Ambient BTEX exposure and mid-pregnancy inflammatory biomarkers in pregnant African American women

Air pollution is associated with preterm birth (PTB), potentially via inflammation. We recently showed the mixture benzene, toluene, ethylbenzene, and xylene (BTEX) is associated with PTB. We examined if ambient BTEX exposure is associated with mid-pregnancy inflammation in a sample of 140 African-American women residing in Detroit, Michigan. The Geospatial Determinants of Health Outcomes Consortium study collected outdoor air pollution measurements in Detroit; these data were coupled with Michigan Air Sampling Network measurements to develop monthly BTEX concentration estimates at a spatial density of 300 m2. First trimester and mid-pregnancy BTEX exposure estimates were assigned to maternal address. Mid-pregnancy (mean 21.3 +/- 3.7 weeks gestation) inflammatory biomarkers (high-sensitivity C-reactive protein, interleukin [IL]-6, IL10, IL-1 beta, and tumor necrosis factor-alpha) were measured with enzyme immunoassays. After covariate adjustment, for every 1-unit increase in first trimester BTEX, there was an expected mean increase in log-transformed IL-1 beta of 0.05 +/- 0.02 units (P = 0.014) and an expected mean increase in log-transformed tumor necrosis factor-alpha of 0.07 +/- 0.02 units (P = 0.006). Similarly, for every 1-unit increase in mid-pregnancy BTEX, there was a mean increase in log IL-1 beta of 0.06 +/- 0.03 units (P = 0.027). There was no association of either first trimester or midpregnancy BTEX with high-sensitivity C-reactive protein, IL-10, or IL-6 (all P > 0.05). Ambient BTEX exposure is associated with inflammation in mid-pregnancy in African-American women. Future studies examining if inflammation mediates associations between BTEX exposure and PTB are needed.

Automated summary

The study found an association between ambient BTEX exposure and mid-pregnancy inflammation in African-American women, indicating a potential mechanism through which preterm birth may occur. Furthermore, results showed that both first trimester and mid-pregnancy BTEX exposure were linked to increases in IL-1 beta and tumor necrosis factor-alpha levels.