Air pollutant exposure and preterm and term small-for-gestational-age births in Detroit, Michigan: Long-term trends and associations

Abstract

Studies in a number of countries have reported associations between exposure to ambient air pollutants and adverse birth outcomes, including low birth weight, preterm birth (PTB) and, less commonly, small for gestational age (SGA). Despite their growing number, the available studies have significant limitations, e.g., incomplete control of temporal trends in exposure, modest sample sizes, and a lack of information regarding individual risk factors such as smoking. No study has yet examined large numbers of susceptible individuals. We investigated the association between ambient air pollutant concentrations and term SGA and PTB outcomes among 164,905 singleton births in Detroit, Michigan occurring between 1990 and 2001. SO2, CO, NO2, O3 and PM10 exposures were used in single and multiple pollutant logistic regression models to estimate odds ratios (OR) for these outcomes, adjusted for the infant’s sex and gestational age, the mother’s race, age group, education level, smoking status and prenatal care, birth season, site of residence, and long-term exposure trends. Term SGA was associated with CO levels exceeding 0.75 ppm (OR=1.14, 95% confidence interval=1.02–1.27) and NO2 exceeding 6.8 ppb (1.11, 1.03–1.21) exposures in the first month, and with PM10 exceeding 35 μg/m3 (1.22, 1.03–1.46) and O3 (1.11, 1.02–1.20) exposure in the third trimester. PTB was associated with SO2 (1.07, 1.01–1.14) exposure in the last month, and with (hourly) O3 exceeding 92 ppb (1.08, 1.02–1.14) exposure in the first month. Exposure to several air pollutants at modest concentrations was associated with adverse birth outcomes. This study, which included a large Black population, suggests the importance of the early period of pregnancy for associations between term SGA with CO and NO2, and between O3 with PTB; and the late pregnancy period for associations between term SGA and O3 and PM10, and between SO2 with PTB. It also highlights the importance of accounting for individual risk factors such as maternal smoking, maternal race, and long-term trends in air pollutant levels and adverse birth outcomes in evaluating relationships between pollutant exposures and adverse birth outcomes.

Associations between exposure to ambient benzene and PM2.5 during pregnancy and the risk of selected birth defects in offspring

“…Exposure has been reported to impact fetal growth (Le et al, 2012;Rich et al, 2009), birth weight (Morello-Frosch et al, 2010;Wilhelm et al, 2012), preterm birth (Chang et al, 2012;Rudra et al, 2011), as well as pregnancy conditions such as preeclampsia Wu et al, 2009;Wu et al, 2011). Several studies have also examined the association between exposure to air pollution and select birth defects (Dadvand et al, 2011a(Dadvand et al, , 2011bDolk et al, 2010;Gilboa et al, 2005;Hansen et al, 2009;Hwang and Jaakkola, 2008;Rankin et al, 2009;Ritz et al, 2002;Stingone et al, 2014;Strickland et al, 2009); however, only until recently have studies included PM 2.5 and benzene as pollutants of interest (Agay-Shay et al, 2013;Lupo et al, 2011;Marshall et al, 2010;Padula et al, 2013aPadula et al, , 2013bPadula et al, , 2013cRamakrishnan et al, 2013;Schembari et al, 2014;Vinikoor-Imler et al, 2013).…”

Term and preterm birth effects of the nutritional status and habits in pregnancy

“…In a study on 164.905 people, those exposed to cigarette smoke were found to have premature births. [20] In another study (n=102), the preterm delivery rate of mothers with smoking habit was found to be higher. [21] Another study conducted on 922 premature and 965 late birth mothers found that 38% of premature births were in females who smoked during pregnancy.…”

The impact of air pollution on low birth weight and infant mortality

“…The indicators of adverse birth outcomes represent the main source of infant mortality and morbidity (6)(7)(8).…”