| Objective:This study investigated the factors influencing the exposure of polycyclic aromatic hydrocarbons(PAHs)and the relationship between PAHs exposure and birth defects in pregnant women of Zhuang in early pregnancy in Guangxi.As well as analyzing the relationship between maternal and infant serum PAHs,to provide some reference for the prevention of birth defects and the formulation of public health intervention measures.Method:Epidemiological investigation combined with experimental study.The object of this research is from the study of the birth defects of Zhuang Nationality in Guangxi.In this study,a case control study was used to collect Zhuang people in Pingguo county,Tiandong county,Tianyang county,Debao county,Longan county and Jingxi county,which accounted for more than 90% of the Zhuang population in Guangxi and collected pregnant women from June 2015 to April 2017.A woman with a birth defects affected pregnancy(including live birth,still birth)was confirmed as a case,while a woman who delivered a term healthy infant at the same hospital was selected to serve as a control,matched to the case by the same county or city of residence,gestational age and ethnic.The content of 4 kinds of PAHs in serum was determined by high performance liquid chromatography fluorescence detection,which were benzo(b)fluoranthene(Bb F),benzo(k)fluoranthene(BkF),benzo(a)pyrene(BaP),dibenz(a,h)anthracene(DB(a,h)A).Since PAHs concentrations were not normally distributed,their skewed distributions were described using the median and interquartile range(IQR).The Mann-Whitney U Test and Wilcoxon Signed Ranks Test was used to assess the difference in PAHs concentration between the case and control and the PAHs concentration between the mother and the baby.Chi-square test or Fisher's exact test was used to compare maternal demographics between cases and controls.Multiple linear regression was used to assess the effect of maternal PAHs concentration.The risk of birth defects associated with PAHs concentrations was estimated by OR and 95% CI.The risk of birth defects and factors related to PAHs levels in maternal serum were adjusted in a non-conditional Logistic model using the forward method to further screen for covariates.SPSS 22.0 was used for statistical analysis.A two-tailed p-value of P<0.05 was used as the statistical significance level.Results:105 women who had birth defect-affected pregnancies(cases)and 111 women who delivered healthy infants(controls)and corresponding 119 infants(fetus)(25 infants with birth defects and 94 healthy infants)were recruited in study.The average age of pregnant women was 28.5 ± 5.4 years;The average gestational age was 10.9±2.4 weeks.The detection rates of maternal serum samples were: B(b)F(40%),B(k)F(63.3%),B(a)P(34.4%),DB(a,h)A(7.4%).The detection rates of umbilical cord serum samples were: B(b)F(33.6%),B(k)F(84%),B(a)P(43.7%),DB(a,h)A(10.8%).The average concentration of 4 serum PAHs and total virulence(T)in serum of pregnant women(215 cases)were B(b)F(0.18 ± 0.30),B(k)F(0.09 ± 0.14),B(a)P(0.07 ± 0.11),DB(a,h)A(0.06 ± 0.12),and T(0.15 ±0.23).The average concentration of 4 kinds of serum PAH in umbilical cord blood(119 cases)were B(b)F(0.13 ± 0.27),B(k)F(0.10 ± 0.11),B(a)P(0.11 ± 0.16),DB(a,h)A(0.07 ± 0.15)and T(0.20 ± 0.29).The results of the balance test showed that pregnant women in the case group and the control group had comparable balances in terms of age,gestation,parity,etc.,but there was a statistically significant difference in BMI distribution between the case group and the control group.Chi-square test for single factor analysis,pregnancy cooking and home ventilation during pregnancy were statistically different between case and control groups(P<0.05).In the case group,80% of pregnant women cook during pregnancy but in the control group only 68.2% of pregnant women cook during pregnancy;Compared with the control group(78.2%),the proportion of cases keeping the family well ventilated was lower(65.7%).In the case group,B(a)P(0.08±0.14),DB(a,h)A(0.08±0.17)and T(0.20±0.32)were higher than that in the control group B(a)P(0.04±0.05),DB(a,h)A(0.03±0.03),T(0.10±0.08)and the difference was statistically significant.There were no significant differences in B(b)F and B(k)F between the total case group and the control group.In birth defect subtypes(deformed limbs,facial deformities,cardiovascular malformations,phenylketonuria,neural tube defects,digestive tract malformations),The concentration of B(a)P in the maternal serum of the children with phenylketonuria was statistically significant,but there was no statistical difference between the B(a)P concentration in the maternal serum of other birth defects subtypes and the control group;The concentration of T in the maternal serum of the children with neural tube defects was statistically significant compared with the control group,but there was no statistical difference between the serum concentration of T in the maternal serum of other birth defects subtypes and the control group;There was no significant difference in the concentration of DB(a,h)A in the maternal serum of children with phenylketonuria and neural tube defects,but there was a statistical difference between the concentration of DB(a,h)A in the maternal serum of other children with other birth defects subtypes and the control.There was no significant difference in the concentration of B(b)F and B(k)F in the maternal serum in the subtype of birth defects(limb deformity,facial deformity,cardiovascular malformation,phenylketonuria,nerve canal defect,digestive tract malformation)and the control group.After adjusting the confounding factors,maternal serum DB(a,h)A was associated with increased risk of birth defects,which may be a risk factor for birth defects(OR=8.31,95%CI 1.84-37.52);In the subtypes of birth defects(limb deformity,facial deformity,cardiovascular malformation,phenylketonuria,neural tube defect,digestive tract malformation),in addition to phenylketonuria and neural tube defects,maternal serum DB(a,h)A is associated with an increased risk of birth defects in the rest of the subtypes;while maternal serum B(b)F,B(k)F,B(a)P,and T were not associated with an increased risk of birth defects subtypes.Multiple linear regression models were used to analyze the factors that might affect the serum PAHs concentration in mothers.Mothers who used wood for cooking had higher levels of B(b)F,B(a)P,and T by 0.366,0.124 and 0.179 units than mothers who used natural gas or electricity when cooking,respectively.The mothers who have no kitchen ventilation equipment have higher levels of B(b)F and B(k)F by 0.257 and 0.229 unit than the mothers who have kitchen ventilation equipment.DB(a,h)A is related to the age of the mother,when the mother's age is increased by 1 year,the DB(a,h)A content in the serum of the mother after logarithmic conversion is increased by 0.007 units.B(a)P and T were associated with peripheric folic acid supplementation,the serum B(a)P content in mothers without folic acid during six months before pregnancy and early pregnancy period was 0.114 and 0.112 units lower than that in the six months before pregnancy and early pregnancy folic acid-supplemented mothers.119 pairs of maternal and neonate's serum PAHs were compared,the concentrations of B(k)F,B(a)P,DB(a,h)A and T in umbilical cord blood were all higher than those of matched maternal blood,and the differences were statistically significant;the concentration of cord blood B(b)F was lower than its matched maternal blood,but the difference was not statistically significant.In addition,the correlation between maternal and infant serum PAHs levels was analyzed in this study,but the difference was not statistically significant.Conclusion:women and their fetuses of Zhuang are exposed to various carcinogenic PAHs in Guangxi.High maternal exposure to PAHs in early pregnancy may be a risk factor for birth defects.Home cooking fuel and kitchen ventilation equipment are associated factors of exposure to PAHs in pregnant women of Zhuang in Guangxi.Use of wood for cooking and unused kitchen ventilation may increase the level of exposure to PAHs in women during pregnancy.In addition,by analyzing the level of PAHs in maternal and fetal serum,it was found that the concentration of PAHs in umbilical cord blood was higher than the concentration of PAHs in paired maternal blood. |
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