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Differences in Birth Weight Associated with the 2008 Beijing Olympics Air Pollution Reduction: Results from a Natural Experiment.

Rich DQ, Liu K, Zhang J, Thurston SW, Stevens TP, Pan Y, Kane C, Weinberger B, Ohman-Strickland P, Woodruff TJ, Duan X, Assibey-Mensah V, Zhang J - Environ. Health Perspect. (2015)

Bottom Line: We did not see significant associations for months 1-7.Short-term decreases in air pollution late in pregnancy in Beijing during the 2008 Summer Olympics, a normally heavily polluted city, were associated with higher birth weight.Differences in birth weight associated with the 2008 Beijing Olympics air pollution reduction: results from a natural experiment.

View Article: PubMed Central - PubMed

Affiliation: Department of Public Health Sciences, School of Medicine and Dentistry, University of Rochester, Rochester, New York, USA.

ABSTRACT

Background: Previous studies have reported decreased birth weight associated with increased air pollutant concentrations during pregnancy. However, it is not clear when during pregnancy increases in air pollution are associated with the largest differences in birth weight.

Objectives: Using the natural experiment of air pollution declines during the 2008 Beijing Olympics, we evaluated whether having specific months of pregnancy (i.e., 1st…8th) during the 2008 Olympics period was associated with larger birth weights, compared with pregnancies during the same dates in 2007 or 2009.

Methods: Using n = 83,672 term births to mothers residing in four urban districts of Beijing, we estimated the difference in birth weight associated with having individual months of pregnancy during the 2008 Olympics (8 August-24 September 2008) compared with the same dates in 2007 and 2009. We also estimated the difference in birth weight associated with interquartile range (IQR) increases in mean ambient particulate matter ≤ 2.5 μm in aerodynamic diameter (PM2.5), sulfur dioxide (SO2), nitrogen dioxide (NO2), and carbon monoxide (CO) concentrations during each pregnancy month.

Results: Babies whose 8th month of gestation occurred during the 2008 Olympics were, on average, 23 g larger (95% CI: 5 g, 40 g) than babies whose 8th month occurred during the same calendar dates in 2007 or 2009. IQR increases in PM2.5 (19.8 μg/m3), CO (0.3 ppm), SO2 (1.8 ppb), and NO2 (13.6 ppb) concentrations during the 8th month of pregnancy were associated with 18 g (95% CI: -32 g, -3 g), 17 g (95% CI: -28 g, -6 g), 23 g (95% CI: -36 g, -10 g), and 34 g (95% CI: -70 g, 3 g) decreases in birth weight, respectively. We did not see significant associations for months 1-7.

Conclusions: Short-term decreases in air pollution late in pregnancy in Beijing during the 2008 Summer Olympics, a normally heavily polluted city, were associated with higher birth weight.

Citation: Rich DQ, Liu K, Zhang J, Thurston SW, Stevens TP, Pan Y, Kane C, Weinberger B, Ohman-Strickland P, Woodruff TJ, Duan X, Assibey-Mensah V, Zhang J. 2015. Differences in birth weight associated with the 2008 Beijing Olympics air pollution reduction: results from a natural experiment. Environ Health Perspect 123:880-887; http://dx.doi.org/10.1289/ehp.1408795.

No MeSH data available.


Related in: MedlinePlus

Change in birth weight (g) (95% CI) among term births, associated with each interquartile range (IQR) increase in mean pollutant concentration during a specified month of pregnancy (2 June 2008 to 30 October 2008). All models included indicator variables for gestational age (complete weeks) at delivery, residential district, maternal education (bachelor’s degree, some college or technical school, high school or less), linear terms for the mean temperature and relative humidity levels during the 8th month of pregnancy, and a smooth term for maternal age (smoothing spline with 4 degrees of freedom).
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f3: Change in birth weight (g) (95% CI) among term births, associated with each interquartile range (IQR) increase in mean pollutant concentration during a specified month of pregnancy (2 June 2008 to 30 October 2008). All models included indicator variables for gestational age (complete weeks) at delivery, residential district, maternal education (bachelor’s degree, some college or technical school, high school or less), linear terms for the mean temperature and relative humidity levels during the 8th month of pregnancy, and a smooth term for maternal age (smoothing spline with 4 degrees of freedom).

Mentions: Interquartile range (IQR) increases in PM2.5, SO2, and CO concentration in the 8th month of pregnancy were associated with significant decreases in birth weight, after adjustment for gestational age at delivery, residential district, maternal education, and mean temperature and relative humidity in the same month [PM2.5: –18 g, 95% CI: –32 g, –3 g; SO2: –23 g, 95% CI: –36 g, –10 g; CO: –17 g, 95% CI: –28 g, –6 g (Figure 3; see also Supplemental Material, Table S1)]. Each IQR increase in the mean NO2 concentration in the 8th month was associated with a similarly sized, albeit nonsignificant, decreased birth weight (–34 g; 95% CI: –72 g, 3 g). IQR increases in other monthly mean pollutant concentrations were generally associated with smaller decreases in birth weight, with some being essentially (e.g., –1 g to 2 g). None were statistically significant (Figure 3; see also Supplemental Material, Table S1). Although not statistically significant, each 13.6-ppb increase in NO2 concentration during the 6th month was associated with a 22-g increase in birth weight (95% CI: –17 g, 60 g). However, 6th-month and 8th-month pollutant concentrations were inversely correlated (PM2.5; r = –0.71; NO2: r = –0.95; SO2: r = –0.88; CO: r = –0.70), likely due to one occurring during the Olympics period and its lower air pollutant concentrations.


Differences in Birth Weight Associated with the 2008 Beijing Olympics Air Pollution Reduction: Results from a Natural Experiment.

Rich DQ, Liu K, Zhang J, Thurston SW, Stevens TP, Pan Y, Kane C, Weinberger B, Ohman-Strickland P, Woodruff TJ, Duan X, Assibey-Mensah V, Zhang J - Environ. Health Perspect. (2015)

Change in birth weight (g) (95% CI) among term births, associated with each interquartile range (IQR) increase in mean pollutant concentration during a specified month of pregnancy (2 June 2008 to 30 October 2008). All models included indicator variables for gestational age (complete weeks) at delivery, residential district, maternal education (bachelor’s degree, some college or technical school, high school or less), linear terms for the mean temperature and relative humidity levels during the 8th month of pregnancy, and a smooth term for maternal age (smoothing spline with 4 degrees of freedom).
© Copyright Policy - public-domain
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4559955&req=5

f3: Change in birth weight (g) (95% CI) among term births, associated with each interquartile range (IQR) increase in mean pollutant concentration during a specified month of pregnancy (2 June 2008 to 30 October 2008). All models included indicator variables for gestational age (complete weeks) at delivery, residential district, maternal education (bachelor’s degree, some college or technical school, high school or less), linear terms for the mean temperature and relative humidity levels during the 8th month of pregnancy, and a smooth term for maternal age (smoothing spline with 4 degrees of freedom).
Mentions: Interquartile range (IQR) increases in PM2.5, SO2, and CO concentration in the 8th month of pregnancy were associated with significant decreases in birth weight, after adjustment for gestational age at delivery, residential district, maternal education, and mean temperature and relative humidity in the same month [PM2.5: –18 g, 95% CI: –32 g, –3 g; SO2: –23 g, 95% CI: –36 g, –10 g; CO: –17 g, 95% CI: –28 g, –6 g (Figure 3; see also Supplemental Material, Table S1)]. Each IQR increase in the mean NO2 concentration in the 8th month was associated with a similarly sized, albeit nonsignificant, decreased birth weight (–34 g; 95% CI: –72 g, 3 g). IQR increases in other monthly mean pollutant concentrations were generally associated with smaller decreases in birth weight, with some being essentially (e.g., –1 g to 2 g). None were statistically significant (Figure 3; see also Supplemental Material, Table S1). Although not statistically significant, each 13.6-ppb increase in NO2 concentration during the 6th month was associated with a 22-g increase in birth weight (95% CI: –17 g, 60 g). However, 6th-month and 8th-month pollutant concentrations were inversely correlated (PM2.5; r = –0.71; NO2: r = –0.95; SO2: r = –0.88; CO: r = –0.70), likely due to one occurring during the Olympics period and its lower air pollutant concentrations.

Bottom Line: We did not see significant associations for months 1-7.Short-term decreases in air pollution late in pregnancy in Beijing during the 2008 Summer Olympics, a normally heavily polluted city, were associated with higher birth weight.Differences in birth weight associated with the 2008 Beijing Olympics air pollution reduction: results from a natural experiment.

View Article: PubMed Central - PubMed

Affiliation: Department of Public Health Sciences, School of Medicine and Dentistry, University of Rochester, Rochester, New York, USA.

ABSTRACT

Background: Previous studies have reported decreased birth weight associated with increased air pollutant concentrations during pregnancy. However, it is not clear when during pregnancy increases in air pollution are associated with the largest differences in birth weight.

Objectives: Using the natural experiment of air pollution declines during the 2008 Beijing Olympics, we evaluated whether having specific months of pregnancy (i.e., 1st…8th) during the 2008 Olympics period was associated with larger birth weights, compared with pregnancies during the same dates in 2007 or 2009.

Methods: Using n = 83,672 term births to mothers residing in four urban districts of Beijing, we estimated the difference in birth weight associated with having individual months of pregnancy during the 2008 Olympics (8 August-24 September 2008) compared with the same dates in 2007 and 2009. We also estimated the difference in birth weight associated with interquartile range (IQR) increases in mean ambient particulate matter ≤ 2.5 μm in aerodynamic diameter (PM2.5), sulfur dioxide (SO2), nitrogen dioxide (NO2), and carbon monoxide (CO) concentrations during each pregnancy month.

Results: Babies whose 8th month of gestation occurred during the 2008 Olympics were, on average, 23 g larger (95% CI: 5 g, 40 g) than babies whose 8th month occurred during the same calendar dates in 2007 or 2009. IQR increases in PM2.5 (19.8 μg/m3), CO (0.3 ppm), SO2 (1.8 ppb), and NO2 (13.6 ppb) concentrations during the 8th month of pregnancy were associated with 18 g (95% CI: -32 g, -3 g), 17 g (95% CI: -28 g, -6 g), 23 g (95% CI: -36 g, -10 g), and 34 g (95% CI: -70 g, 3 g) decreases in birth weight, respectively. We did not see significant associations for months 1-7.

Conclusions: Short-term decreases in air pollution late in pregnancy in Beijing during the 2008 Summer Olympics, a normally heavily polluted city, were associated with higher birth weight.

Citation: Rich DQ, Liu K, Zhang J, Thurston SW, Stevens TP, Pan Y, Kane C, Weinberger B, Ohman-Strickland P, Woodruff TJ, Duan X, Assibey-Mensah V, Zhang J. 2015. Differences in birth weight associated with the 2008 Beijing Olympics air pollution reduction: results from a natural experiment. Environ Health Perspect 123:880-887; http://dx.doi.org/10.1289/ehp.1408795.

No MeSH data available.


Related in: MedlinePlus