Objective To understand the status of perinatal folic acid intake by childbearing-aged women in Shaanxi Province and analyze the influencing factors so as to provide data support for current policy adjustment.Methods We sampled in 10 cities of Shaanxi and Yangling Demonstration area,and chose women who had been pregnant in the past 3 years or were pregnant at the time of the survey to answer questionnaires.The unconditional logistic regression model was used to analyze the influencing factors.Results At the whole provincial level,the intake rate of folic acid was 84.1％.The intake rate of folic acid varied significantly among different regions,being 88.9％ in southern Shaanxi,85.7％ in Guanzhong area,and 88.9％ in northern Shaanxi (x2=24.011,P＜0.001).It also significantly differed between urban and rural areas (89.5％ vs.80.6％,x2=19.974,P ＜ 0.001).The intake rate of folic acid was different significantly among different age groups,too,being lower in the old-age group than in the young-age group (x2 =13.637,P=0.003).The rate of free access to folic acid and duration of folic acid intake also significantly differed among urban and rural areas,different regions and different age groups (P ＜ 0.05).By using logistic regression model we found that the childbearing-aged women's knowlage of folic acid was the most important influencing factors besides urban/rural area,region,age and education level.Among these factors the odds ratio of awareness intake of folic acid during perinatal period was 14.13 (95％ CI:6.16-32.44),the odds ratio of knowing that folic acid can prevent neural-tube defects was 2.71 (95％ CI:1.43-5.14) and odds ratio of knowing the policy of free distribution of folic acid supplements was 2.88 (95％ CI:1.52-5.47).Conclusion The rate of folic acid intake among childbearing-aged women in Shaanxi Province is relatively high,but the duration of folic acid intake is still short.The understanding about folic acid is an important factor which affects the use of folic acid.Improving the cognitive level of folic acid among childbearing-aged women is the most useful way to enhance the effective prevention of neural tube defects.

Birth defects are the abnormalities in structure,function or metabolism of embryonic or fetal development.They are the main cause of early abortion,stillbirth,perinatal mortality,infant mortality and congenital disabilities.Birth defects affect not only the health and life quality of children,but also the population quality of the whole country.This paper reviews the current epidemic situation and possible causes and risk factors of birth defects.It also expounds on the importance of epidemiological study on birth defects,possibility of primary prevention of birth defects,and necessity of interdisciplinary and collaborative research.It may provide reference for prevention and control of birth defects.

Objective To measure the phase values of the deep gray nuclei by using susceptibility weighted imaging(SWI) in underage brains,and to investigate the correlation between the phase value and age.Methods A total of 105 healthy juveniles were examined in this study by using MRI conventional sequence and SWI.Their ages ranged from 0 to 18 years(0-＜ 1 year,60 cases; 1-＜3 years,10 cases; 3-7 years,10 cases; 7-12 years,10 cases; 12-18 years,15 cases).Phase values of deep gray nuclei were measured.The correlation between phase value and age was analyzed by Spearman correlation method.Results During 0-3 years,the phase value of caudate nucleus was the lowest within the same age group (0-＜ 1 year:left-0.0433 ± 0.0291,right-0.0369 ± 0.0215 ; 1-＜ 3 years:left-0.0369 ± 0.0215,right-0.0384 ± 0.0259),whereas the phase value of red nucleus was the highest (0-＜ 1 year:left 0.0286-0.0380,right 0.0254 ±0.0361 ; 1-＜3 years:left 0.0325 ±0.0237,right 0.0395 ±0.0270).After 3 years old,the phase value of globus pallidus was the lowest within the same age group (3-＜7 years:left-0.0967 ± 0.0656,right-0.0953 ± 0.0617; 7-＜ 12 years:left-0.1870 ± 0.0531,right-0.1724 ±0.0547; 12-＜ 18 years:left-0.2037 ±0.0492,right-0.1849-±0.0324),whereas the phase value of thalamus was the highest (3-＜ 7 years:left-0.0019 ± 0.0225,right -0.0007 ± 0.0167 ; 7-＜ 12 years:left-0.0067 ± 0.0104,right-0.0064 ± 0.0118 ; 12-＜ 18 years:left-0.0204 ± 0.0181,right-0.0172 ± 0.0133).During 0-18 years,a moderate negative correlation between phase values of bilateral caudate nucleus,globus pallidus,red nucleus,substantia nigra and age were observed (rs =-0.483,-0.497,-0.67,-0.621,-0.489,-0.43,-0.552,-0.58 respectively) A low negative correlation between phase values of bilateral putamen,thalamus and age were observed (rs =-0.272,-0.213,-0.382,-0.366 respectively).Conclusions There is a negative correlation between phase value and age in the deep gray nuclei of underage brains.And the phase value may be a useful index in the diagnosis of iron deposition related diseases.

Objective To explore the association between folic acid supplementation during periconcerptional period and congenital heart disease in newborns to provide scientific evidence for making intervening measures.Methods Using stratified random cluster sampling,a total of 30 counties were sampled from Shaanxi Province.A questionnaire survey was conducted among childbearing-aged women pregnant between January 2010 and November 2013.All of the included women had definite pregnancy outcomes and had signed the consent form.Logistic regression was performed to investigate the association between folic acid supplementation during pregnancy and congenital heart disease in newborns.Results In total,28 354 questionnaires were available for analysis.The overall prevalence of congenital heart disease among live-birth neonates in the present study was 7.3‰.The percentage of childbearing-age women who had taken folic acid supplementation during pregnancy was 64.4％,while only 17.2％ of them took folic acid according to the specification.Taking folic acid regularly during pregnancy was associated with a lower risk of congenital heart disease among the newborns (OR 0.502,95％ CI:0.279 0.902).The multiple-factor analysis results also showed that taking folic acid regularly during periconcerptional period could reduce the risk of congenital heart disease (adjusted OR=0.512,P=0.046) when we controlled the family background factors,mother factors and exposure risk factors during pregnancy.However,no association was found between irregularly taking folic acid during periconcerptional period and the risk of congenital heart disease.Conclusion Taking folic acid according to the specification during periconcerptional period (taking folic acid during 3 months before pregnancy to 3 months after pregnancy with a daily dose of 0.4mg for more than 90 days) may prevent congenital heart disease of newborns.

Objective To analyze the effect of special risk exposures during periconception period on birth defects of newborns.Methods From Jul.to Dec.2013,the multi-stage stratified random sampling method was adopted.Women of childbearing age between 15 and 49 who were pregnant during 2010 to 2013 in Shaanxi Province were selected as study subjects for investigation on special risk factors exposed during periconception period.The Logistic regression model was adopted to analyze the association between newborns' birth defects and special risk exposures.Results The study included 30 010 women of childbearing age and 29 550 newborns with 572 (193.57/ 10 000) cases of birth defects.After adjusting for demographic factors,the risk factors for birth defects were drinking [OR=2.29,95％ CI (1.22,4.29)] and passive smoking [OR=1.25,95％ CI (1.02,1.53)] during periconception.There was a higher risk of birth defects when exposure to medicine [OR =1.64,95％ CI (1.04,2.61)],pesticides [OR =2.41,95％ CI (1.09,5.35)],biological risk factors [OR-1.64,95％ CI (1.05,2.56)],physical risk factors [OR=1.15,95％ CI (1.13,2.34)] and chemical risk factors [OR =2.36,95％ CI (1.36,4.11)] 3 months both before and after pregnancy.Similarly,after adjusting for demographic factors and behaviors,we found that birth defects were related to antibiotics,salicylates,and antitussive,which could increase the risk of birth defects (P＜0.05).Conclusion Exposure to passive smoking and drinking during periconception and exposure to medicines and pesticides,as well as biological,physical and chemical risk factors 3 months before and after pregnancy could increase the risk of birth defects in newborns.

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.