Decomposition of Disparities in Alzheimer’s Disease and Related Dementia

This study uses Medicare data to non-parametrically evaluate race- and place-of-residence-related disparities in AD/ADRD prevalence and incidence-based mortality, separate them out into the epidemiological causal components including race-related disparities in incidence and survival, and finally explain these in terms of health-care-related factors using causal methods of group variable effects (propensity scores and the rank-and-replace method) and regression-based analyses (extended Fairlie’s model and generalized Oaxaca-Blinder approach for censoring outcomes). Partitioning analysis showed that the incidence rate is the main predictor for temporal changes and racial disparities in AD/ADRD prevalence and mortality, though survival began to play a role after 2010. Arterial hypertension is the leading predictor responsible for racial disparities in AD/ADRD risks. This study demonstrated that Medicare data has sufficient statistical power and potential for studying disparities in AD/ADRD in three interacting directions: multi-ethnic structure of population, place of residence, and time period.

Study of the Level and Structure of Population Immunity to SARS-CoV2 in the Population of the Republic of Tatarstan during the Second Peak of the Spread of COVID-19

Background. The COVID-19 pandemic has become a serious challenge for all of humanity due to the rapid global spread, high frequency of severe forms, increased mortality and required the development of new approaches to managing epidemiological processes. Serological studies are the most important tool for monitoring the infectious process, identifying risk groups, assessing the effect of vaccines used and epidemiological projections.Purpose. Conducting serological monitoring in relation to the modern transferred new coronavirus infection determining the level and structure of population immunity to SARS-CoV-2 in the population of the Republic of Tatarstan; maintaining the period of spread of COVID-19 from August to December 2020.Materials and methods. The study involved 41 444 residents of the Republic of Tatarstan, who filled out questionnaires that included clinical, anamnestic data and an epidemiological history in relation to COVID-19, who were tested for the presence of common antibodies (IgG, IgA and IgM) to the SARS coronavirus. CoV-2 by the method of enhanced chemiluminescence on the VITROS 3600 analyzer using the VITROS Anti-SARS-CoV-2 Total Reagent Pack test systems.Statistical processing was carried out by methods of variation statistics and correlation analysis according to the Pearson method using MS Excel and WinPepi.Results. Seropositivity to SARSCoV-2 in the population of the Republic of Tatarstan averaged 35.8 ± 0.235%. An increase in the level of seropositive persons was noted from 29.95 ± 0.674% in August to 68 ± 9.33% in December. The highest proportion of seropositive individuals was found in was found in the group of the able-bodied population aged 18–59 years. The average geometric titer of antibodies was 4.2 (4.09–4.31), among seropositive – 89.29 (88.13–90.46). In the social and professional structure of the population, the largest proportion of seropositive individuals was found in was found among production workers 40.35 ± 2.177, creative professions – 40 ± 9.798; health care 35.24 ± 0.389; 34.26 ± 1.218 unemployed and 33.06 ± 2.479 civil servants. Among the residents of the Republic of Tatarstan, seropositive to the SARS-CoV-2 virus, the proportion of asymptomatic forms of infection was 82.59 ± 0.446%.Сonclusions. There is a positive dynamics of seropositivity among the population of the Republic of Tatarstan. The results of sero-epidemiological monitoring can be used to predict the epidemiological situation, plan measures for specific and non-specific prophylaxis of COVID19.

SOCIETAL DETERMINANTS AS RISK FACTORS OF HIV-INFECTION SPREAD IN REGIONS IN THE RUSSIAN FEDERATION

The paper dwells on the results obtained via examining dependence between HIV-infection spread and factors related to social environmental and social structure of population in RF regions. These factors are considered to be potential health risk ones. The authors tested a hypothesis about influence exerted by demographic, economic, cultural and behavioral de- terminants and public healthcare availability on differences in territorial spread of the disease within social-epidemiologic approach. To solve the set task, data that characterized 85 RF regions were taken from official statistical reports. Descriptive statistic analysis was performed and regression models were built up; it allowed testing whether the analyzed factors had their influence in RF regions and selecting the most significant ones to be included into the overall regression model. The research revealed significant contextual differences in HIV-infection spread. Regression analysis showed that 22.0 % differences in a number of HIV-infected people detected in RF regions occurred due to differences in urban popu- lation numbers, provision with ambulatories and polyclinics, and unemployment rate. Moreover, a number of registered crimes committed by minors determined 32.5 % difference in a number of patients with the first diagnosed HIV-infection between the examined regions. These results allow assuming that the greatest influence on spread of the disease in RF regions is exerted by conse- quences of urbanization; this process is usually accompanied with a growth in a share of urban population in a given region, instability on the labor market there as well as related migration processes within the country and wider opportunities to pursue individual behavioral strategies including those that involve law violations and/or are destructive for people’s health.

SOCIETAL DETERMINANTS AS RISK FACTORS OF HIV-INFECTION SPREAD IN REGIONS IN THE RUSSIAN FEDERATION

The paper dwells on the results obtained via examining dependence between HIV-infection spread and factors related to social environmental and social structure of population in RF regions. These factors are considered to be potential health risk ones. The authors tested a hypothesis about influence exerted by demographic, economic, cultural and behavioral de- terminants and public healthcare availability on differences in territorial spread of the disease within social-epidemiologic approach. To solve the set task, data that characterized 85 RF regions were taken from official statistical reports. Descriptive statistic analysis was performed and regression models were built up; it allowed testing whether the analyzed factors had their influence in RF regions and selecting the most significant ones to be included into the overall regression model. The research revealed significant contextual differences in HIV-infection spread. Regression analysis showed that 22.0 % differences in a number of HIV-infected people detected in RF regions occurred due to differences in urban popu- lation numbers, provision with ambulatories and polyclinics, and unemployment rate. Moreover, a number of registered crimes committed by minors determined 32.5 % difference in a number of patients with the first diagnosed HIV-infection between the examined regions. These results allow assuming that the greatest influence on spread of the disease in RF regions is exerted by conse- quences of urbanization; this process is usually accompanied with a growth in a share of urban population in a given region, instability on the labor market there as well as related migration processes within the country and wider opportunities to pursue individual behavioral strategies including those that involve law violations and/or are destructive for people’s health.

Distinct neural dynamics underlie the encoding of visual speed in stationary and running mice

Sensory experiences are often driven by an animal's self-motion and locomotion is known to modulate neural responses in the mouse visual system. This modulation is hypothesised to improve the processing of behaviourally relevant visual inputs, which may change rapidly during locomotion. However, little is known about how locomotion modulates the temporal dynamics (time courses) of visually-evoked neural responses. Here, we analysed the temporal dynamics of single neuron and population responses to dot field stimuli moving at a range of visual speeds using the Visual Coding dataset from the Allen Institute for Brain Science (Siegle et al, 2021). Single neuron responses had diverse temporal dynamics that varied between stationary and running sessions. Increased dynamic range and more reliable responses in running sessions enabled faster, stronger and more persistent encoding of visual speed. Population activity reflected the temporal dynamics of single neuron responses, including their modulation by locomotor state - neural trajectories of population activity made more direct transitions between baseline and stimulus steady states in running sessions. The structure of population coding also changed with locomotor state - population activity prioritised the encoding of visual speed in running, but not stationary sessions. Our results reveal a profound influence of locomotion on the temporal dynamics of neural responses. We demonstrate that during locomotion, mouse visual areas prioritise the encoding of potentially fast-changing, behaviourally relevant visual features.

Dynamics of changes in population immunity to the SARS-CоV-2 virus in residents the Irkutsk region in the context of the COVID-19 pandemic

Background. The ongoing COVID-19 pandemic in the world and in Russia remains the main event in 2020. A comprehensive study of the patterns of development and manifestations of the epidemic process of the new coronavirus infection COVID-19 is an urgent line of research. One of the important aspects of the fight against COVID-19 is the study of population immunity to the SARS-CoV-2 virus in order to assess seroprevalence and the formation process of post-infectious humoral immunity to SARS-CoV-2, forecast the development of the epidemiological situation, identify the features of the epidemic process, as well as planning measures for specific and non-specific disease prevention. The aim of the research is to determine the level and structure of population immunity to SARS-CoV-2 among the humans of the Irkutsk region during the COVID-19 epidemic. Materials and methods. As part of the Rospotrebnadzor project to assess population immunity to SARS-CoV-2 in the population of the Russian Federation, research is being conducted among the population of the Irkutsk region in the periods from 06/23/2020 to 07/19/2020 (stage 1), from 09/16/2020 to 09/25/2020 (Stage 2) and from 12/07/2020 to 12/18/2020 (stage 3), taking into account the reacted one recommended by the WHO. The content of antibodies to SARS-CoV-2 was determined by ELISA using a set of tests for human serum or plasma for specific immunoglobulins of class G to the nucleocapsid of the SARS-CoV-2 virus produced by FBUN GNCPMiB Rospotrebnadzor (Obolensk). The results of a research of the humoral immunity of volunteers show that during the period of an epidemic rise in the incidence of COVID-19 in the Irkutsk region, a low level of seroprevalence was formed (stage 1 – 5.8 ± 0.5%, stage 2 – 12,1 ± 0,7%), and in conditions of a long-term maximum increase in the incidence rate ¬– 25,9±1,0% (stage 3). A significant proportion (stage 1 – 81,2±3,2%, stage 2 – 90.9 ±1,9%) of asymptomatic forms of infection characterize the high intensity of the latently developing epidemic process in the first two stages. High levels of IgG in reconvalescents of COVID-19 persisted for an average of 3 to 4.5 months. Conclusion. The results of assessing the population immunity to the SARS-CoV-2 virus in the population of the Irkutsk region indicate that the seroprevalence level at the 3rd stage of the research was 25.9%. After the disease, on average, 41.6% of persons did not detect antibodies. The results obtained should be taken into account when organizing preventive measures, including vaccination, and predicting morbidity.

Humoral immunity to SARS-CoV-2 among the population of Murmansk region amid COVID-19 epidemic

Purpose of the study. Determination of the level and structure of population immunity to SARS-CoV-2 among the population of the Murmansk region against the background of the incidence of COVID-19.Materials and methods. The study was carried out according to a unified method for determining the seroprevalence of the population, developed by Rospotrebnadzor with the participation of the St. Petersburg Pasteur Institute. A total of 3117 volunteers were examined, distributed into 7 age groups. The content of antibodies to SARS-CoV-2 was determined by ELISA using a set of reagents for analyzing human serum or plasma for the presence of specific immunoglobulins of class G to the nucleocapsid of the SARS-CoV-2 virus produced by the FBUN GNCPMiB Rospotrebnadzor (Obolensk) in accordance with the instructions for application.Results. The level of population immunity in the Murmansk region as a whole was 31,2%. The highest seroprevalence was found among children aged 1–6 and 7–13 years (35.6% and 44,1%, respectively), the lowest among the elderly population aged 60–69, as well as 70 and more years (20,4% and 20,9%, respectively). In the cities of the Murmansk region. the herd level of immunity varied from 19,6% (Kola city) to 46,1% (Kandalaksha city). It was not possible to find a reliable relationship between the incidence of the population of the cities of the Murmansk region and seroprevalence. The highest level of seroprevalence was noted among office workers (38,0%), the lowest among transport workers (19,5%). In the presence of contacts with patients with COVID-19, seropositivity increased 1,4 times compared to the average population value. The level of specific humoral immunity in convalescents after COVID-19 is 64,1%, which is 2,2 times higher than the average for half-day. The proportion of asymptomatic forms among seroprevalence volunteers was 89%.

Demographic situation in the Buryat section of the Baikal–Amur Mainline at the turn of the XX–XXI centuries

Throughout the XX century, the demographic policy of the Soviet State was aimed mostly at working-age population or labor resources, taking into account regional and territorial aspects. Demographic change of the early XXI century was the result of political events of the 1990s, when the concept of population policy was under the radar of the government. The socioeconomic cataclysms destabilized the employment structure of population, caused deterioration of living standards, which affected the demographic characteristics of the XXI century. The demographic policy crisis of the late XX century generated one of the crucial organizational issues faced by the northern regions. This article is dedicated to the main demographic trends in the northern regions of Buryatia, which were affected by the construction of the Baikal-Amur Mainline, since completion of the construction project until stabilization of socioeconomic situation in the country by the early 2010s. In the course of construction of the Baikal-Amur Mainline, Buryatia took the lead in terms of birth rate, and ranked last in mortality index per thousand people. This testified to relative density of young poplar and children in the age structure, as well as stable population reproduction with insignificant demographic fluctuations.