Objective: It has been found that COVID-19 increases deaths within common diseases in countries that have implemented strict lockdowns. In order to elucidate the proper national response to a pandemic, the mortality rates within COVID-19 and various diseases need to be studied in countries whose pandemic response differ. Sweden represents a country with lax pandemic restrictions, and we aimed to study the effects of COVID-19 on historical mortality rates within common diseases during 2020. Methods: Regression models and moving averages were used to predict expected premature mortality per the ICD-10 during 2020 using historical data sets. Predicted values were then compared to recorded premature mortality to identify changes in mortality trends. Results: Seasonal increased mortality was found within neurological diseases. Infectious diseases, tumours and cardiac disease mortality rates decreased compared to expected outcome. Conclusions: Changes in mortality trends were observed for several common diseases during the COVID-19 pandemic. Neurological and cardiac conditions, infections and tumours are examples of diseases that were heavily affected by the pandemic. The indirect effects of COVID-19 on certain patient populations should be considered when determining pandemic impact.

Introduction Significant mortality amongst vulnerable populations, such as people living with dementia, might go undetected during pandemic conditions due to refocus of care efforts. There is an urgent need to fully evaluate the pandemic impact on mortality amongst people living with dementia in order to facilitate future healthcare reforms and prevent deaths. The purpose of this study was to determine whether there was any significant difference in mortality amongst people with dementia without COVID-19 during the COVID-19 pandemic compared to previous years. Methods A literature search was conducted in 5 databases. The relative risk ratio and confidence interval was used to estimate the change in mortality rates amongst people with dementia during the COVID-19 pandemic. The I2 value was used to assess heterogeneity, publication bias, and sensitivity analyses were performed. Results Pooled analysis of 11 studies showed that mortality amongst people living with dementia was significantly increased during the COVID-19 pandemic for people with dementia without COVID-19. Mortality risk increased by 25% during the time period studied. Subgroup analysis was not performed due the low number of included studies. Conclusions The results of this study suggest that people with dementia had a significant increased mortality during the pandemic even if they did not have COVID-19. People with dementia should participate in efforts that reduce general social spread and pandemic impact on healthcare system such as vaccinations, mask mandates, and testing. These results have clinical implications as preventing direct COVID-19 infection is not enough to adequately protect people living with dementia from increased mortality. Measures to limit social spread of infections and help support patients should also be a focus for clinicians. Further research should focus on the identification of mechanisms and other explanations for increased mortality as well as contributing factors such as living in care homes and differences between countries with various pandemic strategies.

Background: The 42 amino acids long amyloid-β peptide, Aβ42, may initiate a cascade of events leading to the severe neurodegeneration observed in Alzheimer’s disease (AD) brain. However, the underlying molecular mechanisms remain to be established. Objective: To find early Aβ42-induced AD related mechanisms, we performed a brain proteomics time-course study on a novel App knock-in AD mouse model, AppNL-F, expressing high levels of Aβ42 without AβPP overexpression artifacts. Methods: Hippocampus and cortex were analyzed separately by using 18O-labelling mass spectrometry to reveal alterations in protein levels. Pathway analysis of proteomics data was used to identify altered biological functions. Immunohistochemistry was used to further investigate a significant key regulatory protein. Results: Around 100 proteins were differently expressed in AppNL-F mice at each time point (3, 6, 9, and 18 months of age) as compared to wild type mice. Strikingly, already at 3 months of age—long before Aβ plaque development and memory impairment—several pathways, including long-term potentiation and synaptic plasticity, were downregulated, and neuritogenesis was increased. Huntingtin (HTT) was identified as an upstream regulator, i.e., a key protein affecting the levels of several proteins. Increased levels of HTT in hippocampus of AppNL-F mice was supported by immunofluorescence microscopy. Conclusion: Notably, the proteome was significantly altered already at 3 months of age, 6 months before the development of plaques. Differentially expressed proteins varied over time, indicating that increased Aβ42 levels initiate a cascade of events that eventually manifests in amyloid depositions, inflammation, and decline in memory.