ObjectiveTo analyze the epidemiological characteristics of long COVID and to investigate its main influencing factors by examining individuals infected with SARS-CoV-2 between March and June 2022 in two communities in Shanghai, to lay the foundation for further research on the mechanism and clinical treatment of long COVID, and to provide the basis for the development of inexpensive, convenient, and feasible prevention and intervention strategies. MethodsA cross-sectional study was conducted, enrolling 6 410 individuals infected with SARS-CoV-2. Data were collected through a questionnaire survey. The incidence and common symptoms of long COVID were analyzed, along with their associations with demographic characteristics, medical history, and behavioral factors. A logistic regression model was used to identify the major factors associated with the development of long COVID symptoms. ResultsThe overall incidence rate of long COVID among the study population was 13.9%. The most commonly reported symptoms included fatigue (65.1%), attention disorders (23.1%), and cough (16.9%). The analysis showed that having underlying chronic diseases (OR=2.580, 95%CI: 2.165‒3.074), a history of allergies (OR=1.418, 95%CI: 1.003‒1.971), current smoking (OR=1.461, 95%CI: 1.013‒2.079), ever smoking (OR=2.462, 95%CI: 1.687‒3.551), a greater number of symptoms during the acute phase [1 symptom (OR=1.778, 95%CI: 1.459‒2.162), 2 symptoms (OR=2.749, 95%CI: 2.209‒3.409), ≥3 symptoms (OR=7.792, 95%CI: 6.333‒9.593)] and aggravated symptoms during the acute phase (OR=1.082, 95%CI: 1.070‒1.094) were factors associated with a higher risk of developing long COVID symptoms. Additionally, individuals who had consumed alcohol in the past year (OR=1.914, 95%CI: 1.344‒2.684) were more prone to objective long COVID symptoms. Among individuals under 50 years of age, females (OR=1.427, 95%CI: 1.052‒1.943) were more likely to develop objective long COVID symptoms. ConclusionThis study has identified the diversity of long COVID symptoms, which involve multiple organs and systems, including fatigue, attention disorders, cough, and joint pain. It has also revealed associations between long COVID and various demographic factors (e.g., age, gender), personal medical history (e.g., underlying chronic diseases, history of allergies), acute-phase characteristics (e.g., number and severity of symptoms), and behavioral factors (e.g., smoking, alcohol consumption). These findings highlight the need for further research and ongoing surveillance of long COVID and may inform the development of more targeted health management strategies for specific populations.

ObjectiveTo analyze the epidemiological characteristics and influencing factors of SARS-CoV-2 reinfection by conducting follow-up investigations among community residents who experienced their first SARS-CoV-2 infection between March and June 2022, so as to provide a scientific basis for predicting future epidemic trends and adjusting prevention and control strategies. MethodsA cohort study was conducted in Xuhui District, Shanghai. A total of 1 208 individuals with a documented primary SARS-CoV-2 infection between March and June 2022 were enrolled and followed-up longitudinally. Data were collected using structured questionnaire surveys to assess the reinfection rate, incidence density, and clinical manifestations of SARS-CoV-2 reinfection. A logistic regression model was used to analyze the influencing factors of SARS-CoV-2 reinfection. ResultsA total of 497 SARS-CoV-2 reinfection cases were observed among the 1 208 research subjects, with a reinfection rate of 41.14% and an incidence density of 0.63 cases per 1 000 person-days. The cumulative reinfection rates at 6, 9, 12, 15, and 18 months following the initial infection were 0.08%, 15.31%, 19.04%, 33.53%, and 38.25%, respectively. Compared with the primary infection, reinfection was more likely to be symptomatic, with a greater severity of fever, dry cough, sore throat, and runny nose. Being female, younger age, and symptom duration ≥7 days during the primary infection were identified as influencing factors for SARS-CoV-2 reinfection, while a higher socioeconomic status can reduce the risk of SARS-CoV-2 reinfection. ConclusionSARS-CoV-2 reinfection is relatively common and often symptomatic. Age, gender, income level, and the duration of symptoms during the primary infection are identified as infuencing factors for SARS-CoV-2 reinfection. Continuous monitoring of reinfection in the population is recommended, along with the development of effective strategies to mitigate the impact of reinfection.

Objective:To explore the correlations of sleep quality and architecture with heart rate variability (HRV) in patients with stenoses of vertebrobasilar artery system and internal carotid artery system.Methods:A retrospective study was performed; 72 patients with stenosis or occlusion of the head and neck arteries (not resulting in cerebral infarction) admitted to Department of Neurology, Second Affiliated Hospital of Zhengzhou University from June 2023 to June 2024 were chosen, including 33 patients with moderate-to-severe stenosis or occlusion of the vertebrobasilar system (VB group) and 39 patients with moderate-to-severe stenosis or occlusion of the internal carotid artery system (ICA group). Pittsburgh sleep quality index (PSQI) and polysomnography (PSG) were used to evaluate the sleep quality and architecture, respectively; and 24-hour ambulatory electrocardiogram was used to assess the HRV. Differences in PSQI score, PSG and HRV parameters between the two groups were compared; partial correlation analysis was used to explore the correlations of HRV parameters with PSQI scores and PSG parameters; multivariate linear regression was used to analyze the independent influencing factors for HRV.Results:(1) Compared with the ICA group, the VB group exhibited significantly higher PSQI scores, spontaneous arousal index (SAI), ratio of time of stage 1 non-rapid eye movement sleep/total sleep time (T N1/T t), and apnea-hypopnea index (AHI), while significantly lower ratio of time of rapid eye movement sleep/total sleep time (T R/T t), spindle wave density in stage 2 non-rapid eye movement sleep (N2), lowest blood oxygen saturation, standard deviation of normal to normal intervals (SDNN) of all sinus beats, low-frequency power (LF), and high-frequency power (HF, P<0.05). (2) In both VB group and ICA group, SDNN was negatively correlated with PSQI score ( r=-0.461, P=0.020; r=-0.378, P=0.036). In the VB group, SDNN was negatively correlated with T N1/T t ( r=-0.467, P=0.019) and SAI ( r=-0.551, P=0.004), and positively correlated with ratio of time of stage 3 non-rapid eye movement sleep/total sleep time (T N3/T t, r=0.686, P<0.001) and spindle wave density in N2 ( r=0.518, P=0.008); LF and HF were negatively correlated with SAI ( r=-0.481, P=0.015; r=-0.564, P=0.003). In the ICA group, HF was negatively correlated with spindle wave density in N2 ( r=-0.369; P=0.041). (3) Multivariate linear regression results indicated that T N3/T t (β=0.348, P=0.018), SAI (β=-0.330, P=0.018), and spindle wave density in N2 (β=0.286, P=0.013) were independent influencing factors for Ln_SDNN in patients with moderate-to-severe stenosis or occlusion of the vertebrobasilar system. Conclusion:Patients with stenosis or occlusion of the vertebrobasilar system exhibit poorer subjective sleep quality, increased light sleep, heightened arousal, and reduced sleep stability compared with those with stenosis or occlusion of the internal carotid artery system, which may be caused by the imbalance of autonomic nerve function.

Objective:To explore the correlations of sleep quality and architecture with heart rate variability (HRV) in patients with stenoses of vertebrobasilar artery system and internal carotid artery system.Methods:A retrospective study was performed; 72 patients with stenosis or occlusion of the head and neck arteries (not resulting in cerebral infarction) admitted to Department of Neurology, Second Affiliated Hospital of Zhengzhou University from June 2023 to June 2024 were chosen, including 33 patients with moderate-to-severe stenosis or occlusion of the vertebrobasilar system (VB group) and 39 patients with moderate-to-severe stenosis or occlusion of the internal carotid artery system (ICA group). Pittsburgh sleep quality index (PSQI) and polysomnography (PSG) were used to evaluate the sleep quality and architecture, respectively; and 24-hour ambulatory electrocardiogram was used to assess the HRV. Differences in PSQI score, PSG and HRV parameters between the two groups were compared; partial correlation analysis was used to explore the correlations of HRV parameters with PSQI scores and PSG parameters; multivariate linear regression was used to analyze the independent influencing factors for HRV.Results:(1) Compared with the ICA group, the VB group exhibited significantly higher PSQI scores, spontaneous arousal index (SAI), ratio of time of stage 1 non-rapid eye movement sleep/total sleep time (T N1/T t), and apnea-hypopnea index (AHI), while significantly lower ratio of time of rapid eye movement sleep/total sleep time (T R/T t), spindle wave density in stage 2 non-rapid eye movement sleep (N2), lowest blood oxygen saturation, standard deviation of normal to normal intervals (SDNN) of all sinus beats, low-frequency power (LF), and high-frequency power (HF, P<0.05). (2) In both VB group and ICA group, SDNN was negatively correlated with PSQI score ( r=-0.461, P=0.020; r=-0.378, P=0.036). In the VB group, SDNN was negatively correlated with T N1/T t ( r=-0.467, P=0.019) and SAI ( r=-0.551, P=0.004), and positively correlated with ratio of time of stage 3 non-rapid eye movement sleep/total sleep time (T N3/T t, r=0.686, P<0.001) and spindle wave density in N2 ( r=0.518, P=0.008); LF and HF were negatively correlated with SAI ( r=-0.481, P=0.015; r=-0.564, P=0.003). In the ICA group, HF was negatively correlated with spindle wave density in N2 ( r=-0.369; P=0.041). (3) Multivariate linear regression results indicated that T N3/T t (β=0.348, P=0.018), SAI (β=-0.330, P=0.018), and spindle wave density in N2 (β=0.286, P=0.013) were independent influencing factors for Ln_SDNN in patients with moderate-to-severe stenosis or occlusion of the vertebrobasilar system. Conclusion:Patients with stenosis or occlusion of the vertebrobasilar system exhibit poorer subjective sleep quality, increased light sleep, heightened arousal, and reduced sleep stability compared with those with stenosis or occlusion of the internal carotid artery system, which may be caused by the imbalance of autonomic nerve function.