Objective To explore the relationship between insulin resistance and idiopathic central precocious puberty(ICPP)in girls and the diagnostic value of insulin resistance.Methods Clinical data of 245 girls aged 4 to 7.5 years with low luteinizing hormone(LH)levels(0.2-0.83 IU/L),normal body weight(body mass index standard deviation score between-2 and+2),and early breast development who visited the Department of Pediatric Endocrinology,Henan Provincial Maternal and Child Health Hospital from January 2022 to March 2025 were retrospectively analyzed.According to the Expert Consensus on the Diagnosis and Treatment of Central Precocious Puberty(2022),patients were assigned to an ICPP group(n=123)or a control group(n=122).Correlations between the homeostasis model assessment of insulin resistance(HOMA-IR)and selected indices were assessed.Multivariable logistic regression was used to evaluate the association between HOMA-IR and ICPP,and the diagnostic performance of various indices for ICPP was evaluated.Results HOMA-IR was higher in the ICPP group than in the control group(P<0.001)and was positively correlated with LH peak(rs=0.467,P<0.05)and the LH peak/FSH peak ratio(rs=0.444,P<0.05).The multivariable logistic regression model including age,BMI,and basal LH showed that HOMA-IR was closely associated with ICPP(OR=2.756,95%CI:1.940-3.913).Receiver operating characteristic curve analysis showed that the areas under the curve for basal LH,HOMA-IR,and their combination in diagnosing ICPP were 0.735,0.735,and 0.805,respectively(P<0.05),and the combined model had a greater area under the curve than either basal LH or HOMA-IR alone(both P<0.05).Conclusions HOMA-IR is closely associated with ICPP in girls with low LH and normal body weight,and combining HOMA-IR with basal LH improves early identification and diagnostic efficiency in this population.

Objective:To evaluate the value of ultrasound radiomics combined with machine learning for early diagnosis of seronegative Hashimoto’s thyroiditis (SN-HT) .Methods:This retrospective study included 164 patients from Liaoning Provincial People’s Hospital , Lixin County People’s Hospital, Linghai Dalinghe Hospital, Fengcheng Phoenix Hospital, who underwent thyroidectomy for solitary nodules with normal thyroid function between Nov. 2016 and Jan. 2024. Postoperative pathology confirmed Hashimoto’s thyroiditis (HT) in some cases, who were further categorized into antibody-positive and antibody-negative groups based on serum antibody status. Patients without Hashimoto’s thyroiditis served as the control group. A total of 298 ultrasound images were analyzed. Radiomics features were extracted from hypoechoic non-nodular areas within 0.5 cm surrounding the tumor. Two senior pathologists and two senior ultrasound physicians independently assessed lymphocytic infiltration, eosinophilic changes of follicular epithelium, and the proportion of hypoechoic areas in pathology and ultrasound images, respectively. A machine learning model, CCH-NET, was developed using linear regression and t-distributed stochastic neighbor embedding (t-SNE) techniques. The dataset was divided into a training set (80%) and a validation set (20%) to compare the diagnostic accuracy of CCH-NET with that of senior ultrasound physicians. Results:In internal validation, CCH-NET achieved a diagnostic accuracy of 88.89% for both antibody-positive and antibody-negative groups, significantly higher than the 66.67% accuracy of senior ultrasound physicians ( P<0.01). In external validation, CCH-NET achieved 75.00% and 66.67% accuracy for the two groups, compared to 50.00% by senior ultrasound physicians. For the control group, both methods achieved 93.33% accuracy. The AUC of CCH-NET was 0.848, outperforming senior ultrasound physicians (0.681) ,demonstrating superior diagnostic performance. Conclusion:The radiomics-based CCH-NET model, using non-nodular hypoechoic areas as a specific indicator, can accurately identify early SN-HT in euthyroid patients. It significantly outperforms senior ultrasound physicians, improving diagnostic accuracy and reducing missed diagnoses.

Objective:To evaluate the effect of short-chain fatty acid(SCFA) on perioperative cognitive dysfunction in aged rats through mitogen-activated protein kinase p38(p38 MAPK)/nuclear factor-κB p65(NF-κB p65) pathway.Methods:According to random number table method, 32 healthy SPF-grade male SD rats, aged 16 months and weighing 520~620 g, were divided into control group, short-chain fatty acid group (SCFA group), perioperative cognitive dysfunction group (PCD group) and perioperative cognitive dysfunction+ short-chain fatty acid group (SCFA+ PCD group), with 8 rats in each group. The perioperative cognitive dysfunction model was established by sevoflurane anesthesia plus internal fixation of tibial fractures. Rats in SCFA group and SCFA+ PCD group freely drank water added with SCFA for 28 days. On the 29th day, rats in SCFA+ FCD group underwent tibial fracture internal fixation surgery. Morris water maze test was performed on the 7th day after surgery to evaluate the cognitive function of rats. The Nissl bodies of hippocampus were observed by Nissl's staining. The hippocampus tissue was collected to analyze the expressions of interleukin-1β (IL-1β), interleukin-6 (IL-6), p38 MAPK, phosphorylated p38 MAPK, NF-κB p65 and phosphorylated NF-κB p65 by Western blot.The SPSS 27.0 software was used for statistical analysis. One-way ANOVA was used for comparison among multiple groups, and LSD- t test was used for further pairwise comparison. Results:(1) The results of Morris water maze test showed that the times of crossing the original platform, the escape latency and the residence time in the original platform quadrant were statistically significant among the four groups on the 7th day after surgery ( F=13.80, 47.80, 6.46, all P<0.05). The escape latencies of the SCFA+ PCD group and PCD group were both longer than that in the control group (both P<0.05). The times of crossing the original platform in SCFA+ PCD group and PCD group were less than that of control group (both P<0.05). The residence time in the original platform quadrant in SCFA+ PCD group and PCD group was shorter than that of control group (both P<0.05).Compared with PCD group, the escape latency was shorter, the times of crossing the original platform were more and the residence time in the original platform quadrant was longer in SCFA+ PCD group (all P<0.05). (2) The expression levels of IL-1β, IL-6, phosphorylated p38 MAPK and phosphorylated NF-κB p65 were statistically significant among the four groups ( F=184.28, 139.27, 19.40, 58.47, all P<0.05). The expression levels of IL-1β, IL-6, phosphorylated p38 MAPK and phosphorylated NF-κB p65 were higher in SCFA+ PCD group (0.49±0.10, 0.60±0.05, 0.489±0.012, 0.435±0.005) and PCD group (0.85±0.05, 1.12±0.08, 0.519±0.028, 0.473±0.008) than those in control group (0.13±0.02, 0.42±0.10, 0.437±0.010, 0.362±0.013)(all P<0.05). The expression levels of IL-1β, IL-6, phosphorylated p38 MAPK and phosphorylated NF-κB p65 were lower in SCFA+ PCD group than PCD group (all P<0.05). (3) The average gray value of Nissl bodies was statistically significant different among the four groups ( F=14.65, P<0.05). The average gray value of Nissl bodies was lower in SCFA+ PCD group (193.2±8.1) and PCD group (160.5±14.1) than that of control group (221.2±14.8) (both P<0.05). The average gray value of Nissl bodies was higher in SCFA+ PCD group than that in PCD group( P<0.05). Conclusion:Short-chain fatty acid attenuates cognitive dysfunction, which may be related with inhibiting p38 MAPK/NF-κB p65 pathway and reducing the neuroinflammation.

Objective To examine the expression pattern of apoptosis signal-regulating kinase 1(ASK1)in the intestinal tissues of patients with Crohn's disease(CD),and analyze its mechanistic impact on intestinal epithelial barrier function and inflammatory responses.Methods Ileal tissue samples from Crohn's disease patients and healthy controls were collected.ASK1 protein level was assessed by immunohistochemistry,and its relationship with the Crohn's disease activity index(CDAI)was analyzed.A mouse model of acute colitis was constructed using TNBS,and subjected to qRT-PCR,Western blotting and immunohistochemistry for ASK1 expression,and the association between ASK1 expression and the disease activity index was examined.Lentivirus transfection was employed to create stable Caco-2 cell lines with altered ASK1 expression,and the intestinal barrier integrity and inflammation were assessed by measuring transepithelial electrical resistance(TEER),FITC-dextran leakage,and IL-6,IL-1β levels.Furthermore,the effects of ASK1 expression on Krüppel-like factor 4(KLF4)levels was examined using qRT-PCR and Western blotting.Results ASK1 was highly expressed in the ileum of CD patients and positively correlated with CDAI.In a TNBS-induced mouse model of acute colitis,ASK1 expression was up-regulated and positively correlated with DAI.Inflammation-induced ASK1 overexpression weakened the Caco-2 cell intestinal barrier,whereas ASK1 knockdown strengthened it.Moreover,ASK1 had the capability to enhance the expression of inflammatory factors.Additionally,ASK1 knockdown increased KLF4 expression,while overexpression decreased it,indicating a negative correlation between ASK1 and KLF4.Conclusion ASK1 expression is notably higher in CD and positively correlates with disease activity.ASK1 can influence intestinal barrier integrity and inflammatory factor expression,possibly through its impact on KLF4 expression.

Objective:To evaluate the value of ultrasound radiomics combined with machine learning for early diagnosis of seronegative Hashimoto’s thyroiditis (SN-HT) .Methods:This retrospective study included 164 patients from Liaoning Provincial People’s Hospital , Lixin County People’s Hospital, Linghai Dalinghe Hospital, Fengcheng Phoenix Hospital, who underwent thyroidectomy for solitary nodules with normal thyroid function between Nov. 2016 and Jan. 2024. Postoperative pathology confirmed Hashimoto’s thyroiditis (HT) in some cases, who were further categorized into antibody-positive and antibody-negative groups based on serum antibody status. Patients without Hashimoto’s thyroiditis served as the control group. A total of 298 ultrasound images were analyzed. Radiomics features were extracted from hypoechoic non-nodular areas within 0.5 cm surrounding the tumor. Two senior pathologists and two senior ultrasound physicians independently assessed lymphocytic infiltration, eosinophilic changes of follicular epithelium, and the proportion of hypoechoic areas in pathology and ultrasound images, respectively. A machine learning model, CCH-NET, was developed using linear regression and t-distributed stochastic neighbor embedding (t-SNE) techniques. The dataset was divided into a training set (80%) and a validation set (20%) to compare the diagnostic accuracy of CCH-NET with that of senior ultrasound physicians. Results:In internal validation, CCH-NET achieved a diagnostic accuracy of 88.89% for both antibody-positive and antibody-negative groups, significantly higher than the 66.67% accuracy of senior ultrasound physicians ( P<0.01). In external validation, CCH-NET achieved 75.00% and 66.67% accuracy for the two groups, compared to 50.00% by senior ultrasound physicians. For the control group, both methods achieved 93.33% accuracy. The AUC of CCH-NET was 0.848, outperforming senior ultrasound physicians (0.681) ,demonstrating superior diagnostic performance. Conclusion:The radiomics-based CCH-NET model, using non-nodular hypoechoic areas as a specific indicator, can accurately identify early SN-HT in euthyroid patients. It significantly outperforms senior ultrasound physicians, improving diagnostic accuracy and reducing missed diagnoses.

Objective:To evaluate the effect of short-chain fatty acid(SCFA) on perioperative cognitive dysfunction in aged rats through mitogen-activated protein kinase p38(p38 MAPK)/nuclear factor-κB p65(NF-κB p65) pathway.Methods:According to random number table method, 32 healthy SPF-grade male SD rats, aged 16 months and weighing 520~620 g, were divided into control group, short-chain fatty acid group (SCFA group), perioperative cognitive dysfunction group (PCD group) and perioperative cognitive dysfunction+ short-chain fatty acid group (SCFA+ PCD group), with 8 rats in each group. The perioperative cognitive dysfunction model was established by sevoflurane anesthesia plus internal fixation of tibial fractures. Rats in SCFA group and SCFA+ PCD group freely drank water added with SCFA for 28 days. On the 29th day, rats in SCFA+ FCD group underwent tibial fracture internal fixation surgery. Morris water maze test was performed on the 7th day after surgery to evaluate the cognitive function of rats. The Nissl bodies of hippocampus were observed by Nissl's staining. The hippocampus tissue was collected to analyze the expressions of interleukin-1β (IL-1β), interleukin-6 (IL-6), p38 MAPK, phosphorylated p38 MAPK, NF-κB p65 and phosphorylated NF-κB p65 by Western blot.The SPSS 27.0 software was used for statistical analysis. One-way ANOVA was used for comparison among multiple groups, and LSD- t test was used for further pairwise comparison. Results:(1) The results of Morris water maze test showed that the times of crossing the original platform, the escape latency and the residence time in the original platform quadrant were statistically significant among the four groups on the 7th day after surgery ( F=13.80, 47.80, 6.46, all P<0.05). The escape latencies of the SCFA+ PCD group and PCD group were both longer than that in the control group (both P<0.05). The times of crossing the original platform in SCFA+ PCD group and PCD group were less than that of control group (both P<0.05). The residence time in the original platform quadrant in SCFA+ PCD group and PCD group was shorter than that of control group (both P<0.05).Compared with PCD group, the escape latency was shorter, the times of crossing the original platform were more and the residence time in the original platform quadrant was longer in SCFA+ PCD group (all P<0.05). (2) The expression levels of IL-1β, IL-6, phosphorylated p38 MAPK and phosphorylated NF-κB p65 were statistically significant among the four groups ( F=184.28, 139.27, 19.40, 58.47, all P<0.05). The expression levels of IL-1β, IL-6, phosphorylated p38 MAPK and phosphorylated NF-κB p65 were higher in SCFA+ PCD group (0.49±0.10, 0.60±0.05, 0.489±0.012, 0.435±0.005) and PCD group (0.85±0.05, 1.12±0.08, 0.519±0.028, 0.473±0.008) than those in control group (0.13±0.02, 0.42±0.10, 0.437±0.010, 0.362±0.013)(all P<0.05). The expression levels of IL-1β, IL-6, phosphorylated p38 MAPK and phosphorylated NF-κB p65 were lower in SCFA+ PCD group than PCD group (all P<0.05). (3) The average gray value of Nissl bodies was statistically significant different among the four groups ( F=14.65, P<0.05). The average gray value of Nissl bodies was lower in SCFA+ PCD group (193.2±8.1) and PCD group (160.5±14.1) than that of control group (221.2±14.8) (both P<0.05). The average gray value of Nissl bodies was higher in SCFA+ PCD group than that in PCD group( P<0.05). Conclusion:Short-chain fatty acid attenuates cognitive dysfunction, which may be related with inhibiting p38 MAPK/NF-κB p65 pathway and reducing the neuroinflammation.

Objective:To investigate the clinical significance of serum galectin-9 (Gal-9) in patients with dermatomyositis (DM) or clinically amyopathic dermatomyositis (CADM) .Methods:This cross-sectional study included 105 newly diagnosed patients with DM or CADM who were admitted to the Department of Dermatology in Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, from January 2015 to October 2024, among whom 53 had cancer-associated DM/CADM (CRDM). Additionally, an age-matched control group was included, consisting of 30 newly diagnosed cancer patients without autoimmune diseases, 27 systemic lupus erythematosus (SLE) patients, and 31 healthy controls. Serum levels of Gal-9 and transcriptional intermediary factor 1-gamma (TIF1-γ) were measured using enzyme-linked immunosorbent assay. The relationship between Gal-9 levels and laboratory indicators of DM disease activity was analyzed. Comparisons between different groups were performed using the t-test, Mann-Whitney U test, and chi-square test. Spearman correlation analysis was used to assess the association between Gal-9 levels and laboratory indicators. The diagnostic efficacy of Gal-9 and TIF1-γ for CRDM was evaluated using receiver operating characteristic (ROC) curve analysis. Results:Among the 105 DM/CADM patients, 35 were male (33.3%) and 70 were female (66.7%), with a mean age of 53.2 ± 15.1 years. In the 53 CRDM patients, the incidence rates of V-neck sign, dyschromia, and dysphagia were higher than those in non-CRDM patients (all P > 0.05). Serum Gal-9 levels in DM/CADM patients (21.2 [12.2, 32.3] ng/ml) were significantly higher than those in healthy controls (6.8 [5.4, 7.9] ng/ml, P < 0.001), SLE patients (12.3 [8.1, 15.5] ng/ml, P = 0.011), and cancer patients without autoimmune diseases (7.5 [4.9, 8.5] ng/ml, P < 0.001). Gal-9 levels were positively correlated with serum TIF1-γ antibody levels ( rs = 0.21, P = 0.029), serum ferritin ( rs = 0.29, P = 0.003), lactate dehydrogenase ( rs = 0.44, P < 0.001), creatine kinase ( rs = 0.28, P = 0.004), aspartate aminotransferase ( rs = 0.42, P < 0.001), C-reactive protein ( rs = 0.34, P < 0.001), and erythrocyte sedimentation rate ( rs = 0.46, P < 0.001). Among CRDM patients, those who had not received cancer treatment had higher Gal-9 levels (30.1 [23.3, 38.3] ng/ml) than those in stable condition after cancer treatment (13.5 [10.5, 27.9] ng/ml, P = 0.007). The area under the ROC curve (AUC) for serum TIF1-γ in diagnosing CRDM was 0.718, with an optimal cutoff value of 23.02 U/ml. The AUC for serum Gal-9 was 0.719, with an optimal cutoff value of 55.02 ng/ml. When combining both markers, the AUC increased to 0.783, with a sensitivity of 0.85 and specificity of 0.74. Conclusions:Gal-9 was highly expressed in serum of DM/CADM patients, particularly in CRDM patients. Dynamic monitoring of Gal-9 in CRDM patients may be helpful to monitor the therapeutic effect of malignancies.

Objective:To investigate the acute effects of persistent high exposure to atmospheric fine particulate matter (PM 2.5) on residents' outpatient visits for respiratory diseases. Methods:We collected daily outpatient records from 92 hospitals in 13 cities across the Beijing-Tianjin-Hebei region, along with daily PM 2.5, nitrogen dioxide (NO 2), and meteorological data from 2013 to 2018. Five persistent high PM 2.5 exposure scenarios were defined in terms of daily mean PM 2.5 concentrations (>75 μg/m 3 and >150 μg/m 3), duration (≥2 days and ≥3 days), and whether or not there was concurrent exposure to high levels of NO 2 (daily mean NO 2 concentration >50 μg/m 3). A two-stage statistical analysis strategy based on a generalized linear model was applied to conduct a time-series analysis to assess the exposure-response relationship between persistent high PM 2.5 exposure scenarios and residents' outpatient visits for a variety of respiratory diseases, and to estimate excess outpatient visits. Results:During the period, M ( Q1, Q3) PM 2.5 and NO 2 concentrations were 61.2 (42.3, 95.1) μg/m 3 and 40.2 (31.4, 54.4) μg/m 3, respectively, and the daily respiratory disease outpatient visits were 57 (52, 66) cases. When compared with non-permanent high PM 2.5 exposure periods, exposure scenarios with PM 2.5 >75 μg/m 3 and lasting for ≥2 days caused an increased risk of outpatient visits for respiratory diseases by 2.10% (95% CI: 1.44%-2.77%), and resulted in 43 787 (95% CI: 30 025-57 757) excess visits; in this scenario, the concurrent exposure to high levels of NO 2 had a greater acute effect on respiratory disease visits than the absence of exposure to high levels of NO 2 ( P<0.001). The risk of respiratory disease visits increased substantially by 4.41% (95% CI: 3.15%-5.68%) when the daily mean PM 2.5 concentration exceeded 150 μg/m 3 for ≥2 days. Subgroup disease analyses showed that scenarios with daily mean PM 2.5 concentrations exceeding 75 μg/m 3 for ≥3 days caused a significant increase in the risk of lower respiratory tract infections, chronic lower respiratory disease, and asthma visits. Conclusions:Sustained persistent high PM 2.5 exposure increases the risk of outpatient visits for various respiratory diseases; concurrent exposure to high concentrations of NO 2 leads to a greater risk of visiting the clinic, suggesting that the prevention and control of PM 2.5 pollution should be synchronized with the control of mobile source emissions, to synergistically manage the compound pollution of PM 2.5 and NO 2 in the atmosphere.

Objective:To investigate the clinical significance of serum galectin-9 (Gal-9) in patients with dermatomyositis (DM) or clinically amyopathic dermatomyositis (CADM) .Methods:This cross-sectional study included 105 newly diagnosed patients with DM or CADM who were admitted to the Department of Dermatology in Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, from January 2015 to October 2024, among whom 53 had cancer-associated DM/CADM (CRDM). Additionally, an age-matched control group was included, consisting of 30 newly diagnosed cancer patients without autoimmune diseases, 27 systemic lupus erythematosus (SLE) patients, and 31 healthy controls. Serum levels of Gal-9 and transcriptional intermediary factor 1-gamma (TIF1-γ) were measured using enzyme-linked immunosorbent assay. The relationship between Gal-9 levels and laboratory indicators of DM disease activity was analyzed. Comparisons between different groups were performed using the t-test, Mann-Whitney U test, and chi-square test. Spearman correlation analysis was used to assess the association between Gal-9 levels and laboratory indicators. The diagnostic efficacy of Gal-9 and TIF1-γ for CRDM was evaluated using receiver operating characteristic (ROC) curve analysis. Results:Among the 105 DM/CADM patients, 35 were male (33.3%) and 70 were female (66.7%), with a mean age of 53.2 ± 15.1 years. In the 53 CRDM patients, the incidence rates of V-neck sign, dyschromia, and dysphagia were higher than those in non-CRDM patients (all P > 0.05). Serum Gal-9 levels in DM/CADM patients (21.2 [12.2, 32.3] ng/ml) were significantly higher than those in healthy controls (6.8 [5.4, 7.9] ng/ml, P < 0.001), SLE patients (12.3 [8.1, 15.5] ng/ml, P = 0.011), and cancer patients without autoimmune diseases (7.5 [4.9, 8.5] ng/ml, P < 0.001). Gal-9 levels were positively correlated with serum TIF1-γ antibody levels ( rs = 0.21, P = 0.029), serum ferritin ( rs = 0.29, P = 0.003), lactate dehydrogenase ( rs = 0.44, P < 0.001), creatine kinase ( rs = 0.28, P = 0.004), aspartate aminotransferase ( rs = 0.42, P < 0.001), C-reactive protein ( rs = 0.34, P < 0.001), and erythrocyte sedimentation rate ( rs = 0.46, P < 0.001). Among CRDM patients, those who had not received cancer treatment had higher Gal-9 levels (30.1 [23.3, 38.3] ng/ml) than those in stable condition after cancer treatment (13.5 [10.5, 27.9] ng/ml, P = 0.007). The area under the ROC curve (AUC) for serum TIF1-γ in diagnosing CRDM was 0.718, with an optimal cutoff value of 23.02 U/ml. The AUC for serum Gal-9 was 0.719, with an optimal cutoff value of 55.02 ng/ml. When combining both markers, the AUC increased to 0.783, with a sensitivity of 0.85 and specificity of 0.74. Conclusions:Gal-9 was highly expressed in serum of DM/CADM patients, particularly in CRDM patients. Dynamic monitoring of Gal-9 in CRDM patients may be helpful to monitor the therapeutic effect of malignancies.

Objective:To investigate the acute effects of persistent high exposure to atmospheric fine particulate matter (PM 2.5) on residents' outpatient visits for respiratory diseases. Methods:We collected daily outpatient records from 92 hospitals in 13 cities across the Beijing-Tianjin-Hebei region, along with daily PM 2.5, nitrogen dioxide (NO 2), and meteorological data from 2013 to 2018. Five persistent high PM 2.5 exposure scenarios were defined in terms of daily mean PM 2.5 concentrations (>75 μg/m 3 and >150 μg/m 3), duration (≥2 days and ≥3 days), and whether or not there was concurrent exposure to high levels of NO 2 (daily mean NO 2 concentration >50 μg/m 3). A two-stage statistical analysis strategy based on a generalized linear model was applied to conduct a time-series analysis to assess the exposure-response relationship between persistent high PM 2.5 exposure scenarios and residents' outpatient visits for a variety of respiratory diseases, and to estimate excess outpatient visits. Results:During the period, M ( Q1, Q3) PM 2.5 and NO 2 concentrations were 61.2 (42.3, 95.1) μg/m 3 and 40.2 (31.4, 54.4) μg/m 3, respectively, and the daily respiratory disease outpatient visits were 57 (52, 66) cases. When compared with non-permanent high PM 2.5 exposure periods, exposure scenarios with PM 2.5 >75 μg/m 3 and lasting for ≥2 days caused an increased risk of outpatient visits for respiratory diseases by 2.10% (95% CI: 1.44%-2.77%), and resulted in 43 787 (95% CI: 30 025-57 757) excess visits; in this scenario, the concurrent exposure to high levels of NO 2 had a greater acute effect on respiratory disease visits than the absence of exposure to high levels of NO 2 ( P<0.001). The risk of respiratory disease visits increased substantially by 4.41% (95% CI: 3.15%-5.68%) when the daily mean PM 2.5 concentration exceeded 150 μg/m 3 for ≥2 days. Subgroup disease analyses showed that scenarios with daily mean PM 2.5 concentrations exceeding 75 μg/m 3 for ≥3 days caused a significant increase in the risk of lower respiratory tract infections, chronic lower respiratory disease, and asthma visits. Conclusions:Sustained persistent high PM 2.5 exposure increases the risk of outpatient visits for various respiratory diseases; concurrent exposure to high concentrations of NO 2 leads to a greater risk of visiting the clinic, suggesting that the prevention and control of PM 2.5 pollution should be synchronized with the control of mobile source emissions, to synergistically manage the compound pollution of PM 2.5 and NO 2 in the atmosphere.