases of mother, fetus and pregnancy; Earth and Environmental Science; Environment; Environmental Health; Environmental Monitoring; Environmental pollutants toxicology; Epidemiological Monitoring; Exposure; Female; Gestational Age; Gynecology. Andrology. Obstetrics; Humans; Infant, Newborn; Korea - epidemiology; Male; Medical sciences; Neonates; Occupational Medicine/Industrial Medicine; Odds Ratio; Original Article; Particle Size; Particulate matter; Particulate Matter - adverse effects; Pregnancy; Pregnancy Trimesters; Pregnancy. Fetus. Placenta; Premature birth; Premature Birth - chemically induced; Premature Birth - epidemiology; Proportional Hazards Models; Rehabilitation; Risk exposure; Studies; Time Factors; Toxicology; Young Adult; Asia; South Korea; Korea; Seoul South Korea; Extended Cox model; Preterm birth; exposure; PM; Human; Pregnancy disorders; Toxicity; PM10 exposure; Premature delivery; Exposure; Survival; Coarse particle; Pregnancy; Suspended particle; Cox model; Mother; Prematurity; Aerosols; Air pollution; Exposure time; Time analysis; Public health
• ISSN: 0340-0131; 1432-1246; 1432-1246
• DOI: 10.1007/s00420-008-0380-7

Purpose We conducted this study to determine if the preterm risks due to PM 10 exposure vary with the exposure periods during pregnancy. This study was also conducted to estimate the different effects of PM 10 exposure on preterm birth by exposure periods using the extended Cox model with PM 10 exposure as a time-dependent covariate. Methods We studied birth data obtained from the Korea National Statistical office for 374,167 subjects who were delivered between 1998 and 2000 in Seoul, South Korea. We used PM 10 data that was measured hourly to give 24-h averages at 27 monitoring stations in Seoul. The extended Cox model with time-dependent exposure was used to determine if the risk of preterm delivery could be associated with PM 10 exposures for each trimester during pregnancy. Results Effect of PM10 exposure prior to the 37 weeks of gestational period was stronger on the risk of premature birth than that posterior to the 37 weeks of gestational weeks. This trend was consistent for each trimester; however, the hazard ratios for preterm delivery associated with PM 10 exposure in the first and third trimester were slightly higher than those of the second trimester. Conclusions The risk of preterm birth associated with exposure to PM 10 differed with the exposure period of the neonates. Therefore, when studying the impact of air pollution exposure during pregnancy, the exposure period during pregnancy should be considered.