H3Africa partnerships to empower clinical research sites to generate high-quality biological samples.

BACKGROUND: The Institute of Human Virology Nigeria (IHVN) - Human Heredity and Health in Africa (H3Africa) Biorepository (I-HAB) seeks to provide high-quality biospecimens for research. This depends on the ability of clinical research sites (CRS) - who provide biospecimens - to operate according to well-established industry standards. Yet, standards are often neglected at CRSs located in Africa. Here, I-HAB reports on its four-pronged approach to empower CRSs to prepare high-quality biospecimens for research. OBJECTIVES: I-HAB sought (1) to assess a four-pronged approach to improve biobanking practices and sample quality among CRSs, and (2) to build human capacity. METHODS: I-HAB partnered with two H3Africa principal investigators located in Nigeria and Ghana from August 2013 through to May 2017 to debut its four-pronged approach (needs assessment, training and mentorship, pilot, and continuous quality improvement) to empower CRSs to attain high-quality biospecimens. RESULTS: Close collaborations were instrumental in establishing mutually beneficial and lasting relationships. Improvements during the 12 months of engagement with CRSs involved personnel, procedural, and supply upgrades. In total, 51 staff were trained in over 20 topics. During the pilot, CRSs extracted 50 DNA biospecimens from whole blood and performed quality control. The CRSs shipped extracted DNA to I-HAB and I-HAB that comparatively analysed the DNA. Remediation was achieved via recommendations, training, and mentorship. Preanalytical, analytical and post-analytical processes, standard operating procedures, and workflows were systematically developed. CONCLUSION: Partnerships between I-HAB and H3Africa CRSs enabled research sites to produce high-quality biospecimens through needs assessment, training and mentorship, pilot, and continuous monitoring and improvement.

Interleukin-6 (IL-6) rs1800796 and cyclin dependent kinase inhibitor (CDKN2A/CDKN2B) rs2383207 are associated with ischemic stroke in indigenous West African Men.

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 cardiovascular 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. CONCLUSION: Polymorphisms rs1800796 in IL6 gene and rs2383207 in CDKN2A/CDKN2B gene have significant associations with ischemic stroke in indigenous West African men. CDKN2A/CDKN2B SNP rs2383207 is independently associated with ischemic stroke in indigenous West African men. Further research should focus on the contributions of inflammatory genes and other genetic polymorphisms, as well as the influence of sex on the neurobiology of stroke in people of African ancestry.

Exploring Overlaps Between the Genomic and Environmental Determinants of LVH and Stroke: A Multicenter Study in West Africa.

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 = 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 <45 years (adjusted odds ratio [AOR]: 1.91; 95% confidence interval [CI]: 1.14 to 3.19), female sex (AOR: 2.01; 95% CI: 1.44 to 2.81), and diastolic blood pressure > 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.

Validation of the 8-item questionnaire for verifying stroke free status with and without pictograms in three West African languages.

BACKGROUND: The Questionnaire for Verifying Stroke-free Status (QVSFS) has been validated in Western populations as a method for verifying stroke-free status in participants of clinical, epidemiological and genetic studies. This instrument has not been validated in low-income settings where populations have limited knowledge of stroke symptoms and literacy levels are low. OBJECTIVE: To simultaneously validate the 8-item QVSFS in 3 languages spoken in West Africa (Yoruba, Hausa and Akan) for ascertainment of stroke-free status of control subjects in SIREN. METHODS: Using a cross-sectional study design, 100 participants each from the 3 linguistic groups will be consecutively recruited from neurology and general medicine clinics of 5 tertiary referral hospitals in Nigeria and Ghana. Ascertainment of stroke status will be determined by neurologists using structured neurological examination, review of case records and neuro-imaging (Gold standard). The relative performance of QVSFS without and with pictures of stroke symptoms (pictograms) will be assessed using sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). CONCLUSION: The proposed study will provide valuable data on the performance of the QVSFS in resource-limited settings.

Multilingual Validation of the Questionnaire for Verifying Stroke-Free Status in West Africa.

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.

Phenotyping Stroke in Sub-Saharan Africa: Stroke Investigative Research and Education Network (SIREN) Phenomics Protocol.

BACKGROUND: As the second leading cause of death and the leading cause of adult-onset disability, stroke is a major public health concern particularly pertinent in Sub-Saharan Africa (SSA), where nearly 80% of all global stroke mortalities occur, and stroke burden is projected to increase in the coming decades. However, traditional and emerging risk factors for stroke in SSA have not been well characterized, thus limiting efforts at curbing its devastating toll. The Stroke Investigative Research and Education Network (SIREN) project is aimed at comprehensively evaluating the key environmental and genomic risk factors for stroke (and its subtypes) in SSA while simultaneously building capacities in phenomics, biobanking, genomics, biostatistics, and bioinformatics for brain research. METHODS: SIREN is a transnational, multicentre, hospital and community-based study involving 3,000 cases and 3,000 controls recruited from 8 sites in Ghana and Nigeria. Cases will be hospital-based patients with first stroke within 10 days of onset in whom neurovascular imaging will be performed. Etiological and topographical stroke subtypes will be documented for all cases. Controls will be hospital- and community-based participants, matched to cases on the basis of gender, ethnicity, and age (±5 years). Information will be collected on known and proposed emerging risk factors for stroke. STUDY SIGNIFICANCE: SIREN is the largest study of stroke in Africa to date. It is anticipated that it will shed light on the phenotypic characteristics and risk factors of stroke and ultimately provide evidence base for strategic interventions to curtail the burgeoning burden of stroke on the sub-continent.

The burden of stroke in Africa: a glance at the present and a glimpse into the future.

OBJECTIVE: Information on the current burden of stroke in Africa is limited. The aim of this review was to comprehensively examine the current and projected burden of stroke in Africa. METHODS: We systematically reviewed the available literature (PubMed and AJOL) from January 1960 and June 2014 on stroke in Africa. Percentage change in age-adjusted stroke incidence, mortality and disability-adjusted life years (DALYs) for African countries between 1990 and 2010 were calculated from the Global Burden of Diseases (GBD) model-derived figures. RESULTS: Community-based studies revealed an age-standardised annual stroke incidence rate of up to 316 per 100,000 population, and age-standardised prevalence rates of up to 981 per 100,000. Model-based estimates showed significant mean increases in age-standardised stroke incidence. The peculiar factors responsible for the substantial disparities in incidence velocity, ischaemic stroke proportion, mean age and case fatality compared to high-income countries remain unknown. CONCLUSIONS: While the available study data and evidence are limited, the burden of stroke in Africa appears to be increasing.