Dugandzic Rose, Dodds Linda, Stieb David, Smith-Doiron Marc
Air Health Effects Division, Health Canada, Postal Locator 4602C, Ottawa Ontario, K1A 0K9, Canada.
Environ Health. 2006 Feb 17;5:3. doi: 10.1186/1476-069X-5-3.
Studies in areas with relatively high levels of air pollution have found some positive associations between exposures to ambient levels of air pollution and several birth outcomes including low birth weight (LBW). The purpose of this study was to examine the association between LBW among term infants and ambient air pollution, by trimester of exposure, in a region of lower level exposures.
The relationship between LBW and ambient levels of particulate matter up to 10 um in diameter (PM10), sulfur dioxide (SO2) and ground-level ozone (O3) was evaluated using the Nova Scotia Atlee Perinatal Database and ambient air monitoring data from the Environment Canada National Air Pollution Surveillance Network and the Nova Scotia Department of Environment. The cohort consisted of live singleton births (> or =37 weeks of gestation) between January 1, 1988 and December 31, 2000. Maternal exposures to air pollution were assigned to women living within 25 km of a monitoring station at the time of birth. Air pollution was evaluated as a continuous and categorical variable (using quartile exposures) for each trimester and relative risks were estimated from logistic regression, adjusted for confounding variables.
There were 74,284 women with a term, singleton birth during the study period and with exposure data. In the analyses unadjusted for year of birth, first trimester exposures in the highest quartile for SO2 and PM10 suggested an increased risk of delivering a LBW infant (relative risk = 1.36, 95% confidence interval = 1.04 to 1.78 for SO2 exposure and relative risk = 1.33, 95% confidence interval = 1.02 to 1.74 for PM10). After adjustment for birth year, the relative risks were attenuated somewhat and not statistically significant. A dose-response relationship for SO2 was noted with increasing levels of exposure. No statistically significant effects were noted for ozone.
Our results suggest that exposure during the first trimester to relatively low levels of some air pollutants may be associated with a reduction in birth weight in term-born infants. These findings have implications for the development of effective risk management strategies to minimize the public health impacts for pregnant women.
在空气污染水平相对较高的地区进行的研究发现,暴露于环境空气污染水平与包括低出生体重(LBW)在内的几种出生结局之间存在一些正相关关系。本研究的目的是在一个暴露水平较低的地区,按暴露孕期,研究足月儿低出生体重与环境空气污染之间的关联。
使用新斯科舍省阿特利围产期数据库以及加拿大环境部国家空气污染监测网络和新斯科舍省环境部的环境空气监测数据,评估低出生体重与直径达10微米的颗粒物(PM10)、二氧化硫(SO2)和地面臭氧(O3)的环境水平之间的关系。该队列包括1988年1月1日至2000年12月31日期间的单胎活产(妊娠≥37周)。在出生时,将居住在监测站25公里范围内的妇女的空气污染暴露情况进行赋值。空气污染被评估为每个孕期的连续变量和分类变量(使用四分位数暴露),并通过逻辑回归估计相对风险,对混杂变量进行了调整。
在研究期间有74284名足月单胎分娩的妇女并有暴露数据。在未按出生年份调整的分析中,SO2和PM10最高四分位数的孕早期暴露提示分娩低出生体重婴儿的风险增加(SO2暴露的相对风险 = 1.36,95%置信区间 = 1.04至1.78;PM10暴露的相对风险 = 1.33,95%置信区间 = 1.02至1.74)。在按出生年份调整后,相对风险有所减弱且无统计学意义。观察到SO2存在剂量反应关系,随着暴露水平的增加。未观察到臭氧有统计学意义的影响。
我们的结果表明,孕早期暴露于相对低水平的某些空气污染物可能与足月儿出生体重降低有关。这些发现对于制定有效的风险管理策略以尽量减少对孕妇的公共卫生影响具有启示意义。