Background Childhood asthma has been associated with exposure to particulate matter (PM), and the magnitude of this association may differ by particle size. However, many previous epidemiological studies have generally used trimester-specific or annual average PM concentrations as exposure metrics, which may mask the effects of short-term high-concentration exposures. Furthermore, evidence remains limited regarding weekly sensitive windows of PM exposure during pregnancy and infancy, particularly with respect to sex-specific susceptibility. Objective To identify sensitive windows for the associations of PM exposure of different particle size during pregnancy and infancy with childhood asthma and to examine potential sex differences. Methods As part of the China, Children, Homes, Health (CCHH) study, a questionnaire-based survey was conducted from June 2019 to June 2020 to obtain data on asthma-related information from 28788 preschoolers from seven Chinese cities. A spatiotemporal extremely randomized trees (STET) model was employed to estimate exposure to submicron particulate matter (PM₁), fine particulate matter (PM_2.5), and inhalable particulate matter (PM₁₀). Weekly sensitive exposure windows were assessed using distributed lag nonlinear models (DLNMs), followed by sex-stratified analyses. Restricted cubic spline (RCS) functions were further applied among boys and girls to evaluate the dose–response relationship between size-fractionated PM exposure during the week with the largest effect estimate and childhood asthma. Results The mean concentrations of PM₁, PM_2.5, and PM₁₀ across the seven cities were (34.5±7.2), (62.3±10.4), and (103.5±21.9) μg·m⁻³, respectively, with significant between-city differences. Wuhan had the highest PM₁ and PM_2.5 concentrations, Urumqi had the highest PM₁₀ concentration, and Shanghai generally exhibited lower concentrations across all particle size fractions. The sensitive windows for the associations of PM₁, PM_2.5, and PM₁₀ exposure with childhood asthma started at postnatal weeks 15, 17, and 29, respectively, and persisted until week 52. The maximum effect estimates for all three particle sizes were observed at week 52 (PM₁, OR=1.0358, 95%CI: 1.0135, 1.0587; PM_2.5, OR=1.0191, 95%CI: 1.0087, 1.0296; and PM₁₀, OR=1.0103, 95%CI: 1.0047, 1.0159). No sensitive window was identified during the prenatal period. In sex-stratified analyses, exposure to PM₁, PM_2.5, and PM₁₀ during postnatal weeks 18–52, 22–52, and 24–52, respectively, was associated with increased odds of childhood asthma in boys, whereas no sensitive window was identified in girls. Exposure-response curves showed monotonically increasing asthma risks in boys when PM₁, PM_2.5, and PM₁₀ concentrations exceeded 11.9, 22.3, and 41.7 μg·m⁻³, respectively; this pattern was not observed in girls. Conclusion Postnatal exposure to PM rather than prenatal exposure is associated with increased odds of childhood asthma, with distinct sensitive windows during infancy. Smaller particles, particularly PM₁, show larger effect estimates, earlier onset, and longer duration of sensitive windows. Boys appear to be more susceptible to early-life PM exposure than girls, as reflected by strong associations and more distinct sensitive windows.

Purpose: This study aims to comprehensively evaluate the clinical efficacy of chemotherapy or endocrine therapy maintenance in metastatic breast cancer (MBC) patients. Materials and Methods: The meta-analysis of randomized clinical trials (RCTs) and propensity score matching of multicenter cohort study evaluated MBC patients who underwent first-line chemotherapy or endocrine therapy maintenance. This study is registered with PROSPERO: CRD42017071858 and ClinicalTrials.gov: NCT04258163. Results: A total of 2,867 patients from 15 RCTs and 760 patients from multicenter cohort were included. The results from meta-analysis showed that chemotherapy maintenance improved progression-free survival (PFS) (hazard ratio [HR], 0.63; 95% confidence interval [CI], 0.54 to 0.73; p < 0.001; moderate-quality evidence) and overall survival (OS) (HR, 0.87; 95% CI 0.78 to 0.97; p=0.016; high-quality evidence) than observation. In the cohort study, for hormone receptor–positive MBC patients, chemotherapy maintenance improved PFS (HR, 0.67; 95% CI, 0.52 to 0.85; p < 0.001) and OS (HR, 0.55; 95% CI 0.42 to 0.73; p < 0.001) compared with observation, and endocrine therapy maintenance also improved PFS (HR, 0.65; 95% CI, 0.53 to 0.80; p < 0.001) and OS (HR, 0.55; 95% CI, 0.44 to 0.69; p < 0.001). There were no differences between chemotherapy and endocrine therapy maintenance in PFS and OS (all p > 0.05). Regardless of the continuum or switch maintenance therapy, showed prolonged survival in MBC patients who were response to first-line treatment. Conclusion This study provided evidences for survival benefits of chemotherapy and endocrine therapy maintenance in MBC patients, and there was no difference efficacy between chemotherapy and endocrine therapy maintenance for hormone receptor–positive patients.

Objective:To provide references for the aeromedical qualification of flying personnel with myocardial bridges by retrospectively analysising the clinical characteristics and aeromedical qualification results.Methods:The clinical characteristics and aeromedical qualification of military flying personnel who underwent coronary angiography examinations and diagnosed as myocardial bridges in Air Force Medical Center from January of 2010 to January of 2020 were compared and analyzed.Results:A total of 84 segments of myocardial bridge diseases were detected in 79 flying personnel diagnosed as myocardial bridges located in the left coronary artery system, of which the middle segment of the left anterior descending artery accounted for 73.81% (62/84). A total of 77 single-segment myocardial bridges occurred in the anterior descending artery in 79 flying personnel diagnosed as myocardial bridges, of which 28 cases were combined with atherosclerotic lesions of the anterior descending artery. The areomedical qualification concluded that 49 cases were qualified for flight, 27 cases were temporarily disqualified, and 3 cases were disqualified. There were significant differences in treadmill exercise results and myocardial ischemia between the qualified and temporarily disqualified groups ( χ2 =7.902, 7.832, both P=0.005). Conclusions:Myocardial bridges in military flying personnel mainly occurs in the middle of the left anterior descending artery, which is easy to merge with proximal coronary atherosclerotic lesions, and the existing clinical evaluation indicators are not accurate enough, and the basis for areomedical qualification needs to be further improved.

Objective:To provide references for the aeromedical qualification of flying personnel with myocardial bridges by retrospectively analysising the clinical characteristics and aeromedical qualification results.Methods:The clinical characteristics and aeromedical qualification of military flying personnel who underwent coronary angiography examinations and diagnosed as myocardial bridges in Air Force Medical Center from January of 2010 to January of 2020 were compared and analyzed.Results:A total of 84 segments of myocardial bridge diseases were detected in 79 flying personnel diagnosed as myocardial bridges located in the left coronary artery system, of which the middle segment of the left anterior descending artery accounted for 73.81% (62/84). A total of 77 single-segment myocardial bridges occurred in the anterior descending artery in 79 flying personnel diagnosed as myocardial bridges, of which 28 cases were combined with atherosclerotic lesions of the anterior descending artery. The areomedical qualification concluded that 49 cases were qualified for flight, 27 cases were temporarily disqualified, and 3 cases were disqualified. There were significant differences in treadmill exercise results and myocardial ischemia between the qualified and temporarily disqualified groups ( χ2 =7.902, 7.832, both P=0.005). Conclusions:Myocardial bridges in military flying personnel mainly occurs in the middle of the left anterior descending artery, which is easy to merge with proximal coronary atherosclerotic lesions, and the existing clinical evaluation indicators are not accurate enough, and the basis for areomedical qualification needs to be further improved.