Article Text
Abstract
Introduction The association between early exposure to ambient air pollution and adverse pregnancy outcomes in China is unclear. This study will assess the risk of early-life exposure to air pollutants in Beijing and explore the viability of 8-hydroxydeoxyguanosine (8-OHdG) as a biological indicator to assess oxidative stress induced by early-life exposure to air pollution.
Methods and analysis Here, 2500 women with singleton pregnancies and their infants will be recruited from the Beijing Obstetrics and Gynecology Hospital. We will collect nine types of biological samples, including maternal serum, urine, placental tissue, umbilical cord tissue and umbilical cord blood during all three trimesters. The air pollution data (particulate matter (PM)2.5, PM10 and similar factors) will be recorded at official fixed-site monitoring stations closest to where the pregnant women live. We plan to assess the effect of air pollutants on adverse pregnancy outcomes and infant respiratory and circulatory disease using Cox regression and competitive risk analysis and explore possible critical windows of exposure during pregnancy using daily pollutant concentrations averaged over various periods of pregnancy combined with individual activity and physiological parameters. Maternal and umbilical cord blood samples (1000 samples) will be randomly selected for 8-OHdG assays to assess the correlation between exposures to air pollutants and oxidative stress. We will determine whether air pollutant exposure or 8-OHdG levels are associated with adverse pregnancy outcomes. SPSS and SAS statistical software will be used for data analysis. Cox regression and competing risk analysis will be used to compute the HR and population attributable risk.
Ethics and dissemination This research protocol has already been approved by the Medical Ethics Committee of Beijing Obstetrics and Gynecology Hospital. Written informed consent will be obtained from all study participants prior to enrolment. The results will be published in peer-reviewed journals or disseminated through conference presentations.
Trial registration number This study has been registered in WHO International Clinical Trial Register—Chinese Clinical Trial Registry under registration
number ChiCTR-ROC-16010181 (http :// www.chictr.org.cn / showproj.aspx ?proj=17328).
- Early-life exposure
- air pollutants
- birth cohort
- adverse pregnancy outcomes
- 8-hydroxydeoxyguanosine
This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
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Footnotes
Contributors YC is the chief designer of this trial. JS, LW, YM, NT, SYH, YMD, LHZ and YYK are coinvestigators. YMD assisted in designing the study and developed the objectives and methods of the study. JS and LW drafted the manuscript, and YC was responsible for supervision of the study and revision of the manuscript. All authors have contributed to the composition of the study protocol and have approved the final version of this manuscript. YC, JS, LW, YM and NT were involved in the recruitment of patients. SYH was responsible for the collection of clinical data for pregnant women. LHZ was responsible for the management of biological sample library. YYK was responsible for neonatal follow-up.
Funding This work is a part of a study at the School of Public Health at the Beijing Key Laboratory of Epidemiology at Capital Medical University (a comprehensive study of the effects of air pollution on cardiopulmonary disease in Beijing: exposure science, toxicology and environmental epidemiology) provided by Professor Zhi Wei Sun, with the support of China’s National Natural Science Foundation Program grant funding (81571130090).
Competing interests None declared.
Patient consent Obtained.
Ethics approval The protocol has been approved by the Medical Ethics Committee of Beijing Obstetrics and Gynecology Hospital, Capital Medical University. Written informed consent was obtained from all study participants prior to enrolment in the study.
Provenance and peer review Not commissioned; externally peer reviewed.