BTEX exposure of pregnant women and associations with pro-inflammatory cytokines (IL-6 and TNF-α)

Exposure to benzene, toluene, ethylbenzene, and xylenes (BTEX) may have different adverse effects on the health of pregnant women and fetal health, as pregnant women and fetuses are particularly vulnerable to exposure to contaminants.This cross-sectional study was conducted to investigate the exposure of pregnant women living in the vicinity of the Ilam petrochemical complex to BTEX and associations with serum pro-inflammatory cytokines IL-6 and TNF-alpha. Based on the distance from the petrochemical complex, 110 pregnant women were enrolled in two groups of exposed (n = 60) and control (n = 50). Urinary BTEX was measured by a headspace gas chromatography-mass spectrometry (GC/MS). The serum cytokines were measured using enzyme-linked immunosorbent assay (ELISA) diagnostic method. Results showed that the urinary concentrations of benzene, toluene, ethylbenzene, m-p-xylene, and o-xylene levels in the exposed group were 572, 829, 403, 567, and 416 ng/L, respectively, that were higher than the corresponding values in the control group. The mean serum concentrations of IL-6 and TNF-alpha in the exposed group were 5.26 and 6.0 pg/ml. Based on Spearman's correlation coefficient analysis, in the exposed group, only benzene had the most positive and significant correlation with serum levels of IL-6 (r = 0.515, p < 0.01) and TNF-alpha (r = 0.289, p < 0.05). Also, a positive and significant correlation was observed between the two cytokines (r = 0.608, p < 0.01). According to the above results, long-term residence near the petrochemical industry, due to the adverse effects of exposure to BTEX compounds and their association with increased levels of pro-inflammatory cytokines, may endanger the health of pregnant women.