Objective To characterize Schistosoma japonicum Class F G protein-coupled receptors (GPCRs), and to decipher the biological function of S. japonicum Smoothened receptor (SjSMO), so as to provide insights into screening of novel anti-schistosomal drug targets. Methods Six Class F GPCRs were identified from the S. japonicum GPCR library using a hidden Markov model (HMM) and genome annotation filese, including five frizzled (FZD) receptors (SjFZD4, SjFZD5, SjFZD7, SjFZD8, SjFZD10) and one Smoothened receptor (SjSMO). Protein domain analysis was performed at the SMART website, and a phylogenetic tree was built with the software MEGA 11.0 and refined with the Interactive Tree Of Life (iTOL) tool. The expression profile and tissue localization of S. japonicum class F GPCRs were analyzed using the real-time fluorescence-based quantitative PCR (RT-qPCR) assay and in situ hybridization, and the effects of SjSMO on parasite growth, development, reproduction, and oviposition were examined using in vivo and in vitro RNA interference (RNAi). S. japonicum adult worms were selected for double-stranded RNAi (dsRNA) in in vitro experiments, and a green fluorescent protein (GFP) negative control group and SjFZD4, SjFZD5, SjFZD7, SjFZD8, SjFZD10, and SjSMO dsRNAi groups were assigned to observe the parasite vitality and state and calculate the female and male rating rate. For in-vivo animal experiments, 6-week-old SPF female mice of the Kunming strain were randomly divided into a GFP dsRNA negative control group and SjFZD4, SjFZD5, SjFZD7, SjFZD8, SjFZD10, and SjSMO dsRNAi groups. Worms and liver tissues were collected for measurement of the worm length and estimation of the worm burdens, and changes in the parasite reproductive organs were observed using alum carmine staining. In addition, the number of S. japonicum eggs in mouse livers was counted and the pathological damages of mouse livers were recorded. Results The five FZD receptors and one Smoothened receptor all contained a conserved Frizzled domain. Phylogenetic analysis revealed that SjSMO formed an independent evolutionary clade, which exhibited a far genetic distance from the FZD family. RT-qPCR assay quantified stable SjSMO expression in male worms but gradually decreased in female worms with worm development, and in situ hybridization revealed high systemic expression of SjSMO. In vitro RNAi results revealed a significant difference in pairing rates among all groups (χ² = 130.530, P < 0.000 1). Only the SjSMO interference group exhibited a markedly reduced worm pairing rate of 20.00%, which was significantly lower than that of the control group (94.74%) (P < 0.000 1), accompanied by decreased worm vitality. In contrast, no statistically significant differences in pairing rates were observed between each FZD family gene interference group and the control group (all P > 0.05). In vivo RNAi assay revealed that SjSMO dsRNAi 1 to 26 days post-infection resulted in a significant reduction in worm length, with reductions in the male worm length by 32.27% and female worm length by 36.77% as compared to controls [male worms: (6.51 ± 1.77) mm vs. (9.62 ± 1.44) mm, t = 7.196, P < 0.000 1; female worms: (5.49 ± 1.36) mm vs. (8.68 ± 2.60) mm, t = 5.953, P < 0.000 1], as well as arrest of testicular development in male worms and ovarian development in females. In addition, SjSMO dsRNAi 26 to 42 days post-infection was found to significantly reduce hepatic egg burdens in mice, with a 49.10% reduction in the count of liver eggs in the SjSMO dsRNAi group relative to the GFP dsRNA negative control group [(2 824 ± 844) eggs per gram vs. (5 548 ± 797) eggs per gram; t = 4.064, P < 0.05], and to alleviate granuloma formation and severity of hepatic fibrosis. Conclusion SjSMO is a key receptor that regulates the growth, development, reproduction, and oviposition of S. japonicum, which provides a new potential target for development of anti-schistosomal drugs.

ObjectiveTo observe the clinical effectiveness of horticultural therapy involving the planting of Chinese medicinal herbs （mint and lily potted plants） combined with intradermal needling therapy for generalized anxiety disorder （GAD） of liver depression transforming into fire syndrome under transcranial magnetic stimulation and basic psychological therapy， and to explore the possible mechanisms of action. MethodsA total of 180 patients with GAD of liver depression transforming into fire syndrome were randomly divided into three groups， horticultural therapy group， intradermal needling group， and horticultural therapy+intradermal needling group， with 60 patients in each. All groups received basic treatment including basic psychological therapy and transcranial magnetic stimulation. The horticultural therapy group received horticultural therapy in addition to the basic treatment； the intradermal needling group received intradermal needling therapy once a week for 8 weeks in addition to the basic treatment； the horticultural therapy+intradermal needling group received both horticultural therapy and intradermal needling therapy， following the same procedures and duration. Hamilton Anxiety Rating Scale （HAMA）， Self-Rating Anxiety Scale （SAS）， and Pittsburgh Sleep Quality Index （PSQI） scores were assessed at baseline and after 2， 4， 6， and 8 weeks of treatment. Serum levels of adrenocorticotropic hormone （ACTH） and corticosterone （CORT） were measured before treatment and after 8 weeks of treatment. Motor-evoked potential （MEP） baseline levels were recorded before treatment， and MEP amplitude ratios were compared after 1 week and 8 weeks of treatment. Clinical effectiveness and safety were evaluated after 8 weeks of treatment. Pearson correlation analysis was used to examine the relationships between serum ACTH and CORT levels， MEP amplitude， and anxiety. ResultsIn the horticultural therapy group and intradermal needling group， HAMA， SAS and PSQI scores after 4， 6， and 8 weeks treatment were lower than baseline scores （P＜0.05）. In the horticultural therapy+intradermal needling group， these scores showed a significant decline starting after 2 weeks treatment and continuing through 8 weeks after treatment （P＜0.05）. The HAMA， SAS， and PSQI scores in the horticultural therapy+intradermal needling group were significantly lower than those in the other two groups after 2， 4， 6， and 8 weeks treatment （P＜0.05）. After 8 weeks of treatment， serum CORT and ACTH levels in the horticultural therapy+intradermal needling group were significantly lower than baseline levels （P＜0.05） and were also lower than those in the horticultural therapy group and intradermal needling group at the same time point （P＜0.01）. When comparing the level after 8 weeks treatment to that after 1 week treatment， under PAS10 stimulation， the MEP amplitude ratio in the intradermal needling group decreased at 30 minutes， while in the horticultural therapy+intradermal needling group， the MEP amplitude ratio decreased at all time points （P＜0.05 or P＜0.001）； under PAS25 stimulation， the MEP amplitude ratio in the horticultural therapy group increased at 20 minutes， and in the intradermal needle group at 10 minutes （P＜0.05）. In the horticultural therapy+intradermal needling group， the MEP amplitude ratio increased significantly at all time points after treatment （P＜0.001）. The cure rate in the horticultural therapy+intradermal needling group （74.14%， 43/58） was significantly higher than that in the horticultural therapy group （30.00%， 18/60） and the intradermal needling group （48.28%， 28/58， P＜0.05）. Correlation analysis revealed that serum ACTH and CORT levels were positively correlated with HAMA scores （r = 0.488， P＜0.01； r = 0.428， P＜0.01）. Following PAS10 intervention， the MEP amplitude ratio was positively correlated with HAMA scores （r = 0.458， P＜0.01）， whereas after PAS25 intervention， the MEP amplitude ratio was negatively correlated with HAMA scores （r = -0.562， P＜0.01）. ConclusionHorticultural therapy combined with intradermal needling treatment， under transcranial magnetic stimulation and basic psychological therapy， demonstrates significant clinical effectiveness in patients with GAD of liver depression transforming into fire syndrome. Its mechanism of action may be related to the regulation of hyperactivation of the hypothalamic-pituitary-adrenal （HPA） axis and the reduction of cortical excitability.

BACKGROUND: Congenital heart disease (CHD) is a leading cause of birth defect-related mortality. However, more recent CHD mortality data for China are lacking. Additionally, limited studies have evaluated sex, rural-urban, and region-specific disparities of CHD mortality in China. METHODS: We designed a population-based study using data from the Dataset of National Mortality Surveillance in China between 2008 and 2021. We calculated age-adjusted CHD mortality using the sixth census data of China in 2010 as the standard population. We assessed the temporal trends in CHD mortality by age, sex, area, and region from 2008 to 2021 using the joinpoint regression model. RESULTS: From 2008 to 2021, 33,534 deaths were attributed to CHD. The period witnessed a two-fold decrease in the age-adjusted CHD mortality from 1.61 to 0.76 per 100,000 persons (average annual percent change [AAPC] = -5.90%). Females tended to have lower age-adjusted CHD mortality than males, but with a similar decline rate from 2008 to 2021 (females: AAPC = -6.15%; males: AAPC = -5.84%). Similar AAPC values were observed among people living in urban (AAPC = -6.64%) and rural (AAPC = -6.12%) areas. Eastern regions experienced a more pronounced decrease in the age-adjusted CHD mortality (AAPC = -7.86%) than central (AAPC = -5.83%) and western regions (AAPC = -3.71%) between 2008 and 2021. Approximately half of the deaths (46.19%) due to CHD occurred during infancy. The CHD mortality rates in 2021 were lower than those in 2008 for people aged 0-39 years, with the largest decrease observed among children aged 1-4 years (AAPC = -8.26%), followed by infants (AAPC = -7.01%). CONCLUSIONS CHD mortality in China has dramatically decreased from 2008 to 2021. The slower decrease in CHD mortality in the central and western regions than in the eastern regions suggested that public health policymakers should pay more attention to health resources and health education for central and western regions.
Humans ; Heart Defects, Congenital/mortality* ; Male ; Female ; China/epidemiology* ; Infant ; Child, Preschool ; Adult ; Child ; Adolescent ; Infant, Newborn ; Middle Aged ; Young Adult ; Aged ; Rural Population

BACKGROUND: Generalized pustular psoriasis (GPP), a rare and recurrent autoinflammatory disease, imposes a substantial burden on patients and society. Awareness of GPP in China remains limited. METHODS: This cross-sectional survey, conducted between September 2021 and May 2023 across 14 hospitals in China, included GPP patients of all ages and disease phases. Data collected encompassed demographics, clinical characteristics, economic impact, disease severity, quality of life, and treatment-related complications. Risk factors for GPP recurrence were analyzed. RESULTS: Among 127 patients (female/male ratio = 1.35:1), the mean age of disease onset was 25 years (1st quartile [Q1]-3rd quartile [Q3]: 11-44 years); 29.2% had experienced GPP for more than 10 years. Recurrence occurred in 75.6% of patients, and nearly half reported no identifiable triggers. Younger age at disease onset ( P  = 0.021) and transitioning to plaque psoriasis ( P  = 0.022) were associated with higher recurrence rates. The median diagnostic delay was 8 months (Q1-Q3: 2-41 months), and 32.3% of patients reported misdiagnoses. Comorbidities were present in 53.5% of patients, whereas 51.1% experienced systemic complications during treatment. Depression and anxiety affected 84.5% and 95.6% of patients, respectively. During GPP flares, the median Dermatology Life Quality Index score was 19.0 (Q1-Q3: 13.0-23.5). This score showed significant differences between patients with and without systemic symptoms; it demonstrated correlations with both depression and anxiety scores. Treatment costs caused financial hardship in 55.9% of patients, underscoring the burden associated with GPP. CONCLUSIONS The substantial disease and economic burdens among Chinese GPP patients warrant increased attention. Patients with early onset disease and those transitioning to plaque psoriasis require targeted interventions to mitigate the high recurrence risk.
Humans ; Male ; Female ; Psoriasis/pathology* ; Adult ; Cross-Sectional Studies ; Adolescent ; Child ; Young Adult ; Quality of Life ; Middle Aged ; China/epidemiology* ; Recurrence ; Risk Factors ; Surveys and Questionnaires ; East Asian People

BACKGROUND: Alpha-glucosidase inhibitors or dipeptidyl peptidase-4 inhibitors are both hypoglycemia agents that specifically impact on postprandial hyperglycemia. We compared the effects of acarbose and sitagliptin add on to metformin on time in range (TIR) and glycemic variability (GV) in Chinese patients with type 2 diabetes mellitus through continuous glucose monitoring (CGM). METHODS: This study was a randomized, open-label, active-con-trolled, parallel-group trial conducted at 15 centers in China from January 2020 to August 2022. We recruited patients with type 2 diabetes aged 18-65 years with body mass index (BMI) within 19-40 kg/m 2 and hemoglobin A1c (HbA1c) between 6.5% and 9.0%. Eligible patients were randomized to receive either metformin combined with acarbose 100 mg three times daily or metformin combined with sitagliptin 100 mg once daily for 28 days. After the first 14-day treatment period, patients wore CGM and entered another 14-day treatment period. The primary outcome was the level of TIR after treatment between groups. We also performed time series decomposition, dimensionality reduction, and clustering using the CGM data. RESULTS: A total of 701 participants received either acarbose or sitagliptin treatment in combination with metformin. There was no statistically significant difference in TIR between the two groups. Time below range (TBR) and coefficient of variation (CV) levels in acarbose users were significantly lower than those in sitagliptin users. Median (25th percentile, 75th percentile) of TBR below target level <3.9 mmol/L (TBR 3.9 ): Acarbose: 0.45% (0, 2.13%) vs . Sitagliptin: 0.78% (0, 3.12%), P = 0.042; Median (25th percentile, 75th percentile) of TBR below target level <3.0 mmol/L (TBR 3.0 ): Acarbose: 0 (0, 0.22%) vs . Sitagliptin: 0 (0, 0.63%), P = 0.033; CV: Acarbose: 22.44 ± 5.08% vs . Sitagliptin: 23.96 ± 5.19%, P <0.001. By using time series analysis and clustering, we distinguished three groups of patients with representative metabolism characteristics, especially in GV (group with small wave, moderate wave and big wave). No significant difference was found in the complexity of glucose time series index (CGI) between acarbose users and sitagliptin users. By using time series analysis and clustering, we distinguished three groups of patients with representative metabolism characteristics, especially in GV. CONCLUSIONS: Acarbose had slight advantages over sitagliptin in improving GV and reducing the risk of hypoglycemia. Time series analysis of CGM data may predict GV and the risk of hypoglycemia. TRIAL REGISTRATION Chinese Clinical Trial Registry: ChiCTR2000039424.
Humans ; Metformin/therapeutic use* ; Sitagliptin Phosphate/therapeutic use* ; Acarbose/therapeutic use* ; Diabetes Mellitus, Type 2/blood* ; Middle Aged ; Male ; Female ; Adult ; Blood Glucose/drug effects* ; Hypoglycemic Agents/therapeutic use* ; Aged ; Glycated Hemoglobin/metabolism* ; Adolescent ; Young Adult ; China ; East Asian People

Objective:To analyze the association between daily physical activity patterns and dyslipidemia among people receiving physical examination aged 40-65 years.Methods:This cross-sectional study consecutively enrolled 864 participants aged 40-65 years and met the inclusion and exclusion criteria who underwent health check-ups at the Physical Examination Center of Fuquan First People′s Hospital from March to November in 2022. The data of general characteristics, physical activity, physical examination findings, and lipid profiles were collected. The daily physical activity patterns were identified using K-means clustering analysis. The unconditional binary logistic regression was employed to explore the associations between these activity patterns and dyslipidemia, followed by subgroup analyses.Results:The physical activity of the 864 study participants (517 males and 347 females) included in the analysis was divided into 4 patterns (G1: low physical activity; G2: active commuting; G3: housework; G4: leisure exercise). Using G1 as a reference, after adjusting for confounders, G4 was negatively associated with low high density lipoprotein cholesterol (HDL-C) ( OR=0.37, 95% CI: 0.14-1.00) ( P=0.05). In the male, G3 was negatively associated with dyslipidemia ( OR=0.44, 95% CI: 0.21-0.93) and low HDL-C ( OR=0.25, 95% CI: 0.10-0.68) (both P<0.05). In the subjects aged 50 years and above, G2 was negatively associated with dyslipidemia ( OR=0.52, 95% CI: 0.30-0.90), hypertriglyceridemia ( OR=0.50, 95% CI: 0.28-0.90) and low HDL-C ( OR=0.47, 95% CI: 0.24-0.91) (all P<0.05). In those who never or occasionally stayed up late, G2 was negatively associated with hypertriglyceridemia ( OR=0.31, 95% CI: 0.13-0.75) ( P<0.05); in those who stayed up late often, G4 was negatively associated with dyslipidemia ( OR=0.33, 95% CI: 0.13-0.85) and low HDL-C ( OR=0.19, 95% CI: 0.04-0.84) (both P<0.05). In the centrally obese population, G2 was negatively associated with dyslipidemia ( OR=0.55, 95% CI: 0.35-0.88) and hypertriglyceridemia ( OR=0.54, 95% CI: 0.33-0.86) (both P<0.05). Conclusions:Association between different physical activity patterns and dyslipidemia varied among adults aged 40-65 years undergoing health check-ups. Leisure-time exercise is associated with a reduced risk of dyslipidemia, while household activities also emerges as a beneficial factor linked to lower dyslipidemia risk particularly in the male population.

Objective:To investigate the effect of changes in metabolic syndrome status and persistence on carotid plaque risk.Methods:This retrospective cohort study analyzed individuals who underwent routine health check-ups at the health management center of the Second Affiliated Hospital of Dalian Medical University from 2014 to 2023. Participants with at least three carotid ultrasound records meeting the inclusion criteria were classified into 4 groups based on changes in metabolic status: persistently metabolic health, transitioning from metabolic health to unhealth, transitioning from metabolic unhealth to health, and persistently metabolic unhealth. The cumulative incidence of carotid plaque in these groups was compared. A Cox proportional risk model was used to evaluate the relationship between changes in metabolic syndrome status, the number of metabolic syndrome components, and the risk of carotid plaque development. Restricted cubic spline analysis was applied to explore the association between changes in individual metabolic syndrome components and carotid plaque risk.Results:Compared to the persistently metabolic health group, the persistent unhealth group had the highest risk of developing carotid plaque( HR=1.35, 95% CI 1.05-1.74, P=0.021), followed by those who transitioned from metabolic health to unhealth and those who improved from metabolic unhealth to health. Furthermore, the risk of carotid plaque increased progressively with the number of metabolic syndrome components. Restricted cubic spline analysis revealed a nonlinear relationship between fasting blood glucose change and carotid plaque risk, while systolic blood pressure, diastolic blood pressure, waist circumference, triglycerides, and high-density lipoprotein-cholesterol showed a linear dose-response relationship with carotid plaque. Conclusions:The change of metabolic syndrome is associated with the risk of developing carotid plaque, and maintaining metabolic health, recovering from metabolic syndrome, or minimizing the number of metabolic syndrome components may be effective strategies to prevent carotid plaque formation.

Objective:To explore the relationship between thyroid hormone sensitivity and metabolic dysfunction-associated steatotic liver disease(MASLD) in a population with normal thyroid function, with a particular focus on sex-specific differences.Methods:This retrospective study included 41 355 euthyroid cases who underwent routine health examinations at the Health Management Centre of the Second Affiliated Hospital of Dalian Medical University from January 2014 to December 2023 were included. The free triiodothyronine(FT 3) to free thyroxine(FT 4) ratio(FT 3/FT 4) was calculated in order to reflect the peripheral sensitivity of the thyroid gland. Similarly, thyroid feedback quantile-based index(TFQI), thyrotrophic thyroxine resistance index(TT 4RI), and the FT 3-based TFQI-derived index(TFQI-FT 3) were calculated in order to reflect the central sensitivity of the thyroid gland. A Logistic regression was employed to analyse the effect of sex-specific thyroid hormone sensitivity indices on the prevalence of MASLD. The restricted cubic spline was used to analyse the non-linear relationship between the thyroid sensitivity hormone indices and MASLD. Furthermore, the correlation between the thyroid hormone sensitivity indices and MASLD in different subgroups was also analysed. Results:The prevalence of MASLD in the study population was 28.8%. After adjusting the model for confounders, the risk of MASLD increased by 7%, 3%, 10%, and 5% for each standard deviation increase in FT 3/FT 4, TFQI, TFQI-FT 3, and TT 4RI in the total population, respectively. The risk of MASLD increased by 6% and 5% for each standard deviation increase in FT 3/FT 4 and TFQI-FT 3 in men, respectively. For each standard deviation increase in FT 3/FT 4, TFQI, TFQI-FT 3, and TT 4RI in women, the risk of MASLD increased by 6%, 5%, 11%, and 5%, respectively. Higher FT 3/FT 4 and TFQI-FT 3 were positively associated with the risk of developing MASLD in men, and higher FT 3/FT 4, TFQI, TFQI-FT 3, and TT 4RI were positively associated with the risk of developing MASLD in women. There was a non-linear, inverted U-shaped relationship between TFQI and risk of MASLD in women. Subgroup analyses showed positive associations between FT 3/FT 4, TFQI, TFQI-FT 3, and MASLD. Conclusions:The thyroid hormone sensitivity indices may provide a basis for clinical prevention and management of MASLD in individuals with normal thyroid function. Additionally, FT 3/FT 4 and TFQI-FT 3 may indicate the risk of MASLD in the general population, while TFQI and TT 4RI are more suitable for assessing the risk of MASLD in women.

Objective To investigate the effect of ginsenoside Re on angiotensin Ⅱ(Ang Ⅱ)-induced proliferation,migration,and phenotype transformation of vascular smooth muscle cells(VSMCs)by regulating the Ras homologous gene family member A(RhoA)/mitogen activated protein kinase(MAPK)pathway.Methods MOVAS cells were divided into control group,Ang Ⅱ group,ginsenoside Re low dose group,ginsenoside Re medium dose group,ginsenoside Re high dose group,andginsenoside Re high dose+RhoA activator(U46619)group.MOVAS cell proliferation was detected by CCK-8.MOVAS cell migration was detected by scratch assay.Immunocytochemistry was used to detect the positive expression of α-smooth muscle actin(α-SMA)and osteopontin(OPN)proteins in MOVAS cells.qRT-PCR was used to detect the mRNA expression of PCNA,MMP-9,and MMP-2 in MOVAS cells.Western blot was used to detect RhoA,phosphorylated extracellular signal regulated kinase 1/2(p-ERK1/2),phosphorylated stress activated protein kinase 1(p-JNK1),and p-P38 protein in MOVAS cells.Results Compared with the control group,the OD450 value,scratch healing rate,OPN protein positive expression,PCNA,MMP-9,MMP-2 mRNA expression,RhoA,p-ERK1/2,p-JNK1,p-P38 protein expression of MOVAS cells in the Ang II group increased,while the positive expression of α-SMA protein decreased significantly(P<0.05).Compared with the Ang Ⅱ group,the OD450 value,scratch healing rate,OPN protein positive expression,PCNA,MMP-9,MMP-2 mRNA expression,and RhoA,p-ERK1/2,p-JNK1,and p-P38 proteins of MOVAS cells in the low,medium,and high dose groups of ginsenoside Re decreased,while the positive expression of α-SMA protein increased.The trend was most significant in the high dose group of ginsenoside Re(P<0.05).Compared with ginsenoside Re high-dose group,OD450 value,scratch healing rate,OPN protein positive expression,PCNA,MMP-9,MMP-2 mRNA expression and RhoA,p-ERK1/2,p-JNK1,p-P38 protein in ginsenoside Re high-dose+U46619 group increased,the positive expression of α-SMA protein decreased significantly(P<0.05).Conclusion Ginsenoside Re may inhibit the proliferation,migration,and phenotype transformation of Ang Ⅱ in MOVAS cells by suppressing the RhoA/MAPK pathway.

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.