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29,141 result(s) for "African populations"
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Population Differentiation at the PVT1 Gene Locus: Implications for Prostate Cancer
Genetic variation in susceptibility to complex diseases, such as cancer, is well-established. Enrichment of disease associated alleles in specific populations could have implications for disease incidence and prevalence. Prostate cancer (PCa) is a disease with well-established higher incidence, prevalence, and worse outcomes among men of African ancestry in comparison to other populations. PCa is a multi-factorial, complex disease, but the exact mechanisms for its development and progression are unclear. The gene desert located on chromosome 8q24 is associated with aggressiveness of PCa. Interestingly, the non-protein coding gene locus Plasmacytoma Variant Translocation (PVT1) is present at chromosome 8q24 and is overexpressed in PCa. PVT1 gives rise to multiple transcripts with potentially different molecular and cellular functions. In an analysis of the PVT1 locus using data from the 1000 Genomes Project, we found the chromosomal region spanning PVT1 exons 4A and 4B to be highly differentiated between African and non-African populations. We further investigated levels of gene expression of PVT1 exons 4A and 4B and observed significant overexpression of these exons in PCa tissues relative to benign prostatic hyperplasia and to normal prostate tissues obtained from men of African ancestry. These results indicate that PVT1 exons 4A and 4B may have clinical implications in PCa a conclusion supported by the observation that transient and stable overexpression of PVT1 exons 4A and 4B significantly induce greater prostate epithelial cell migration and proliferation. We anticipate that further exploration of the role of PVT1 exons 4A and 4B may lead to the development of diagnostic, therapeutic, and other clinical applications in PCa.
African evolutionary history inferred from whole genome sequence data of 44 indigenous African populations
Background Africa is the origin of modern humans within the past 300 thousand years. To infer the complex demographic history of African populations and adaptation to diverse environments, we sequenced the genomes of 92 individuals from 44 indigenous African populations. Results Genetic structure analyses indicate that among Africans, genetic ancestry is largely partitioned by geography and language, though we observe mixed ancestry in many individuals, consistent with both short- and long-range migration events followed by admixture. Phylogenetic analysis indicates that the San genetic lineage is basal to all modern human lineages. The San and Niger-Congo, Afroasiatic, and Nilo-Saharan lineages were substantially diverged by 160 kya (thousand years ago). In contrast, the San and Central African rainforest hunter-gatherer (CRHG), Hadza hunter-gatherer, and Sandawe hunter-gatherer lineages were diverged by ~ 120–100 kya. Niger-Congo, Nilo-Saharan, and Afroasiatic lineages diverged more recently by ~ 54–16 kya. Eastern and western CRHG lineages diverged by ~ 50–31 kya, and the western CRHG lineages diverged by ~ 18–12 kya. The San and CRHG populations maintained the largest effective population size compared to other populations prior to 60 kya. Further, we observed signatures of positive selection at genes involved in muscle development, bone synthesis, reproduction, immune function, energy metabolism, and cell signaling, which may contribute to local adaptation of African populations. Conclusions We observe high levels of genomic variation between ethnically diverse Africans which is largely correlated with geography and language. Our study indicates ancient population substructure and local adaptation of Africans.
Racial disparities in outcomes for high‐grade uterine cancer: A California cancer registry study
Background Endometrial cancer (EC) is the most common gynecologic malignancy. We examined factors affecting overall prognosis and survival among different racial groups diagnosed with high‐grade EC. Methods We utilized the California Cancer Registry database (CCR) to identify women with high‐grade II EC from 1998 to 2009. Using the Kaplan‐Meier method, we described disease‐specific survival. Survival by stage, race, and time to treatment category was compared using the log‐rank test. The associations of race with disease‐specific survival were modeled using Cox proportional hazards regression. Covariates were selected a priori. Results A total of 10 647 patients met study eligibility criteria. The majority of patients in this cohort of high‐grade EC were non‐Hispanic (NH) white (64.1%), followed by Hispanic (15.7%), Asian (10.4%), and NH black (9.8%). NH black women had higher incidence of certain aggressive histologic subtypes in comparison with NH whites, including serous carcinomas and carcinosarcoma. Non‐Hispanic black patients had a worse 5‐year disease‐specific survival (DSS) when compared to other racial groups. The five‐year DSS for NH black women was 54% (51%‐57%), compared to NH white women 66% (65%‐67%), Hispanic 67% (64%‐69%), and Asians 69% (67%‐72%) (P < 0.0001). This clear survival disadvantage of NH black women persisted when controlling for other factors. Conclusions Non‐Hispanic black women have a higher incidence of more aggressive histologic subtypes even among a cohort of women high‐grade EC and have a disproportionately worse disease‐specific survival after controlling for factors such as age, histologic subtype, stage, time to treatment, and type of treatment. We utilized the California Cancer Registry database to identify women with high‐grade endometrial cancer (EC) from 1998 to 2009. Using the Kaplan‐Meier method, we described disease‐specific survival. Non‐Hispanic black women have a higher incidence of more aggressive histologic subtypes even among a cohort of women with high‐grade EC and have a disproportionately worse disease‐specific survival after controlling for factors such as age, histologic subtype, stage, time to treatment, and type of treatment.
Impacts of Layoffs and Government Assistance on Mental Health during COVID-19: An Evidence-Based Study of the United States
This study evaluates the impact of unemployment and government financial assistance during the COVID-19 pandemic on the working-age population’s mental health and further examines the differential impacts between urban and non-urban groups, as well as African American (AA) and non-African American groups. Based on the COVID-19 Household Impact Survey, four measures of mental health conditions (nervous, depressed, lonely, and hopeless) are constructed. Our empirical analysis applies the ordinal regression model (ordered logit model) that takes both the week and regional factors into consideration to control for potential time effects and time-invariant confounders varying across regions. The results show that government aid only mitigates the psychological symptoms for the group in non-urban areas, with no significant impacts on the urban group. On the other hand, the AA working-age group experiences similar or more favorable mental health than other ethnic groups, while government aid does not alleviate the mental pressure for the AA group. Therefore, government interventions should recognize the heterogeneity of impacts on socioeconomic groups within the target population.
What Could Explain the Lower COVID-19 Burden in Africa despite Considerable Circulation of the SARS-CoV-2 Virus?
The differential spread and impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing Coronavirus Disease 2019 (COVID-19), across regions is a major focus for researchers and policy makers. Africa has attracted tremendous attention, due to predictions of catastrophic impacts that have not yet materialized. Early in the pandemic, the seemingly low African case count was largely attributed to low testing and case reporting. However, there is reason to consider that many African countries attenuated the spread and impacts early on. Factors explaining low spread include early government community-wide actions, population distribution, social contacts, and ecology of human habitation. While recent data from seroprevalence studies posit more extensive circulation of the virus, continuing low COVID-19 burden may be explained by the demographic pyramid, prevalence of pre-existing conditions, trained immunity, genetics, and broader sociocultural dynamics. Though all these prongs contribute to the observed profile of COVID-19 in Africa, some provide stronger evidence than others. This review is important to expand what is known about the differential impacts of pandemics, enhancing scientific understanding and gearing appropriate public health responses. Furthermore, it highlights potential lessons to draw from Africa for global health on assumptions regarding deadly viral pandemics, given its long experience with infectious diseases.
Genomic and environmental risk factors for cardiometabolic diseases in Africa: methods used for Phase 1 of the AWI-Gen population cross-sectional study
There is an alarming tide of cardiovascular and metabolic disease (CMD) sweeping across Africa. This may be a result of an increasingly urbanized lifestyle characterized by the growing consumption of processed and calorie-dense food, combined with physical inactivity and more sedentary behaviour. While the link between lifestyle and public health has been extensively studied in Caucasian and African American populations, few studies have been conducted in Africa. This paper describes the detailed methods for Phase 1 of the AWI-Gen study that were used to capture phenotype data and assess the associated risk factors and end points for CMD in persons over the age of 40 years in sub-Saharan Africa (SSA). We developed a population-based cross-sectional study of disease burden and phenotype in Africans, across six centres in SSA. These centres are in West Africa (Nanoro, Burkina Faso, and Navrongo, Ghana), in East Africa (Nairobi, Kenya) and in South Africa (Agincourt, Dikgale and Soweto). A total of 10,702 individuals between the ages of 40 and 60 years were recruited into the study across the six centres, plus an additional 1021 participants over the age of 60 years from the Agincourt centre. We collected socio-demographic, anthropometric, medical history, diet, physical activity, fat distribution and alcohol/tobacco consumption data from participants. Blood samples were collected for disease-related biomarker assays, and genomic DNA extraction for genome-wide association studies. Urine samples were collected to assess kidney function. The study provides base-line data for the development of a series of cohorts with a second wave of data collection in Phase 2 of the study. These data will provide valuable insights into the genetic and environmental influences on CMD on the African continent.
The Separate City
A ground-breaking collaborative study merging perspectives from history, political science, and urban planning,The Separate Cityis a trenchant analysis of the development of the African-American community in the urban South. While similar in some respects to the racially defined ghettos of the North, the districts in which southern blacks lived from the pre-World War II era to the mid-1960s differed markedly from those of their northern counterparts. The African- American community in the South was (and to some extent still is) a physically expansive, distinct, and socially heterogeneous zone within the larger metropolis. It found itself functioning both politically and economically as a \"separate city\" -- a city set apart from its predominantly white counterpart. Within the separate city itself, internal conflicts reflected a structural divide between an empowered black middle class and a larger group comprising the working class and the disadvantaged. Even with these conflicts, the South's new black leadership gained political control in many cities, but it could not overcome the economic forces shaping the metropolis. The persistence of a separate city admitted to the profound ineffectiveness of decades of struggle to eliminate the racial barriers with which southern urban leaders -- indeed all urban America -- continue to grapple today.
Oral microbiome homogeneity across diverse human groups from southern Africa: first results from southwestern Angola and Zimbabwe
Background While the human oral microbiome is known to play an important role in systemic health, its average composition and diversity patterns are still poorly understood. To gain better insights into the general composition of the microbiome on a global scale, the characterization of microbiomes from a broad range of populations, including non-industrialized societies, is needed. Here, we used the portion of non-human reads obtained through an expanded exome capture sequencing approach to characterize the saliva microbiomes of 52 individuals from eight ethnolinguistically diverse southern African populations from Angola (Kuvale, Kwepe, Himba, Tjimba, Kwisi, Twa, !Xun) and Zimbabwe (Tshwa), including foragers, food-producers, and peripatetic groups (low-status communities who provide services to their dominant neighbors). Results Our results indicate that neither host genetics nor livelihood seem to influence the oral microbiome profile, with Neisseria , Streptococcus , Prevotella , Rothia , and Porphyromonas being the five most frequent genera in southern African groups, in line with what has been shown for other human populations. However, we found that some Tshwa and Twa individuals display an enrichment of pathogenic genera from the Enterobacteriaceae family (i.e. Enterobacter , Citrobacter , Salmonella ) of the Proteobacteria phylum, probably reflecting deficient sanitation and poor health conditions associated with social marginalization. Conclusions Taken together, our results suggest that socio-economic status, rather than ethnolinguistic affiliation or subsistence mode, is a key factor in shaping the salivary microbial profiles of human populations in southern Africa.
Topographic and morphometric characterization of the humerii nutrient foramina and their implications for fracture repair and healing
Fractures of the humerus are common on the midshaft of the bone, often causing injury to the nutrient artery. Successful fracture repair and healing requires preservation of the blood supply to the long bones which is conveyed through the nutrient foramina (NF). The topography of long bone NF varies in different populations. These variations can affect the preservation of blood supply to long bones during fracture repair management. The current study aimed to determine the topography and morphometry of the NF of the humerus in different populations of South Africa including the South African Africans (SAA), South Africans of European descent (SAED), and South Africans of mixed ancestry (SAMA). The study examined 596 dry humerii from the three South African populations, sourced from Raymond A. Dart Collection of Modern Human Skeletons. The parameters examined included the presence, number, location, position, size and direction of the NF, and foramina index (FI). The NF were present in 97.1% of the humerii. Majority of bones (76.8%) evinced a single NF with a diameter equal to or larger than 1.27 mm. The number of NF varied across the different population groups ( p  = 0.000), with SAA having more humerii presenting with a single NF and SAED having more humerii with two NF. The position of NF varied within and across populations ( p  = 0.002). Males in SAED had a higher mean FI on both the right ( p  = 0.030) (effect size = 0.258) and left ( p  = 0.022) (effect size = 0.421) sides than females. SAED had a lower mean FI than SAMA ( p  = 0.002) (effect size = 0.384). The location of NF varied across different populations ( p  = 0.000), with SAA having more NF located on the anteromedial surface and medial border, and SAED having more NF located on the lateral border ( p  = 0.000). NF were directed towards the distal ends of the shafts in 99.8% of bones and towards the proximal end in 0.2% of bones. The topography and morphometry of the nutrient foramina of the humerus are variable in the South African populations. Knowledge of the NF variations may aid in the management of humerus fractures.
Genetics of Waardenburg Syndrome in Africa: A Systematic Review
Waardenburg syndrome (WS) represents a group of genetic conditions characterized by auditory and pigmentation defects. Pathogenic variants in PAX3, MITF, SOX10, EDN3, EDNRB, SNAI2, and KITLG genes have been associated with WS across multiple populations; a comprehensive study of WS in Africa has not yet been reported. We conducted a systematic review of clinical expressions and genetics of WS across Africa. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were followed, and the study protocol was registered on PROSPERO, the International Prospective Register of Systematic Reviews (2025 CRD420250655744). A literature search was performed on Google Scholar, PubMed, Scopus, Directory of Open Access Journals (DOAJ), Global Index Medicus, African-Wide Information, ScienceDirect, Connecting Repositories (CORE), and the Web of Science databases. We reviewed a total of 15 articles describing 84 WS cases, which showed no gender bias and a mean age at reporting of 17.5 years. Congenital, sensorineural, and profound hearing loss was described in most cases (66.7%; n = 56/84). WS type 2 (WS2), with characteristically no dystopia canthorum, is the predominant subtype (36.9%; n = 31/84). Pathogenic variants in four WS known genes, i.e., PAX3 (13 families), SOX10 (7 families), EDNRB (4 families), and EDN3 (1 family), were reported in Morocco, Tunisia, and South Africa. One candidate gene (PAX8) was described in one family in Ghana. Two non-syndromic hearing loss (NSHL) genes (BDP1 and MYO6) were reported in two separate families in South Africa, suggesting a possible phenotypic expansion. The highest number of WS cases was described in South Africa (38.1%; n = 32/84) and Tunisia (26.2%; n = 22/84). Gene variants were missense (27/43), deletion (7/43), splicing (5/43), nonsense (2/43), indel (1/43), and duplication (1/43), chiefly segregating in an autosomal dominant inheritance mode. There was no functional data to support the pathogenicity of putative causative variants. This review showed that WS2 is the most common in Africa. Variants in PAX3 and SOX10 were the predominant genetic causes. This study emphasizes the need to further investigate in-depth clinical characterization, molecular landscape, and the pathobiology of WS in Africa.