Ambient air pollutant PM10 and risk of preterm birth in Lanzhou, China

Abstract

Importance Exposure to ambient particulate matter during pregnancy has been suggested as a risk factor for preterm birth. However results from limited epidemiologic studies have been inconclusive. Very few studies have been conducted in areas with high air pollution levels. Objective We investigated the hypothesis that high level exposure to particulate matter with aerodynamic diameter no larger than 10µm (PM10) during pregnancy increases the risk of preterm birth. Methods A birth cohort study was carried out between 2010–2012 in Lanzhou, China, including 8,969 singleton live births with available information on daily PM10 levels from four monitoring stations, individual exposures during pregnancy were calculated using inverse-distance weighting based on both home and work addresses. Unconditional logistic regression modeling was used to examine the associations between PM10 exposure and risk of preterm birth and its clinical subtypes. Results Increased risk of very preterm birth was associated with exposure to PM10 during the last two months of pregnancy (OR, 1.07; 95%CI, 1.02–1.13 per 10µg/m3 increase for last four weeks before delivery; 1.09; 1.02–1.15 for last six weeks before delivery; 1.10; 1.03–1.17 for last eight weeks before delivery). Compared to the U.S. National Ambient Air Quality Standard (150µg/m3), higher exposure level (≥150µg/m3) of PM10 during entire pregnancy was associated with an increased risk of preterm birth (1.48; 1.22–1.81) and the association was higher for medically indicated preterm birth (1.80, 1.24–2.62) during entire pregnancy and for very preterm during last 6 weeks before delivery (2.03, 1.11–3.72). Conclusions and relevance Our study supports the hypothesis that exposure to high levels of ambient PM10 increases the risk of preterm birth. Our study also suggests that the risk may vary by clinical subtypes of preterm birth and exposure time windows. Our findings are relevant for health policy makers from China and other regions with high levels of air pollution to facilitate the efforts of reducing air pollution level in order to protect public health.

The association between ambient air pollution and selected adverse pregnancy outcomes in China: A systematic review

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Metals compositions of indoor PM2.5, health risk assessment, and birth outcomes in Lanzhou, China

“…The households in this study were selected from among participants in a birth cohort study in Lanzhou from 2010-2012 (Zhao et al, 2015). In brief, participants in the birth cohort were recruited at the Gansu Provincial Maternity and Child Care Hospital (GPMCCH), the largest maternity and child care hospital in Lanzhou, China, Eligible women included pregnant women who came to the hospital for delivery with gestational age ≥20 weeks, who had no mental illness, and who were aged 18 years or older.…”

Folic acid supplementation, dietary folate intake and risk of preterm birth in China

“…The study population has been described previously [35][36][37]. In brief, a birth cohort study was conducted during 2010-2012 at the Gansu Provincial Maternity & Child Care Hospital, the largest maternity and child care hospital in Lanzhou, China.…”