Objective: To analyze the impact of maternal metal exposure during early pregnancy on the physical development of offspring at 1 and 3 years of age, so as to provide scientific evidence for reducing the adverse effects of heavy metals on their health. Methods: From 2024 to 2018, a total of 1 588 mother child pairs from the Jiangsu Birth Cohort (JBC) were included in this study. Multiple linear regression models, generalized estimating equations (GEE), and weighted quantile sum (WQS) regression models were used to assess the associations between 24 urinary metal mass concentrations (adjusted for specific gravity, SG) during early pregnancy and offspring growth outcomes, including length/height for age Z score(HAZ), weight for age Z score(WAZ), weight for length/height Z score(WHZ), and head circumference for age Z score(HCAZ) at 1 and 3 years of age. Results: After adjusting for confounders, GEE analysis revealed that each natural log unit increase in maternal urinary concentrations of vanadium, tin, cerium, lead, and uranium during early pregnancy was associated with an average reduction in HCAZ by 14.29%, 4.82%, 2.62 %, 5.04 %, and 8.33%, respectively, at 1 and 3 years of age (FDR- P <0.05). Multiple linear regression analysis revealed that increased urinary vanadium concentration was associated with reduced HAZ at 1 year of age, while increased urinary concentrations of vanadium, chromium, tin, antimony, and uranium were associated with reduced HCAZ at 1 year of age (FDR- P <0.05). In the WQS regression model, each unit increase in the WQS index was associated with a 22.64% reduction in HCAZ at 1 year of age, with tin (22.2%) contributing the highest weight, followed by uranium (16.2%), lead (11.5%), vanadium (10.0%), arsenic (6.5%), and chromium (5.0%). Conclusions Prenatal exposure to specific metals and their mixtures may significantly impact the physical development of offspring at 1 and 3 years of age, particularly head circumference. These findings highlight the need to enhance monitoring of maternal metal exposure during early pregnancy to reduce the potential health risks posed by environmental metal pollution to infants and young children.

Objective:To compare the efficacy of Ilizarov ring external fixation and unilateral rail external fixation in the treatment of infected bone defects following surgery for tibial fractures.Methods:A retrospective cohort study was conducted to analyze the clinical data of 50 patients with infected bone defects after surgery for tibial fractures, who were admitted to the 940th Hospital of the Joint Logistics Support Force of the PLA from August 2019 to November 2021, including 37 males and 13 females, aged 19-59 years [(42.2±8.8)years]. After debridement and osteotomy, 28 patients were treated with Ilizarov ring external fixation (Ilizarov group) and 22 with unilateral rail external fixation (unilateral fixation group). All the patients in the two groups had previously undergone internal fixation with plates or Kirschner wires for tibial fracture before bone transport. Bone transport started at one week for three stages after successful infection control and osteotomy and was conducted. The following parameters were compared between the two groups: frame-wearing time and healing index after bone transport, self-rating anxiety scale (SAS) grade at 6 months after bone transport, Paley score and Association for the Study and Application of the Method of Ilizarov (ASAMI) score at the last follow-up, Hospital for Special Surgery (HSS) knee score and Baird-Jackson ankle score on admission, after external fixator removal and at the last follow-up, and incidence of postoperative complications.Results:All the patients were followed up for 28-36 months [(32.5±1.6)months]. There were no significant differences in frame-wearing time or healing index between the two groups after bone transport ( P>0.05). At 6 months after bone transport, the SAS grade in the unilateral fixation group (13 patients with mild anxiety, 8 with moderate anxiety, and 1 with severe anxiety) was better than that in the Ilizarov group (6 patients with mild anxiety, 19 with moderate anxiety, 3 with severe anxiety) ( P<0.01). No significant differences were found in the Paley score or ASAMI score between the two groups at the last follow-up ( P>0.05). There were no significant differences in HSS knee score or Baird-Jackson ankle score between the two groups on admission, after external fixator removal or at the last follow-up ( P>0.05). No significant differences were observed in the incidence of pin tract infection, poor healing, infection in the bone elongation area, or re-fracture between the two groups ( P>0.05). The incidence of postoperative axial deviation was 0 in the Ilizarov group, lower than 18% in the unilateral fixation group (4/22) ( P<0.05). Conclusion:Although Ilizarov ring external fixation and unilateral rail external fixation demonstrate comparable efficacy in the treatment of infected bone defects after surgery for tibial fractures, the former provides superior mechanical stability and postoperative axial deviation correction, while the latter offers advantages in reducing psychological burden and enhancing treatment tolerance.

Objective:To compare the efficacy of Ilizarov ring external fixation and unilateral rail external fixation in the treatment of infected bone defects following surgery for tibial fractures.Methods:A retrospective cohort study was conducted to analyze the clinical data of 50 patients with infected bone defects after surgery for tibial fractures, who were admitted to the 940th Hospital of the Joint Logistics Support Force of the PLA from August 2019 to November 2021, including 37 males and 13 females, aged 19-59 years [(42.2±8.8)years]. After debridement and osteotomy, 28 patients were treated with Ilizarov ring external fixation (Ilizarov group) and 22 with unilateral rail external fixation (unilateral fixation group). All the patients in the two groups had previously undergone internal fixation with plates or Kirschner wires for tibial fracture before bone transport. Bone transport started at one week for three stages after successful infection control and osteotomy and was conducted. The following parameters were compared between the two groups: frame-wearing time and healing index after bone transport, self-rating anxiety scale (SAS) grade at 6 months after bone transport, Paley score and Association for the Study and Application of the Method of Ilizarov (ASAMI) score at the last follow-up, Hospital for Special Surgery (HSS) knee score and Baird-Jackson ankle score on admission, after external fixator removal and at the last follow-up, and incidence of postoperative complications.Results:All the patients were followed up for 28-36 months [(32.5±1.6)months]. There were no significant differences in frame-wearing time or healing index between the two groups after bone transport ( P>0.05). At 6 months after bone transport, the SAS grade in the unilateral fixation group (13 patients with mild anxiety, 8 with moderate anxiety, and 1 with severe anxiety) was better than that in the Ilizarov group (6 patients with mild anxiety, 19 with moderate anxiety, 3 with severe anxiety) ( P<0.01). No significant differences were found in the Paley score or ASAMI score between the two groups at the last follow-up ( P>0.05). There were no significant differences in HSS knee score or Baird-Jackson ankle score between the two groups on admission, after external fixator removal or at the last follow-up ( P>0.05). No significant differences were observed in the incidence of pin tract infection, poor healing, infection in the bone elongation area, or re-fracture between the two groups ( P>0.05). The incidence of postoperative axial deviation was 0 in the Ilizarov group, lower than 18% in the unilateral fixation group (4/22) ( P<0.05). Conclusion:Although Ilizarov ring external fixation and unilateral rail external fixation demonstrate comparable efficacy in the treatment of infected bone defects after surgery for tibial fractures, the former provides superior mechanical stability and postoperative axial deviation correction, while the latter offers advantages in reducing psychological burden and enhancing treatment tolerance.

Abstract In recent years, the prevention and treatment of eye diseases in children has become one of the worldwide recognized public health issues. Both genetic and environmental factors can influence the development of offspring visual systems, leading to abnormal vision acuity such as refractive errors, strabismus, and nystagmus. With the aim of elucidating the influencing factors and mechanisms of early life adverse exposures on offspring vision outcomes, the article summarizes the research on exposure in early life and visual acuity in offspring from different perspectives, including tobacco exposure during pregnancy, exposure to microelements, gestational diabetes, gestational hypertension, and drug abuse during pregnancy, so as to provide scientific evidence for the development of more effective strategies to prevent and control eye diseases in children and adolescents.

Objective:To investigate the association of exposure to PM 2.5 and its constituents during pregnancy and fetal growth and to further identify critical windows of exposure for fetal growth. Methods:We included 4 089 mother-child pairs from the Jiangsu Birth Cohort Study between January 2016 and October 2019. Data of general characteristics, clinical information, daily average PM 2.5 exposure, and its constituents during pregnancy were collected. Fetal growth parameters, including head circumference (HC), abdominal circumference (AC), and femur length (FL), were measured by ultrasound after 20 weeks of gestation, and then estimated fetal weight (EFW) was calculated. Generalized linear mixed models were adopted to examine the associations of prenatal exposure to PM 2.5 and its constituents with fetal growth. Distributed lag nonlinear models were used to identify critical exposure windows for each outcome. Results:A 10 μg/m 3 increase in PM 2.5 exposure during pregnancy was associated with a decrease of 0.025 ( β=-0.025, 95% CI: -0.048- -0.001) in HC Z-score, 0.026 ( β=-0.026, 95% CI: -0.049- -0.003) in AC Z-score, and 0.028 ( β=-0.028, 95% CI:-0.052--0.004) in EFW Z-score, along with an increased risk of 8.5% ( RR=1.085, 95% CI: 1.010-1.165) and 13.5% ( RR=1.135, 95% CI: 1.016-1.268) for undergrowth of HC and EFW, respectively. Regarding PM 2.5 constituents, prenatal exposure to black carbon, organic matter, nitrate, sulfate (SO 42-) and ammonium consistently correlated with decreased HC Z-score. SO 42- exposure was also associated with decreased FL Z-scores. In addition, we found that gestational weeks 2-5 were critical windows for HC, weeks 4-13 and 19-40 for AC, weeks 4-13 and 23-37 for FL, and weeks 4-12 and 20-40 for EFW. Conclusions:Our findings demonstrated that exposure to PM 2.5 and its constituents during pregnancy could adversely affect fetal growth and the critical windows for different fetal growth parameters are not completely consistent.

Population based health data collection and analysis are important in epidemiological research. In recent years, with the rapid development of big data, Internet and cloud computing, artificial intelligence has gradually attracted attention of epidemiological researchers. More and more researchers are trying to use artificial intelligence algorithms for genome sequencing and medical image data mining, and for disease diagnosis, risk prediction and others. In recent years, machine learning, a branch of artificial intelligence, has been widely used in epidemiological research. This paper summarizes the key fields and progress in the application of machine learning in epidemiology, reviews the development history of machine learning, analyzes the classic cases and current challenges in its application in epidemiological research, and introduces the current application scenarios and future development trends of machine learning and artificial intelligence algorithms for the better exploration of the epidemiological research value of massive medical health data in China.

Birth cohort study has played an important role in exploring the effect of exposures in early life on long-term health of offspring. With the rapid increase of problems of reproductive health among couples at childbearing age, the assisted reproductive technology (ART) has been widely introduced into clinical practice. However, the influences of ART on long-term outcomes of mothers and infants have not been fully studied. In 2016, the China National Birth Cohort (CNBC), a multicenter prospective cohort study recruiting families with ART-conceived pregnancies and spontaneous-conceived pregnancies simultaneously was launched officially. By June 30, 2021, a total of 72 000 families covering 39 000 ART- pregnancies and 33 000 spontaneous- pregnancies have been recruited in the study, their information and biological samples were collected at multiple time points, i.e., before assisted reproductive treatment, in embryo transfer period, in first, second and third trimesters, at delivery, and at 42 days after birth, 6 months, 1 year old and 3 years old. The main objectives of this study are to assess the development and health of offspring born after ART treatment, identify risk factors associated with adverse birth outcomes and childhood diseases and provide scientific basis for the strategies to improve the quality of new birth population. This paper will give a brief introduction to the establishment and research progress of CNBC.

With the rapid changes in lifestyle, natural and social environment, the reproductive health status of couples in childbearing age continues to decline, and long-term outcomes of the rapidly increasing offspring conceived by assisted reproductive technology (ART) needs to be evaluated urgently. Therefore, the focus of research now needs to be extended from death and severe diseases to full life cycle and full disease spectrum. In order to meet the demand for such research, we launched the China National Birth Cohort (CNBC) study, an ongoing prospective and longitudinal study aiming to recruit 30 000 families underwent ART and 30 000 families with spontaneous pregnancies. Long-term follow-up programs will be conducted for both spouses and their offspring. Data of couples and their offspring, such as environmental exposure, reproductive history, psychological and behavioral status, will be collected during follow-up. Peripheral blood, urine, umbilical blood, follicular fluid, semen were also collected at different follow-up nodes. Based on high-quality data and biological samples, CNBC will play an extremely important supporting role and have a far-reaching impact on maternal and children's health care and reproductive health in China. This paper is exactly a brief introduction to the construction and basic design of CNBC.

Birth cohort is an effective method to explore the relationship between various prepregnant and pregnant exposures and the health of fetuses, infants and young children. It is a long construction period to build a birth cohort and the quality of research may be affected by many factors. This paper reviews the quality assurance and quality control measures in the process of China National Birth Cohort (CNBC), and summarizes the construction experience. We aim to provide experience for related cohort studies, which could improve the quality of cohort studies through removing the impact of related factors. CNBC adopted a series of measures to ensure the quality of research in the top-level design of quality assurance, including screening research center, developing member management system, formulating standard operating procedures and training staff by it. In terms of quality control, it includes real-time, timely and timing quality control for the process of data generation, full-cycle quality control for biological sample collection, processing, storage and comprehensive three-dimensional quality control for staff training, supervision and quantitative assessment.

Objective:To explore the effects of environmental, genetic factors as well as the interactions in early life on the short-term and long-term health of offspring and to systematically evaluate the pregnancy outcomes and health of offspring after birth between families with assisted reproductive technology (ART) conception and families with spontaneous conception.Methods:The China National Birth Cohort (CNBC), a multicenter prospective birth cohort study, includes both families with ART conception and families with spontaneous conception. Since 2016, CNBC has recruited families from 24 hospitals located in 12 provinces, municipalities and autonomous regions throughout China. Information and biospecimens were collected before ART treatment, embryo transfer, at early, second, third trimester and delivery, and at 42 days, 6, 12 and 36 months after birth.Results:By June 2020, CNBC had included 27 044 families with ART conception and 29 589 families with spontaneous conception. The majority of the participants are urban residents. Among the families with ART conception, 65.5% of the men and 63.7% of the women had college degrees or higher. The mean age distribution of men and women was (33.83±5.52) and (32.38±4.67) years. 83.2% of women were primiparas, and the prevalence rates of current regular smokers and current alcohol drinkers were 0.8% and 2.1% in women. Among the families with spontaneous conception, 81.5% of the men and 86.5% of the women had college degrees or higher. The mean age distribution of men and women was (32.06±5.09) and (30.40±4.27) years. 67.2% of women were primiparas, and the prevalence rates of current regular smokers and current alcohol drinkers were 0.1% and 2.2% in women. The baseline characteristics were different between the families with ART conception and spontaneous conception in different regions.Conclusion:CNBC provides a powerful and rich resource in studying the impact of genetic, environmental factors and interactions in early life and ART treatment on the health of offspring after birth.