Association Between Maternal Exposure to SO2 and Congenital Ear Malformations in Offspring: A Population-Based Case-Control Study in Liaoning Province, China.

Objectives: To examine associations between maternal sulfur dioxide (SO2) exposure and congenital ear malformations risk in offspring. Methods: We surveyed 1676 cases with congenital ear malformations and 7950 controls from the Maternal and Child Health Certificate Registry of Liaoning Province between 2010 and 2015. SO2 concentrations were obtained from the Municipal Environment Protection Bureau of Liaoning Province. Multivariable logistic regression models and Restricted cubic splines (RCS) model were used to assess the aforementioned association. Results: There were significant associations between maternal SO2 exposure and congenital ear malformations risk during the 3 months before conception (OR Q4 vs. Q1 = 1.93, 95% CI = 1.43-2.59) and the 3 months after conception (OR Q4 vs. Q1 = 1.63, 95% CI = 1.22-2.18). Similar results were obtained in the analysis of single-month exposure windows, except for the third month before conception and the third month after conception. Moreover, these findings were broadly consistent across subgroups and robust in sensitivity analyses. There were non-linear dose-response associations between SO2 exposure and congenital ear malformations based on restricted cubic spline model analysis. Conclusion: Maternal SO2 exposure is associated with increased congenital ear malformations risk in offspring.

Maternal Exposure to Sulfur Dioxide and Risk of Omphalocele in Liaoning Province, China: A Population-Based Case-Control Study.

Evidence of the association between maternal sulfur dioxide (SO2) exposure and the risk of omphalocele is limited and equivocal. We aimed to assess the aforementioned topic during the first trimester of pregnancy. A population-based case-control study was carried out in infants consisting of 292 cases of omphalocele and 7,950 healthy infant controls. Exposure to SO2, particulate matter with aerodynamic diameters ≤ 10 µm, and nitrogen dioxide was assessed by averaging the concentration from all stations in the mother's residential city. SO2 exposure was categorized into three groups, with the lowest tertile defined as the reference category. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression models. Higher SO2 exposure during the first trimester was significantly associated with omphalocele risk [per standard deviation (42 ug/m3) increment: OR = 1.39, 95% CI = 1.22-1.65]. When focusing on shorter exposure windows, similar positive associations were observed for SO2 exposure in the first and third months of pregnancy. In addition, compared with the lowest tertile, high SO2 exposure in the second month of pregnancy increased the risk of omphalocele (OR = 2.80, 95% CI = 1.61-4.97). Maternal exposure to SO2 during the first trimester may increase the risk of omphalocele in offspring.

Association between maternal exposure to PM10 and risk of anorectal atresia/stenosis in offspring: a population-based case-control study in Liaoning Province, China.

The potential association between maternal exposure to PM10 ranging from 3 months prior to conception to the end of the early trimester and the risk of anorectal atresia/stenosis in offspring has not been established. Thus, we determined the association between maternal exposure to PM10 and risk of anorectal atresia/stenosis in offspring in this study. We recruited 713 patients including 480 male and 233 female with anorectal atresia/stenosis and 7950 randomly selected healthy offspring from the Maternal and Child Health Certificate Registry of Liaoning Province and delivered between 1 January 2010 and 31 December 2015. Monthly PM10 concentrations were retrieved from the Environment Protection Bureau of each city in Liaoning Province. We established a multivariable logistic regression model to calculate the adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Maternal exposure to PM10 was associated with an increased risk for anorectal atresia/stenosis in offspring during the 3 months prior to conception (per 10 µg/m3 increment: OR = 1.15, 95% CI = 1.03-1.20; per SD [27 µg/m3] increment: OR = 1.33, 95% CI = 1.09-1.63) and the first trimester (per 10 µg/m3 increment: OR = 1.08, 95% CI = 1.00-1.17; per SD [28 µg/m3] increment: OR = 1.26, 95% CI = 1.01-1.57). Evaluation of the association with a shorter exposure window (1 month) revealed a positive association between anorectal atresia/stenosis and PM10 from the 3rd month prior to pregnancy to each month of the 1st trimester. Maternal exposure to PM10 3 months prior to conception and during the 1st trimester was associated with an increased risk of anorectal atresia/stenosis in the offspring. Future perspective cohort studies are needed to confirm our findings.

Maternal PM10 Exposure Increases Risk for Spina Bifida: A Population-Based Case-Control Study.

Limited studies have focused on the impact of ambient air pollution on spina bifida. A population-based case-control study was conducted in Liaoning Province, China to assess the associations between maternal PM10 exposures in various exposure windows and spina bifida risk. Data on spina bifida cases born between 2010 and 2015 were available from the Maternal and Child Health Certificate Registry of Liaoning Province. Controls were a random sample of healthy livebirths without any birth defects delivered in the selected five cities during 2010-2015. Ambient air monitoring data for PM10 were obtained from 75 monitoring stations in Liaoning Province. The multivariable logistic regression models were established to calculate adjusted odds ratios (OR) and 95% confidence intervals (CI). We further performed sensitivity analyses by using three propensity score methods. A total of 749 spina bifida cases and 7,950 controls were included. After adjusting for potential confounders, spina bifida was associated with a 10 µg/m3 increment in PM10 during the first trimester of pregnancy (adjusted OR = 1.06, 95% CI: 1.00-1.12) and the 3 months before pregnancy (adjusted OR = 1.12, 95% CI: 1.06-1.19). The adjusted ORs in the final model for the highest vs. the lowest quartile were 1.51 (95% CI: 1.04-2.19) for PM10 during the first trimester of pregnancy and 2.01 (95% CI: 1.43-2.81) for PM10 during the 3 months before pregnancy. Positive associations were found between PM10 exposures during the single month exposure windows and spina bifida. Sensitivity analyses based on two propensity score methods largely reported similar positive associations. Our findings support the evidence that maternal PM10 exposure increases the risk of spina bifida in offspring. Further, validation with a prospective design and a more accurate exposure assessment is warranted.

Maternal exposure to sulfur dioxide before and after conception and the risk of hypospadias in offspring.

As far as we know, there have been no studies exploring the association between maternal sulfur dioxide (SO2 ) exposure and the risk of hypospadias in offspring. We aimed to evaluate this association during the 3 months before conception and the first trimester. A population-based case-control study was conducted in male infants, consisting of 348 cases of hypospadias and 4023 controls. Maternal exposure to SO2 , particulate matter with aerodynamic diameters ≤10 µm (PM10 ), and nitrogen dioxide (NO2 ) was assessed by averaging the concentrations recorded at all stations in the mother's city of residence. Air pollutants were tested for multicollinearity using variance inflation factor analysis. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by multivariable logistic regression models. SO2 exposure during the 3 months before conception was significantly associated with the risk of hypospadias (highest tertile: OR = 7.40, 95% CI: 3.54-15.62). When focusing on shorter exposure windows, similar associations were observed for SO2 exposure in the first and second month before and the first month after conception. In conclusion, maternal exposure to SO2 during the 3 months before and the first and second months after conception may increase the risk of hypospadias in offspring.

Maternal exposure to sulfur dioxide and the risk of oral clefts in Liaoning Province, China: a population-based case-control study.

There is limited and equivocal epidemiological evidence relating to the association between maternal sulfur dioxide (SO2) exposure and the risk of oral clefts (OCs) in offspring. We performed a population-based case-control study in Liaoning province to evaluate aforementioned relationship during 3 months before conception, the first trimester of pregnancy, and their single months. The study involved 3086 patients with OCs and 7950 controls. Data relating to SO2 concentration was acquired from air monitoring stations throughout the study period. We used a multivariable logistic regression model to evaluate the association between exposure to SO2 and the risk of OCs during the exposure windows. Maternal SO2 exposure was positively related to OCs during the 3 months before conception (odds ratio = 1.38, 95% confidence interval: 1.15-1.65; P for trend < 0.01). Positive relationships were obtained from the first and second months before conception and the first month of pregnancy. Thus, our research reflects a relationship between SO2 exposure and the risk of OCs. Future studies are now required to verify the association between SO2 exposure and OCs during pregnancy and indicate the most relevant vulnerable exposure time windows.

Maternal exposure to ambient levels of sulfur dioxide and risk of neural tube defects in 14 cities in Liaoning province, China: a population-based case-control study.

Epidemiological studies on the association of sulfur dioxide (SO2) with neural tube defects (NTDs) are lacking. The purpose of this study was to assess the aforementioned association through a population-based case-control study. This study involved 1457 NTDs cases and 7950 randomly selected healthy infants born in 14 cities in Liaoning province between 2010 and 2015. Ambient SO2 levels were acquired from 75 monitoring stations. The exposure assessment was based on the mean concentration of all stations in mother's residential city. We used logistic regression models to assess the associations. In multivariable models adjusted for the confounding variables selected based on the 10 percent change-in-estimate method, we found that maternal SO2 exposure was positively associated with an increased risk of NTDs during the first month after conception (per 10 µg/m3 increase: adjusted odds ratio [aOR] = 1.02, 95% confidence interval [CI]: 1.00-1.04; highest versus lowest quartile: aOR = 2.55, 95% CI: 1.97-3.31) and the second month after conception (per 10 µg/m3 increase: aOR = 1.02, 95% CI: 1.00-1.04; highest versus lowest quartile: aOR=2.31, 95% CI: 1.77-3.00). For other exposure windows, positive associations also emerged in high- versus low-exposure analyses, except for the third month before conception; however, we could not further confirm significant findings from the continuous exposure analyses. Our study provides a new evidence that SO2 exposure may increase the risk of NTDs.

Maternal exposure to ambient SO2 and risk of polydactyly and syndactyly: a population-based case-control study in Liaoning Province, China.

Evidence links exposure to maternal sulfur dioxide (SO2) and the risk of limb defects have been inconsistent. To investigate associations between SO2 exposure during preconception and the first trimester and risks of polydactyly and syndactyly. The study population was acquired from the Maternal and Child Health Certificate Registry of Liaoning Province between 2010 to 2015, and consisted of 2605 polydactyly, 595 syndactyly cases, and 7950 controls. Ambient air pollutants levels were retrieved from air quality monitoring stations. We used multivariable logistic regression model to assess the adjusted odds ratios (ORs) and 95% confidence intervals (CIs). We found that exposure to increased SO2 concentrations was associated with polydactyly during both the 3 months preconception (ORQ4 vs. Q1 = 3.76; 95% CI 2.61, 5.42; per 10 µg/m3 increment: OR = 1.07; 95% CI 1.04, 1.10) and the first trimester (ORQ4 vs. Q1 = 2.03; 95% CI 1.41, 2.92; per 10 µg/m3 increment: OR = 1.07; 95% CI 1.03, 1.11). However, we only observed increased risk for syndactyly in the analysis of high vs. low quartiles (three months preconception: ORQ4 vs. Q1 = 3.72; 95% CI 2.05, 6.75; first trimester: ORQ4 vs. Q1 = 1.98; 95% CI 1.11, 3.51). Most results of analyses based on single-month exposure window generally showed similar positive associations. Additionally, these findings were broadly consistent across subgroups and sensitivity analyses. Maternal SO2 exposure increase the risk of polydactyly and syndactyly.

Maternal preconception and first trimester exposure to PM10 and the risk of oral clefts in offspring: a population-based, case-control study.

BACKGROUND: Current literature describes limited and controversial evidence on the associations between maternal preconception and first trimester exposure to particulate matter with a diameter ≤10 µm (PM10) and the risk of oral cleft (OC). METHODS: We conducted a case-control study involving 3086 OC cases and 7950 controls, registered in the Maternal and Child Health Certificate Registry in Liaoning Province between 2010 and 2015. PM10 concentrations were obtained from the Environment Protection Bureau. The exposure windows included the 3 months before pregnancy, the first trimester and the individual months. Unconditional logistic regression model was performed to estimate the OR and 95% CI for the association between PM10 exposure and the risk of OC, cleft lip only (CLO), cleft palate only (CPO), and cleft lip and palate (CLP). RESULTS: Maternal PM10 exposure was positively associated with an increased risk for OC during the 3 months preconception (per 10 µg/m3 increment: OR=1.04, 95% CI 1.01 to 1.07; highest vs lowest quartile: OR=1.23, 95% CI 1.04 to 1.45) and the first trimester (per 10 µg/m3 increment: OR=1.05, 95% CI 1.02 to 1.08; highest vs lowest quartile: OR=1.37, 95% CI 1.15 to 1.64). Analyses based on individual months presented similar positive associations, particularly in the second month of pregnancy (OR=1.77, 95% CI 1.51 to 2.09) for highest versus lowest quartile. In the subtype analysis, stronger associations were observed for CLO, whereas there was negligible evidence for CPO and CLP. Sensitivity analyses using propensity score matching generated similar findings. CONCLUSIONS: Our study provides evidence that PM10 exposure during the 3 months preconception and the first trimester increases the risk of OC.

Maternal exposure to ambient particulate matter 10 µm or less in diameter before and after pregnancy, and anencephaly risk: A population-based case-control study in China.

BACKGROUND: There is no epidemiological evidence on the effects of maternal exposure to ambient particulate matter 10 µm or less in diameter (PM10) and anencephaly risk in offspring. METHODS: We conducted a population-based case-control study in Liaoning Province, China. The case group consisted of 663 cases with anencephaly and the control group consisted of 7950 healthy infants from the Maternal and Child Health Certificate Registry of Liaoning Province that were born between 2010 and 2015. Daily PM10 concentrations were obtained from 77 monitoring stations located within the study area. A multivariable logistic regression model was established to calculate the adjusted odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Maternal PM10 exposure was significantly associated with an increased risk of anencephaly at three months before conception (highest versus lowest tertile: OR = 1.74, 95% CI: 1.29-2.34; per 10 µg/m3 increment: OR = 1.13, 95% CI: 1.06-1.20) and three months after conception (highest versus lowest tertile: OR = 1.93, 95% CI: 1.44-2.60; per 10 µg/m3 increment: OR = 1.01, 95% CI: 0.95-1.08). The evaluation of shorter exposure windows revealed similar associations for PM10 exposure from the third month before pregnancy to the third month after pregnancy. CONCLUSIONS: Maternal PM10 exposure is positively associated with anencephaly risk during the critical period of neural system development.

Association between maternal exposure to PM10 and polydactyly and syndactyly: A population-based case-control study in Liaoning province, China.

BACKGROUND: The number of studies on air pollution with birth defects as the primary outcome has increased dramatically over the past two decades, but the potential role of specific air pollutants in congenital limb anomalies remains unclear. OBJECTIVES: To evaluate associations between preconception and first-trimester PM10 exposure and polydactyly and syndactyly in a population-based case-control study. METHODS: Polydactyly cases (n = 2605), syndactyly cases (n = 595), and controls without any birth defects (n = 7950) born between 2010 and 2015 were selected from the Maternal and Child Health Certificate Registry of Liaoning Province. The monthly mean PM10 concentrations were obtained from 75 air monitoring stations, and the exposure assessment was based on the mean concentration of all stations in mother's residential city. A multivariable logistic regression model was constructed to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs). RESULTS: PM10 exposure was positively associated with the risks of polydactyly (preconception: aORT3 vs. T1 = 1.95, 95% CI 1.56-2.45, aOR = 1.06, 95% CI 1.01-1.10 [per 10-µg/m3 increment]; first-trimester: aORT3 vs. T1 = 2.51, 95% CI 2.00-3.15) and syndactyly (preconception: aORT3 vs. T1 = 2.86, 95% CI 1.98-4.13, aOR = 1.11, 95% CI 1.03-1.20 [per 10-µg/m3 increment]; first-trimester: aORT3 vs. T1 = 3.10, 95% CI 2.11-4.56). Analyses based on single month exposure windows basically showed similar positive associations. Additionally, these findings were robust in sensitivity analyses and broadly consistent across subgroups. CONCLUSION: Our study suggest that preconception and first-trimester PM10 exposures are related to increased risks of polydactyly and syndactyly.

Association between maternal exposure to ambient PM10 and neural tube defects: A case-control study in Liaoning Province, China.

BACKGROUND: The potential association between maternal exposure to ambient PM10 and offspring neural tube defects (NTDs) is a contentious issue. This study aims to evaluate the aforementioned association at a provincial level in China. METHODS: A total of 2736 cases and 7950 randomly selected healthy infants included in the Maternal and Child Health Certificate Registry of Liaoning Province and delivered between 2010 and 2015 were recruited. Daily PM10 concentrations were obtained from all available monitoring stations located within the study area. A multivariable logistic regression model was established to calculate the adjusted odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: PM10 exposure was significantly associated with the risk of NTDs during the three months preconception (per 10 µg/m3 increment: OR = 1.10, 95% CI 1.07-1.14; per standard deviation [27 µg/m3] increment: OR = 1.29, 95% CI 1.18-1.41; highest tertile: OR = 1.61, 95% CI 1.37-1.91) and the first trimester (highest tertile: OR = 1.57, 95% CI: 1.31-1.87). When focusing on shorter exposure windows, similar associations were observed for PM10 exposure from the third month before pregnancy to the third month after pregnancy. Sensitivity analyses using propensity score matching yielded consistent findings. CONCLUSIONS: Maternal exposure to PM10 is positively associated with NTDs during the critical period of fetal neural tube development. However, due to the limitation of the exposure assessment as well as potential residual confounding, further research is warranted to confirm our findings.