1,306 research outputs found

    MtDNA Haplogroups in the Populations of Croatian Adriatic Islands

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    The number of previous anthropological studies pointed to very complex ethnohistorical processes that shaped the current genetic structure of Croatian island isolates. The scope of this study was limited to the general insight into their founding populations and the overall level of genetic diversity based on the study mtDNA variation. A total of 444 randomly chosen adult individuals from 32 rural communities of the islands of Krk, Brač, Hvar and Korčula were sampled. MtDNA HVS-I region together with RFLP sites diagnostic for main Eurasian and African mtDNA haplogroups were analysed in order to determine the haplogroup structure. The most frequent haplogroups were »H« (27.8–60.2%), »U« (10.2–24.1%), »J« (6.1–9.0%) and »T« (5.1–13.9%), which is similar to the other European and Near Eastern populations. The genetic drift could have been important aspect in history, as there were examples of excess frequencies of certain haplogroups (11.3% of »I« and 7.5% of »W« in Krk, 10.5% of »HV« in Brač, 13.9% of »J« in Hvar and 60.2% of »H« in Korčula). As the settlements on the islands were formed trough several immigratory episodes of genetically distant populations, this analysis (performed at the level of entire islands) showed greater genetic diversity (0.940–0.972) than expected at the level of particular settlements

    Measures of Autozygosity in Decline: Globalization, Urbanization, and Its Implications for Medical Genetics

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    This research investigates the influence of demographic factors on human genetic sub-structure. In our discovery cohort, we show significant demographic trends for decreasing autozygosity associated with population variation in chronological age. Autozygosity, the genomic signature of consanguinity, is identifiable on a genome-wide level as extended tracts of homozygosity. We identified an average of 28.6 tracts of extended homozygosity greater than 1 Mb in length in a representative population of 809 unrelated North Americans of European descent ranging in chronological age from 19–99 years old. These homozygous tracts made up a population average of 42 Mb of the genome corresponding to 1.6% of the entire genome, with each homozygous tract an average of 1.5 Mb in length. Runs of homozygosity are steadily decreasing in size and frequency as time progresses (linear regression, p<0.05). We also calculated inbreeding coefficients and showed a significant trend for population-wide increasing heterozygosity outside of linkage disequilibrium. We successfully replicated these associations in a demographically similar cohort comprised of a subgroup of 477 Baltimore Longitudinal Study of Aging participants. We also constructed statistical models showing predicted declining rates of autozygosity spanning the 20th century. These predictive models suggest a 14.0% decrease in the frequency of these runs of homozygosity and a 24.3% decrease in the percent of the genome in runs of homozygosity, as well as a 30.5% decrease in excess homozygosity based on the linkage pruned inbreeding coefficients. The trend for decreasing autozygosity due to panmixia and larger effective population sizes will likely affect the frequency of rare recessive genetic diseases in the future. Autozygosity has declined, and it seems it will continue doing so

    The Global Epidemiological Transition in Cardiovascular Diseases:Unrecognised Impact of Endemic Infections on Peripheral Artery Disease

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    An epidemiological transition in the prevalence of peripheral artery disease (PAD) is taking place especially in low- and middle-income countries (LMICs) where an ageing population and adoption of western lifestyles are associated with an increase in PAD. We discuss the limited evidence which suggests that infection, potentially mediated by inflammation, may be a risk factor for PAD, and show by means of an ecological analysis that country-level prevalence of the major endemic infections of HIV, tuberculosis and malaria are associated with the prevalence of PAD. While further research is required, we propose that scientists and health authorities pay more attention to the interplay between communicable and non-communicable diseases, and we suggest that limiting the occurrence of endemic infections might have some effect on slowing the epidemiological transition in PAD

    Long-term dynamics of aberrant neuronal activity in awake Alzheimer's disease transgenic mice

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    Alzheimer's disease (AD) is associated with aberrant neuronal activity, which is believed to critically determine disease symptoms. How these activity alterations emerge, how stable they are over time, and whether cellular activity dynamics are affected by the amyloid plaque pathology remains incompletely understood. We here repeatedly recorded the activity from identified neurons in cortex of awake APPPS1 transgenic mice over four weeks during the early phase of plaque deposition using in vivo two-photon calcium imaging. We found that aberrant activity during this stage largely persisted over the observation time. Novel highly active neurons slowly emerged from former intermediately active neurons. Furthermore, activity fluctuations were independent of plaque proximity, but aberrant activity was more likely to persist close to plaques. These results support the notion that neuronal network pathology observed in models of cerebral amyloidosis is the consequence of persistent single cell aberrant neuronal activity, a finding of potential diagnostic and therapeutic relevance for AD

    Estimating the global and regional burden of meningitis in children caused by Haemophilus influenzae type b:A systematic review and meta-analysis

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    BACKGROUND: Haemophilus influenzae Type B (Hib) meningitis caused significant public health concern for children. Recent assessment in 2015 suggests vaccination has virtually eliminated invasive Hib diseases. However, many countries launched their programs after 2010, and few are yet to establish routine Hib immunisations. We therefore aimed to update the most recent global burden of Hib meningitis before the impact of COVID-19 pandemic, from 2010 to 2020, in order to aid future public health policies on disease management and prevention. METHODS: Epidemiological data regarding Hib meningitis in children <5 years old were systematically searched and evaluated from PubMed and Scopus in August, 2020. We included studies published between 2010 and 2019 that reported incidence, prevalence, mortality, or case-fatality-ratio (CFR), and confirmation of meningitis by cerebrospinal fluid culture, with a minimum one year study period and ten cases. Each data was stratified by one study-year. Median study-year was used if information was not available. Quality of all studies were assessed using our adapted assessment criteria from Grading of Recommendations Assessment, Development and Evaluation (GRADE) and Study Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies from National Heart, Lung and Blood Institute (NHLBI). We constructed and visually inspected a funnel plot of standard error by the incidence rate and performed an Egger’s regression test to statistically assess publication bias. To ascertain incidence and CFR, we performed generalised linear mixed models on crude individual study estimates. Heterogeneity was assessed using I-squared statistics whilst further exploring heterogeneity by performing subgroup analysis. RESULTS: 33 studies were identified. Pooled incidence of global Hib meningitis in children was 1.13 per 100 000-child-years (95% confidence interval (CI) = 0.80-1.59). Southeast Asian Region (SEAR) of World Health Organisation (WHO) region reported the highest incidence, and European Region (EUR) the lowest. Considering regions with three or more data, Western Pacific Region (WPR) had the highest incidence rate of 5.22 (95% CI = 3.12-8.72). Post-vaccination incidence (0.67 cases per 100 000-child-years, 95% CI = 0.48-0.94) was dramatically lower than Pre-vaccination incidence (4.84 cases per 100 000-child-years, 95% CI = 2.95-7.96). Pooled CFR in our meta-analysis was 11.21% (95% CI = 7.01-17.45). Eastern Mediterranean Region (EMR) had the highest CFR (26.92, 95% CI = 13.41-46.71) while EUR had the lowest (4.13, 95% CI = 1.73-9.54). However, considering regions with three or more data, African Region (AFR) had the highest CFR at 21.79% (95% CI = 13.65-32.92). Before the coronavirus disease 2019 (COVID-19) impact, the estimation for global Hib meningitis cases in 2020 is 7645 and 857 deaths. CONCLUSIONS: Global burden of Hib meningitis has markedly decreased, and most regions have implemented vaccination programs. Extrapolating population-at-risk from studies has possibly led to an underestimation. Continuous surveillance is necessary to monitor vaccination impact, resurgence, vaccine failures, strain variance, COVID-19 impact, and to track improvement of regional and global Hib meningitis mortality

    Estimating pneumonia deaths of post-neonatal children in countries of low or no death certification in 2008

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    BACKGROUND: Pneumonia is the leading cause of child deaths globally. The aims of this study were to: a) estimate the number and global distribution of pneumonia deaths for children 1-59 months for 2008 for countries with low (85% coverage of death certification countries was used. For 87 high child-mortality countries pneumonia death estimates were obtained by applying a regression model developed from published and unpublished verbal autopsy data from high child-mortality settings. The total number of 1-59 months pneumonia deaths for the year 2008 for these 122 countries was estimated to be 1.18 M (95% CI 0.77 M-1.80 M), which represented 23.27% (95% CI 17.15%-32.75%) of all 1-59 month child deaths. The country level estimation correlation coefficient between these two methods was 0.40. INTERPRETATION: Although the overall number of post-neonatal pneumonia deaths was similar irrespective to the method of estimation used, the country estimate correlation coefficient was low, and therefore country-specific estimates should be interpreted with caution. Pneumonia remains the leading cause of child deaths and is greatest in regions of poverty and high child-mortality. Despite the concerns about gender inequity linked with childhood mortality we could not estimate sex-specific pneumonia mortality rates due to the inadequate data. Life-saving interventions effective in preventing and treating pneumonia mortality exist but few children in high pneumonia disease burden regions are able to access them. To achieve the United Nations Millennium Development Goal 4 target to reduce child deaths by two-thirds in year 2015 will require the scale-up of access to these effective pneumonia interventions

    Associated factors and global adherence of cervical cancer screening in 2019:a systematic analysis and modelling study

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    BACKGROUND: Cervical cancer screening is vital for its prevention. Adherence is a crucial indicator that implies the individual willingness to take cervical cancer screening. We aimed to estimate the global and regional adherence rates of cervical cancer screening in 2019 and identify its associated factors among general women. METHOD: We searched studies in PubMed, Web of Science, Embase, China National Knowledge Infrastructure, Wanfang Database, ProQuest theses database and Google Web, without a lower time limit and until 23 June, 2021. Survey studies were considered eligible if they investigated cervical cancer screening adherence among general women, with data on sample size, the number of adherent subjects, and/or adherence rate. Random-effects were used to pool the odds ratios (ORs) of associated factors of adherence. Using modelling analysis, we estimated 2019 overall and age-specific adherence rates at the global and regional levels in women aged 20–69 years. RESULTS: Eight thousand two hundred ninety records were identified, and 153 articles were included. Being married (vs not married: OR, 1.34; 95% confidence interval [CI]: 1.23–1.46), higher educational attainment (higher than high school vs less than high school: OR, 1.44; 95% CI: 1.35–1.53), having healthcare (OR, 1.64; 95% CI: 1.43–1.88), former smoking (OR, 1.20; 95% CI: 1.07–1.34), physical activity (OR, 1.19; 95% CI: 1.05–1.36), parity (OR, 1.07; 95% CI: 1.01–1.12), and chronic disease (OR, 1.17; 95% CI: 1.04–1.32) were associated with better adherence, whereas obesity (vs normal: OR, 0.85; 95% CI: 0.74–0.97) and current smoking (vs former/never: OR, 0.64; 95% CI: 0.54–0.76) were associated with worse adherence. In 2019, the adherence was at 33.66% (95% CI: 23.34–39.30%) worldwide, and was higher in high-income countries (HICs) (75.66, 95% CI: 66.74–82.81%) than in low and middle-income countries (LMICs) (24.91, 95% CI: 14.30–30.24%). It varied across regions, the highest in the European region (65.36, 95% CI: 55.40–74.19%), but the lowest in the African region (5.28, 95% CI: 3.43–8.03%). CONCLUSIONS: Cervical cancer screening adherence remained low globally, exhibiting geographical discrepancy with HICs higher than LMICs. Further implementations of screening programs should comprehensively consider the local economy, social benefits, and demographic structure to adapt delivery for vulnerable or underserved women to boost screening adherence. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12992-022-00890-w
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