FACULTY OF PUBLIC HEALTH
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Item Echocardiographic abnormalities and determinants of 1-month outcome of stroke among West Africans in the SIREN Study(American Heart Association, 2019) Adeoye A. M.; Ovbiagele B.; Akinyemi J. O.; Ogah O. S.; Akinyemi R.; Gebregziabher M.; Wahab K.; Fakunle A. G.; Akintunde A.; Adebayo O.; Aje A.; Tiwari H. K; Arnett D.; Agyekum F.; Appiah L. T.; Amusa G.; Olunuga T. O.; Akpa O.; Sarfo F. S.; Akpalu A.; Jenkins C.; Lackland D.Background-—Little is known about the relationship between echocardiographic abnormalities and outcome among patients with acute stroke. We investigated the pattern and association of baseline echocardiographic variables with 1-month disability and mortality among patients with stroke in the SIREN (Stroke Investigative Research and Education Network) study. Methods and Results-—We enrolled and followed up consecutive 1020 adult patients with acute stroke with baseline transthoracic echocardiography from west Africa. To explore the relationship between echocardiographic variables and 1-month disability (using modified Rankin scale >3) and fatality, regression models were fitted. Relative risks were computed with 95% CIs. The participants comprised 60% men with a mean age of 59.2_14.6 years. Ischemic stroke was associated with smaller aortic root diameter (30.2 versus 32.5, P=0.018) and septal (16.8 versus 19.1, P<0.001) and posterior wall thickness at systole (18.9 versus 21.5, P=0.004). Over 90% of patients with stroke had abnormal left ventricular (LV) geometry with eccentric hypertrophy predominating (56.1%). Of 13 candidate variables investigated, only baseline abnormal LV geometry (concentric hypertrophy) was weakly associated with 1-month disability (unadjusted relative risk, 1.80; 95% CI, 0.97–5.73). Severe LV systolic dysfunction was significantly associated with increased 1-month mortality (unadjusted relative risk, 3.05; 95% CI, 1.36–6.83). Conclusions-—Nine of 10 patients with acute stroke had abnormal LV geometry and a third had systolic dysfunction. Severe LV systolic dysfunction was significantly associated with 1 month mortality. Larger studies are required to establish the independent effect and unravel predictive accuracy of this associationItem 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 interventionsItem Stroke Among Young West Africans Evidence From the SIREN (Stroke Investigative Research and Educational Network) Large Multisite Case–Control Study.(American Heart Association, Inc., 2019) Sarfo F. S.; Ovbiagele B.; Gebregziabher M.; Wahab K.; Akinyemi R. O.; Akpalu A.; Akpa O.; Obiako R.; Owolabi L.; Jenkins C.; Owolabi M. O.Background and purpose: Stroke in lower and middle-income countries affects a young and productive age group. Data on factors associated with stroke in the young are sorely lacking from lower and middle-income countries. Our objective is to characterize the nature of stroke and its risk factors among young West Africans aged <50 years old. Methods: The SIREN (Stroke Investigative Research and Educational Network) is a multicenter, case-control study involving 15 sites in Nigeria and Ghana. Cases included adults aged ≥18 years with computed tomography/magnetic resonance imaging-confirmed stroke. Controls were age-and gender-matched stroke-free adults recruited from the communities in catchment areas of cases. Comprehensive evaluation for vascular, lifestyle, and psychosocial factors was performed. We used conditional logistic regression to estimate odds ratios and population attributable risks with 95% confidence intervals. Results: Five hundred fifteen (24.3%) out of 2118 cases enrolled were <50 years old. Among subjects <50 years old, hemorrhagic stroke proportion was 270 (52.5%) versus 245 (47.5%) for ischemic strokes. Etiologic subtypes of ischemic strokes included large artery atherosclerosis (40.0%), small vessel disease (28.6%), cardioembolism (11.0%), and undetermined (20.4%). Hypertension (91.7%), structural lesions (3.4%), and others (4.9%) were causally associated with hemorrhagic stroke. Six topmost modifiable factors associated with stroke in descending order of population attributable risk (95% confidence interval) were hypertension: 88.7% (82.5%-94.8%), dyslipidemia: 48.2% (30.6%-65.9%), diabetes mellitus: 22.6% (18.7%-26.5%), low green vegetable consumption: 18.2% (-6.8%-43.2%), stress: 14.5% (4.9%-24.1%), and cardiac disease: 8.4% (5.8%-11.1%). Conclusions: The high and rising burden of stroke among young Africans should be curtailed via aggressive, population-wide vascular risk factor control.Item 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.Item 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 ancestryItem Multilingual Validation of the Questionnaire for Verifying Stroke-Free Status in West Africa(Lippincott Williams & Wilkins, 2016) Sarfo F.; Gebregziabher M.; Ovbiagele B.; Akinyemi R.; Owolabi L.; Obiako R.; Akpa O.; Armstrong K.; Akpalu A.; Adamu S.; Obese V.; Boa-Antwi N.; Appiah L.; Arulogun O.; Mensah Y.; Adeoye A.; Tosin A.; Adeleye O.; Tabi-Ajayi E.; Phillip I.; Sani A.; Isah S.; Tabari N.; Mande A.; Agunloye A.; Ogbole G.; Akinyemi J.; Laryea R.; Melikam S.; Uvere E.; Adekunle G.; Kehinde S.; Azuh P.; Dambatta A.; Ishaq N.; Saulson R.; Arnett D.; Tiwari H.; Jenkins C.; Lackland D.; Owolabi M.Background and Purpose—The Questionnaire for Verifying Stroke-Free Status (QVSFS), a method for verifying stroke-free status in participants of clinical, epidemiological, and genetic studies, has not been validated in low-income settings where populations have limited knowledge of stroke symptoms. We aimed to validate QVSFS in 3 languages, Yoruba, Hausa and Akan, for ascertainment of stroke-free status of control subjects enrolled in an on-going stroke epidemiological study in West Africa. Methods—Data were collected using a cross-sectional study design where 384 participants were consecutively recruited from neurology and general medicine clinics of 5 tertiary referral hospitals in Nigeria and Ghana. Ascertainment of stroke status was by neurologists using structured neurological examination, review of case records, and neuroimaging (gold standard). Relative performance of QVSFS without and with pictures of stroke symptoms (pictograms) was assessed using sensitivity, specificity, positive predictive value, and negative predictive value. Results—The overall median age of the study participants was 54 years and 48.4% were males. Of 165 stroke cases identified by gold standard, 98% were determined to have had stroke, whereas of 219 without stroke 87% were determined to be stroke-free by QVSFS. Negative predictive value of the QVSFS across the 3 languages was 0.97 (range, 0.93–1.00), sensitivity, specificity, and positive predictive value were 0.98, 0.82, and 0.80, respectively. Agreement between the questionnaire with and without the pictogram was excellent/strong with Cohen k=0.92. Conclusions—QVSFS is a valid tool for verifying stroke-free status across culturally diverse populations in West Africa.Item Carotid IMT is more associated with stroke than risk calculators(John Wiley & Sons Ltd., 2015) Owolabi, M. O.; Akpa, O. M.; Agunloye, A. M.Background – It is unclear whether a natural marker of atherosclerosis (carotid intima-media thickness: CIMT) or calculated risk score is more associated with stroke. We therefore comparatively examined the relationship between CIMT as well as two cardiovascular risk calculators (Omnibus Risk Score -ORS and Framingham Risk Score- FRS) and the occurrence of stroke among hypertensive African patients. Methods – CIMT was measured in 555 consecutive consenting hypertensive adults (377 stroke patients and 178 strokefree subjects). The 10-year cardiovascular risk was calculated for each participant with the FRS and ORS. The strengths of association between FRS, ORS, CIMT, and stroke occurrence were examined using logistic regression. The discriminative capacity of FRS, ORS, and CIMT for stroke occurrence was assessed with c-statistics. Results – Higher average CIMT (OR 11.71; 95% CI 1.65–83.07; P = 0.01) was strongly associated with stroke after adjusting for age, sex, blood pressure, serum cholesterol, and blood sugar. Neither the FRS (OR: 1.03; CI: 0.89–1.19, P = 0.68) nor the ORS (OR: 1.08; CI: 0.90–1.30; P = 0.41) was significantly associated with stroke. CIMT had a higher c-statistic for differentiating stroke patients from hypertensive controls (right: c = 0.63, P < 0.001; left: c = 0.67, P < 0.001; average: c = 0.66, P < 0.001) than some conventional risk factors. Neither FRS (P = 0.39) nor ORS (P = 0.55) was able to independently differentiate between stroke and hypertensive patients. Conclusion – CIMT, but neither FRS nor ORS, is independently associated with stroke among Nigerian African hypertensive patients. CIMT may be a better tool for estimating the overall risk of stroke than FRS or ORS in this population.Item Can common carotid intima media thickness serve as an indicator of both cardiovascular phenotype and risk among black Africans?(Sage publications, 2014) Owolabi, M. O.; Agunloye, A. M.; Umeh, E. O.; Akpa, O. M.Background: It is not known whether common carotid intima media thickness (CIMT) can serve as a surrogate marker of cardiovascular risk among black Africans. Therefore, we examined whether CIMT differed significantly among individuals with distinct cardiovascular phenotype and correlated significantly with traditional cardiovascular risk factors in a black African population Methods: CIMT was measured in 456 subjects with three distinct cardiovascular phenotypes – 175 consecutive Nigerian African stroke patients, 161 hypertensive patients without stroke and 120 normotensive non-smoking adults. For each pair of cardiovascular phenotypes, c-statistics were obtained for CIMT and traditional vascular risk factors (including age, gender, weight, waist circumference, smoking, alcohol, systolic and diastolic blood pressures, fasting plasma glucose, fasting total cholesterol). Pearson’s correlation coefficients were calculated to quantify bivariate relationships. Findings: Bilaterally, CIMT was significantly different among the three cardiovascular phenotypes (right: p < 0.001, F ¼ 33.8; left: p < 0.001, F ¼ 48.6). CIMT had a higher c-statistic for differentiating stroke versus normotension (c ¼ 0.78 right; 0.82 left, p < 0.001) and hypertension versus normotension (c ¼ 0.65 right; 0.71 left, p < 0.001) than several traditional vascular risk factors. Bilaterally, combining all subjects, CIMT was the only factor that correlated significantly (right: 0.12 r 0.41, 0.018 p < 0.0001; left: 0.18 r 0.41, 0.005 p < 0.0001) to all the traditional cardiovascular risk factors assessed. Conclusion: Our findings support CIMT as a significant indicator of both cardiovascular risk and phenotype among adult black Africans. However, specific thresholds need to be defined based on prospective studies.