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Exposure to Elemental Carbon, Organic Carbon, Nitrate, and Sulfate Fractions of Fine Particulate Matter and Risk of Preterm Birth in New Jersey, Ohio, and Pennsylvania (2000-2005).

Rappazzo KM, Daniels JL, Messer LC, Poole C, Lobdell DT - Environ. Health Perspect. (2015)

Bottom Line: We estimated risk differences (RD) of PTB (reported per 106 pregnancies) associated with change in ambient concentrations of elemental carbon (EC), organic carbon (OC), nitrates (NO3), and sulfates (SO4).EC was positively associated with PTB after 27 and before 35 weeks of gestation.We observed effect measure modification for associations between EC and PTB by race/ethnicity and smoking status.

View Article: PubMed Central - PubMed

Affiliation: Department of Epidemiology, UNC Gillings School of Global Public Health, Chapel Hill, North Carolina, USA.

ABSTRACT

Background: Particulate matter ≤ 2.5 μm in aerodynamic diameter (PM2.5) has been consistently associated with preterm birth (PTB) to varying degrees, but roles of PM2.5 species have been less studied.

Objective: We estimated risk differences (RD) of PTB (reported per 106 pregnancies) associated with change in ambient concentrations of elemental carbon (EC), organic carbon (OC), nitrates (NO3), and sulfates (SO4).

Methods: From live birth certificates from three states, we constructed a cohort of singleton pregnancies at or beyond 20 weeks of gestation from 2000 through 2005 (n = 1,771,225; 8% PTB). We estimated mean species exposures for each week of gestation from monitor-corrected Community Multi-Scale Air Quality modeling data. RDs and 95% confidence intervals (CIs) for four PTB categories were estimated for each exposure using linear regression, adjusted for maternal race/ethnicity, marital status, education, age, smoking, maximum temperature, ozone, and season of conception. We also adjusted for other species in multi-species models.

Results: RDs varied by exposure window and outcome period. EC was positively associated with PTB after 27 and before 35 weeks of gestation. For example, for a 0.25-μg/m(3) increase in EC exposure during gestational week 9, RD = 96 (95% CI: -20, 213) and RD = 145 (95% CI: -50, 341) for PTB during weeks 28-31 and 32-34, respectively. Associations with OCs were or negative. RDs for NO3 were elevated with exposure in early weeks of gestation, and in later weeks. RDs for SO4 exposure were positively associated with PTB, though magnitude varied across gestational weeks. We observed effect measure modification for associations between EC and PTB by race/ethnicity and smoking status.

Conclusion: EC and SO4 may contribute to associations between PM2.5 and PTB. Associations varied according to the timing of exposure and the timing of PTB.

No MeSH data available.


Related in: MedlinePlus

Effect measure modification by black race/ethnicity (left) and smoking status (right) for elemental carbon. Models were adjusted for maternal education level, marital status, age at delivery, smoking status (race/ethnicity models), race/ethnicity (smoking status models), season of conception, maximum temperature, and co-occurring ozone. ExPTB: birth at 20–27 weeks, VPTB: birth at 28–31 weeks, MPTB: birth at 32–34 weeks, and LPTB: birth at 35–36 weeks of gestation. Weeks where interaction terms have p < 0.05 are: ExPTB: none; VPTB: all; MPTB: all; LPTB: all.
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f5: Effect measure modification by black race/ethnicity (left) and smoking status (right) for elemental carbon. Models were adjusted for maternal education level, marital status, age at delivery, smoking status (race/ethnicity models), race/ethnicity (smoking status models), season of conception, maximum temperature, and co-occurring ozone. ExPTB: birth at 20–27 weeks, VPTB: birth at 28–31 weeks, MPTB: birth at 32–34 weeks, and LPTB: birth at 35–36 weeks of gestation. Weeks where interaction terms have p < 0.05 are: ExPTB: none; VPTB: all; MPTB: all; LPTB: all.

Mentions: No EMM (interaction term p < 0.05) was observed for any species by infant sex or maternal parity, data not shown. RDs for EC exposure and VPTB, MPTB, and LPTB were higher than would be expected on an additive scale for women of black race/ethnicity and women who smoked during pregnancy (Figure 5). There was evidence for modification of effect estimates for OC exposures with race/ethnicity and smoking status, following similar patterns for EC estimates (see Supplemental Material, Figure S1). However, EMM for OC was less consistent across exposure categories than EMM for EC; where interaction terms met criteria at most or all weeks of exposure for EC, there was considerable variation in OC interaction terms across exposure weeks and outcome groups. For NO3, potential EMM was observed only for maternal smoking status in LPTB outcomes with exposure in early gestation (see Supplemental Material, Figure S2). There was limited to no evidence for EMM for SO4 exposures (see Supplemental Material, Figure S3).


Exposure to Elemental Carbon, Organic Carbon, Nitrate, and Sulfate Fractions of Fine Particulate Matter and Risk of Preterm Birth in New Jersey, Ohio, and Pennsylvania (2000-2005).

Rappazzo KM, Daniels JL, Messer LC, Poole C, Lobdell DT - Environ. Health Perspect. (2015)

Effect measure modification by black race/ethnicity (left) and smoking status (right) for elemental carbon. Models were adjusted for maternal education level, marital status, age at delivery, smoking status (race/ethnicity models), race/ethnicity (smoking status models), season of conception, maximum temperature, and co-occurring ozone. ExPTB: birth at 20–27 weeks, VPTB: birth at 28–31 weeks, MPTB: birth at 32–34 weeks, and LPTB: birth at 35–36 weeks of gestation. Weeks where interaction terms have p < 0.05 are: ExPTB: none; VPTB: all; MPTB: all; LPTB: all.
© Copyright Policy - public-domain
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4590756&req=5

f5: Effect measure modification by black race/ethnicity (left) and smoking status (right) for elemental carbon. Models were adjusted for maternal education level, marital status, age at delivery, smoking status (race/ethnicity models), race/ethnicity (smoking status models), season of conception, maximum temperature, and co-occurring ozone. ExPTB: birth at 20–27 weeks, VPTB: birth at 28–31 weeks, MPTB: birth at 32–34 weeks, and LPTB: birth at 35–36 weeks of gestation. Weeks where interaction terms have p < 0.05 are: ExPTB: none; VPTB: all; MPTB: all; LPTB: all.
Mentions: No EMM (interaction term p < 0.05) was observed for any species by infant sex or maternal parity, data not shown. RDs for EC exposure and VPTB, MPTB, and LPTB were higher than would be expected on an additive scale for women of black race/ethnicity and women who smoked during pregnancy (Figure 5). There was evidence for modification of effect estimates for OC exposures with race/ethnicity and smoking status, following similar patterns for EC estimates (see Supplemental Material, Figure S1). However, EMM for OC was less consistent across exposure categories than EMM for EC; where interaction terms met criteria at most or all weeks of exposure for EC, there was considerable variation in OC interaction terms across exposure weeks and outcome groups. For NO3, potential EMM was observed only for maternal smoking status in LPTB outcomes with exposure in early gestation (see Supplemental Material, Figure S2). There was limited to no evidence for EMM for SO4 exposures (see Supplemental Material, Figure S3).

Bottom Line: We estimated risk differences (RD) of PTB (reported per 106 pregnancies) associated with change in ambient concentrations of elemental carbon (EC), organic carbon (OC), nitrates (NO3), and sulfates (SO4).EC was positively associated with PTB after 27 and before 35 weeks of gestation.We observed effect measure modification for associations between EC and PTB by race/ethnicity and smoking status.

View Article: PubMed Central - PubMed

Affiliation: Department of Epidemiology, UNC Gillings School of Global Public Health, Chapel Hill, North Carolina, USA.

ABSTRACT

Background: Particulate matter ≤ 2.5 μm in aerodynamic diameter (PM2.5) has been consistently associated with preterm birth (PTB) to varying degrees, but roles of PM2.5 species have been less studied.

Objective: We estimated risk differences (RD) of PTB (reported per 106 pregnancies) associated with change in ambient concentrations of elemental carbon (EC), organic carbon (OC), nitrates (NO3), and sulfates (SO4).

Methods: From live birth certificates from three states, we constructed a cohort of singleton pregnancies at or beyond 20 weeks of gestation from 2000 through 2005 (n = 1,771,225; 8% PTB). We estimated mean species exposures for each week of gestation from monitor-corrected Community Multi-Scale Air Quality modeling data. RDs and 95% confidence intervals (CIs) for four PTB categories were estimated for each exposure using linear regression, adjusted for maternal race/ethnicity, marital status, education, age, smoking, maximum temperature, ozone, and season of conception. We also adjusted for other species in multi-species models.

Results: RDs varied by exposure window and outcome period. EC was positively associated with PTB after 27 and before 35 weeks of gestation. For example, for a 0.25-μg/m(3) increase in EC exposure during gestational week 9, RD = 96 (95% CI: -20, 213) and RD = 145 (95% CI: -50, 341) for PTB during weeks 28-31 and 32-34, respectively. Associations with OCs were or negative. RDs for NO3 were elevated with exposure in early weeks of gestation, and in later weeks. RDs for SO4 exposure were positively associated with PTB, though magnitude varied across gestational weeks. We observed effect measure modification for associations between EC and PTB by race/ethnicity and smoking status.

Conclusion: EC and SO4 may contribute to associations between PM2.5 and PTB. Associations varied according to the timing of exposure and the timing of PTB.

No MeSH data available.


Related in: MedlinePlus