Background Air pollution exposure has a significant impact on maternal and child health. However, the research on the association between ambient ozone (O₃) exposure during pregnancy and the risk of premature birth in newborns is limited, and the conclusions are inconsistent. Objective To investigate the association of ambient O₃ exposure during pregnancy with the risk of preterm birth in Guangdong Province. Methods Data of pregnant women in Guangzhou from 2013 to 2019 and Foshan from 2018 to 2023 were collected, and O₃ concentrations during different trimesters were assessed according to maternal residential addresses. Bilinear interpolation was used to evaluate the concentrations of air pollution. A cohort study design was adopted in our study. Restricted cubic spline curves were used to evaluate the exposure-response relationship between O₃ exposure and preterm birth risk and explore potential exposure threshold of O₃. Logistic regression models were used to evaluate the association of O₃ exposure with preterm birth. Results A total of 702 924 pregnant women were included in this study, of whom 43 051 (6.12%) were preterm. The average O₃ exposure concentrations of pregnant women during the first, second, third, and whole trimesters were 95.51, 97.51, 100.60, and 97.87 μg·m⁻³, respectively. We observed J-shaped associations between O₃ exposure and preterm birth risk during the second, third, and whole trimesters of pregnancy using restricted cubic spline curves. This study found that there were threshold concentrations between O₃ exposure and preterm birth risk during different gestational periods, and the threshold concentrations in the first, second, third, and whole trimesters were 112.32, 99.83, 111.74, and 112.46 μg·m⁻³, respectively. During the second, third, and whole trimesters of pregnancy, after adjusting for maternal age, baby sex, pre-pregnancy body mass index, mode of delivery, baby birth weight, gestational diabetes, and gestational hypertension, the odds ratios (OR) of preterm birth were 1.02 (95%CI: 1.01, 1.04), 1.02 (95%CI: 1.00, 1.03), and 1.17 (95%CI: 1.13, 1.21) for each 10 μg·m⁻³ increase in O₃ concentration above the O₃ threshold. No significant association was found between O₃ exposure and the risk of preterm birth during the first trimester. Conclusion There is a nonlinear association between the risk of preterm birth and O₃ exposure during pregnancy, and higher concentrations of O₃ exposure during pregnancy are associated with the risk of preterm birth. Above the O₃ threshold concentration during pregnancy, especially during the second, third, and whole trimesters, the risk of preterm birth elevates with the increase of O₃ exposure concentrations.

To guide transfusion practice in critically ill children who often need plasma and platelet transfusions, the Transfusion and Anemia Expertise Initiative-Control/Avoidance of Bleeding (TAXI-CAB) developed Recommendations and Expert Consensus for Plasma and Platelet Transfusion Practice in Critically Ill Children. This guideline addresses 53 recommendations related to plasma and platelet transfusion in critically ill children with 8 kinds of diseases, laboratory testing, selection/treatment of plasma and platelet components, and research priorities. This paper introduces the specific methods and results of the recommendation formation of the guideline.

Objective To analyze the clinical characteristics of patients with gastrointestinal bleeding after renal transplantation and summarize the diagnostic and therapeutic experience. Methods Clinical data of 16 patients with gastrointestinal bleeding after renal transplantation admitted to the Third Affiliated Hospital of Sun Yat-sen University from January 2015 to January 2025 were collected, including clinical manifestations, laboratory tests and auxiliary examination results such as gastroscopy and colonoscopy. The bleeding sites, causes, treatment plans and outcomes of the patients were analyzed, and relevant literature was reviewed. Results Among the 16 patients with gastrointestinal bleeding, 12 had upper gastrointestinal bleeding (3 with esophageal bleeding, 7 with gastric bleeding and 2 with duodenal bleeding) and 4 had lower gastrointestinal bleeding (2 with ileal bleeding and 2 with anal bleeding). Among the 16 patients, the 4 with lower gastrointestinal bleeding all presented with hematochezia. Of the 12 with upper gastrointestinal bleeding, 2 patients only had positive fecal occult blood and decreased hemoglobin levels without hematemesis or melena, 9 patients had melena and 1 patient had hematemesis. The hemoglobin levels of the 16 patients were (71±18) g/L. One patient had symptoms of shock, 9 had symptoms of anemia such as dizziness, fatigue and chest tightness, and 6 had good general conditions. Among the 16 patients, 10 had mild gastrointestinal bleeding and stable general conditions, which were curable by drugs. Two patients with peptic ulcers and exposed vessels on gastroscopy were treated with hemostasis by titanium clips. One patient with gastroesophageal tear was treated with hemostasis by titanium clips. One patient with esophageal variceal rupture bleeding was treated with endoscopic variceal ligation. One patient with hemorrhoidal bleeding underwent selective annual resection of the superior hemorrhoidal mucosa with stapled hemorrhoidopexy. One patient with active ileal bleeding on emergency enhanced abdominal CT was treated with endovascular embolization of the mesenteric artery. One patient was discharged automatically due to coma caused by extensive cerebral infarction, and the remaining patients were all cured and discharged with good prognosis. Conclusions Gastrointestinal bleeding after renal transplantation has diverse clinical manifestations, varying severity and many causes. Early diagnosis and treatment should be actively carried out. In addition to drug therapy, endoscopic, interventional or surgical treatment may be used when necessary to improve the diagnostic and therapeutic effects and minimize the functional damage of gastrointestinal bleeding to the transplant kidney.

Objective: To understand the current status, international cooperation, research hotspots, and development trends of nutritional studies on patients with head and neck cancer from 2014 to 2024, and to predict future research trends. Methods: The Web of Science Core Collection database was searched to retrieve nutritional studies on patients with head and neck cancer from January 2014 to March 2024. The type of studies were “articles,” the language was English, CiteSpace 6.1 R6 software was used to conduct the bibliometric analysis, and the results were visualized to form a scientific knowledge map. Results: A total of 1 528 documents were retrieved, with a linear increase in the number of annual publications. The country with the highest number of publications was the United States, and the institution with the highest number of publications was the University of Queensland, with closer collaboration between authors and institutions. The most frequently cited publication was a set of nutrition guidelines, and the highest-impact articles were mainly concerned with performing percutaneous endoscopic gastrostomy. Keyword analysis showed that quality of life, radiotherapy, and weight loss were the keywords of highest interest. The keyword cluster analysis resulted in 17 clusters, which were divided into five main categories: head and neck cancer, treatment, outcome results, intervention modalities, and rehabilitation. Body composition, enteral nutrition, and accelerated postoperative rehabilitation were persistent research hotspots. Keyword highlighting revealed that “enhanced recovery after surgery” has been the focus of research in the last two years, with “index” and “model” emerging as theme words. Conclusion The number of publications in the literature related to nutrition for patients with head and neck cancer has increased annually over the past 10 years. The research hotspots mainly focus on the quality of life and weight loss during radiotherapy, the content and application prospect of body composition assessment, different modes of nutritional support interventions and enteral nutritional tube feeding routes, and perioperative nutritional management in enhanced recovery after surgery. The potential clinical value of preoperative nutritional intervention under the concept of enhanced recovery and the construction of new types of nutritional index are the trends of future research.

Objective To understand the situation of dental cone beam computed tomography (CBCT) quality control testing phantoms in radiation health technical service institutions in Guangdong province, analyze the differences among different phantoms, and provide a reference for dental CBCT quality control testing. Methods The testing phantoms of 49 radiation health technical service institutions were used as the research objects. The designated CBCT equipment was used for scanning and imaging. The Z-score method was used to evaluate the high-contrast resolution, low-contrast resolution, and distance measurement deviation of each phantom. Results The satisfaction rates of various items for the phantoms in 49 institutions ranged from 85.7% to 100%. The distance measurement deviations of four institutions were “suspicious”, and the high-contrast resolution of four institutions and the distance measurement deviation of one institution were “unsatisfactory”. Conclusion The overall performance of dental CBCT quality control testing phantoms in radiological health technical service institutions in Guangdong province is satisfactory. However, there are still some phantoms with poor results in items such as distance measurement deviation and high-contrast resolution. The structural design, material selection, and manufacturing process of the phantom may all affect the results of quality control testing. Therefore, appropriate phantoms, optimized exposure conditions, and suitable reconstruction algorithms should be used in CBCT quality control testing to ensure accurate and reliable measurements.

Objective: To explore the association between negative life events and smartphone addiction among middle school students, so as to provide theoretical support and practical guidance for prevention and intervention of smartphone addiction among middle school students. Methods: Using cluster sampling, 8 890 students were selected to survey from 27 junior high schools and 3 senior high schools in a district of Shenzhen in 2022 (baseline) and 2023 (followup). Data were collected through selfresigned questionnaires on basic information, the Smartphone Addiction Scale-Short Version, and the Adolescent Selfrating Life Events Checklist. Mixedeffects models were employed to analyze the association. Results: Compared to 2022, the punishment scores of middle school students in 2023 [1.00 (0.00, 6.00) and 1.00 (0.00, 6.00)] decreased (Z=4.27), while the scores of interpersonal stress, learning stress and adaptation [4.00(0.00, 8.00), 4.00(0.00, 8.00); 4.00(1.00, 8.00), 5.00(2.00, 9.00); 2.00 (0.00, 6.00), 3.00 (0.00, 7.00)] increased (Z=-3.04, -8.36, -6.80) (P<0.01). Mixedeffects models revealed a positive doseresponse relationship between negative life events and smartphone addiction (OR=1.08-1.17, P<0.01). Stepwise regression showed independent positive effects of interpersonal stress (OR=1.05), academic stress (OR=1.03), and adaptation stress (OR=1.11) on smartphone addiction (P<0.01). Subgroup analysis of nonaddicted students in 2022 confirmed persistent associations for academic stress (OR=1.03) and adaptation (OR=1.07) (P<0.01). Conclusion Negative life events exhibit a positive doseresponse relationship with smartphone addiction, particularly interpersonal stress, academic stress, and adaptationrelated events.

Objective: To explore the longitudinal association between only-child status and smartphone addiction among middle school students, so as to provide a basis for establishing family intervention measures for smartphone addiction in middle school students. Methods: In October 2022 and October 2023, a preliminary survey and follow-up were conducted among 8 759 middle and high school students from 30 schools in a district of Shenzhen. A self-designed questionnaire was used to determine whether the students were the only-child, and the Chinese Version of the Smartphone Addiction Scale-Short Version (C-SAS-SV) was utilized to assess the students smartphone addiction status. A multilevel mixed-effects model and subgroup analysis were applied to examine the association between only-child status and smartphone addiction among middle school students. Results: During 2022 to 2023, the prevalence of smartphone addiction in the cohort of middle school students increased from 24.1% to 25.2%. Compared with only-child, non-only child were more likely to be addicted to smartphones (adjusted model: OR =1.2, 95% CI =1.1-1.4) and also scored higher on smartphone addiction (adjusted model: β =0.9, 95% CI =0.2-1.5)( P <0.05). Subgroup analysis further revealed that compared to baseline, non-only child demonstrated an increased prevalence of smartphone addiction (adjusted model: OR = 1.2 , 95% CI =1.0-1.5) and higher addiction scores (adjusted model: β =0.8, 95% CI =0.2-1.5) after one year( P <0.05). Conclusions Non-only child face higher risk of smartphone addiction. Under the current population policy, it is crucial to address smartphone addiction among middle school students who is not only child.

Objective: To explore the potential causal association between adolescent compulsive behaviour and smartphone addiction based on longitudinal data, so as to provide reference for the establishment of adolescent smartphone addiction interventions. Methods: A preliminary survey and follow-up were conducted on 8 907 middle and high school students in a district of Shenzhen in 2022 and 2023, respectively. Compulsive behaviours were measured by using the Mental Health Inventory for Middle School Students-60 Items (MMHI-60), smartphone addiction was assessed by using the Smartphone Addiction Scale-Short Version ( SAS- SV), and the associations between compulsive behaviours and smartphone addiction were analysed by using multilevel mixed-effects models and subgroup analyses. Results: Smartphone addiction detection rates among middle school students were significantly associated with genders, father s education level, mother s education level, study load subgroups, and whether or not they were single-parent families, and there were statistical differences ( χ 2=17.21-175.34, P <0.05). Students with compulsive behaviours were 2.98 times more likely to develop smartphone addiction than those without compulsive behaviours ( OR=2.98, 95%CI=2.77-3.22, P <0.05). Subgroup analysis of middle school students without smartphone addiction in the first year found that compulsive behaviours significantly predicted smartphone addiction ( OR= 1.76 , 95%CI=1.54-2.01, P <0.05). Conclusion There is a potential causal association between obsessive-compulsive behaviours and smartphone addiction in middle school students, and obsessive-compulsive behaviours in middle school students could significantly predicted the occurrence of smartphone addiction.

Background: The association of changes in metabolic syndrome (MetS) with cognitive function remains unclear. We explored this association using prospective and Mendelian randomization (MR) studies. Methods: MetS components including high-density lipoprotein cholesterol (HDL-C), systolic blood pressure (SBP), waist circumference (WC), fasting plasma glucose (FPG), and triglycerides were measured at baseline and two follow-ups, constructing a MetS index. Immediate, delayed memory recall, and cognitive function along with its dimensions were assessed by immediate 10- word recall test (IWRT) and delayed 10-word recall test (DWRT), and mini-mental state examination (MMSE), respectively, at baseline and follow-ups. Linear mixed-effect model was used. Additionally, the genome-wide association study (GWAS) of MetS was conducted and one-sample MR was performed to assess the causality between MetS and cognitive function. Results: Elevated MetS index was associated with decreasing annual change rates (decrease) in DWRT and MMSE scores, and with decreases in attention, calculation and recall dimensions. HDL-C was positively associated with an increase in DWRT scores, while SBP and FPG were negatively associated. HDL-C showed a positive association, whereas WC was negatively associated with increases in MMSE scores, including attention, calculation and recall dimensions. Interaction analysis indicated that the association of MetS index on cognitive decline was predominantly observed in low family income group. The GWAS of MetS identified some genetic variants. MR results showed a non-significant causality between MetS and decrease in DWRT, IWRT, nor MMSE scores. Conclusion Our study indicated a significant association of MetS and its components with declines in memory and cognitive function, especially in delayed memory recall.