Browsing by Author "Olowoyo P."

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African Ancestry, APOL1, candidate genes, CDKN2A/CDKN2B, HDAC9, small vessel disease, stroke, West Africa
(John Wiley & Sons Ltd, 2017) Akinyemi R.; Tiwari H. K.; Arnett D. K.; Ovbiagele B.; Irvin M. R.; Wahab K.; Sarfo F.; Srinivasasainagendra V.; Adeoye A.; Perry R. T.; Akpalu A.; Jenkins C.; Arulogun O.; Gebregziabher M.; Owolabi L.; Obiako R.; Sanya E.; Komolafe M.; Fawale M.; Adebayo P.; Osaigbovo G.; Sunmonu T.; Olowoyo P.; Chukwuonye I.; Obiabo Y.; Onoja A.; Akinyemi J.; Ogbole G.; Melikam S.; Saulson R.; Owolabi M.
Objective: Worldwide, the highest frequencies of APOL1-associated kidney variants are found in indigenous West Africans among whom small vessel disease (SVD) is chemic stroke is the most common stroke phenotype. The objective of this study was to investigate the association and effect sizes of 23 selected SNPs in 14 genes of relevance, including the APOL1 G1 variants, with the occurrence of SVD ischemic stroke among indigenous West African participants in the Stroke Investigative Research and Education Network (SIREN) Study. Materials and Methods: Cases were consecutively recruited consenting adults (aged 18 years or older) with neuroimaging—confirmed first clinical stroke. Stroke-free controls were ascertained using a locally validated version of the Questionnaire for Verifying Stroke-Free Status (QVSFS). Logistic regression models adjusting for known vascular risk factors were fitted to assess the associations of the 23 SNPs in rigorously phenotyped cases (N = 154) of SVD ischemic stroke and stroke-free (N = 483) controls. Results: Apolipoprotein L1 (APOL1) rs73885319 (OR = 1.52; CI: 1.09-2.13, P value = .013), rs2383207 in CDKN2A/CDKN2B (OR = 3.08; CI: 1.15-8.26, P – value = .026) and rs2107595 (OR = 1.70; CI: 1.12-2.60, P-value = .014) and rs28688791 (OR = 1.52; CI: 1.03-2.26, P-value = .036) in HDAC9 gene were associated with SVD stroke at 0.05 significance level. Polymorphisms in other genes did not show significant associations. Conclusion: This is the first report of a specific association of APOL1 with a stroke subtype. Further research is needed to confirm these initial findings and deepen understanding of the genetics of stroke in people of African ancestry with possible implications for other ancestries as all humans originated from Africa
Differential impact of risk factors on stroke occurrence among men versus women in West Africa The SIREN Study
(American Heart Association, Inc., 2019) Akpalu A.; Gebregziabher M.; Ovbiagele B.; Sarfo F.; Iheonye H.; Akinyemi R.; Akpa O.; Tiwari H. K.; Arnett D.; Wahab K.; Lackland D.; Abiodun A.; Ogbole G.; Jenkins C.; Arulogun O.; Akpalu J.; Obiako R.; Olowoyo P.; Fawale M.; Komolafe M.; Osaigbovo G.; Obiabo Y.; Chukwuonye I.; Owolabi L.; Adebayo P.; Sunmonu T.; Owolabi M.
Background and Purpose—The interplay between sex and the dominant risk factors for stroke occurrence in sub-Saharan Africa has not been clearly delineated. We compared the effect sizes of risk factors of stroke by sex among West Africans. Methods—SIREN study (Stroke Investigative Research and Educational Networks) is a case-control study conducted at 15 sites in Ghana and Nigeria. Cases were adults aged >18 years with computerized tomography/magnetic resonance imaging confirmed stroke, and controls were age- and sex-matched stroke-free adults. Comprehensive evaluation for vascular, lifestyle, and psychosocial factors was performed using validated tools. We used conditional logistic regression to estimate odds ratios and reported risk factor specific and composite population attributable risks with 95% CIs. Results—Of the 2118 stroke cases, 1193 (56.3%) were males. The mean±SD age of males was 58.1±13.2 versus 60.15±14.53 years among females. Shared modifiable risk factors for stroke with adjusted odds ratios (95% CI) among females versus males, respectively, were hypertension [29.95 (12.49–71.77) versus 16.1 0(9.19–28.19)], dyslipidemia [2.08 (1.42–3.06) versus 1.83 (1.29–2.59)], diabetes mellitus [3.18 (2.11–4.78) versus 2.19 (1.53–3.15)], stress [2.34 (1.48–3.67) versus 1.61 (1.07–2.43)], and low consumption of green leafy vegetables [2.92 (1.89–4.50) versus 2.00 (1.33–3.00)]. However, salt intake and income were significantly different between males and females. Six modifiable factors had a combined population attributable risk of 99.1% (98.3%–99.6%) among females with 9 factors accounting for 97.2% (94.9%–98.7%) among males. Hemorrhagic stroke was more common among males (36.0%) than among females (27.6%), but stroke was less severe among males than females. Conclusions—Overall, risk factors for stroke occurrence are commonly shared by both sexes in West Africa favoring concerted interventions for stroke prevention in the region.
Exploring overlaps between the genomic and environmental determinants of LVH and stroke
(Elsevier Ltd, 2017) Adeoye A. M.; Ovbiagele B.; Kolo P.; Appiah L.; Ajek A.; Adebayo O.; Sarfo F.; Akinyemi J.; Adekunle G.; Agyekum F.; Shidali V.; Ogah O.; Lackland D.; Gebregziabher M.; Arnett D.; Tiwari H. K.; Akinyemi R.; Olagoke O. O.; Oguntade A. S.; Olunuga T.; Uwanruochi K.; Jenkins C.; Adadey P.; Iheonye H.; Owolabi L.; Obiako R.; Akinjopo S.; Armstrong K.; Akpalu A.; Fakunle A.; Saulson R.; Aridegbe M.; Olowoyo P.; Osaigbovo G.; Akpa O.
Background: Whether left ventricular hypertrophy (LVH) is determined by similar genomic and environmental risk factors with stroke, or is simply an intermediate stroke marker, is unknown. Objectives: We present a research plan and preliminary findings to explore the overlap in the genomic and environmental determinants of LVH and stroke among Africans participating in the SIREN (Stroke Investigative Research and Education Network) study. Methods: SIREN is a transnational, multicenter study involving acute stroke patients and age-, ethnicity-, and sex-matched control subjects recruited from 9 sites in Ghana and Nigeria. Genomic and environmental risk factors and other relevant phenotypes for stroke and LVH are being collected and compared using standard techniques. Results: This preliminary analysis included only 725 stroke patients (mean age 59.1 13.2 years; 54.3% male). Fifty-five percent of the stroke subjects had LVH with greater proportion among women (51.6% vs. 48.4%; p < 0.001). Those with LVH were younger (57.9 12.8 vs. 60.6 13.4; p ¼ 0.006) and had higher mean systolic and diastolic blood pressure (167.1/99.5 mm Hg vs 151.7/90.6 mm Hg; p < 0.001). Uncontrolled blood pressure at presentation was prevalent in subjects with LVH (76.2% vs. 57.7%; p < 0.001). Significant independent predictors of LVH were age 90 mm Hg (AOR: 2.10; 95% CI: 1.39 to 3.19; p < 0.001). Conclusions: The prevalence of LVH was high among stroke patients especially the younger ones, suggesting a genetic component to LVH. Hypertension was a major modifiable risk factor for stroke as well as LVH. It is envisaged that the SIREN project will elucidate polygenic overlap (if present) between LVH and stroke among Africans, thereby defining the role of LVH as a putative intermediate cardiovascular phenotype and therapeutic target to inform interventions to reduce stroke risk in populations of African ancestry
Interleukin–6 (IL-6) rs1800796 and cyclin dependent kinase inhibitor (CDKN2A/CDKN2B) rs2383207 are associated with ischemic stroke in indigenous West African Men
(Elvsevier B. V, 2017) Akinyemi R.; Arnett D. K.; Tiwari H. K.; Ovbiagele B.; Sarfo F.; Srinivasasainagendra V.; Irvin M. R.; Adeoye A.; Perry R. T.; Akpalu A.; Jenkins C.; Owolabi L.; Obiako R.; Wahab K.; Sanya E.; Komolafe M.; Fawale M.; Adebayo P.; Osaigbovo G.; Sunmonu T.; Olowoyo P.; Chukwuonye I.; Obiabo Y.; Akpa O.; Melikam S.; Saulson R.; Kalaria R.; Ogunniyi A.; Owolabi M.
Background: Inherited genetic variations offer a possible explanation for the observed peculiarities of stroke in sub - Saharan African populations. Interleukin–6 polymorphisms have been previously associated with ischemic stroke in some non-African populations. Aim: Herein we investigated, for the first time, the association of genetic polymorphisms of IL-6, CDKN2A CDKN2B and other genes with ischemic stroke among indigenous West African participants in the Stroke Investigative Research and Education Network (SIREN) Study. Methods: Twenty-three previously identified single nucleotide polymorphisms (SNPs) in 14 genes of relevance to the neurobiology of ischemic stroke were investigated. Logistic regression models adjusting for known cardio vascular disease risk factors were constructed to assess the associations of the 23 SNPs in rigorously phenotyped cases (N = 429) of ischemic stroke (Men = 198; Women = 231) and stroke– free (N = 483) controls (Men = 236; Women = 247). Results: Interleukin-6 (IL6) rs1800796 (C minor allele; frequency: West Africans = 8.6%) was significantly associated with ischemic stroke in men (OR = 2.006, 95% CI = [1.065, 3.777], p = 0.031) with hypertension in the model but not in women. In addition, rs2383207 in CDKN2A/CDKN2B (minor allele A with frequency: West Africans = 1.7%) was also associated with ischemic stroke in men (OR = 2.550, 95% CI = [1.027, 6.331], p = 0.044) with primary covariates in the model, but not in women. Polymorphisms in other genes did not show significant association with ischemic stroke.
Knowledge, attitudes and practices of West Africans on genetic studies of stroke: Evidence from the SIREN Study
(World Stroke Organization Reprints and permissions, 2018) Akinyemi R. O.; Sarfo F. S.; Akinyemi J.; Singh A.; Akpa M. O.; Akpalu A.; Owolabi L.; Adeoye A. M.; Obiako R.; Wahab K.; Sanya E.; Komolafe M.; Ogbole G.; Fawale M.; Adebayo P.; Osaigbovo G.; Sunmonu T.; Olowoyo P.; Chukwuonye I.; Obiabo Y.; Adeniji O.; Fakunle G.; Melikam E.; Saulson R.; Yaria J.; Uwanruochi K.
Background: It is crucial to assess genomic literacy related to stroke among Africans in preparation for the ethical, legal and societal implications of the genetic revolution which has begun in Africa. Objective: To assess the knowledge, attitudes and practices (KAP) of West Africans about stroke genetic studies. Methods: A comparative cross-sectional study was conducted among stroke patients and stroke-free controls recruited across 15 sites in Ghana and Nigeria. Participants’ knowledge of heritability of stroke, willingness to undergo genetic testing and perception of the potential benefits of stroke genetic research were assessed using interviewer-administered questionnaire. Descriptive, frequency distribution and multiple regression analyses were performed. Results: Only 49% of 2029 stroke patients and 57% of 2603 stroke-free individuals knew that stroke was a heritable disorder. Among those who knew, 90% were willing to undergo genetic testing. Knowledge of stroke heritability was associated with having at least post-secondary education (OR 1.51, 1.25–1.81) and a family history of stroke (OR 1.20, 1.03–1.39) while Islamic religion (OR¼0.82, CI: 0.72–0.94), being currently unmarried (OR ¼ 0.81, CI: 0.70–0.92), and alcohol use (OR ¼ 0.78, CI: 0.67–0.91) were associated with lower odds of awareness of stroke as a heritable disorder. Willingness to undergo genetic testing for stroke was associated with having a family history of stroke (OR 1.34, 1.03– 1.74) but inversely associated with a medical history of high blood pressure (OR ¼ 0.79, 0.65–0.96). Conclusion: To further improve knowledge of stroke heritability and willingness to embrace genetic testing for stroke, individuals with less formal education, history of high blood pressure and no family history of stroke require targeted interventions
The epidemiology of stroke in Africa: A systematic review of existing methods and new approaches
(Wiley Periodicals, Inc., 2017) Owolabi M.; Olowoyo P.; Popoola F.; Lackland D.; Jenkins C.; Arulogun O.; Akinyemi R.; Akinyemi O.; Akpa O.; Olaniyan O.; Uvere E.; Kehinde I.; Selassie A.; Gebregziabher M.; Tagge R.; Ovbiagele B.
Accurate epidemiological surveillance of the burden of stroke is direly needed to facilitate the development and evaluation of effective interventions in Africa. The authors therefore conducted a systematic review of the methodology of stroke epidemiological studies conducted in Africa from 1970 to 2017 using gold standard criteria obtained from landmark epidemiological publications. Of 1330 articles extracted, only 50 articles were eligible for review grouped under incidence, prevalence, case-fatality, health-related quality of life, and disability-adjusted life-years studies. Because of various challenges, no study fulfilled the criteria for an excellent stroke incidence study. The relatively few stroke epidemiology studies in Africa have significant methodological flaws. Innovative approaches leveraging available information and communication technology infrastructure are recommended to facilitate rigorous epidemiological studies for accurate stroke surveillance in Africa.