The prevalence of preterm and low birth weight infants among migrant women in the Pearl River Delta region, China: a population-based birth cohort study.

BACKGROUND: The existing literature evaluating the association between neonatal morbidity and migrant status presents contradictory results. The purpose of this study was to compare the risk of preterm birth (PTB) and low birth weight (LBW) among newborns from local and migrant women in China's Pearl River Delta (PRD) region. METHODS: In this observational population-based study, we included all live singleton deliveries from PRD region local women and migrant women. Data were sourced from the Guangdong Medical Birth Registry Information System between Jan 1, 2014, and Dec 31, 2020. Women were categorized into three groups by maternal migrant status: local women from PRD region, migrant women from Guangdong province or from other provinces. The outcome variables that were examined included two adverse birth outcomes: PTB and LBW. The association between the risk of PTB and LBW and maternal migrant status was assessed using logistic regression. RESULTS: During 2014-2020, 5,219,133 single live deliveries were recorded, corresponding 13.22% to local women and the rest to migrant women coming from Guangdong (53.51%) and other provinces (33.26%). PTB prevalence was highest among local women (5.79%), followed by migrant women from Guangdong (5.29%), and the lowest among migrants from other provinces (4.95%). This association did not change after including maternal age, infant sex, delivery mode, and birth season in the models. Compared to local women, migrant women from other provinces had a lower risk of LBW (4.00% vs. 4.98%, P < 0.001). The prevalence of PTB and LBW was higher among local women than migrants. The odds of delivery PTB and LBW were higher for women who were age ≥ 35. Among the three maternal migration groups, the age-LBW association displayed a typical U-shaped pattern, with those in the youngest (16-24 years) and oldest (≥ 35) age categories exhibiting the higher odds of delivering a LBW neonate. With respect to infant sex, the prevalence of PTB was significantly higher in males than females among the three maternal migration groups. An opposite trend was found for LBW, and the prevalence of LBW was higher in females among the three maternal migration groups. CONCLUSION: The findings of this study contribute to the understanding of the epidemiology of PTB and LBW among migrant women. Our study suggests that it is the health and robust nature of migrant mothers that predisposes them to better birth outcomes. It is important to recognize that the results of this study, while supportive of the healthy migrant effect, cannot be considered definitive without some exploration of motivation for moving and changes in lifestyle postmigration.

Extreme temperature exposure increases the risk of preterm birth in women with abnormal pre-pregnancy body mass index: a cohort study in a southern province of China.

Background: Prior literature has found that extreme temperature exposure is associated with preterm birth (PTB). However, current evidence provides heterogeneous conclusions, and data on extreme cold and across different pre-pregnancy body mass index (BMI) statuses are limited. Methods: We conducted a population-based retrospective cohort of 251,257 women between 2014 and 2017 in Guangdong, China, to evaluate whether the association between extreme temperature exposure and PTB varied in pre-pregnancy BMI status. Participants were divided into three categories based on pre-pregnancy BMI: underweight (BMI < 18.5 kg/m2), normal weight (18.5-23.9 kg/m2), overweight or obesity (≥ 24.0 kg/m2). We fitted Cox proportional hazards models to assess the association between daily mean temperature and PTB at each trimester for each BMI category separately. The hazard ratios (HRs) at the 5th and 95th percentiles of temperature (defined as low and high temperatures respectively) were provided using the median temperature at each trimester as a reference. Results: 58,220 (23.2%) were underweight, and 27,865 (11.1%) were overweight or obese. Of the 251,257 women, 18,612 (7.41%) had PTB delivery. Both low-and high-temperature exposure increased the risk of PTB in the third trimester, while cold exposure mostly mitigated the risk for the first and second trimesters. The association with low temperature was the strongest in the third trimester, especially for underweight women (HR: 1.825; 95%CI: 1.529 ~ 2.179), while the association with high temperature was the strongest also in the third trimester, especially for obese or overweight women (HR:1.825; 95%CI:1.502 ~ 2.218). Furthermore, the attributable fractions of PTB risk in the third trimester were estimated as 5.59% (95% CI: 3.58, 7.98%) for cold exposure among underweight women and 3.31% (95% CI: 2.01, 4.88%) for hot exposure among overweight or obese women. Conclusion: Exposure to either low temperature in the third trimester or high temperature during pregnancy was associated with a higher risk of PTB. Moreover, pre-pregnancy BMI status might affect the susceptibility of pregnant women. Such findings would be useful to develop targeted measures for vulnerable populations.

Co-occurrence of Spondyloepiphyseal Dysplasia and X-Linked Hypophosphatemia in a Three-Generation Chinese Family.

Rare genetic skeletal disorders (GSDs) remain the major problem in orthopedics and result in significant morbidity in patients, but the causes are highly diverse. Precise molecular diagnosis will benefit management and genetic counseling. This study aims to share the diagnostic experience on a three-generation Chinese family with co-occurrence of spondyloepiphyseal dysplasia (SED) and X-linked hypophosphatemia (XLH), and evaluate the therapeutic effects of two third-generation siblings. The proband, his younger brother, and mother presented with short stature, skeletal problems, and hypophosphatemia. His father, paternal grandfather, and aunt also manifested short stature and skeletal deformities. Whole exome sequencing (WES) of proband-brother-parents initially only found the proband and his younger brother had a pathogenic c.2833G > A(p.G945S) variant in the COL2A1 gene inherited from their father. Re-analysis of WES uncovered the proband and his younger brother also harbored a pathogenic ex.12 del variant in the PHEX gene transmitted from their mother. Sanger sequencing, agarose gel electrophoresis, and quantitative polymerase chain reaction proved these results. The proband and his younger brother were confirmed to have a paternally inherited SED and a maternally inherited XLH. During a 2.8-year follow-up, these two siblings remained short stature and hypophosphatemia, but their radiographic signs and serum bone alkaline phosphatase levels were improved with treatment of oral phosphate and calcitriol. Our study presents the first report of co-occurrence of SED and XLH, shows the possibility that two different rare GSDs co-exist in a single patient, and alerts clinicians and geneticists to be cautious about this condition. Our study also suggests that next-generation sequencing has limit in detecting exon-level large deletions.

Epidemiology of hepatitis B virus infection among preconception couples in South China: a cross-sectional study.

OBJECTIVES: Hepatitis B virus (HBV) infection is a global public health threat, and couples of reproductive age comprise a key population in aiming to reduce both the vertical and horizontal transmission of HBV. We aimed to update knowledge on the seroepidemiology status of HBV in Guangdong, China among a large number of couples planning conception, and to identify high-risk subgroups. DESIGN: A cross-sectional study was performed in Guangdong, China from 2014 to 2017. SETTING: The data were collected from 641 642 couples (1 283 284 individuals) participating in the National Free Preconception Health Examination Project in Guangdong, China from 1 January 2014 to 31 December 2017. For each participant, sociodemographic data were obtained and a serum sample was tested for HBV infection status. RESULTS: 161 204 individuals (12.56%) were positive for hepatitis B surface antigen (HBsAg+), and 47 318 (3.69%) were positive for both HBsAg and hepatitis B e antigen (HBsAg+ and HBeAg+). There was a higher prevalence of HBsAg+ (12.77% vs 9.42%, p<0.05) and HBsAg+ and HBeAg+ (3.77% vs 2.45%, p<0.05) among the participants with a Guangdong household registration than a non-Guangdong household registration. Similarly, the prevalence of HBsAg (13.26% vs 11.72%, p<0.05) and HBsAg+ and HBeAg+ (4.31% vs 2.94%, p<0.05) was higher among participants not living in the Pearl River Delta than those living in the Pearl River Delta. At the couple level, 12 446 couples (1.94%) were both positive; in 51 849 (8.08%), only the wife was positive; in 84 463 (13.16%), only the husband was positive. Moreover, HBsAg+ prevalence was lowest in couples where both individuals were vaccinated (18.63%) and highest in couples where neither the wife or husband was vaccinated (24.46%). CONCLUSION: There was a relatively high HBsAg+ prevalence in married couples in this high-epidemic region and urgent prevention strategies are required, such as ensuring access to health services for those not living in the Pearl River Delta, and expanding vaccine programmes to high-risk adults.

Associations between maternal complications during pregnancy and childhood asthma: a retrospective cohort study.

Background: Studies on the associations between maternal complications during pregnancy and childhood asthma are exclusively conducted in Western countries. The findings are mixed and may not be translated to other populations. We aimed to investigate the associations among the Chinese population and to determine whether the associations were mediated through pre-term birth, caesarean delivery, low birthweight and not breastfeeding in the first 6 months. Methods: We conducted a retrospective cohort study of 166 772 children in Guangzhou, China. Information on maternal gestational hypertension, gestational diabetes and gestational anaemia during pregnancy was extracted from medical records. Ever-diagnosis of asthma in children aged 6-12 years was obtained by questionnaire. Logistic regression models and mediation analyses were used to estimate the adjusted odds ratios (aORs) and 95% confidence intervals for childhood asthma. Results: Gestational hypertension, gestational diabetes and gestational anaemia during pregnancy were associated with an increased risk of ever-diagnosed childhood asthma: aOR 1.48 (95% CI 1.37-1.60), 1.71 (95% CI 1.65-1.78) and 1.34 (95% CI 1.26-1.45), respectively. A stronger association was observed for two or three gestational complications (aOR 2.02 (95% CI 1.93-2.16)) than one gestational complication (aOR 1.64 (95% CI 1.52-1.77)). The aOR for the three gestational complications was 1.35 (95% CI 1.26-1.45), 1.63 (95% CI 1.58-1.70) and 1.32 (95% CI 1.24-1.43), respectively, after controlling for the mediators, including pre-term birth, caesarean delivery, low birthweight and not breastfeeding in the first 6 months. Conclusions: Gestational hypertension, gestational diabetes and gestational anaemia were associated with childhood asthma, and the associations were partially explained by the mediation effects.

Exploration of the Value of Combined UA, IL-6, and fPSA/tPSA in the Diagnosis of Prostate Cancer.

Objective: To investigate the differences in uric acid (UA), interleukin-6 (IL-6), and free prostatic-specific antigen (fPSA)/total prostatic-specific antigen (tPSA) (F/T) between patients with and without prostate cancer (PCa) in order to discover the value of the three indicators in improving PCa diagnostic accuracy. Methods: Patients with pathologically diagnosed PCa (PCa group, n = 25), patients with other benign prostate diseases (benign group, n = 25), and men who underwent normal physical examination (control group, n = 25) at the First Affiliated Hospital of Guangzhou University of Chinese Medicine between October 2020 and January 2021 were included. The serum UA, IL-6, and F/T levels of participants in the three groups were measured, and the measured data were statistically analyzed. Results: There were statistically significant differences in IL-6 and F/T among the three groups (all P < 0.05), but there were no statistically significant differences in UA (P > 0.05). The area under the receiver operating characteristic (ROC) curve (AUC) for the three indicators was, respectively, as follows: PCa group-benign group 0.5416, 0.6776, and 0.6832; PCa group-control group 0.5432, 0.9536, and 0.9887; and benign group-control group 0.5000, 0.8784, and 0.9456. Logistic regression analysis indicated that IL-6 and F/T were independent predictors of PCa, with AUCs of 0.6776 and 0.6832, respectively, and a combined accuracy of 72.0%. Conclusion: These results suggest that IL-6 and F/T have a good detection effect for PCa screening. Compared with the detection of F/T alone, the combined detection of IL-6 and F/T can improve the diagnosis rate of PCa to a certain extent, providing effective guidance for the clinical diagnosis and treatment of patients. The value of UA needs to be further studied, and its feasibility in the diagnosis of PCa needs to be further explored.

The Asian Games, air pollution and birth outcomes in South China: An instrumental variable approach.

We estimate the effects of air-pollution exposure on low birthweight, birthweight, and prematurity risk in South China, for all expectant mothers and by maternal age group and child sex. We do so by exploiting exogenous improvement in air quality during the 2010 Guangzhou Asian Games, when strict regulations were mandated to assure better air quality. We use daily air-pollution levels collected from monitoring stations in Guangzhou, the Asian Games host city, and Shenzhen, a nearby control city, between 2009 and 2011. We first show that air quality during the Asian Games significantly improved in Guangzhou, relative to Shenzhen. Next, using birth-certificate data for both cities for 2009-2011 and using expected pregnancy overlap with the Asian Games as an instrumental variable, we study the effects of three pollutants (PM10, SO2, and NO2) on birth outcomes. Four main conclusions emerge: 1) air pollutants significantly reduce average birthweight and increase preterm risk; 2) for birthweight, late pregnancy is most sensitive to PM10 exposure, but there is not consistent evidence of a sensitive period for other pollutants and outcomes; 3) for birthweight, babies of mothers who are at least 35 years old show more vulnerability to all three air pollutants; and 4) male babies show more vulnerability than female babies to PM10 and SO2, but birthweights of female babies are more sensitive than those of male babies to NO2.

PM2.5 exposure increases the risk of preterm birth in pre-pregnancy impaired fasting glucose women: A cohort study in a Southern province of China.

Previous studies have indicated maternal exposure to particles with aerodynamic diameter <2.5 µm (PM2.5) is associated with preterm birth (PTB). However, no study has investigated this effect in pre-pregnancy impaired fasting glucose (IFG) women. This study aimed to differentiate the effects of maternal PM2.5 exposure on PTB between pre-pregnancy IFG and normoglycemia women, and to further identify the susceptible window. This cohort study was conducted between January 2014 and December 2017 in 21 Chinese cities. All the recruited women received pre-pregnancy fasting serum glucose (FSG) tests and were followed up for their delivery outcomes. The PM2.5 exposures were estimated by the daily air pollution concentrations of the nearby monitors. Women with FSG below 7.0 mmol/L were included in the analysis. We employed the Cox proportional hazards models to examine whether PM2.5 exposure was associated with PTB. 237957 women were included and 7055 (3.0%) of them were pre-pregnancy IFG. During the entire pregnancy, we found 24.1% (HR = 1.241; 95% CI: 1.069, 1.439), 61.8% (HR = 1.618; 95% CI: 1.311, 1.997) and 18.6% (HR = 1.186; 95% CI: 1.004, 1.402) of increases in risk for all PTB, early PTB (20-33 gestational weeks) and late PTB (34-36 gestational weeks) among the pre-pregnancy IFG women, and 15.9% (HR = 1.159; 95% CI: 1.127, 1.192), 33.9% (HR = 1.339; 95% CI: 1.255, 1.430) and 13.2% (HR = 1.132; 95% CI: 1.098, 1.168) of increases in risk for all PTB, early PTB and late PTB among the normoglycemia women, with each 10 µg/m3 increment of PM2.5 exposure, respectively. Furthermore, PM2.5 exposure had the strongest effect on all PTB during trimester 1 (0-12 gestational weeks) among the pre-pregnancy IFG women, compared with the less strong effect during trimester 1 among the normoglycemia women. In conclusion, pre-pregnancy IFG increases the risk of PTB attributed to PM2.5, especially during trimester 1. Moreover, the effects of PM2.5 are greater on early PTB than late PTB for both pre-pregnancy IFG and normoglycemia women.

Maternal PM2.5 exposure associated with stillbirth: A large birth cohort study in seven Chinese cities.

BACKGROUND: Maternal exposure to fine particulate matter (PM2.5) has been associated with a few adverse birth outcomes. However, its effect on stillbirth remains unknown in China, especially the susceptible windows and potential modifiers. OBJECTIVE: This study aimed to evaluate the associations between maternal PM2.5 exposure and stillbirth in seven Chinese cities. METHODS: We used birth cohort data of 1,273,924 mother-and-birth pairs in seven cities in southern China between 2014 and 2017 to examine these associations. Pregnant women were recruited in the cohort at their first visit to a doctor for pregnancy, and stillbirths were recorded at the time of birth. Air pollution exposures were assessed through linking daily air pollutant concentrations from nearby monitoring stations to the mother's residential community. Cox regression models were applied to determine the associations between PM2.5 and stillbirth for different gestational periods. RESULTS: Among the participants, 3150 (2.47‰) were identified as stillbirth cases. The hazard ratio (HR) of stillbirths was 1.52 (95% CI: 1.42, 1.62) for each 10 µg/m3 increase in PM2.5 during the entire pregnancy after controlling for some important covariates. Relatively stronger associations were observed during the second trimester [adjusted HR = 1.67 (95% CI: 1.57, 1.77)] than trimesters 1 [HR = 1.44 (95% CI: 1.37, 1.52)] and trimester 3 [HR = 1.23 (95% CI: 1.16, 1.30)]. Stratified analyses also showed a stronger association among pregnant women without previous pregnancy and previous delivery experiences. CONCLUSION: The study indicates that maternal exposure to PM2.5, especially during the midpoint period of pregnancy, might increase the risk of stillbirths. Maternal previous pregnancy and delivery may modify this association.

Exosomal miR-486-5p derived from human placental microvascular endothelial cells regulates proliferation and invasion of trophoblasts via targeting IGF1.

Preeclampsia (PE) is a serious complication of pregnancy. Exosomes are known to be upregulated in PE. In this study, we sought to investigate the effect of miR-486-5p from human placental microvascular endothelial cells, on the function of trophoblast cells. To investigate the function of human placental microvascular endothelial cell (HPVEC)-derived exosomes on trophoblast cells, HPVECs were treated with hypoxia/reoxygenation (H/R). The separation efficiency of exosomes was determined by transmission electron microscopy, nanosight and Western blot. Cell Counting Kit-8, EdU staining, wound-healing, and transwell assay were performed to detect the effect of exosomally transferred miR-486-5p inhibitor on proliferation, migration and invasion of trophoblast cells. MiRDB and dual-luciferase report assay were used to find the target of miR-486-5p. Our data revealed that miR-486-5p was significantly upregulated in H/R-treated HPVEC-Exo, and miR-486-5p was enriched in HPVEC-Exo. miR-486-5p inhibitor carried by HPVEC-Exo significantly inhibited the proliferation, migration and invasion of trophoblast cells. Insulin-like growth factor 1 (IGF1) was found to be the target of miR-486-5p, and IGF1 overexpression notably reversed the effect of miR-486-5p inhibitor from HPVEC-Exo on trophoblast cell function. In summary, H/R-treated HPVEC-derived exosomally expressing miR-486-5p inhibitor significantly inhibited the proliferation, migration and invasion of trophoblast cells via downregulation of IGF1. The findings from the present study may be useful in the development of treatments for PE.

Prevalence of small for gestational age infants in 21 cities in China, 2014-2019.

Infants who are small for gestational age (SGA) are at increased risk of neonatal and infant death, non-communicable diseases and growth retardation. However, the epidemiological characteristics of SGA remain unclear. We aim to explore the prevalence of SGA and to examine its socioeconomic associations by using data from 21 cities. 10,515,494 single live birth records between 2014 and 2019 from the Guangdong Women and Children Health Information System were included in the study. Descriptive statistical methods were used to analyze the prevalence trend of SGA and its distribution. We also analyze the associations between the prevalence of SGA and per-capita GDP. The prevalence of SGA in Guangdong Province from the years 2014-2019 was 13.17%, 12.96%, 11.96%, 12.72%, 11.45%, 11.30% respectively, and the overall prevalence was 12.28%. The prevalence of term SGA infants in Guangdong Province was 12.50%, which was much higher than that of preterm SGA (7.71%). There was a significant negative correlation between the SGA prevalence and per-capita GDP in 21 cities of Guangdong Province. The level of economic development may affect the prevalence of SGA. The prevalence of SGA in full term infants is significantly higher than in premature infants, suggesting that most SGA infants may be born at a later gestational age.

Penalized Fieller's confidence interval for the ratio of bivariate normal means.

Constructing a confidence interval for the ratio of bivariate normal means is a classical problem in statistics. Several methods have been proposed in the literature. The Fieller method is known as an exact method, but can produce an unbounded confidence interval if the denominator of the ratio is not significantly deviated from 0; while the delta and some numeric methods are all bounded, they are only first-order correct. Motivated by a real-world problem, we propose the penalized Fieller method, which employs the same principle as the Fieller method, but adopts a penalized likelihood approach to estimate the denominator. The proposed method has a simple closed form, and can always produce a bounded confidence interval by selecting a suitable penalty parameter. Moreover, the new method is shown to be second-order correct under the bivariate normality assumption, that is, its coverage probability will converge to the nominal level faster than other bounded methods. Simulation results show that our proposed method generally outperforms the existing methods in terms of controlling the coverage probability and the confidence width and is particularly useful when the denominator does not have adequate power to reject being 0. Finally, we apply the proposed approach to the interval estimation of the median response dose in pharmacology studies to show its practical usefulness.

Proteomics analysis of potential serum biomarkers for insulin resistance in patients with polycystic ovary syndrome.

The aim of the present study was to identify potential serum biomarkers for insulin resistance (IR) in patients with polycystic ovary syndrome (PCOS) by comparing the differences in serum protein expression levels between PCOS patients with and without IR. PCOS patients aged from 18 to 35 years were recruited at Guangdong Women and Children's Hospital from January, 2013 to February, 2014. A total of 218 PCOS patients were enrolled and divided into the insulin resistance (PCOS­IR) and non­insulin resistance (PCOS­NIR) groups according to their homeostasis model assessment of insulin resistance. Two­dimensional difference gel electrophoresis (2D­DIGE) and matrix­assisted laser desorption/ionization time­of­flight mass spectrometry (MALDI­TOF­MS/MS) techniques were used to identify differences in protein expression levels between the PCOS­IR and PCOS­NIR groups. The present study demonstrated that the total cholesterol (TCH), triglycerides (TG), low­density lipoprotein (LDL), fasting plasma glucose (FPG), 3­h blood glucose (3hBG) and uric acid (UA) levels in the PCOS­IR group were higher than those in the PCOS­NIR group (P<0.05). Between the PCOS­IR and PCOS­NIR groups, a total of 20 differentially expressed protein spots were detected by 2D­DIGE. Among these, 4 proteins, namely afamin, serotransferrin, complement C3 and apolipoprotein C3 (APOC3), were also identified by MALDI­TOF­MS/MS. The alteration of APOC3 was further confirmed by western blot analysis and enzyme­linked immunosorbent assay (ELISA). The present study also confirmed that the expression level of APOC3 was positively associated with the homeostasis model assessment of insulin resistance (HOMA­IR). On the whole, the data indicate that APOC3 may be a potential diagnostic marker for PCOS­IR patients.

Effectiveness of resilience group counseling on mental health of junior high school students / 中国学校卫生

Objective@#This study amis to evaluate the effect of resilience group counseling based on Achieving Success Everyday(ASE) group counseling model on mental health promotion of junior high school students.@*Methods@#An experimental design of 2 (experimental group/control group)×3(pre-test/post-test/follow-up test) was adopted to conduct resilience group counseling for junior high school students in a school in southern Xinjiang (8 weeks, once a week, each activity lasts for 60-90 min), followed by a detailed analysis of intervention effect.@*Results@#After intervention, scores of resilience, goal focus, emotional control, family support, interpersonal assistance, core self-evaluation, coping styles and positive coping in intervention group increased significantly(t=8.93, 3.78, 6.62, 3.17, 6.13, 5.18, 4.01, 2.91, P<0.01). The scores of mental health and negative coping significantly decreased (t=-4.24, -3.01, P<0.01) and was lower than control group(t=-2.58, -3.11, P<0.05). The scores of resilience, goal focus, interpersonal assistance, core self-evaluation, coping styles and positive coping were significantly higher than those of the control group(t=3.88, 2.84, 3.18, 4.19, 3.68, 2.49, P<0.01). The results of the follow-up test showed that the scores of resilience and goal concentration, emotional control, positive cognition, family support, interpersonal assistance, core self-evaluation and positive coping were still significantly higher than those of the pretest(t=5.69, 3.50, 2.26, 2.80, 2.64, 4.13, 3.39, 2.13, P<0.05), and the scores of mental health were still significantly lower than the pretest(t=-4.62, P<0.01).@*Conclusion@#Mental resilience group counseling based on ASE model can effectively improve students’ mental health level, and at the same time, it shows positive effect on improving core self-evaluation and coping styles.

Migrant population is more vulnerable to the effect of air pollution on preterm birth: Results from a birth cohort study in seven Chinese cities.

BACKGROUND: Studies have reported that exposure to air pollution during pregnancy was associated with preterm birth (PTB). However, it remains unknown whether this association differs between local residents and migrants. OBJECTIVE: This study aimed to differentiate the associations between maternal air pollution exposure and PTB between local residents and migrants. METHODS: We established a retrospective birth cohort in seven Chinese cities in Pearl River Delta (PRD) region during 2015-2017. The mothers were included in the cohort at their first time of hospital visit for pregnancy, and the endpoint events were identified using the birth registry. The air pollution exposure was estimated based on the daily air pollution concentrations in the nearby air monitoring stations during different pregnancy periods. Cox proportional hazards models were utilized to estimate the associations between each air pollutant and PTB for different pregnancy periods. RESULTS: Our cohort included a total of 628,439 mother-and-live-birth pairs. Among them, 308,201 women were local residents, and 320,238 were migrants. We observed stronger effects of air pollutants among the migrants than the local residents. For the exposure during the entire pregnancy, the hazard ratio (HR) among the migrants and local residents were 1.56 (95% CI: 1.50, 1.63) and 0.98 (95% CI: 0.93, 1.02) for each 10 µg/m3 increase in PM2.5, 1.32 (95% CI: 1.27, 1.39) and 1.18 (95% CI: 1.12, 1.23) for each 10 ppb increase in O3, and 1.48 (95% CI: 1.40, 1.57) and 0.99 (95% CI: 0.93, 1.05) for each 10 µg/m3 increase in SO2, respectively. Similarly higher effects were observed among the migrants for the exposures in different trimesters of pregnancy. However, the effects of NO2 were comparable between the two groups. CONCLUSION: Our study suggests that maternal PM2.5, O3 and SO2 exposures might be important risk factors of preterm birth, particularly among the migrants. More specific protective and education measures should be considered for the migrant pregnant women.

The prevalence of deafness-associated mutations in neonates: A meta-analysis of clinical trials.

OBJECTIVE: The causative genes associated with autosomal recessive non-syndromic hearing loss (ARNSHL) have been identified, in order of prevalence are GJB2, SLC26A4, MYO15A, OTOF, CDH23, and TMC1. To evaluate the prevalence of deafness-associated mutations in neonates and the clinical value of screening, we performed a meta-analysis of clinical trials. METHODS: The main criteria used to select articles was that the studies were designed to detect deafness genetic mutations in Chinese's neonates, and the screening kits were designed to detect 9 or 20 sites in four deafness-causative genes. The combined effect of genetic screening was measured by the pooled prevalence of mutations with 95% confidence intervals (CIs). The Random Model was used to estimate the pooled prevalence of mutations. RESULTS: We included 18 studies (a total of 261766 neonates) from studies using 9-mutation screening kit, and 15 studies (a total of 131158 neonates) from studies using the 20-mutation screening kit to conduct meta-analysis. The Random Model was used to estimate the pooled prevalence of mutations due to large heterogeneity (9 sites: I2 = 89.1%, P = 0.0000; 20 sites: I2 = 97.3%, P = 0.0002). The pooled prevalence of mutations in 9 sites group was 0.043 (95%CI:0.039-0.047, Z = 21.49, P = 0.000)and 20 sites group was 0.047(95%CI:0.041-0.053, Z = 15.84, P = 0.000). CONCLUSIONS: The prevalence of deafness-associated mutations in neonates in China is 4.7%; Based on the current detection technology and deafness genetics knowledge, it may be more reasonable to offer 1494C > T and 1555A > G mutation screening to pregnant women. Decision makers should think about how to use the current deafness genetic screening to amplify the effectiveness of hearing screening.

Ambient PM2.5 and birth outcomes: Estimating the association and attributable risk using a birth cohort study in nine Chinese cities.

BACKGROUND: Previous studies have reported that maternal exposure to particles with aerodynamic diameter <2.5 µm (PM2.5) is associated with birth outcomes. However, a multicity birth cohort study has not been conducted in China, and the attributable fraction of adverse birth outcomes due to PM2.5 exposure remains unknown. METHODS: We examined associations in a birth cohort of 1,455,026 mother-and-live-birth pairs who were followed up from the first hospital visit for pregnancy until the birth of the baby during 2014-2017 in nine cites of the Pearl River Delta (PRD) region, China. The PM2.5 exposures were estimated based on the air pollution concentrations of the nearby monitors. Cox proportional hazards regressions were employed to examine the associations. RESULTS: We found 1% (HR = 1.01; 95% CI: 1.00, 1.02), 6% (HR = 1.06; 95% CI: 1.05, 1.07), and 7% (HR = 1.07; 95% CI: 1.06, 1.08) increases in risk of PTB and 20% (HR = 1.20; 95% CI: 1.18, 1.22), 18% (HR = 1.18; 95% CI: 1.15, 1.20), and 20% (HR = 1.20; 95% CI: 1.17, 1.23) increases in risk of LBW, with each 10 µg/m3 increase in PM2.5 from trimester 1 to trimester 3, respectively. For PTB, highest HRs were observed during trimester 3, as for LBW, stronger effect were observed during trimester 1 and trimester 3. We further estimated that 7.84% (95% CI: 6.21%, 9.50%) of PTB and 14.85% (95% CI: 13.00%, 16.61%) of the LBW cases could be attributable to PM2.5 exposure during the third trimester. CONCLUSION: The results indicate that maternal PM2.5 exposure is a risk factor for both LBW and PTB, and responsible for considerable burdens of PTB and LBW in the Pearl River Delta region.

Effect of the 2008 cold spell on preterm births in two subtropical cities of Guangdong Province, Southern China.

BACKGROUND: A few studies have reported that low temperatures were associated with an increased risk of preterm birth. However, the effect of extreme weather events, such as cold spell, on preterm birth has not been studied in China. OBJECTIVE: This study was conducted to evaluate the impact of the 2008 cold spell on preterm birth in two subtropical cities of Guangdong Province. METHODS: Data of daily preterm birth, air pollution and meteorological variables from 2006 to 2010 were collected in Dongguan and Shenzhen. A Poisson regression with a distributed lag nonlinear model was used to investigate the association between the 2008 cold spell and daily rate of preterm birth for each city. RESULTS: During the 2008 cold spell, total vaginal preterm births were increased by 22.44% and 21.25% in Dongguan and Shenzhen, respectively. The effect of the cold spell on preterm births lasted for more than 1 week, the lag0-6 days cumulative relative risk (RR) is 1.32 (95% CI: 1.10-1.58) and 1.40 (95% CI: 1.18-1.68) in Dongguan and Shenzhen, respectively. The effects were found to be more pronounced for the pregnant women with 34-36 gestation weeks, maternal age < 35 years group. CONCLUSION: This study demonstrates that cold spell could increase the risk of preterm births in Dongguan and Shenzhen, and the effect lasts for more than 1 week. Specific measures should be considered to protect the pregnant women, especially the vulnerable subgroups.

Temporal trends of preterm birth in Shenzhen, China: a retrospective study.

BACKGROUND: Preterm birth is the leading cause of child mortality under 5 years of age. Temporal trends in preterm birth rates are highly heterogeneous among countries and little information exists for China. To address this data gap, we investigated annual changes in preterm birth incidence rate and explored potential determinants of these changes in Shenzhen, China. METHODS: A total of 1.4 million live births, during 2003-2012, were included from the Shenzhen birth registry. Negative-binominal regression models were used to estimate the annual percent changes in incidence. To identify the potential determinants behind temporal trends, we estimated the contribution of each changing risk factor to changes in rate by calculating the difference in population-attributable risk fraction. RESULTS: Annual preterm birth incidence rates increased by 0.94% (95% CI 0.30%, 1.58%) overall, 3.60% (95% CI 2.73%, 4.48%) for medically induced, and 3.13% (95% CI 1.01%, 5.31%) for preterm premature rupture of membranes, but decreased by 2.34% (95% CI 1.62%, 3.06%) for spontaneous preterm labor. Higher maternal educational attainment (0.20 rate increase), lower proportion of inadequate prenatal care (0.15 rate reduction), more multipara (0.08 rate reduction), decreased proportion of preeclampsia or eclampsia (0.05 rate reduction), and larger proportion of young and older pregnant women (0.04 rate increase) were significant contributors to the overall change over time. Contributions of changing risk factors were different between preterm birth subtypes. CONCLUSIONS: Preterm birth rate in Shenzhen, China increased overall during 2003-2012, although trends varied across three preterm birth subtypes. The rising rates were associated with changes in maternal education and age.

A systematic study on the prevention and treatment of retinopathy of prematurity in China.

BACKGROUND: To identify the prevention situation, the main factors influencing prevention effects and to develop control measures over retinopathy of prematurity in China. METHODS: Using stratified random sampling method, we randomly selected 23 provincial and ministerial hospitals (8 in Guangdong province, 5 in Hunan province and 10 in Shaanxi province), 81 municipal hospitals (38 in Guangdong province, 19 in Hunan province and 24 in Shaanxi province), 180 district and county hospitals (76 in Guangdong province, 57 in Hunan province and 47 in Shaanxi province) in China. A total of 284 hospitals were enrolled in the study, with questionnaires distributed investigating the status and constrain factors of ROP presentation. Significant outcomes were analyzed thereafter by SPSS 19.0. RESULTS: The screening rate of ROP in medical institutions from eastern, central and western China were 84.6%, 35.0% and 56.7%, respectively. The screening rate of tertiary and secondary medical institutions were 84.6% and 25.7% in the eastern, 35.0% and 4.9% in the central, 56.7% and 5.9% in the western region. Screening was carried out better in the tertiary than that in the secondary and primary institutions. Treatment for ROP was available in 15.7% of all the tertiary hospitals surveyed. Lack of professionals, equipments and technologies were considered to be major restrain factors for screening. CONCLUSIONS: The ROP screening and treatment status have demonstrated significant regional diversity due to uneven distribution of medical resources in China. Developed areas had established intraregional cooperation models, whereas less-developed areas should consider set up a large-scale, three-level ROP prevention network. It is of paramount importance that education and training towards ophthalmologists should be vigorously strengthened. It is strongly recommended that implement ROP telemedicine and integrated ROP prevention and management platforms through the Internet should be established.