Ambient Air Pollution and Low Birth Weight in Connecticut and Massachusetts

Abstract

BackgroundSeveral studies have examined whether air pollution affects birth weight; however results vary and many studies were focused on Southern California or were conducted outside of the United States.ObjectivesWe investigated maternal exposure to particulate matter with aerodynamic diameter < 10, < 2.5 μm (PM10, PM2.5), sulfur dioxide, nitrogen dioxide, and carbon monoxide and birth weight for 358,504 births in Massachusetts and Connecticut from 1999 to 2002.MethodsAnalysis included logistic models for low birth weight (< 2,500 g) and linear models with birth weight as a continuous variable. Exposure was assigned as the average county-level concentration over gestation and each trimester based on mother’s residence. We adjusted for gestational length, prenatal care, type of delivery, child’s sex, birth order, weather, year, and mother’s race, education, marital status, age, and tobacco use.ResultsAn interquartile increase in gestational exposure to NO2, CO, PM10, and PM2.5 lowered birth weight by 8.9 g [95% confidence interval (CI), 7.0–10.8], 16.2 g (95% CI, 12.6–19.7), 8.2 g (95% CI, 5.3–11.1), and 14.7 g (95% CI, 12.3–17.1), respectively. Lower birth weight was associated with exposure in the third trimester for PM10, the first and third trimesters for CO, the first trimester for NO2 and SO2, and the second and third trimesters for PM2.5. Effect estimates for PM2.5 were higher for infants of black mothers than those of white mothers.ConclusionsResults indicate that exposure to air pollution, even at low levels, may increase risk of low birth weight, particularly for some segments of the population.

Are environmental pollutants risk factors for low birth weight?

“…Meanwhile, our findings disagree with those of Medeiros & Gouveia 8 and Bell et al 14 . Kannan et al 19 propose mechanisms resulting in low birth weight due to exposure to PM 10 .…”

“…Unlike other studies 7,8,13,14 , the current study opted to investigate the effects of pollutants after excluding potential confounding factors. The option to study the final weeks of pregnancy was due to the fact that this period shows a major fetal weight gain, representing slightly more than 1,500g in final birth weight 11 .…”

“…SO 2 was another pollutant whose values were associated with low birth weight. It has frequently been reported as a risk factor for low birth weight 6,7,13,14,18 . As with other pollutants, the mechanism of action for SO 2 is still not well known.…”

Biomonitoring of polycyclic aromatic hydrocarbon exposure in pregnant women in Trujillo, Peru — Comparison of different fuel types used for cooking

“…We selected pregnant women because a growing body of research indicates that the human fetus is vulnerable to air pollution (Bell et al, 2007;Bobak, 2000;Brauer et al, 2008;Choi et al, 2008;Makri and Stilianakis, 2008;Mishra et al, 2004;Parker et al, 2005;Šrám et al, 2005).…”

The relationship between low birth weight and exposure to inhalable particulate matter

“…Research in Massachusetts and Connecticut (United States) showed an association between low birth weight and exposure to PM 10 (third trimester), CO (first and third trimesters), NO 2 and SO 2 (first trimester) and PM 2,5 (second and third trimesters). The same study found an apparently higher risk of low birth weight in children born to black mothers exposed to fine-mode aerosols (PM 2.5 ) 26 . Nasci- Odds ratio (OR) for low birth weight by pregnancy trimester and PM 10 quartiles.…”