Objective:To explore the spatial distribution and clustering in birth defects from 2010 to 2013 in Shaanxi Province.Methods:Spatial distribution was used to describe the birth defects,while ordinary Kriging method was used to predict the status of birth defects in Shaanxi province.The spatial characteristics for the birth defects at the county/district level were analyzed by spatial autocorrelation.Results:The overall incidence of birth defects was 219.196/10 000;Birth defect did not appear to be a random distribution but show a significant spatial aggregation.Spatial interpolation predicted the geographic distribution for occurrence of birth defects in Shaanxi Province.Local autocorrelation analysis showed nine hot spot areas for birth defects,such as Qian County,Liquan County,Yongshou County,Bin County,Fufeng County,Jingyang County,Chunhua County,Wugong County and Xingping City,and seven cold spot areas including Jia County,Yuyang District,Mizhi County,Suide County,Wubu County,Qingjian County and Zizhou District.Conclusion:There are spatial clustering in birth defects from 2010 to 2013 in Shaanxi Province.Spatial interpolation and spatial autocorrelation can be used to predict the spatial features of birthdefects in the whole province and provide evidence for the further intervention.

Objective To predict the incidence of birth defects in Xi'an using the auto-regressive integrated moving average product seasonal model.Methods In Xi'an,the trend of the incidence of birth defects was analyzed and tested from October 2009 to August 2015.Using the data from September to December 2015,the actual birth defects were compared with the model fitting data to evaluate the predictive performance of the model.Multiple seasonal ARIMA model was then fitted under time series to predict the incidence of birth defects in 2016.Results Seasonal effect was seen in the incidence of birth defects in Xi'an.A multiple seasonal ARIMA(0,0,1) (0,1,1)12 was established.The mean of absolute error and the relative error were 9.5 and 0.084,respectively,when compared to the simulated number of patients from September to December in 2015,suggesting that ARIMA (0,0,1) (0,1,1)12 has a better predictive ability.Results under the prediction of multiple seasonal ARIMA model showed that the number of patients in 2016 was similar to that of 2015 in Xi'an,with a slight increase and a decrease in the peak value.Conclusion Multiple seasonal ARIMA(0,0,1)(0,1,1)12 model could be used to successfully predict the incidence of birth defects in Xi'an.

Objective To investigate the dynamic epidemiological characteristics of perinatal birth defects in Xi'an so as to provide scientific evidence for the priority of future birth defect prevention.Methods We made a statistical description of the data of perinatal birth defects from 2010 to 2015 reported by all the maternity hospitals in Xi'an.Results The incidence of birth defects in Xi'an from 2010 to 2015 was 89.62/104 (87.60/104,91.74/ 104) and had an annual ascending tendency (x2-157.13,P＜0.01).The top five main birth defects in a descending order were congenital heart disease (26.53/104),polydactyly (13.10/104),total cleft lip (11.42/104),neural tube defects (6.06 /104),and congenital hydrocephalus (5.08/104),accounting for 69.39％ of the total number of birth defects.And the incidence of congenital heart diseases showed a year-by-year ascending trend (x2=837.65,P＜ 0.01).The incidence of birth defects was higher in urban areas than in rural areas (OR 1.108,95％ CI:1.056-1.162).The birth defects were more frequently seen in males than in females (OB=1.151,95％ CI:1.097-1.208).Mother's age ＜20 (OR=1.764,95％ CI..1.532-2.032) and mother'sage≥35 (OR=1.283,95％ CI:1.179-1.395) also were risk factors for birth defects.Up to 72.54％ of the defects were live births.There were 52.83％ cases diagnosed by ultrasound and 46.24％ ones by clinical examination.The prenatal diagnosis rate was 33.20％.Conclusion The incidence of perinatal birth defects in Xi'an from 2010 to 2015 showed an annual ascending trend.We should improve the prenatal diagnosis level of all monitored hospitals in order to reduce incidence of birth defects and increase the quality of population.

Objective To study the effects of air pollution including sulphur dioxide (SO2),nitrogen dioxide (NO2) and PM10 in Xi'an on birth defects.Methods We collected the birth defects data from Xi'an Maternal and Child Health Hospital,meteorological data from Xi'an Bureau of Meteorology,and the air pollution data from Xi'an Environment Monitoring Station from 2010 to 2015.Generalized additive model (GAM) was used to explore the relationship between air pollution and birth defects after adjusting the effects of long-term and seasonal trend,temperature,and relative humidity.Results The monthly average birth defects were 89 cases;the monthly average concentration of SO2,NO2 and PM10 was 34.05 μg/m3,45.13 μg/m3,and 96.77 μg/m3,respectively.In the GAM,the monthly average temperature was 13.57 ℃ and the relative humidity was 63.20％.The three kinds of air pollutants all had a certain lag effect in 10 months,which reached the maximum.With an increase of concentration by 10 μg/m3 in three air pollutants,the relative risks and confidence interval of SO2,NO2,and PM10 were 1.060 (1.023-1.097),1.033 (1.014-1.052) and 1.018 (1.007-1.029),with significant differences (P＜0.05).Conclusion Exposure to SO2,NO2,and PM10 may be associated with the risk of birth defects.

Objective To analyze the spatial distribution characteristics of birth defects and air pollution in Xi'an and the correlation between air pollution exposure and birth defects.Methods In this study,we calculated the mean and median concentration of air pollutants in Xi'an between 2010 and 2015 to describe their concentration trends.Then we analyzed quartile range to describe their discrete trend.The spatial distribution of air pollution in the whole study area was calculated by inverse distance weighted spatial interpolation method to describe its overall occurrence level.The global trend was analyzed to describe the main body change pattern in the birth defect space.The total number of birth defects in the districts and counties of Xi'an between 2010 and 2015 was calculated and the incidence of birth defects was calculated according to the monitoring data of live births.Correlation between birth defects and air pollution was analyzed by rank correlation analysis.Results The spatial distribution of air pollutants in Xi'an between 2010 and 2015 was as follows:the concentration of SO2 was relatively high in Lianhu District,Yanta District,Baqiao District,Beilin District,and Xincheng District.The concentration of NO2 was relatively high in Yanta District,Baqiao District,Lianhu District,Beilin District,and Xincheng District.The concentration of PM10 was relatively high in Baqiao District,Yanta District,Xincheng District,Weiyang District,and Yanliang District.In Baqiao District,Xincheng District,Lianhu District,Weiyang District,and Gaoling District,the concentration of PM2.5 was relatively high.The total number of birth defects was 6 858 cases in Xi'an between 2010 and 2015,and the total number of perinatal births was 752 142 cases,with the incidence of 91.18 (1/10 000).The spatial distribution of birth defects from the west to the east direction and from south to north direction was generally characterized of inverted U type.The birth defects were positively correlated with NO2 concentration.Conclusion There are obvious regional differences in air pollution and birth defects in Xi'an.Birth defects may be related to NO2.

Objective To analyze the trend of birth defects and air pollution in Xi'an and discuss the correlation between air pollution exposure and birth defects.Methods Time series multiplication model was used to decompose the time series of birth defects and concentration of air pollutants to describe their long-term trend and seasonal variations.The rank correlation and cross-correlation between birth defects and air pollutants were analyzed by ecological approach.Results During 2010-2015,the results of air pollution analysis in Xi'an showed that the overall trend of NO2 increased in 2013 and then fluctuated at a high level.Generally,SO2 showed a trend of slow decline,but there were two peaks in 2012 and 2013.The overall trend of PM10 had two small peaks in 2013 and 2014,and during the rest of the time the change was stable.The overall trend of PM2.5 showed a slow decline,but after 2015 it showed a slight increase.Analysis of the birth defects during 2010-2015 in Xi'an showed that the long-term trend of total birth defects and congenital heart disease increased in 2010-2014,but then decreased rapidly.The long-term trend of cleft lip and palate and neural tube defects fluctuated at a low level.Analysis of the correlation between air pollutants and birth defects showed that total birth defects and congenital heart disease were positively correlated with NO2 at 3 months before pregnancy and early 3 months of pregnancy.Congenital heart disease 3 months before pregnancy had a positive correlation with PM10.Conclusion Birth defects and air pollution in Xi'an have trend variations and seasonal regularity.There is a positive correlation of women's exposure to NO2 3 months before pregnancy and the first 3 months of pregnancy with the incidence of congenital heart disease.

Objective: To investigate the relationship between maternal disease in early pregnancy of women of childbearing age and congenital heart disease of neonates. Methods: A cross-sectional design was used in this study and stratified multistage random sampling method was used. A questionnaire survey was conducted in the childbearing-aged women during 2010-2013 in Shaanxi province. Propensity score (PS) matched (1∶1) analysis was used to match participants with diseases to those without disease in early pregnancy. Through the control of the confounders step by step, a logistic regression model was established to evaluate the ORs of congenital heart disease according to the independent variable of maternal disease. Results: A total of 28 680 pairs of mothers and infants were included in this study, the proportion of the women with disease in early pregnancy was 20.25% (5 807). After PS matching, 5 436 pairs were matched. After adjusting all confounding factors, the multivariable logistic regression analysis results showed that maternal disease (OR=1.86, 95%CI: 1.23-2.81), especially cold (OR=2.19, 95%CI: 1.46-3.28), gynecological disease (OR=4.74, 95%CI: 2.03-11.09) and diabetes (OR=14.00, 95%CI: 1.64-119.21), in early pregnancy were the risk factors for congenital heart disease of neonate. Conclusion In women of childbearing age, disease in early pregnancy, especially cold, gynecological disease and diabetes, can increase the risk of congenital heart disease in neonates.

Objective: As the prevention and control of COVID-19continues to advance, the active nucleic acid test screening in the close contacts of the patients has been carrying out in many parts of China. However, the false-positive rate of positive results in the screening has not been reported up to now. But to clearify the false-positive rate during screening is important in COVID-19 control and prevention. Methods: Point values and reasonable ranges of the indicators which impact the false-positive rate of positive results were estimated based on the information available to us at present. The false-positive rate of positive results in the active screening was deduced, and univariate and multivariate-probabilistic sensitivity analyses were performed to understand the robustness of the findings. Results: When the infection rate of the close contacts and the sensitivity and specificity of reported results were taken as the point estimates, the positive predictive value of the active screening was only 19.67%, in contrast, the false-positive rate of positive results was 80.33%. The multivariate-probabilistic sensitivity analysis results supported the base-case findings, with a 75% probability for the false-positive rate of positive results over 47%. Conclusions In the close contacts of COVID-19 patients, nearly half or even more of the 'asymptomatic infected individuals’ reported in the active nucleic acid test screening might be false positives.

Objective To assess the association between exposure to prenatal outdoor air pollution and preterm birth to provide evidence in setting up programs for prevention on premature birth.Methods Case-control studies regarding association between pregnant exposure to outdoor air pollution and preterm birth were collected.Data were analyzed with Stata 12.0.Results Ten articles including 48 556 cases and 548 495 controls were qualified for inclusion.Results from Meta-analyses showed pooled ORs for exposure to NO2,PM10,CO,PM2.5,and NO during the entire pregnancy were 0.960 (95％CI:0.935-0.985),1.068 (95％CI:1.035-1.103),1.122 (95％CI:1.078-1.168),1.110 (95％ CI:1.043-1.181) and 0.994 (95％ CI:0.973-1.016).Association between air pollution and preterm birth varied with the periods of exposure.Pooled ORs for NO2,PM10 and SO2 exposure during the first trimester were 1.117 (95％CI:1.052-1.186),0.968 (95％CI:0.812-1.153) and 1.258 (95％CI:0.758-2.089).Pooled ORs for NO2,PM10,SO2 exposure during the second trimester were 1.000 (95％ CI:0.982-1.019),1.127 (95％ CI:0.896-1.416) and 0.977 (95％CI:0.711-1.342).Pooled ORs for NO2,PM10,SO2 exposure during the third trimester were 1.006 (95％CI:1.002-1.010),1.053 (95％CI:0.973-1.139) and 1.003 (95％CI:1.000-1.006).Conclusion Exposures to PM10,CO and PM2.5 during the entire pregnancy,to NO2 during the first trimester,or to NO2 and SO2 during the third trimester were associated with preterm births.

Objective To analyze the incidence and influencing factors on fetal macrosomia among single live birth neonates in Xi'an.Methods A questionnaire survey was conducted among women at the childbearing age who were selected through multi stage stratified random sampling in Xi'an during 2010-2013.All the childbearing aged women involved,were in pregnancy or having definite pregnancy outcomes.Results A total of 4 970 women at childbearing age and their infants were investigated.The overall incidence of fetal macrosomia weight among the single live birth neonates under study,was 9.7％ during 2010-2013 (8.9％ in 2010,8.1％ in 2011,10.0％ in 2012 and 10.1％ in 2013,respectively).The incidence rates of fetal macrosomia appeared 10.5％ in the central district and,8.6％ in the rural-urban area of Xi'an.There were statistically significant differences (P＜0.05) seen between the two areas.Results of logistic regression analysis suggested that factors as:having male newborn (OR=1.717,95％ CI:1.402-2.102),drinking during pregnancy (OR=2.174,95％ CI:1.042-4.533),gestational diabetes (OR=1.680,95％CI:1.100-2.568) gestational age≥42 (compared with 37-41,OR=2.565,95％CI:1.306-5.039),being multipara (OR=1.874,95％CI:1.492-2.354)were risk factors for the fetal macrosomia.Conclusion The incidence of fetal macrosomia in Xi'an was higher than the national figures.The incidence of fetal macrosomia was higher in the central district than in rural-urban area.Having male neonate,postmature birth,gestational diabetes,being multipara,drinking during pregnancy were the risk factors related to fetal macrosomia.