COVID-19 Infection and Dementia: Analyses of time-varying risk, subtypes, and subpopulations from the UK Biobank (preprint)

Background Although COVID-19 patients were suggested to experience worse cognitive outcomes, there is a paucity of evidence on time-varying risk of dementia, especially the subtypes, as well as among critical subpopulations.Methods Out of over 50000 individuals from general population in the UK Biobank, SARS-COV-2 infected patients between March 1, 2020, and July 31, 2021 and maximally 5:1 propensity score matched contemporary non-infected individuals were selected, with baseline dementia excluded. Matching was done on demographic characteristics, lifestyle, and comorbidities. Dementia was captured according to primary care, inpatient records, and death registry, with the follow-up ending at the earliest of outcome occurrence, death, or August 31, 2021. Associations were evaluated using time-varying hazard ratios (HRs) and odds ratios (ORs).Results With a mean age of 64.5 years for 18032 COVID-19 patients and 83,008 controls, participants were followed for a median of 247 (IQR: 204–305) days and 255 dementia cases occurred, including 90 Alzheimer’s disease (AD) cases and 42 vascular dementia (VaD) cases. Compared with matched controls, dementia risk declined drastically after COVID-19 infection and sustained for all-cause dementia, VaD, and other dementia. During the acute phase (first 30 days), COVID-19 infection was associated with increased risks of dementia, with HRs (95% CIs) being 12.77 (6.77, 24.08) for all-cause dementia, 9.21 (2.77, 30.59) for AD, 5.53 (1.69, 18.11) for VaD, and 25.35 (8.74, 73.56) for other dementia. Among those not hospitalized within 30 days of enrollment, elevated dementia risk remained for all-cause dementia, VaD, and other dementia, with ORs being 1.82, 4.55, and 1.64, respectively. Among most of the subpopulations classified by demographic characteristics, APOE genotype, and comorbidities (except for those with chronic obstructive pulmonary diseases at enrollment), COVID-19 infection was associated with an elevated all-cause dementia risk and no modification effect was detected.Conclusions Declined yet sustained elevated dementia risk since COVID-19 infection was found and vascular risk factors may need extra attention during the long-term follow-up. Increased dementia risk from COVID-19 infection also applied for the non-hospitalized during the acute phase and most subpopulations. The potential dementia risk associated with Omicron and newer variants warrants further evaluation.

COVID-19 Infection and Dementia: A Prospective Analysis of Time-Varying Risk, Subtypes, and Subpopulations from the UK Biobank (preprint)

Background: Although COVID-19 patients were suggested to experience worse cognitive outcomes, there is a paucity of evidence on time-varying risk of dementia, especially the subtypes, as well as among critical subpopulations. Methods: Out of over 50000 individuals from general population in the UK Biobank, SARS-COV-2 infected patients between March 1, 2020, and July 31, 2021 and maximally 5:1 propensity score matched contemporary non-infected individuals were selected, with baseline dementia excluded. Matching was done on demographic characteristics, lifestyle, and comorbidities. Dementia was captured according to primary care, inpatient records, and death registry, with the follow-up ending at the earliest of outcome occurrence, death, or August 31, 2021. Associations were evaluated using time-varying hazard ratios (HRs) and odds ratios (ORs). Results: With a mean age of 64.5 years for 18032 COVID-19 patients and 83,008 controls, participants were followed for a median of 247 (IQR: 204–305) days and 255 dementia cases occurred, including 90 Alzheimer’s disease (AD) cases and 42 vascular dementia (VaD) cases. Compared with matched controls, dementia risk declined drastically after COVID-19 infection and sustained for all-cause dementia, VaD, and other dementia. During the acute phase (first 30 days), COVID-19 infection was associated with increased risks of dementia, with HRs (95% CIs) being 12.77 (6.77, 24.08) for all-cause dementia, 9.21 (2.77, 30.59) for AD, 5.53 (1.69, 18.11) for VaD, and 25.35 (8.74, 73.56) for other dementia. Among those not hospitalized within 30 days of enrollment, elevated dementia risk remained for all-cause dementia, VaD, and other dementia, with ORs being 1.82, 4.55, and 1.64, respectively. Among most of the subpopulations classified by demographic characteristics, APOE genotype, and comorbidities (except for those with chronic obstructive pulmonary diseases at enrollment), COVID-19 infection was associated with an elevated all-cause dementia risk and no modification effect was detected. Conclusion: Declined yet sustained elevated dementia risk since COVID-19 infection was found and vascular risk factors may need extra attention during the long-term follow-up. Increased dementia risk from COVID-19 infection also applied for the non-hospitalized during the acute phase and most subpopulations. The potential dementia risk associated with Omicron and newer variants warrants further evaluation.

Country parks as sites of emergency medical facilities A case of Covid-19 in Guangzhou, China (preprint)

As COVID-19 has swept across the world, the escalating number of confirmed and suspected cases overwhelmed the admission capacity of the designated hospitals. Faced with such a grim situation, governments made a quick decision to build emergency medical facilities to address the outbreak, which was an important step toward controlling the growing epidemic and improving the recovery rate. However, the emergency medical facilities faced a huge risk of epidemic spread and improper site could lead to serious secondary transmission. Make use of the disaster prevention function of urban green space, the problems can be alleviated to a certain extent through the “combined with peacetime and epidemic period” design. Through comparison, it is found that country parks are highly compatible with the needs of emergency medical facilities in terms of site selection, scale, environment, infrastructure and coverage. Incorporate country parks into the emergency plan for urban public health emergencies, through early reasonable site selection and layout, pre-exploration and laying of pipe network, strengthen the sewage and garbage treatment system, reasonable planning of health function and other means, greatly improve the construction speed of emergency medical facilities in case of epidemic disaster, and reduce the harm of infectious diseases to the population and the environment.

Development strategy of crayfish industry under COVID-19 epidemic taking Jingzhou city in Hubei Province as an example

The pandemic situation of COVID-19 has seriously influenced the whole chain of crayfish industry--aquaculture, logistic, processing, and service in Jingzhou. In the short term, each link of the industry was difficult to get well completely, the relevant enterprises and new types of agricultural businesses lack of confidence. After undergoing rapid development for many years, it presented some new changes under the epidemic influence: firstly, the cultivation area tend to be stable and rational, and a large scale of crayfish aquaculture was transformed to high quality aquaculture;secondly, the storage and deep processing industry would be developed rapidly;thirdly, the online consumption mode would become widely accepted. Based on our investigation, some suggestions were put forward for crayfish industry to resume production and to promote the sustainable-healthy development. The first, crayfish aquaculture in paddy field should be changed from high production to high quality;the second, processing and server-side should develop new products and new marketing models;the third, the industry management department should strengthen guidance and supervision, local governments at all levels should strongly support from policy, finance and publicity, so that jointly guide the industry upgrading and create regional brands.

Follow-up survey of general practitioners in Zhejiang Province post-completion of position transition training in 2017–2020 (preprint)

Background: Position transition training for general practitioners in Zhejiang Province started in 2017 and has since been held once a year. By the beginning of 2022, four training sessions were completed. The purpose of this survey was to establish the current situation of trainees after their graduation and provide reference for the evaluation of the training effect.Methods: Of the 738 trainees who completed the training, 253 were contacted and followed up. A self-designed questionnaire was used to conduct the survey through online filling in. The content included questions to elucidate the following information: whereabouts after the training, registration as a general practitioner, undertaken general practice teaching and scientific research work, current occupational environment, improvement of post competence after receiving position transition training, willingness to complete survey, willingness to participate in future training programs, etc.Results: A number of 253 valid questionnaires were collected with a recovery rate of 100%. Notably, 93.68% of the participants successfully completed their training and obtained the Training Certificate of General Practitioners. Further, 83.4% were registered as general practitioners, 82.94% of which added on the basis of the original registered scope of practice. Currently, most of them work in primary health care institutions, primarily occupied with medical treatment, chronic disease management, COVID-19 prevention and control, health education, and prevention and health care. Of them, 27.01% were currently undertaking teaching work, and only 3.32% of them were conducting scientific research work related to general practice. The overall satisfaction of the trainees in the three theoretical training bases was above 90%, with no statistically significant difference among them (P > 0.05). Importantly, 84.11% of the followed-up personnel hoped to continue to participate in similar training in the future to improve their general practitioner core competences.Conclusion: The position transition training in Zhejiang Province has achieved good results, but the details of training and the implementation of policies in individual regions need to be improved. Most of the graduates were willing to continue their education, especially in general practitioners with special interests.

Meta-Seg: A Survey of Meta-learning for Image Segmentation

A well-performed deep learning model in image segmentation relies on a large number of labeled data. However, it is hard to obtain sufficient high-quality raw data in industrial applications. Meta-learning, one of the most promising research areas, is recognized as a powerful tool for approaching image segmentation. To this end, this paper reviews the state-of-the-art image segmentation methods based on meta-learning. We firstly introduce the background of the image segmentation, including the methods and metrics of image segmentation. Second, we review the timeline of meta-learning and give a more comprehensive definition of meta-learning. The differences between meta-learning and other similar methods are compared comprehensively. Then, we categorize the existing meta-learning methods into model-based, optimization-based, and metric-based. For each categorization, the popular used meta-learning models are discussed in image segmentation. Next, we conduct comprehensive computational experiments to compare these models on two pubic datasets: ISIC-2018 and Covid-19. Finally, the future trends of meta-learning in image segmentation are highlighted.

Characteristics of asymptomatic COVID-19 infection and progression: A multicenter, retrospective study.

Novel coronavirus disease 2019 (COVID-19), caused by novel coronavirus SARS-CoV-2, has spread globally since the end of 2019. Asymptomatic carriers are of great concern as they can undermine the interventions to stop the pandemic. However, there is limited information about the characteristics and outcomes of the asymptomatic patients. Therefore, we conducted this retrospective study and retrieved data of 79 asymptomatic COVID-19 patients at admission from three designated hospitals in Wuhan, China. The asymptomatic patients could happen at any age, ranged from 9 to 96 years. These patients also had lower levels of alanine aminotransferase and C-reactive protein. Patchy shadowing was the most common manifestation in computed tomography scan. Some asymptomatic carriers developed mild or moderate symptoms during hospitalization. Age and comorbidities, especially hypertension, may be predictive factors for symptom development in the initially asymptomatic carriers at admission. Early detection and treatment for these presymptomatic patients before symptom onset can shorten the communicable period for the coronavirus and reduce the occurrence of severe cases.

Modifiable lifestyle factors and severe COVID-19 risk: Evidence from Mendelian randomization analysis (preprint)

BackgroundLifestyle factors including obesity and smoking are suggested to be related to increased risk of COVID-19 severe illness or related death. However, little is known about whether these relationships are causal, or the relationships between COVID-19 severe illness and other lifestyle factors, such as alcohol consumption and physical activity. MethodsGenome-wide significant genetic variants associated with body mass index (BMI), lifetime smoking, alcohol consumption and physical activity identified by large-scale genome-wide association studies (GWAS) were selected as instrumental variables. GWAS summary statistics of these genetic variants for relevant lifestyle factors and severe illness of COVID-19 were obtained. Two-sample Mendelian randomization (MR) analyses were conducted. ResultsBoth genetically predicted BMI and lifetime smoking were associated with about 2-fold increased risks of severe respiratory COVID-19 and COVID-19 hospitalization (all P<0.05). Genetically predicted physical activity was associated with about 5-fold (95% confidence interval [CI], 1.4, 20.3; P=0.02) decreased risk of severe respiratory COVID-19, but not with COVID-19 hospitalization, though the majority of the 95% CI did not include one. No evidence of association was found for genetically predicted alcohol consumption, but associations were found when using pleiotropy robust methods. ConclusionEvidence is found that BMI and smoking causally increase and physical activity causally decreases the risk of COVID-19 severe illness. This study highlights the importance of maintaining a healthy lifestyle in protecting from COVID-19 severe illness and its public health value in fighting against COVID-19 pandemic.

Clinical Characteristics and Short-Term Outcomes of Severe Patients with COVID-19 in Wuhan, China (preprint)

ObjectiveA novel pneumonia (COVID-19) which is sweeping the globe was started in December, 2019, in Wuhan, China. Most deaths occurred in severe and critically cases, but information on prognostic risk factors for severe ill patients is incomplete. Further research is urgently needed to guide clinicians, so we prospectively evaluate the clinical outcomes of 114 severe ill patients with COVID-19 for short-term in the Union Hospital in Wuhan, China. MethodsIn this single-centered, prospective and observational study, we enrolled 114 severe ill patients with confirmed COVID-19 from Jan 23, 2020 to February 22, 2020. Epidemiological, demographic and laboratory information were collected at baseline, data on treatment and outcome were collected until the day of death or discharge or for the first 28 days after severe ill diagnosis, whichever was shorter. Univariate and multivariate Cox proportional hazard models were used to determine hazard ratios (HRs) and 95% confidence intervals (CIs) of poor outcome. ResultsAmong enrolled 114 patients, 94 (82.5%) had good outcome while 20 (17.5%) had poor outcome. No significant differences were showed in age, gender and the prevalence of coexisting disorders between outcome groups. Results of multivariate Cox analyses indicated that higher levels of oxygen saturation (HR, 0.123; 95% CI, 0.041-0.369), albumin (HR, 0.060; 95% CI, 0.008-0.460) and arterial partial pressure of oxygen (HR, 0.321; 95% CI, 0.106-0.973) were associated with decreased risk of developing poor outcome within 28 days. In the other hand, higher levels of leucocytes (HR, 5.575; 95% CI, 2.080-14.943), neutrophils (HR, 2.566; 95% CI, 1.022-6.443), total bilirubin (HR, 6.171; 95% CI, 2.458- 15.496), globulin (HR, 2.526; 95% CI, 1.027-6.211), blood urea nitrogen (HR, 5.640; 95% CI, 2.193-14.509), creatine kinase-MB (HR, 3.032; 95% CI, 1.203-7.644), lactate dehydrogenase (HR, 4.607; 95% CI, 1.057-20.090), hypersensitive cardiac troponin I (HR, 5.023; 95% CI, 1.921-13.136), lactate concentration (HR,15.721; 95% CI, 2.099-117.777), Interleukin-10 (HR, 3.551; 95% CI, 1.280-9.857) and C-reactive protein (HR, 5.275; 95% CI, 1.517-18.344) were associated with increased risk of poor outcome development. We also found that traditional Chinese medicine can significantly improve the patients condition, which is conducive to the transformation from severe to mild. ConclusionIn summary, we firstly reported this single-centered, prospective and observational study for short-term outcome in severe patients with COVID-19. We found that cytokine storm and uncontrolled inflammation responses, liver, kidney, cardiac dysfunction may play important roles in final outcome of severe ill patients with COVID-19. Our study will provide clinicians to be benefit to rapidly estimate the likelihood risk of short-term poor outcome for severe patients.

The closer to the Europe Union headquarters, the higher risk of COVID-19? Cautions regarding ecological studies of COVID-19 (preprint)

Several ecological studies of the coronavirus disease 2019 (COVID-19) have reported correlations between group-level aggregated exposures and COVID-19 outcomes. While some studies might be helpful in generating new hypotheses related to COVID-19, results of such type of studies should be interpreted with cautions. To illustrate how ecological studies and results could be biased, we conducted an ecological study of COVID-19 outcomes and the distance to Brussels using European country-level data. We found that, the distance was negatively correlated with COVID-19 outcomes; every 100 km away from Brussels was associated with approximately 6% to 17% reductions (all P<0.01) in COVID-19 cases and deaths in Europe. Without cautions, such results could be interpreted as the closer to the Europe Union headquarters, the higher risk of COVID-19 in Europe. However, these results are more likely to reflect the differences in the timing of and the responding to the outbreak, etc. between European countries, rather than the 'effect' of the distance to Brussels itself. Associations observed at the group level have limitations to reflect individual-level associations - the so-called ecological fallacy. Given the public concern over COVID-19, ecological studies should be conducted and interpreted with great cautions, in case the results would be mistakenly understood.