BackgroundAttention deficit hyperactivity disorder （ADHD） is a neurodevelopmental disorder characterized by age-inappropriate inattention， excessive activities incongruous with setting， and emotional impulsivity. Subthreshold ADHD （sADHD） is clinically defined as the presence of ADHD symptoms that do not meet the full diagnostic criteria for ADHD. Children with sADHD exhibit deficits in executive function， demonstrate more conduct， learning， and anxiety-related problems compared to typically developing children， and show even poorer working memory performance than children diagnosed with ADHD. Currently， there is limited epidemiological research on sADHD in China， with few studies simultaneously investigating the prevalence of both ADHD and sADHD in children. ObjectiveTo investigate the prevalence of ADHD and sADHD among children aged 6–13 years in Chongqing， analyzing their distribution characteristics within this population， with the aim of providing references for developing preventive measures against both ADHD and sADHD. MethodsFrom October to November 2023， a total of 3 398 students in grades 1–6 from six primary schools in Jiangbei District， Chongqing were selected using a stratified cluster random sampling method. The occurrence of ADHD and sADHD was evaluated by using the short version （18-item version） of the Swanson， Nolan， and Pelham IV rating scales （SNAP-IV） and the Chinese vision of Schedule for Affective Disorder and Schizophrenia for School-aged Children-Present and Lifetime Version （K-SADS-PL）. ResultsThe ADHD detection rate among children in Chongqing was 1.90% （95% CI： 0.014–0.024）. Boys showed a significantly higher ADHD detection rate than girls （χ²=7.733， P=0.005）. No statistically significant differences were found in ADHD detection rates across different grades or age groups （χ²=7.347， 12.362， P>0.05）. The sADHD detection rate was 6.32% （95% CI： 0.054–0.072）. Similarly， boys exhibited significantly higher sADHD detection rates than girls （χ²=21.005， P<0.01）. Significant differences emerged across different grades （χ²=20.559， P=0.001）， while no statistically significant difference was observed in age groups （χ²=12.070， P=0.060）. ConclusionThe ADHD detection rates were comparable across all grade levels and age groups from 6–13 years old. Second-grade children demonstrated notably higher sADHD rates compared to other grades， while boys demonstrated higher prevalence rates than girls for both ADHD and sADHD. ［Funded by Science and Health Joint Medical Research Project in Jiangbei District， Chongqing City in the Second Half of 2023 （number， 2023JBKWLH022）］

Objective To explore the underlying mechanism of β2 adrenergic receptor(ADRB2)in fibrogenesis during wound healing.Methods Non-specific ADRB2 gene knockdown adeno-associated virus(AAV-ADRB2 group,6 mice)and control virus(AAV-NC group,6 mice)was injected randomly into the back skin of 12 mice for 21 days,a full-thickness skin defected wound healing murine model was established.Wound healing rates were recorded at the 1st,3rd,5th,and 7th day after operation.Histological examinations by H-E staining,Masson staining,and immunohistochemistry were conducted to observe wounded skin tissue structure,fibrosis,and α-SMA protein expression;quantitative PCR was employed to analyze ADRB2 and matrix metalloproteinase(MMP)mRNA levels;Western blotting was utilized to assess the protein expression levels of COL1A1,COL3A1,TGF-β1,and Smad3.Results On postoperative day 5 and 7,the wound healing rate of the AAV-ADRB2 group significantly decreased(P＜0.05),accompanied by a series pathological changes,including thickened epidermis,exaggerated inflammation,reduced fibroblast count,and inhibited collagen deposition;the α-SMA expression showed a significant decrease(P＜0.05),and the ratio of COL1A1 to COL3A1 decreased(P＜0.05);ADRB2 mRNA levels significantly decreased(P＜0.01),while MMP-1 and MMP-8 mRNA levels increased(P＜0.01);the protein levels of TGF-β1 and Smad3 exhibited a significant decrease(P＜0.05).Conclusions ADRB2 knockdown reduced fibrosis during wound healing and degenerated connective tissue content around the wound bed by inhibiting the TGF-β1/Smad3 signaling pathway,which leads to an increase in MMP mRNA levels and a decrease in the ratio of type Ⅰ to type Ⅲ collagen.