Objective: To explore the correlation between traditional Chinese medicine (TCM) constitution and depressive symptom among school aged children and adolescents, so as to provide evidences for informing constitution based regulation and prevention of depressive symptom. Methods: From June to December 2024, a total of 4 729 students aged 6-14 were recruited by cluster random sampling from 10 primary schools in Baoding (Hebei Province), Heze and Liaocheng (Shandong Province). General information, TCM constitution and depressive symptom were collected. Restricted cubic spline (RCS) models were used to analyze related factors and threshold effects of depressive symptom. Binary Logistic regression was applied to examine the association between depressive symptom and TCM constitution, with subgroup analyses conducted. Results: The detection rate of depressive symptom among the included children and adolescents was 25.82%. RCS analyses indicated non linear associations between depressive symptom and age (inflection point at 10 years old), bedtime (inflection point at 22:00), and wake up time (inflection point at 6:30 ) (all P non linearity <0.01). Linear associations were observed with body mass index (BMI) and sleep duration (all P non linearity > 0.05 ). After adjusting for covariates such as age, BMI and sleep status, binary Logistic regression analyses showed that Yin deficient constitution ( OR =1.26, 95% CI =1.09-1.45) and Phlegm-dampness constitution ( OR =1.42, 95% CI =1.11-1.82) were significantly associated with depressive symptom among children and adolescents (all P <0.05). Conclusions Depressive symptom among school aged children and adolescents is primarily associated with Yin deficiency and Phlegm dampness constitutions in TCM constitution. Active attention should be paid to susceptible TCM constitution among children and adolescents. Targeted health guidance and interventions should be implemented to improve TCM constitution health status for preventing the occurrence of depressive symptom.

Objective:This study aims to explore the predictive value of the ratio of caliceal pelvic height to infundibular length（CPH/IL）for the stone-free rate（SFR）in the treatment of lower calyx stones using flexible ureteroscopic lithotripsy（FURL）combined with a distally bendable negative pressure suction sheath.Methods:A retrospective analysis was conducted on the clinical data and anatomical parameters of 312 patients with lower calyx stones or combined lower calyx stones admitted to the Third Xiangya Hospital of Central South University from September 2022 to December 2023，all of whom were treated with FURL combined with a distally bendable negative pressure suction sheath. Stone clearance was defined as no residual stones or residual stones with a diameter of ≤3 mm without any symptoms. Patients were divided into the clearance group（265 cases，84.90%）and the non-clearance group（47 cases，15.10%）. There were no significant differences in gender（male/female：173/92 cases vs. 29/18 cases），age［（44.69 ± 13.14）years vs.（42.60 ± 10.93）years］，degree of hydronephrosis（no hydronephrosis/mild hydronephrosis/moderate to severe hydronephrosis：122/85/58 cases vs. 21/12/14 cases），side of lower calyx stones（left/right：157/108 cases vs. 31/16 cases），maximum diameter of stones（MDS）［（19.23 ± 6.41）mm vs.（17.77 ± 6.18）mm］，and CT value of stones［（993.46 ± 249.12）Hu vs.（1013.43 ± 300.90）Hu］between the two groups（ P > 0.05），indicating comparability between groups. There was no significant difference in the distance from the midpoint of the lower lip of the renal pelvis to the ureter at the lowest plane of the lower calyx（K-A line）between the clearance and non-clearance groups［（26.16 ± 5.18）mm vs.（25.70 ± 8.66）mm， P > 0.05］. However，significant differences were observed in the infundibulopelvic angle（IPA）［（53.97 ± 15.72）° vs.（37.43 ± 15.39）°］，infundibular length（IL）［（27.26 ± 5.11）mm vs.（33.04 ± 7.38）mm］，infundibular width（IW）［（8.27 ± 2.82）mm vs.（7.09 ± 3.20）mm］，caliceal pelvic height（CPH）［（19.96 ± 4.63）mm vs.（30.32 ± 7.56）mm］，ureter-lower calyx distance（ULD）［（23.00 ± 5.59）mm vs.（18.78 ± 6.31）mm］，CPH/IL ratio［（0.73 ± 0.11）vs.（0.92 ± 0.09）］，and curvature of the lower calyx of the renal pelvis［（0.06 ± 0.01）mm -1 vs.（0.08 ± 0.03）mm -1］between the two groups（ P <0.05）. Univariate and logistic multivariate regression analyses were used to identify the independent risk factors affecting the postoperative SFR of FURL-treated lower calyx stones and to assess the value of CPH/IL for SFR in the treatment of lower calyx stones using FURL combined with a distally bendable negative pressure suction sheath. A logistic multivariate regression model and a corresponding nomogram were constructed，and the predictive ability of the model for SFR was evaluated using the receiver operating characteristic（ROC）curve. The calibration curve and the Hosmer -Lemeshow test were used to assess the consistency and accuracy of the model. The clinical utility of the model was evaluated using decision curve analysis（DCA）. Results:Univariate analysis revealed that seven anatomical parameters differed significantly between the clearance and non-clearance groups（all P < 0.05）：infundibulopelvic angle（IPA， OR = 0.27，95% CI 0.17-0.42， P < 0.01），infundibular length（IL， OR = 2.52，95% CI 1.83-3.47， P < 0.01），infundibular width（IW， OR = 0.64，95% CI 0.45-0.90， P = 0.011），caliceal pelvic height（CPH， OR = 5.78，95% CI 3.67-9.10， P < 0.01），ureter-lower calyx distance（ULD， OR = 0.43，95% CI 0.30-0.63， P < 0.01），CPH/IL ratio（ OR = 13.62，95% CI 6.86-27.03， P < 0.01），and curvature of the lower calyx of the renal pelvis（ O = 3.15，95% CI 2.08-4.78， P < 0.01）. Multivariate logistic regression further identified CPH/IL（ OR = 9.87，95% CI 4.92-19.79， P < 0.01），IPA（ OR = 0.41，95% CI 0.23-0.71， P = 0.001），and ULD（ OR = 0.50，95% CI 0.29-0.87， P = 0.014）as independent risk factors influencing the stone-free rate after flexible ureteroscopic lithotripsy combined with a distally bendable negative-pressure suction sheath. The area under the ROC curve（AUC）of the univariate regression model showed that for IPA，the AUC was 0.788（95% CI 0.711-0.864）；for IL，it was 0.731（95% CI 0.643-0.819）；for ULD，it was 0.677（95% CI 0.586-0.767）；for CPH，it was 0.867（95% CI 0.804-0.929）；for IW，it was 0.628（95% CI 0.535-0.721）；for CPH/IL，it was 0.906（95% CI 0.850-0.961）with an optimal cutoff value of 0.882，corresponding to a sensitivity of 83.02% and a specificity of 92.08%；and for curvature of the lower calyx of the renal pelvis，it was 0.744（95% CI 0.662-0.827）. The AUC of the multivariate regression model was 0.929（95% CI 0.884-0.974）with an optimal cutoff value of 0.364，corresponding to a sensitivity of 82.98% and a specificity of 95.09%. Calibration curves demonstrated close agreement between the predicted and actual stone-free rates after FURL（C-index = 0.921）. The Hosmer-Lemeshow goodness-of-fit test indicated no significant discrepancy between predicted and observed probabilities（ P = 0.135，>0.05）. Decision-curve analysis further revealed that basing clinical decisions on the model ，s predicted probability yields a higher net clinical benefit than either withholding FURL for all patients or treating all patients regardless of risk，and it also outperforms strategies guided by any single independent predictor alone. Conclusions:IPA，IL，IW，CPH，ULD，CPH/IL ratio，and curvature of the lower calyx of the renal pelvis can all predict the postoperative SFR of FURL combined with a distally bendable negative pressure suction sheath for the treatment of lower calyx stones to varying degrees. Among them，CPH/IL has the highest predictive value. When CPH/IL >0.88，it may be difficult to use FURL to treat lower calyx stones.

In this work,four salicylhydrazone compounds(L1?L4)were designed and synthesized by using vanillin derivatives as raw material.The structures were confirmed by nuclear magnetic resonance(NMR)and high-resolution mass spectrometry(HRMS).The optical experiments showed that probe L1 and probe L3 could be used as aluminium ion(Al3+)fluorescence probes.The fluorescence color of probe L1 solution changed from colorless to blue after adding Al3+,and the limit of detection was 25.1 nmol/L.Compared with probe L1,the fluorescence color of probe L3 solution changed from colorless to green after complexing with Al3+,and the limit of detection was 17.3 nmol/L.Probe L1 and probe L3 showed the advantages of fast response speed,high selectivity and good anti-interference.The mechanism of Al3+recognition was further demonstrated by HRMS and 1H NMR.Cell imaging experiments showed that probe L1 and L3 had low cytotoxicity and had great application potential in detection of Al3+in vivo.

Lung cancer poses a serious threat to global public health security.Chemotherapy,as the main strategy for cancer treatment,faces challenges such as high toxicity and drug resistance.Anticancer peptides have the potential of being developed into new anticancer drugs due to their advantages of broad-spectrum anticancer activity,rapid action,and difficulty in generating drug resistance,but they also face shortcomings such as weak activity and strong toxic side effects.The weakly acidic microenvironment of tumors(pH 6.5-6.8)provides a good idea for the design of anticancer peptides of high-efficiency and low-toxicity.Previously,we designed the acid-sensitive antibacterial peptide pHly-1 using the wolf spider(Lycosa singoriensis)toxin Lycosin-Ⅰ as a template.In this study,we found that pHly-1 also had acid-sensitive anticancer activity.Further alanine scanning analysis of pHly-1 was carried out,and we ob-tained a mutant pHTP-2 with better acid sensitivity,whose IC50(half maximal inhibitory concentration)against A549 cells was 15.68 μmol/L at pH 6.6 and was greater than 100 μmol/L at pH 7.4.At pH 6.6,pHTP-2 could act on various lung cancer cell lines and induce the death of A549 cells by rapid ly-sis;at pH 7.4,500 μmol/L pHTP-2 had weak toxicity to red blood cells(the hemolysis rate was ap-proximately 38％)and primary myocardial cells(the inhibition rate was 49.7％,with P＜0.05).Analy-sis of its charge,particle size,morphology,and secondary structure showed that at pH 6.6,the histidine in the sequence of pHTP-2 was protonated,increasing the positive charge(P＜0.01),decreasing the hy-drated particle size(P＜0.05)and forming an α-helical structure to induce membrane lysis of A549 cells.At pH 7.4,it was deprotonated,the positive charge decreases,a β-sheet structure was formed and self-aggregation occurred,limiting its effect on the A549 cell membrane and showing weak activity.In summary,pHTP-2 could respond to the weakly acidic microenvironment of tumors to exert selective cyto-toxic activity,effectively overcoming the shortcomings of anticancer peptides such as low efficiency and high toxicity.Our findings suggest that it is a high-quality lead molecule for anticancer drugs.

Lung cancer poses a serious threat to global public health security.Chemotherapy,as the main strategy for cancer treatment,faces challenges such as high toxicity and drug resistance.Anticancer peptides have the potential of being developed into new anticancer drugs due to their advantages of broad-spectrum anticancer activity,rapid action,and difficulty in generating drug resistance,but they also face shortcomings such as weak activity and strong toxic side effects.The weakly acidic microenvironment of tumors(pH 6.5-6.8)provides a good idea for the design of anticancer peptides of high-efficiency and low-toxicity.Previously,we designed the acid-sensitive antibacterial peptide pHly-1 using the wolf spider(Lycosa singoriensis)toxin Lycosin-Ⅰ as a template.In this study,we found that pHly-1 also had acid-sensitive anticancer activity.Further alanine scanning analysis of pHly-1 was carried out,and we ob-tained a mutant pHTP-2 with better acid sensitivity,whose IC50(half maximal inhibitory concentration)against A549 cells was 15.68 μmol/L at pH 6.6 and was greater than 100 μmol/L at pH 7.4.At pH 6.6,pHTP-2 could act on various lung cancer cell lines and induce the death of A549 cells by rapid ly-sis;at pH 7.4,500 μmol/L pHTP-2 had weak toxicity to red blood cells(the hemolysis rate was ap-proximately 38％)and primary myocardial cells(the inhibition rate was 49.7％,with P＜0.05).Analy-sis of its charge,particle size,morphology,and secondary structure showed that at pH 6.6,the histidine in the sequence of pHTP-2 was protonated,increasing the positive charge(P＜0.01),decreasing the hy-drated particle size(P＜0.05)and forming an α-helical structure to induce membrane lysis of A549 cells.At pH 7.4,it was deprotonated,the positive charge decreases,a β-sheet structure was formed and self-aggregation occurred,limiting its effect on the A549 cell membrane and showing weak activity.In summary,pHTP-2 could respond to the weakly acidic microenvironment of tumors to exert selective cyto-toxic activity,effectively overcoming the shortcomings of anticancer peptides such as low efficiency and high toxicity.Our findings suggest that it is a high-quality lead molecule for anticancer drugs.

Objective:This study aims to explore the predictive value of the ratio of caliceal pelvic height to infundibular length（CPH/IL）for the stone-free rate（SFR）in the treatment of lower calyx stones using flexible ureteroscopic lithotripsy（FURL）combined with a distally bendable negative pressure suction sheath.Methods:A retrospective analysis was conducted on the clinical data and anatomical parameters of 312 patients with lower calyx stones or combined lower calyx stones admitted to the Third Xiangya Hospital of Central South University from September 2022 to December 2023，all of whom were treated with FURL combined with a distally bendable negative pressure suction sheath. Stone clearance was defined as no residual stones or residual stones with a diameter of ≤3 mm without any symptoms. Patients were divided into the clearance group（265 cases，84.90%）and the non-clearance group（47 cases，15.10%）. There were no significant differences in gender（male/female：173/92 cases vs. 29/18 cases），age［（44.69 ± 13.14）years vs.（42.60 ± 10.93）years］，degree of hydronephrosis（no hydronephrosis/mild hydronephrosis/moderate to severe hydronephrosis：122/85/58 cases vs. 21/12/14 cases），side of lower calyx stones（left/right：157/108 cases vs. 31/16 cases），maximum diameter of stones（MDS）［（19.23 ± 6.41）mm vs.（17.77 ± 6.18）mm］，and CT value of stones［（993.46 ± 249.12）Hu vs.（1013.43 ± 300.90）Hu］between the two groups（ P > 0.05），indicating comparability between groups. There was no significant difference in the distance from the midpoint of the lower lip of the renal pelvis to the ureter at the lowest plane of the lower calyx（K-A line）between the clearance and non-clearance groups［（26.16 ± 5.18）mm vs.（25.70 ± 8.66）mm， P > 0.05］. However，significant differences were observed in the infundibulopelvic angle（IPA）［（53.97 ± 15.72）° vs.（37.43 ± 15.39）°］，infundibular length（IL）［（27.26 ± 5.11）mm vs.（33.04 ± 7.38）mm］，infundibular width（IW）［（8.27 ± 2.82）mm vs.（7.09 ± 3.20）mm］，caliceal pelvic height（CPH）［（19.96 ± 4.63）mm vs.（30.32 ± 7.56）mm］，ureter-lower calyx distance（ULD）［（23.00 ± 5.59）mm vs.（18.78 ± 6.31）mm］，CPH/IL ratio［（0.73 ± 0.11）vs.（0.92 ± 0.09）］，and curvature of the lower calyx of the renal pelvis［（0.06 ± 0.01）mm -1 vs.（0.08 ± 0.03）mm -1］between the two groups（ P <0.05）. Univariate and logistic multivariate regression analyses were used to identify the independent risk factors affecting the postoperative SFR of FURL-treated lower calyx stones and to assess the value of CPH/IL for SFR in the treatment of lower calyx stones using FURL combined with a distally bendable negative pressure suction sheath. A logistic multivariate regression model and a corresponding nomogram were constructed，and the predictive ability of the model for SFR was evaluated using the receiver operating characteristic（ROC）curve. The calibration curve and the Hosmer -Lemeshow test were used to assess the consistency and accuracy of the model. The clinical utility of the model was evaluated using decision curve analysis（DCA）. Results:Univariate analysis revealed that seven anatomical parameters differed significantly between the clearance and non-clearance groups（all P < 0.05）：infundibulopelvic angle（IPA， OR = 0.27，95% CI 0.17-0.42， P < 0.01），infundibular length（IL， OR = 2.52，95% CI 1.83-3.47， P < 0.01），infundibular width（IW， OR = 0.64，95% CI 0.45-0.90， P = 0.011），caliceal pelvic height（CPH， OR = 5.78，95% CI 3.67-9.10， P < 0.01），ureter-lower calyx distance（ULD， OR = 0.43，95% CI 0.30-0.63， P < 0.01），CPH/IL ratio（ OR = 13.62，95% CI 6.86-27.03， P < 0.01），and curvature of the lower calyx of the renal pelvis（ O = 3.15，95% CI 2.08-4.78， P < 0.01）. Multivariate logistic regression further identified CPH/IL（ OR = 9.87，95% CI 4.92-19.79， P < 0.01），IPA（ OR = 0.41，95% CI 0.23-0.71， P = 0.001），and ULD（ OR = 0.50，95% CI 0.29-0.87， P = 0.014）as independent risk factors influencing the stone-free rate after flexible ureteroscopic lithotripsy combined with a distally bendable negative-pressure suction sheath. The area under the ROC curve（AUC）of the univariate regression model showed that for IPA，the AUC was 0.788（95% CI 0.711-0.864）；for IL，it was 0.731（95% CI 0.643-0.819）；for ULD，it was 0.677（95% CI 0.586-0.767）；for CPH，it was 0.867（95% CI 0.804-0.929）；for IW，it was 0.628（95% CI 0.535-0.721）；for CPH/IL，it was 0.906（95% CI 0.850-0.961）with an optimal cutoff value of 0.882，corresponding to a sensitivity of 83.02% and a specificity of 92.08%；and for curvature of the lower calyx of the renal pelvis，it was 0.744（95% CI 0.662-0.827）. The AUC of the multivariate regression model was 0.929（95% CI 0.884-0.974）with an optimal cutoff value of 0.364，corresponding to a sensitivity of 82.98% and a specificity of 95.09%. Calibration curves demonstrated close agreement between the predicted and actual stone-free rates after FURL（C-index = 0.921）. The Hosmer-Lemeshow goodness-of-fit test indicated no significant discrepancy between predicted and observed probabilities（ P = 0.135，>0.05）. Decision-curve analysis further revealed that basing clinical decisions on the model ，s predicted probability yields a higher net clinical benefit than either withholding FURL for all patients or treating all patients regardless of risk，and it also outperforms strategies guided by any single independent predictor alone. Conclusions:IPA，IL，IW，CPH，ULD，CPH/IL ratio，and curvature of the lower calyx of the renal pelvis can all predict the postoperative SFR of FURL combined with a distally bendable negative pressure suction sheath for the treatment of lower calyx stones to varying degrees. Among them，CPH/IL has the highest predictive value. When CPH/IL >0.88，it may be difficult to use FURL to treat lower calyx stones.

Objective To investigate the clinical effect of unilateral percutaneous vertebroplasty(PVP)combined with 3D printing technology for the treatment of thoracolumbar osteoporotic compression fracture.Methods A total of 77 patients with thoracolumbar osteoporotic compression fractures from October 2020 to April 2022 were included in the study,all of which were vertebral body compression fractures caused by trauma.According to different treatment methods,they were di-vided into experimental group and control group.Thirty-two patients used 3D printing technology to improve unilateral transpedicle puncture vertebroplasty in the experimental group,there were 5 males and 27 females,aged from 63 to 91 years old with an average of(77.59±8.75)years old.Forty-five patients were treated with traditional bilateral pedicle puncture vertebroplasty,including 7 males and 38 females,aged from 60 to 88 years old with an average of(74.89±7.37)years old.Operation time,intraoperative C-arm X-ray times,anesthetic dosage,bone cement injection amount,bone cement diffusion good and good rate,complications,vertebral height,kyphotic angle(Cobb angle),visual analogue scale(VAS),Oswestry disability index(ODI)and other indicators were recorded before and after surgery,and statistically analyzed.Results All patients were followed up for 6 to 23 months,with preoperative imaging studies,confirmed for thoracolumbar osteoporosis com-pression fractures,two groups of patients with postoperative complications,no special two groups of patients'age,gender,body mass index(BMI),time were injured,the injured vertebral distribution had no statistical difference(P＞0.05),comparable data.Two groups of patients with bone cement injection,bone cement dispersion rate,preoperative and postoperative vertebral body height,protruding after spine angle(Cobb angle),VAS,ODI had no statistical difference(P＞0.05).The operative time,intra-operative fluoroscopy times and anesthetic dosage were statistically different between the two groups(P＜0.05).Compared with the traditional bilateral puncture group,the modified unilateral puncture group combined with 3D printing technology had shorter operation time,fewer intraoperative fluoroscopy times and less anesthetic dosage.The height of anterior vertebral edge,kyphosis angle(Cobb angle),VAS score and ODI of the affected vertebrae were statistically different between two groups at each time point after surgery(P＜0.05).Conclusion In the treatment of thoracolumbar osteoporotic compression fractures,3D printing technology is used to improve unilateral puncture PVP,which is convenient and simple,less trauma,short operation time,fewer fluoroscopy times,satisfactory distribution of bone cement,vertebral height recovery and kyphotic Angle correction,and good functional improvement.

Objective To evaluate the efficacy and safety of brexpiprazole in treating acute schizophrenia.Methods Patients with schizophrenia were randomly divided into treatment group and control group.The treatment group was given brexpiprozole 2-4 mg·d-1 orally and the control group was given aripiprazole 10-20 mg·d-1orally,both were treated for 6 weeks.Clinical efficacy of the two groups,the response rate at endpoint,the changes from baseline to endpoint of Positive and Negative Syndrome Scale(PANSS),Clinical Global Impression-Improvement(CGI-S),Personal and Social Performance scale(PSP),PANSS Positive syndrome subscale,PANSS negative syndrome subscale were compared.The incidence of treatment-related adverse events in two groups were compared.Results There were 184 patients in treatment group and 186 patients in control group.After treatment,the response rates of treatment group and control group were 79.50％(140 cases/184 cases)and 82.40％(150 cases/186 cases),the scores of CGI-I of treatment group and control group were(2.00±1.20)and(1.90±1.01),with no significant difference(all P＞0.05).From baseline to Week 6,the mean change of PANSS total score wese(-30.70±16.96)points in treatment group and(-32.20±17.00)points in control group,with no significant difference(P＞0.05).The changes of CGI-S scores in treatment group and control group were(-2.00±1.27)and(-1.90±1.22)points,PSP scores were(18.80±14.77)and(19.20±14.55)points,PANSS positive syndrome scores were(-10.30±5.93)and(-10.80±5.81)points,PANSS negative syndrome scores were(-6.80±5.98)and(-7.30±5.15)points,with no significant difference(P＞0.05).There was no significant difference in the incidence of treatment-related adverse events between the two group(69.00％vs.64.50％,P＞0.05).Conclusion The non-inferiority of Brexpiprazole to aripiprazole was established,with comparable efficacy and acceptability.

Objective To investigate the incidence rate,clinical characteristics,and prognosis of neonatal stroke in Shenzhen,China.Methods Led by Shenzhen Children's Hospital,the Shenzhen Neonatal Data Collaboration Network organized 21 institutions to collect 36 cases of neonatal stroke from January 2020 to December 2022.The incidence,clinical characteristics,treatment,and prognosis of neonatal stroke in Shenzhen were analyzed.Results The incidence rate of neonatal stroke in 21 hospitals from 2020 to 2022 was 1/15 137,1/6 060,and 1/7 704,respectively.Ischemic stroke accounted for 75％(27/36);boys accounted for 64％(23/36).Among the 36 neonates,31(86％)had disease onset within 3 days after birth,and 19(53％)had convulsion as the initial presentation.Cerebral MRI showed that 22 neonates(61％)had left cerebral infarction and 13(36％)had basal ganglia infarction.Magnetic resonance angiography was performed for 12 neonates,among whom 9(75％)had involvement of the middle cerebral artery.Electroencephalography was performed for 29 neonates,with sharp waves in 21 neonates(72％)and seizures in 10 neonates(34％).Symptomatic/supportive treatment varied across different hospitals.Neonatal Behavioral Neurological Assessment was performed for 12 neonates(33％,12/36),with a mean score of(32±4)points.The prognosis of 27 neonates was followed up to around 12 months of age,with 44％(12/27)of the neonates having a good prognosis.Conclusions Ischemic stroke is the main type of neonatal stroke,often with convulsions as the initial presentation,involvement of the middle cerebral artery,sharp waves on electroencephalography,and a relatively low neurodevelopment score.Symptomatic/supportive treatment is the main treatment method,and some neonates tend to have a poor prognosis.

Objective To investigate the risk factors for bronchopulmonary dysplasia(BPD)in twin preterm infants with a gestational age of<34 weeks,and to provide a basis for early identification of BPD in twin preterm infants in clinical practice.Methods A retrospective analysis was performed for the twin preterm infants with a gestational age of<34 weeks who were admitted to 22 hospitals nationwide from January 2018 to December 2020.According to their conditions,they were divided into group A(both twins had BPD),group B(only one twin had BPD),and group C(neither twin had BPD).The risk factors for BPD in twin preterm infants were analyzed.Further analysis was conducted on group B to investigate the postnatal risk factors for BPD within twins.Results A total of 904 pairs of twins with a gestational age of<34 weeks were included in this study.The multivariate logistic regression analysis showed that compared with group C,birth weight discordance of>25%between the twins was an independent risk factor for BPD in one of the twins(OR=3.370,95%CI:1.500-7.568,P<0.05),and high gestational age at birth was a protective factor against BPD(P<0.05).The conditional logistic regression analysis of group B showed that small-for-gestational-age(SGA)birth was an independent risk factor for BPD in individual twins(OR=5.017,95%CI:1.040-24.190,P<0.05).Conclusions The development of BPD in twin preterm infants is associated with gestational age,birth weight discordance between the twins,and SGA birth.