[Construction of natural population cohort on telephone follow-up management quality control system and discussion regarding critical issues by REDCap system].

With completing a baseline survey of a large natural population cohort, conducting regular follow-up has become a key factor in further improving the quality of cohort construction and ensuring its sustainable development. Typical cohort follow-up methods include repeat surveys, routine monitoring, and community-oriented surveillance. However, in practical applications, there are often issues such as high costs, difficulty, and high error rates. Telephone follow-up is an important supplementary method to the methods mentioned above, as it has the characteristics of low cost, fast response, and high quality. However, the with difficult organization, quality control is challenging, response rates are low, and management levels vary widely, which limits its widespread use in large-scale population cohort studies. Given the above problems, this study draws on customer relationship management based on the actual needs of the China Northwest Cohort follow-up. It relies on the REDCap electronic data collection platform to build a telephone follow-up management and quality control system. Targeted solutions are provided for key issues in telephone follow-up implementation, including organizational structure, project management, data collection, and process quality control, to improve the quality control level of telephone follow-up comprehensively and thereby enhance the quality and efficiency of follow-up. We hope to provide standardized follow-up programs and efficient quality control tools for newly established and existing cohort studies.

[Association between muscle mass and quality of life in Shaanxi adults].

Objective: To investigate the association between muscle mass and quality of life in adults in Shaanxi adults. Methods: The data in this analysis were part of the baseline survey of the Regional Ethnic Cohort Study in Northwest China from June 2018 to May 2019 in Shaanxi Province. The participants' quality of life, including physical component summary (PCS) and mental component summary (MCS), was assessed by the 12-Item Short Form Survey, and the Body Fat Determination System measured muscle mass. A logistic regression model with adjustment for confounding factors was established to analyze the association between muscle mass and quality of life in different genders. Further, sensitivity and subgroup analyses were conducted to explore its stability. Finally, a restricted cubic spline was employed to investigate the dose-response relationship between muscle mass and quality of life in different genders. Results: A total of 20 595 participants were included, with an average age of 55.0, and 33.4% were male. After controlling for potential confounders, compared with the Q1 group, the risk of low PCS was reduced by 20.6% (OR=0.794, 95%CI: 0.681-0.925) and the risk of low MCS was lower reduced by 20.1% (OR=0.799, 95%CI: 0.689-0.926) in female Q5 groups. Compared with the Q1 group, the risk of low PCS was reduced by 24.4% (OR=0.756, 95%CI: 0.644-0.888) in the male Q2 group. However, no significant association between muscle mass and MCS in males has been found. In females, restricted cubic spline analysis showed a significant linear dose-response relationship between muscle mass and PCS and MCS. Conclusions: There is a positive association between muscle mass and quality of life in Shaanxi adults, especially females. With the increase in muscle mass, the physical and mental functions of the population continue to improve.

[Application of isotemporal substitution model in epidemiological research].

Isotemporal substitution model is a powerful tool to explore the real association between physical behavior and health outcomes, which has the potential of the application in large-scale cohort study. This paper systematically introduces the principle of isotemporal substitution model and its implementation method in specific analysis to provide analytical ideas for the epidemiological research related to physical behavior in China. The baseline data of Regional Ethic Cohort Study in Northwest China conducted in Shaanxi province were used to analyze the relationship between physical behavior and cardiovascular disease with single-factor model, partition model and isotemporal substitution model. The advantages and disadvantages of different models were compared, and the advantages of isotemporal substitution model in quantifying physical activity health risk were introduced. Isotemporal substitution model could qualify physical behavior and health outcomes, which has wide application value in epidemiological research.

[The association between calcium supplementation in antenatal childbearing aged women and risk of small for gestational age among neonatal singleton in Shaanxi province].

Objective: This study explored the association between antenatal calcium supplementation in the childbearing aged women and risk of small for gestational age infant (SGA) among singleton in Shaanxi province,China. Methods: Multi-stage random cluster sampling method was employed to collect information about pregnant women, who were pregnant and had definite outcomes, and their infants, from 30 districts (counties) in 2010 to 2013. Information was collected by face-to-face questionnaire survey. Generalized linear mixed models were employed after adjusting covariates. Dependent variable was whether single-birth neonate was SGA, and independent variable was calcium supplementation of childbearing aged women in different pregnant periods. Results: A total of 28 357 childbearing aged women was recruited in this study. The age of these women was (28.08±4.74) years old, of which, 79.28% were rural residents and 60.90% had calcium supplementation intake. There was a number of 12 810 female in singleton neonates. The neonatal birth weight and gestational age were (3.27±0.16) kg and (277.44±8.80) day, respectively. The prevalence of SGA was 11.35% in total, and 10.48% in mothers with maternal calcium supplementation and 12.70% in mothers without maternal calcium supplementation in whole antenatal period. There were statistically significant differences seen in antenatal calcium supplementation within the subgroups of maternal age (whether the mother was an advanced maternal woman), residential area, maternal occupation, maternal parity, maternal education level, and household incomes (P<0.05). After adjusting these covariates, the risk of SGA among childbearing aged women with antenatal calcium supplementation showed 16% decreased risk (OR=0.84, 95%CI: 0.77-0.92). Further analysis of the different antenatal periods showed that calcium supplementation during the second and third trimester had a statistically significant difference in reducing the risk of neonatal SGA (P<0.05). Besides, subgroup analysis showed that there was a statistically significant difference between the perinatal calcium supplementation and the single-born neonates with SGA Significance (P<0.05) in non-advanced women, those who had a low education level and moderate household economic status groups. Conclusion: The risk reduction of SGA among singleton neonates is related to calcium supplementation during antenatal period in Shaanxi province.

[Method of double data entry and quality control by REDCap system].

In medical research, the quality of data is the key to success. Thus, data quality control becomes an important part of ensuring the research's high quality. REDCap system is an emerging data acquisition system in medical research, which is gradually applied in research at home and abroad. It is a hot issue to realize double data entry and data quality control in using the REDCap system, which researchers are concerned about when this system is supposed to apply. This article will systematically introduce how to use the REDCap system for double data entry and quality control from the aspects of research project creation, data collection tool design, double data entry, data checking and exporting.

[Application of electronic data acquisition system REDCap in large natural population-based cohort studies].

Cohort study is one of the basic methods used in epidemiological research. With the development of the etiological analysis of complex diseases such as cardiovascular diseases, large natural population-based cohort study has become a popular topic in medical research. In the process of cohort development, one of the important issues is to ensure the efficiency and safety on data collection. As a database management system, with open source, free clinical research data collection and high quality, REDCap can widely be applied in large population-based cohort studies. This article summarizes the baseline survey and follow-up procedures on cohort studies and introduces a REDCap-system-based solution for data collection and management. Contents on the establishment of data working groups, data collection, cohort follow-up methods and field application are also discussed in this paper, in order to improve the efficiency of data collection and management in cohort study to help the development of cohort study in China.

[WITHDRAWN: Potential false-positive rate among the 'asymptomatic infected individuals' in close contacts of COVID-19 patients].

Editor office's response for Ahead of Print article withdrawn The article "Potential false-positive rate among the 'asymptomatic infected individuals' in close contacts of COVID-19 patients" was under strong discussion after pre-published. Questions from the readers mainly focused on the article's results and conclusions were depended on theoretical deduction, but not the field epidemiology data and further researches were needed to prove the current theory. Based on previous discussions, the article was decided to be offline by the editorial board from the pre-publish lists. 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.

[Association between congenital heart disease and maternal disease in early pregnancy in women of childbearing age].

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.

[Interaction between pregnancy-induced hypertension and history of preterm birth on the risk of small for gestational age].

Objective: To investigate the interaction of pregnancy-induced hypertension and history of preterm birth on the risk of small for gestational age. Methods: Stratified multistage random sampling method was used to choose samples from 30 districts and counties of Shaanxi province. Information on childbearing-age women with their children between January 2010 and November 2013 was retrospectively collected through face-to-face questionnaire survey. The childbearing-aged women were in pregnancy or having had definite outcomes of pregnancy. Enumeration data were described by percentage, and measurement data were described by Mean±SD, and χ(2) test was used to compare the rates. Unconditional logistic regression analysis was performed to estimate the interaction between pregnancy-induced hypertension and history of preterm birth on the risk of small for gestational age, and by using small for gestational age as dependent variables, pregnancy-induced hypertension and history of preterm birth as independent variables. Confounding factors were under control. Firstly, the association between pregnancy-induced hypertension and small for gestational age has been analyzed in primiparas, secondly, interaction of pregnancy-induced hypertension and history of preterm birth on the risk of small for gestational age has been analyzed in multiparas. Results: A total of 25 751 women of childbearing age and their children were recruited. 60.55% (15 592/25 751) were primiparas, 39.45% (10 159/25 751) were multiparas, the rate of history of preterm birth was 1.89% (192/10 159) for multiparas. The incidence rates of pregnancy-induced hypertension and small for gestational age were 1.55% and 15.49% in pregnant woman (400/25 751) and their newborns (3 990/25 751). Unconditioned logistic regression analysis showed that compared with woman without pregnancy-induced hypertension, primiparas with pregnancy-induced hypertension had increased risk of small for gestational age (OR=1.43, 95%CI: 1.02-2.00, P=0.041). Regarding multiparas, the main effect of pregnancy-induced hypertension had a positive correlation with small for gestational age (OR=1.34, 95%CI: 0.91-1.96), but there was no statistical significance (P=0.138). The main effect of history of preterm birth was positively correlated with small for gestational age (OR=1.61, 95%CI: 1.13-2.31, P=0.009). The interaction term "pregnancy-induced hypertension×history of preterm birth" was positively associated with risk of small for gestational age (OR=5.93, 95%CI: 1.19-29.61, P=0.030). Conclusions: Pregnancy-induced hypertension was associated with increased risk for small for gestational age in both primiparas and multiparas, and history of preterm birth further increased risk for small for gestational age in pregnant women with pregnancy-induced hypertension, indicating that there was multiplication interaction between pregnancy-induced hypertension and history of preterm birth.

MiR-21 promotes fracture healing by activating the PI3K/Akt signaling pathway.

OBJECTIVE: This study aims to elucidate the potential mechanism of micro ribonucleic acid (miR)-21 in promoting fracture healing. MATERIALS AND METHODS: 30 male Sprague-Dawley rats were randomly divided into group A (phosphate-buffered saline, PBS, n=10), group B (AntagomiR-21, n=10) and group C (AntagomiR-NC, n=10) according to the different treatments. The femoral fracture operation was performed in every rat, which was pathologically diagnosed via X-ray. After the successful modeling, 50 µL (2 nmoL) PBS, 50 µL AntagomiR-21 or 50 µL AntagomiR-NC was intraperitoneally injected into rats in group A, B or C, respectively. The above agents were injected once a week for 6 weeks. At 6 weeks, 3 rats were executed in each group, and the tissue at the fracture end was observed via hematoxylin-eosin (HE) staining. The fracture healing of rats was evaluated via imaging at 1 and 7 weeks. At the same time, the expression of miR-21 in the three groups was detected via Reverse Transcription-Polymerase Chain Reaction (RT-PCR), and the expression of phosphatidylinositol 3-hydroxy kinase (PI3K) and phosphorylated-serine/threonine-protein kinase B (p-Akt) in the three groups was detected via Western blotting. RESULTS: According to the histological staining, the bone repair at the fracture end of rats in group B was not significant with fracture and poor continuity compared with those in group A and group C. The imaging evaluation revealed that in group B, the callus tissues were significantly reduced, the fracture line had undesirable healing. There were no displacement and loosening of internal fixation compared with group A and group C. Besides, RT-PCR showed that the miR-21 expression declined markedly in group B compared with that in group A and group C, and the differences were statistically significant (p<0.05). Western blotting manifested that the protein levels of PI3K and p-Akt also declined in group B compared with those in group A and group C, and there were statistically significant differences (p<0.05). CONCLUSIONS: MiR-21 promotes the fracture healing in fractured rats by activating the PI3K/Akt signaling pathway.

[A propensity score-matched study on relationship between maternal respiratory infection in early pregnancy and gestational age].

Objective: To explore the association between maternal respiratory infection in early pregnancy and gestational age of single live birth. Methods: A face to face questionnaire survey was conducted among child bearing aged women in 30 counties (district) of Shaanxi province selected through stratified multistage sampling. Propensity score (PS) matched (1∶1) analysis was used to match participants with respiratory infections to those without respiratory infections. A multilevel linear model was used to investigate the association between respiratory infections and gestational age. Through the control of the confounders step by step, three models were established in this study: model 1 for the variable of respiratory infections before PS matching, model 2 was adjusted for variables in model 1 plus some other individual differences of mother and baby, and model 3 for the variable of respiratory infections after PS matching. Results: Of 28 848 child bearing aged women surveyed, 3 676 (12.74%) had respiratory infections in early pregnancy. After PS matching, 2 762 pairs were matched. Analysis with model 1 indicated that a decrease of 0.111 week (P<0.001) in gestational age was associated with a respiratory infection during the first trimester. Analysis with model 2 and model 3 indicated that a decrease of 0.058 week (P=0.025) and a decrease of 0.076 week (P=0.036) were associated with respiratory infection during the first trimester, respectively. Conclusion: The respiratory infection during the first trimester was associated with the decrease of the gestational age of newborn.

[Association between illness and mental status in pregnant women and birth defects].

Objective: To understand the prevalence of birth defects, related diseases and mental status of women during pregnancy in Shaanxi province and to analyse the major risk factors on birth defects and congenital heart disease. Possible association between maternal diseases or mental status and the risk of birth defects, was also explored. Methods: A cross-sectional design was used in this study and stratified multistage random sampling method was used. The whole survey was from Jury 2013 to November 2013. Logistic regression method was used to analyze the association between maternal diseases, mental status during pregnancy and birth defects. Results: The overall prevalence of birth defects was 195.04 per 10 000 in Shaanxi. Among the 29 121 mothers participating in this study, 51.1% developed illness and 6.8% "changed their mental status during pregnancy. After adjusting all the confounding factors, results showed that, histories of cold" , fever, and intrahepatic cholestasis were (OR=1.33, 95%CI: 1.10-1.61, OR=1.54, 95%CI: 1.09-2.16, and OR=32.77, 95%CI:4.08-263.04) respectively, during pregnancy that related to birth defects. Self-reported unstable mental status (OR=1.60, 95%CI: 1.19-2.15) and family friction (OR=2.07, 95%CI: 1.12-3.79) were both related to the birth rates. Histories of cold and fever (OR=1.59, 95%CI: 1.28-1.98; OR=1.43, 95%CI: 1.48-4.00), during early pregnancy, unstable mental status during mid-pregnant period (OR=1.52, 95%CI: 1.05-2.19), unstable mental status during late-pregnant period (OR=1.63, 95%CI: 1.05-2.19) and family friction during late-pregnant period (OR=2.89, 95%CI: 1.16-7.20) were found to be related to birth defects. Compared with those without history of cold, those with the history of cold during first (OR=1.24, 95%CI: 1.02-1.52) and second stages (OR=2.06, 95%CI: 1.30-3.26) of pregnancy were more likely to bear fetus with birth defects. Compared with those without these histories, those with histories of fever (OR=1.49, 95%CI: 1.04-2.13), emotional problem (OR=1.71, 95%CI: 1.19-2.45) and related diseases (OR=2.67, 95%CI: 1.32-5.39) during the first period of pregnancy were more likely to bear fetus with birth defects. Conclusion: The incidence of birth defects in Shaanxi was high. Histories of cold, fever, unstable mental status and family friction during pregnancy, seemed to have increased the risks of bearing child with birth defects.

[Relationship between air pollution exposure during pregnancy and birth weight of term singleton live-birth newborns].

Objective: This study explored the association between air pollution exposure and birth weight by using the multilevel linear model, after controlling related meteorological factors and individual differences of both mothers and babies. Methods: Women of childbearing age who were pregnant in Xi'an from 2010 to 2013, were selected as objects of this study. Multistage random sampling method was used to select 4 631 subjects followed by a self-designed questionnaire survey. Data related to quality of air and meteorology were gathered from routine monitoring system. Gestational age and date of birth, together with the average levels of air pollution were calculated for each trimester on each mother, and then the impact of air pollution on birth weight was assessed. A multilevel linear model was employed to investigate the association between the levels of exposure to air pollution by birth weight. Confounding factors were under control. We established three models in this study: Model 1 which involving the variable of air pollution exposure. Model 2 was adjusted for variables in Model 1 plus some other individual differences of both mother and baby. Model 3 was adjusted for variables in Model 2 plus meteorological factors. Results: There were significant differences seen in birth weight within the subgroups of gender, gestational age, mother's reproductive age, maternal education, residential areas and family incomes (P<0.01) of the infants. However, there was no difference found in Model 1 (P>0.05). Data from Model 3 indicated that a decrease of 13.3 g(10.9 g in Model 2) and 6.6 g (5.9 g in Model 2) in birth weight that were associated with an increase of 10 µg/m(3) in the average level of NO(2) and PM(10) during the second trimester; A decrease of 13.7 g (9.8 g in Model 2) in birth weight was associated with an increase of 10 µg/m(3) in the average level of NO(2) during the third trimester. Conclusion: After controlling for meteorological factors, the levels of exposure to NO(2) and PM(10) during the second trimester and NO(2) during the third trimester were negatively associated with birth weight.

[Temperature that modifies the effect of air pollution on emergency room visits for circulatory and respiratory diseases in Beijing, China].

Objective: To analyze the temperature modification effect on emergency room visits for circulatory and respiratory diseases caused by air pollution, in Beijing. Methods: Data on both circulatory and respiratory diseases in 2010 and 2011 were collected, Both meteorological and air pollutants related data were obtained from the National Scientific Data Sharing Platform for Population and Health. By using the stratified time-series models, we analyzed the effects of air pollution on emergency room visits for circulatory and respiratory diseases under different temperature zones, from 2010 to 2011, in Beijing. Results: Low temperature (daily average temperature<-4.9 ℃) seemed to have obviously enhanced the effect of air pollution index (API) on emergency room visits for circulatory diseases, Under 10 units of API, the relative risks and confidence interval appeared as 1.067 (1.054-1.080). However, high (daily average temperature between 24.4 ℃ and 28.5 ℃) and extra-high temperature (daily average temperature >28.5 ℃) could enhance the effect of API on emergency room visits for respiratory diseases, Under 10 units of API, the relative risks and confidence interval were 1.021 (1.015-1.028) and 1.006 (1.003-1.008), respectively. Conclusion: Temperature seemed to have modified the association between air pollution and both circulatory and respiratory diseases.

[Study on relationship between mother's animal sourced food intake during pregnancy and neonate birth weight].

Objective: To explore the effect of maternal animal sourced food intake during pregnancy on neonate birth weight and provide scientific basis for guiding the reasonable diet intake in pregnant women and increasing neonate birth weight. Methods: Data were derived from a cross-sectional project of"the prevalence and risk factors of birth defects in Shaanxi province" , which were conducted in 30 counties in Shaanxi province from July to November in 2013. A stratified multistage random sampling method was used to select women who were pregnant between January 2010 and December 2013 for a random semi-quantitative food frequency questionnaire survey to collect the data on the frequency and amount of food consumption on animal protein sources and the data of newborns. Children aged 0-1 years and their mothers were selected as the study subjects. The generalized linear model was used to analyze the relationship between the neonate birth weight and maternal animal sourced food intake during pregnancy, and by using neonate birth weight as dependent variable, food intake frequency as independent variable, three adjustment models were established for stratified analysis. Results: Totally 11 459 participants were involved in this study. The average birth weight of newborn was (3 279.9±454.6) g, the average weekly intake of animal sourced foods was4.00 times for egg, 1.50 times for meat, 3.00 times for dairy foods, 0.50 times for fish and 5.00 times for overall animal sourced foods in pregnant women. Without stratification, three models shown that meat and overall animal sourced food intake had effects on neonate birth weight. After adjustment for gestational weeks, maternal age, social and demographic factors and others, meat intake increased by 1 time a week, the increase of neonate birth weight was about 5.26 (95%CI: 1.32-9.20) g, and the overall animal food increased by 1 times a week, the average neonate birth weight increased by 3.24 (95%CI: 1.09-5.39) g. Stratified analysis showed that meat and overall animal sourced food always had more influences on baby girls and those living in rural area. In the region classification, the overall animal sourced food intake had more influences on women living in northern area and Guanzhong area of Shaanxi, and meat intake had greater influence on women living in southern Shaanxi. And the influences were positive, the more animal sourced foods were taken, the greater the birth weight increased. Conclusion: Animal sourced food intake during pregnancy would benefit the increase of neonate birth weight. It suggests that pregnant women should pay more attention to the intake of animal sourced food.

[Relationship between exposure to air pollutants during pre-pregnancy or early pregnancy and birth defects in Xi'an, 2013-2015: a case crossover study].

Objective: To understand the levels of exposure to traffic-related air pollutants including nitrogen dioxide (NO(2)), PM(10) and PM(2.5), and the relationship between the exposure to air pollutants during pre-pregnancy or early pregnancy and birth defects. Methods: Data on air pollution and birth defects from 2013 to 2015 was collected. A case-crossover design was employed to analyze the exposure-response relationship between traffic-related air pollutants and birth defects. Results: A total of 4 235 pregnant women were studied. During the study period, the daily average concentrations of ambient NO(2), PM(10) and PM(2.5) appeared as 60.83 µg/m(3), 104.94 µg/m(3) and 103.88 µg/m(3), respectively, with the concentration of PM(2.5) larger than the 2(nd) version of Standard National Ambient Air Quality Standard. In addition, there were strong correlations seen between each of the pollutants (P<0.01). After adjustment for the influence of meteorological factors, it was found that the exposure to high level of NO(2) and PM(10) during pre-pregnancy or early pregnancy increased the risk on birth defects (P<0.05). Conclusion: Levels of exposure to adverse environmental factors during pre- pregnancy or early pregnancy could increase the risk of birth defects, suggesting that in these sensitive periods, women should try to avoid being exposed to high concentration of traffic-related air pollutants as NO(2), PM(10) etc. in order to reduce the risk of birth defects.

[Epidemiological study on adverse pregnancy outcomes in Shaanxi province].

Objective: To understand the incidence and epidemiological characteristics of adverse pregnancy outcome in Shaanxi province. Methods: General information of the study was derived from the prevalence and risk factors of birth defects in Shaanxi province in 2010-2013. Descriptive epidemiological method was used to analyze the data of adverse pregnancy outcome. Results: The overall incidence of adverse pregnancy outcome was 25.45% during 2010-2013 (26.84% in 2010, 26.11% in 2011, 24.96% in 2012 and 24.80% in 2013, respectively). Fetal macrosomia and low birth weight accounted for 31.91% and 23.42%, spontaneous abortion and premature delivery accounted for 18.94% and 16.65%, while birth defects and embryo death in the palace accounted for 7.38% and 1.70%, respectively. There were significant differences in distribution of adverse pregnancy outcome among different age groups (P<0.001) and different years (P<0.05). Age was positively associated with risk on adverse pregnancy outcomes (P<0.001). The incidence of adverse pregnancy outcome were high in Liquan (37.49%), Wugong (35.50%) and Qianxian counties (35.13%). Conclusions: The overall incidence of adverse pregnancy outcome was 25.45% in Shaanxi. Fetal macrosomia, low birth weight and spontaneous abortion were the three major types of adverse pregnancy outcome, while age and area were related factors. Targeted strategies should be taken to reduce the incidence of adverse pregnancy outcome in Shaanxi.

[Incidence of fetal macrosomia among single live birth neonates and influencing factors in Xi' an, 2010-2013].

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.

[Prenatal exposure to outdoor air pollution and preterm birth: a Meta-analysis].

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.