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Comparing exposure assessment methods for traffic-related air pollution in an adverse pregnancy outcome study.
Environ Res. 2011 Jul; 111(5):685-92.ER

Abstract

BACKGROUND

Previous studies reported adverse impacts of traffic-related air pollution exposure on pregnancy outcomes. Yet, little information exists on how effect estimates are impacted by the different exposure assessment methods employed in these studies.

OBJECTIVES

To compare effect estimates for traffic-related air pollution exposure and preeclampsia, preterm birth (gestational age less than 37 weeks), and very preterm birth (gestational age less than 30 weeks) based on four commonly used exposure assessment methods.

METHODS

We identified 81,186 singleton births during 1997-2006 at four hospitals in Los Angeles and Orange Counties, California. Exposures were assigned to individual subjects based on residential address at delivery using the nearest ambient monitoring station data [carbon monoxide (CO), nitrogen dioxide (NO(2)), nitric oxide (NO), nitrogen oxides (NO(x)), ozone (O(3)), and particulate matter less than 2.5 (PM(2.5)) or less than 10 (PM(10))μm in aerodynamic diameter], both unadjusted and temporally adjusted land-use regression (LUR) model estimates (NO, NO(2), and NO(x)), CALINE4 line-source air dispersion model estimates (NO(x) and PM(2.5)), and a simple traffic-density measure. We employed unconditional logistic regression to analyze preeclampsia in our birth cohort, while for gestational age-matched risk sets with preterm and very preterm birth we employed conditional logistic regression.

RESULTS

We observed elevated risks for preeclampsia, preterm birth, and very preterm birth from maternal exposures to traffic air pollutants measured at ambient stations (CO, NO, NO(2), and NO(x)) and modeled through CALINE4 (NO(x) and PM(2.5)) and LUR (NO(2) and NO(x)). Increased risk of preterm birth and very preterm birth were also positively associated with PM(10) and PM(2.5) air pollution measured at ambient stations. For LUR-modeled NO(2) and NO(x) exposures, elevated risks for all the outcomes were observed in Los Angeles only--the region for which the LUR models were initially developed. Unadjusted LUR models often produced odds ratios somewhat larger in size than temporally adjusted models. The size of effect estimates was smaller for exposures based on simpler traffic density measures than the other exposure assessment methods.

CONCLUSION

We generally confirmed that traffic-related air pollution was associated with adverse reproductive outcomes regardless of the exposure assessment method employed, yet the size of the estimated effect depended on how both temporal and spatial variations were incorporated into exposure assessment. The LUR model was not transferable even between two contiguous areas within the same large metropolitan area in Southern California.

Authors+Show Affiliations

Program in Public Health and Department of Epidemiology, Anteater Instruction and Research Office, University of California, Irvine, CA 92697-3957, USA. junwu@uci.eduNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

21453913

Citation

Wu, Jun, et al. "Comparing Exposure Assessment Methods for Traffic-related Air Pollution in an Adverse Pregnancy Outcome Study." Environmental Research, vol. 111, no. 5, 2011, pp. 685-92.
Wu J, Wilhelm M, Chung J, et al. Comparing exposure assessment methods for traffic-related air pollution in an adverse pregnancy outcome study. Environ Res. 2011;111(5):685-92.
Wu, J., Wilhelm, M., Chung, J., & Ritz, B. (2011). Comparing exposure assessment methods for traffic-related air pollution in an adverse pregnancy outcome study. Environmental Research, 111(5), 685-92. https://doi.org/10.1016/j.envres.2011.03.008
Wu J, et al. Comparing Exposure Assessment Methods for Traffic-related Air Pollution in an Adverse Pregnancy Outcome Study. Environ Res. 2011;111(5):685-92. PubMed PMID: 21453913.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Comparing exposure assessment methods for traffic-related air pollution in an adverse pregnancy outcome study. AU - Wu,Jun, AU - Wilhelm,Michelle, AU - Chung,Judith, AU - Ritz,Beate, Y1 - 2011/03/30/ PY - 2010/07/22/received PY - 2011/03/01/revised PY - 2011/03/14/accepted PY - 2011/4/2/entrez PY - 2011/4/2/pubmed PY - 2011/8/9/medline SP - 685 EP - 92 JF - Environmental research JO - Environ. Res. VL - 111 IS - 5 N2 - BACKGROUND: Previous studies reported adverse impacts of traffic-related air pollution exposure on pregnancy outcomes. Yet, little information exists on how effect estimates are impacted by the different exposure assessment methods employed in these studies. OBJECTIVES: To compare effect estimates for traffic-related air pollution exposure and preeclampsia, preterm birth (gestational age less than 37 weeks), and very preterm birth (gestational age less than 30 weeks) based on four commonly used exposure assessment methods. METHODS: We identified 81,186 singleton births during 1997-2006 at four hospitals in Los Angeles and Orange Counties, California. Exposures were assigned to individual subjects based on residential address at delivery using the nearest ambient monitoring station data [carbon monoxide (CO), nitrogen dioxide (NO(2)), nitric oxide (NO), nitrogen oxides (NO(x)), ozone (O(3)), and particulate matter less than 2.5 (PM(2.5)) or less than 10 (PM(10))μm in aerodynamic diameter], both unadjusted and temporally adjusted land-use regression (LUR) model estimates (NO, NO(2), and NO(x)), CALINE4 line-source air dispersion model estimates (NO(x) and PM(2.5)), and a simple traffic-density measure. We employed unconditional logistic regression to analyze preeclampsia in our birth cohort, while for gestational age-matched risk sets with preterm and very preterm birth we employed conditional logistic regression. RESULTS: We observed elevated risks for preeclampsia, preterm birth, and very preterm birth from maternal exposures to traffic air pollutants measured at ambient stations (CO, NO, NO(2), and NO(x)) and modeled through CALINE4 (NO(x) and PM(2.5)) and LUR (NO(2) and NO(x)). Increased risk of preterm birth and very preterm birth were also positively associated with PM(10) and PM(2.5) air pollution measured at ambient stations. For LUR-modeled NO(2) and NO(x) exposures, elevated risks for all the outcomes were observed in Los Angeles only--the region for which the LUR models were initially developed. Unadjusted LUR models often produced odds ratios somewhat larger in size than temporally adjusted models. The size of effect estimates was smaller for exposures based on simpler traffic density measures than the other exposure assessment methods. CONCLUSION: We generally confirmed that traffic-related air pollution was associated with adverse reproductive outcomes regardless of the exposure assessment method employed, yet the size of the estimated effect depended on how both temporal and spatial variations were incorporated into exposure assessment. The LUR model was not transferable even between two contiguous areas within the same large metropolitan area in Southern California. SN - 1096-0953 UR - https://www.unboundmedicine.com/medline/citation/21453913/Comparing_exposure_assessment_methods_for_traffic_related_air_pollution_in_an_adverse_pregnancy_outcome_study_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0013-9351(11)00091-0 DB - PRIME DP - Unbound Medicine ER -