Stroke risk prediction models: A systematic review and meta-analysis.

BACKGROUND: Prediction algorithms/models are viable methods for identifying individuals at high risk of stroke across diverse populations for timely intervention. However, evidence summarizing the performance of these models is limited. This study examined the performance and weaknesses of existing stroke risk-score-prediction models (SRSMs) and whether performance varied by population and region. METHODS: PubMed, EMBASE, and Web of Science were searched for articles on SRSMs from the earliest records until February 2022. The Prediction Model Risk of Bias Assessment Tool was used to assess the quality of eligible articles. The performance of the SRSMs was assessed by meta-analyzing C-statistics (0 and 1) estimates from identified studies to determine the overall pooled C-statistics by fitting a linear restricted maximum likelihood in a random effect model. RESULTS: Overall, 17 articles (cohort study = 15, nested case-control study = 2) comprising 739,134 stroke cases from 6,396,594 participants from diverse populations/regions (Asia; n = 8, United States; n = 3, and Europe and the United Kingdom; n = 6) were eligible for inclusion. The overall pooled c-statistics of SRSMs was 0.78 (95%CI: 0.75, 0.80; I2 = 99.9%), with most SRSMs developed using cohort studies; 0.78 (95%CI: 0.75, 0.80; I2 = 99.9%). The subgroup analyses by geographical region: Asia [0.81 (95%CI: 0.79, 0.83; I2 = 99.8%)], Europe and the United Kingdom [0.76 (95%CI: 0.69, 0.83; I2 = 99.9%)] and the United States only [0.75 (95%CI: 0.72, 0.78; I2 = 73.5%)] revealed relatively indifferent performances of SRSMs. CONCLUSION: SRSM performance varied widely, and the pooled c-statistics of SRSMs suggested a fair predictive performance, with very few SRSMs validated in independent population group(s) from diverse world regions.

Stroke occurrence by hypertension treatment status in Ghana and Nigeria: A case-control study.

BACKGROUND: Hypertension is preeminent among the vascular risk factors for stroke occurrence. The wide gaps in awareness, detection, treatment, and control rates of hypertension are fueling an epidemic of stroke in sub-Saharan Africa. PURPOSE: To quantify the contribution of untreated, treated but uncontrolled, and controlled hypertension to stroke occurrence in Ghana and Nigeria. METHODS: The Stroke Investigative Research and Educational Network (SIREN) is a case-control study across 16 study sites in Ghana and Nigeria. Cases were acute stroke (n = 3684) with age- and sex-matched stroke-free controls (n = 3684). We evaluated the associations of untreated hypertension, treated but uncontrolled hypertension, and controlled hypertension at BP of <140/90 mmHg with risk of stroke occurrence. We assessed the adjusted odds ratio and population-attributable risk of hypertension treatment control status associated with stroke occurrence. RESULTS: The frequencies of no hypertension, untreated hypertension, treated but uncontrolled hypertension and controlled hypertension among stroke cases were 4.0%, 47.7%, 37.1%, and 9.2% vs 40.7%, 34.9%, 15.9%, and 7.7% respectively among stroke-free controls, p < 0.0001. The aOR and PAR (95% CI) for untreated hypertension were 6.58 (5.15-8.41) and 35.4% (33.4-37.4); treated but uncontrolled hypertension was 9.95 (7.60-13.02) and 35.9% (34.2-37.5); and controlled hypertension 5.37 (3.90-7.41) and 8.5% (7.6-9.5) respectively. Untreated hypertension contributed a PAR of 47.5% to the occurrence of intracerebral hemorrhage vs 29.5% for ischemic stroke. The aOR of untreated hypertension for stroke occurrence was 13.31 (7.64-23.19) for <50 years; 7.14 (4.51-11.31) for 50-64 years; and 3.48 (2.28-5.30) for 65 years or more. CONCLUSION: The contribution of untreated hypertension and treated but uncontrolled hypertension to stroke occurrence among indigenous Africans is substantial. Implementing targeted interventions that address gaps in hypertension prevention and treatment, involving the local population, healthcare providers, and policymakers, can potentially substantially reduce the escalating burden of strokes in Africa.

Novel functional insights into ischemic stroke biology provided by the first genome-wide association study of stroke in indigenous Africans.

BACKGROUND: African ancestry populations have the highest burden of stroke worldwide, yet the genetic basis of stroke in these populations is obscure. The Stroke Investigative Research and Educational Network (SIREN) is a multicenter study involving 16 sites in West Africa. We conducted the first-ever genome-wide association study (GWAS) of stroke in indigenous Africans. METHODS: Cases were consecutively recruited consenting adults (aged > 18 years) with neuroimaging-confirmed ischemic stroke. Stroke-free controls were ascertained using a locally validated Questionnaire for Verifying Stroke-Free Status. DNA genotyping with the H3Africa array was performed, and following initial quality control, GWAS datasets were imputed into the NIH Trans-Omics for Precision Medicine (TOPMed) release2 from BioData Catalyst. Furthermore, we performed fine-mapping, trans-ethnic meta-analysis, and in silico functional characterization to identify likely causal variants with a functional interpretation. RESULTS: We observed genome-wide significant (P-value < 5.0E-8) SNPs associations near AADACL2 and miRNA (MIR5186) genes in chromosome 3 after adjusting for hypertension, diabetes, dyslipidemia, and cardiac status in the base model as covariates. SNPs near the miRNA (MIR4458) gene in chromosome 5 were also associated with stroke (P-value < 1.0E-6). The putative genes near AADACL2, MIR5186, and MIR4458 genes were protective and novel. SNPs associations with stroke in chromosome 2 were more than 77 kb from the closest gene LINC01854 and SNPs in chromosome 7 were more than 116 kb to the closest gene LINC01446 (P-value < 1.0E-6). In addition, we observed SNPs in genes STXBP5-AS1 (chromosome 6), GALTN9 (chromosome 12), FANCA (chromosome 16), and DLGAP1 (chromosome 18) (P-value < 1.0E-6). Both genomic regions near genes AADACL2 and MIR4458 remained significant following fine mapping. CONCLUSIONS: Our findings identify potential roles of regulatory miRNA, intergenic non-coding DNA, and intronic non-coding RNA in the biology of ischemic stroke. These findings reveal new molecular targets that promise to help close the current gaps in accurate African ancestry-based genetic stroke's risk prediction and development of new targeted interventions to prevent or treat stroke.

Dietary patterns associated with hypertension among stroke-free indigenous Africans: insights from the Stroke Investigative Research and Educational Network study.

BACKGROUND: The dietary factors associated with the high burden of hypertension among indigenous Africans remain poorly understood. We assessed the relationship between dietary patterns and hypertension among indigenous Africans. METHOD: In this study, 1550 participants with hypertension matched (for age: ±â€Š5 years, sex and ethnicity) with 1550 participants without hypertension were identified from the stroke-free population in the Stroke Investigative Research and Educational Network study in Ghana and Nigeria. Food consumption was assessed using a food frequency questionnaire, and dietary information was summarized using principal component analysis to identify seven dietary patterns. Conditional logistic regression was applied to compute the odds ratio (OR) and 95% confidence interval (CI) for the risk of hypertension by tertiles of dietary patterns adjusting for age, education, income, smoking, alcohol use, physical inactivity, family history of cardiovascular diseases, obesity and salt intake at a two-sided P less than 0.05. RESULTS: Multivariable-adjusted OR [95% confidence interval (CI)] for risk of hypertension by second and third tertiles [using the lowest (first) tertile as reference] of dietary patterns were 0.62 (0.48-0.80), 0.70 (0.54-0.90) for whole grains and fruit drinks; 0.87 (0.68-1.12), 0.83 (0.64-1.08) for fruits; 0.85 (0.65-1.10), 0.97 (0.75-1.26) for vegetables, legumes and potatoes; 0.78 (0.60-1.00), 0.84 (0.65-1.08) for fried foods and sweetened drinks; 1.13 (0.88-1.45), 0.80 (0.62-1.03) for poultry product and organ meat; 1.11 (0.86-1.43), 0.88 (0.68-1.14) for red meat; and 1.14 (0.88-1.48), 1.09 (0.84-1.43) for processed foods ( P  < 0.05). CONCLUSION: A higher adherence to dietary consumption of whole grains and fruits was inversely associated with low odds of hypertension in this population.

Factors associated with frequency of fruit and vegetable consumption among selected sub-Saharan African populations: evidence from the Cardiovascular H3Africa Innovation Resource Project.

BACKGROUND: Frequent fruit and vegetable consumption is considered a promising dietary behaviour that protects health. However, most existing studies about the factors associated with this phenomenon among Africans are based on single-country reports, apart from one meta-regression combining smaller studies. This study harmonized large datasets and assessed factors associated with the frequency of fruit and vegetable consumption in this population. METHODS: Individual-level data on sociodemographics, lifestyle and diet from 20 443 participants across five African countries (Burkina Faso, Ghana, Kenya, South Africa and Nigeria), from the Stroke Investigative Research and Educational Network (SIREN) and Africa Wits-INDEPTH partnership for Genomic Research (AWI-Gen) studies, were harmonized. Total frequency of fruit and vegetable consumption (in portions/week) was classified as 'low' (≤6), 'moderate' (7-14) and 'high' (≥15). Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) of factors associated with the total frequency of fruit and vegetable consumption (using 'low' consumption as the reference) were estimated using multinomial regression models. RESULTS: Mean age of participants was 54.3 ± 11.8 years, 10 641 (52.1%) were female, and the median (interquartile range) frequency of total fruit and vegetable consumption was 10.0 (4.0, 21.0) portions/week. Participants with a family history of cardiovascular disease [moderate (aOR, 0.92; 95% CI, 0.85, 1.00) and high (aOR, 0.85; 95% CI, 0.78, 0.92)], current smokers [moderate (aOR, 0.83; 95% CI, 0.74, 0.94) and high (aOR, 0.78; 95% CI, 0.69, 0.88)], current alcohol users [moderate (aOR, 0.92; 95% CI, 0.85, 1.00) and high (aOR, 0.82; 95% CI, 0.76, 0.89)] and physically inactive participants [moderate (aOR, 0.85; 95% CI, 0.75, 0.96) and high (aOR, 0.80; 95% CI, 0.70, 0.90)] were less likely to consume fruits and vegetables frequently. CONCLUSION: Africans with lifestyle risk factors for cardiovascular disease were less likely to consume fruit and vegetables frequently.

Association of second-hand smoking with sleep quality among adults in Ibadan, Nigeria: a cross-sectional evaluation of data from the COMBAT-CVDs study.

PURPOSE: Sleep quality (SQ) is essential in the overall well-being and quality of life, but little is known about the association of secondhand smoking (SHS) with SQ. This study assessed the relationship between SHS and SQ among adults who had never smoked in Ibadan, Nigeria. METHODS: We identified 3193 respondents who had never smoked or used any form of tobacco product in the Community-based Investigation of the Risk Factors for Cardiovascular Diseases in the Ibadan and suburbs (COMBAT-CVDs) study. SHS was self-reported, SQ assessed using a sleep quality scale, and SQ scores were classified by the quartile distributions of SQ scores in this sample as good (< 7), moderate (7-13), fair (14-20), and poor (≥ 21), and logistic regression models were used to estimate the multivariable-adjusted odds ratio and 95% confidence interval (CI) of the association between SHS and SQ in a two-sided test at P < 0.05. RESULTS: The mean (SD) of age in this sample was 34.8 ± 15.1 years; 1621 (50.8%) were females, and 848 (26.6%) experienced SHS. The multivariable-adjusted odds by categories of SQ scores (using good SQ as reference) in the light of SHS were OR: 1.64 (95%CI 1.28, 2.12) for moderate SQ, OR: 1.88 (95%CI 1.46, 2.42) for fair SQ and OR: 2.14 (95%CI 1.66, 2.75) for poor SQ; P < 0.0001 after adjusting for relevant covariates. The sex- and age groups- stratified analyses revealed similar trends. CONCLUSION: SHS is associated with higher odds of poor SQ in this study. Culturally relevant interventions for mitigating exposure to SHS might improve SQ and overall quality of life, particularly among vulnerable populations.

Non-cigarette tobacco use and stroke among West Africans: evidence from the SIREN study.

INTRODUCTION: Non-cigarette tobacco (NCT) represents a form of tobacco use with a misperceived significance in chronic disease events. Whether NCT use is sufficient to promote stroke events, especially among Africans, is yet to be understood. This study assessed the relationship between NCT use and stroke among indigenous Africans. METHODS: A total of 7,617 respondents (NCT users: 41 vs. non-NCT: 7576) from the Stroke Investigation Research and Educational Network study were included in the current analysis. NCT use was defined as self-reported use of smoked (cigars or piper) or smokeless (snuff or chewed) tobacco in the past year preceding stroke events. Stroke was defined based on clinical presentation and confirmed with a cranial CT/MRI. Multivariable-adjusted logistic regression was applied to estimate the odds ratio (OR) and 95% confidence interval (CI) for the relationship between NCT and stroke at p<0.05. RESULTS: Out of the 41 (0.54%) who reported NCT use, 27 (65.9%) reported using smokeless NCT. NCT users were older than non-smokers (62.8±15.7 vs 57.7±14.8 years). Overall, NCT use was associated with first-ever stroke (OR: 2.08; 95%CI: 1.02, 4.23) in the entire sample. Notably, smokeless NCT use was independently associated with higher odds of stroke (OR: 2.74; 95%CI: 1.15, 6.54), but smoked NCT use (OR: 0.16; 95%CI: 0.02, 1.63) presented a statistically insignificant association after adjusting for hypertension and other covariates. CONCLUSIONS: NCT use was associated with higher odds of stroke, and public health interventions targeting NCT use might be promising in reducing the burden of stroke among indigenous Africans. IMPLICATIONS: A detailed understanding of the relationship between NCT use and stroke will likely inform well-articulated policy guidance to promote evidence-based recommendations for public health prevention and management of stroke on the African continent.

Risk Assessment Score and Chi-Square Automatic Interaction Detection Algorithm for Hypertension Among Africans: Models From the SIREN Study.

BACKGROUND: This study aimed to develop a risk-scoring model for hypertension among Africans. METHODS: In this study, 4413 stroke-free controls were used to develop the risk-scoring model for hypertension. Logistic regression models were applied to 13 risk factors. We randomly split the dataset into training and testing data at a ratio of 80:20. Constant and standardized weights were assigned to factors significantly associated with hypertension in the regression model to develop a probability risk score on a scale of 0 to 1 using a logistic regression model. The model accuracy was assessed to estimate the cutoff score for discriminating hypertensives. RESULTS: Mean age was 59.9±13.3 years, 56.0% were hypertensives, and 8 factors, including diabetes, age ≥65 years, higher waist circumference, (BMI) ≥30 kg/m2, lack of formal education, living in urban residence, family history of cardiovascular diseases, and dyslipidemia use were associated with hypertension. Cohen κ was maximal at ≥0.28, and a total probability risk score of ≥0.60 was adopted for both statistical weighting for risk quantification of hypertension in both datasets. The probability risk score presented a good performance-receiver operating characteristic: 64% (95% CI, 61.0-68.0), a sensitivity of 55.1%, specificity of 71.5%, positive predicted value of 70.9%, and negative predicted value of 55.8%, in the test dataset. Similarly, decision tree had a predictive accuracy of 67.7% (95% CI, 66.1-69.3) for the training set and 64.6% (95% CI, 61.0-68.0) for the testing dataset. CONCLUSIONS: The novel risk-scoring model discriminated hypertensives with good accuracy and will be helpful in the early identification of community-based Africans vulnerable to hypertension for its primary prevention.

Determinants of First-Ever Stroke Severity in West Africans: Evidence From the SIREN Study.

Background Baseline stroke severity is probably partly responsible for poor stroke outcomes in sub-Saharan Africa. However, there is a paucity of information on determinants of stroke severity among indigenous Africans. We sought to identify the factors associated with stroke severity among West Africans in the SIREN (Stroke Investigative Research and Educational Networks) study. Methods and Results Stroke was diagnosed clinically and confirmed with brain neuroimaging. Severe stroke was defined as a Stroke Levity Scale score of ≤5. A multivariate logistic regression model was constructed to identify factors associated with stroke severity at 95% CI and a nominal cutoff of 5% type 1 error. A total of 3660 stroke cases were included. Overall, 50.7%% had severe stroke, including 47.6% of all ischemic strokes and 56.1% of intracerebral hemorrhage. Factors independently associated with severe stroke were meat consumption (adjusted odds ratio [aOR], 1.97 [95% CI, 1.43-2.73]), low vegetable consumption (aOR, 2.45 [95% CI, 1.93-3.12]), and lesion volume, with an aOR of 1.67 (95% CI, 1.03-2.72) for lesion volume of 10 to 30 cm3 and aOR of 3.88 (95% CI, 1.93-7.81) for lesion volume >30 cm3. Severe ischemic stroke was independently associated with total anterior circulation infarction (aOR, 3.1 [95% CI, 1.5-6.9]), posterior circulation infarction (aOR, 2.2 [95% CI, 1.1-4.2]), and partial anterior circulation infarction (aOR, 2.0 [95% CI, 1.2-3.3]) compared with lacunar stroke. Increasing age (aOR, 2.6 [95% CI, 1.3-5.2]) and lesion volume >30 cm3 (aOR, 6.2 [95% CI, 2.0-19.3]) were independently associated with severe intracerebral hemorrhage. Conclusions Severe stroke is common among indigenous West Africans, where modifiable dietary factors are independently associated with it. These factors could be targeted to reduce the burden of severe stroke.

Patient-level and system-level determinants of stroke fatality across 16 large hospitals in Ghana and Nigeria: a prospective cohort study.

BACKGROUND: Every minute, six indigenous Africans develop new strokes. Patient-level and system-level contributors to early stroke fatality in this region are yet to be delineated. We aimed to identify and quantify the contributions of patient-level and system-level determinants of inpatient stroke fatality across 16 hospitals in Ghana and Nigeria. METHODS: The Stroke Investigative Research and Educational Network (SIREN) is a multicentre study involving 16 sites in Ghana and Nigeria. Cases include adults (aged ≥18 years) with clinical and radiological evidence of an acute stroke. Data on stroke services and resources available at each study site were collected and analysed as system-level factors. A host of demographic and clinical variables of cases were analysed as patient-level factors. A mixed effect log-binomial model including both patient-level and system-level covariates was fitted. Results are presented as adjusted risk ratios (aRRs) with respective 95% CIs. FINDINGS: Overall, 814 (21·8%) of the 3739 patients admitted with stroke died as inpatients: 476 (18·1%) of 2635 with ischaemic stroke and 338 (30·6%) of 1104 with intracerebral haemorrhage. The variability in the odds of stroke fatality that could be attributed to the system-level factors across study sites assessed using model intracluster correlation coefficient was substantial at 7·3% (above a 5% threshold). Stroke units were available at only five of 16 centres. The aRRs of six patient-level factors associated with stroke fatality were: low vegetable consumption, 1·19 (95% CI 1·07-1·33); systolic blood pressure, 1·02 (1·01-1·04) for each 10 mm Hg rise; stroke lesion volume more than 30 cm3, 1·48 (1·22-1·79); National Institutes of Health Stroke Scale (NIHSS) score, 1·20 (1·13-1·26) for each 5-unit rise; elevated intracranial pressure, 1·75 (1·31-2·33); and aspiration pneumonia, 1·79 (1·16-2·77). INTERPRETATION: Studies are needed to assess the efficacy of interventions targeting patient-level factors such as aspiration pneumonia in reducing acute stroke fatality in this region. Policy directives to improve stroke unit access are warranted. FUNDING: US National Institutes of Health. TRANSLATIONS: For the Twi, Yoruba and Hausa translations of the abstract see Supplementary Materials section.

Are there differences in perceptions, preferences and attitudes towards disclosure of genetic testing for Stroke? A qualitative study among stroke-free SIREN-SIBS genomics study participants.

OBJECTIVE: This study explored perceptions, preferences and attitudes towards disclosure of genetic testing results for stroke among stroke-free controls (and their family members) in the SIREN-SIBS Genomics Study, healthcare providers and policymakers. MATERIALS AND METHODS: We conducted a qualitative thematic analysis of key informant interviews with 61 participants recruited from community advisory boards (30) and health care providers (31) across seven sites in Nigeria and Ghana. RESULTS: Major findings illustrate differences in the knowledge of genetic testing with superior knowledge among health care professionals. Relatives and religious leaders were opined as the best to receive the disclosure as they would be able to break the news to the patient in a culturally sensitive manner to reduce the likely resultant emotional outburst. Poor level of awareness of national guidelines for disclosing genetic results exist. Key facilitating factors for disclosure are education, enabling environment, involvement of religious and community leaders, campaigns, and possible treatment options. Disclosure inhibitors include inadequate information, fear of marital break-up or family displacement, fear of stigmatization, fear of isolation, religious beliefs, health worker attitude, and lack of preparedness to accept results. CONCLUSIONS: These necessitate culturally sensitive interventions for continuing education, increased awareness and sustained engagement to equip all stakeholders in genetic testing disclosure process.

Dietary patterns associated with stroke among West Africans: A case-control study.

BACKGROUND: The relationship of diet with stroke risk among Africans is not well understood. AIM: The aim of this study was to investigate the association between dietary patterns and stroke risk among West Africans. METHODS: In this multi-center case-control study, 3684 stroke patients matched (for age and sex) with 3684 healthy controls were recruited from Nigeria and Ghana. Food consumption was assessed using a food frequency questionnaire, and dietary patterns were summarized using principal component analysis. Stroke was defined using predefined criteria primarily on clinical evaluation following standard guidelines. Conditional logistic regression was applied to compute odds ratio (OR) and 95% confidence interval (CI) for stroke risk by tertiles of dietary patterns adjusting for relevant confounders. RESULTS: Overall, mean age was 59.0 ± 13.9 years, and 3992 (54.2%) were males. Seven dietary patterns were identified. Multivariable-adjusted OR (95% CI) for risk of stroke by second and third tertiles (using the lowest and first tertile as reference) of dietary patterns was 1.65 (1.43, 1.90) and 1.74 (1.51, 2.02), for "poultry product and organ meat"; 1.69 (1.47, 1.96) and 1.51 (1.31, 1.75) for "red meat"; 1.07 (0.92, 1.23) and 1.21 (1.04, 1.40) for "fried foods and sweetened drinks"; 0.69 (0.60, 0.80) and 0.45 (0.39, 0.53) for "vegetables"; 0.84 (0.72, 0.97) and 0.81 (0.70, 0.93) for "whole-grain and fruit drinks"; and 0.97 (0.84, 1.12) and 0.85 (0.73, 0.98) for "fruits" respectively (p < 0.05). CONCLUSION: These data suggest that plant-based diets are associated with a lower risk of stroke and might be a beneficial dietary recommendation for the primary prevention of stroke among Africans.

Secondhand smoke exposure is independently associated with stroke among non-smoking adults in West Africa.

BACKGROUND: Stroke is a leading cause of disability and mortality worldwide, but little is known about the contribution of secondhand smoke exposure (SHSE) to stroke epidemiology among indigenous Africans. OBJECTIVE: To evaluate the association of SHSE with stroke among indigenous Africans. METHODS: We analyzed the relationship of SHSE with stroke among 2990 case-control pairs of adults who had never smoked (identified in the SIREN study) using conditional logistic regression at a two-sided P < 0.05. RESULTS: Multivariable-adjusted odds ratio and 95% confidence interval; 1.25 (1.04, 1.50; P = 0.02) revealed SHSE was positively associated with stroke independent of stroke subtypes. CONCLUSION: Culturally relevant primary prevention strategies targeted at SHSE might be promising in preventing stroke among Africans.

Frequent vegetable consumption is inversely associated with hypertension among indigenous Africans.

AIMS: The relationship between vegetable consumption and hypertension occurrence remains poorly characterized in sub-Saharan Africa. This study assessed the association of vegetable consumption with odds of hypertension among indigenous Africans. METHODS AND RESULTS: We harmonized data on prior vegetable consumption and hypertension occurrence (defined as one of the following conditions; systolic blood pressure ≥140 or diastolic blood pressure ≥90 mmHg or previous diagnosis or use of antihypertensive medications) from 16 445 participants across five African countries (Nigeria, South Africa, Kenya, Ghana and Burkina Faso) in the Stroke Investigative Research and Educational Network and Africa Wits-INDEPTH partnership for Genomic studies. Vegetable consumption (in servings/week) was classified as 'low' (<6). 'moderate' (6-11), 'sufficient' (12-29), and 'high' (≥30). Odds ratios (ORs) and 95% confidence interval (CI) of hypertension were estimated by categories of vegetable consumption (using 'low' consumption as reference), adjusting for sex, age in years, family history of cardiovascular diseases, education, smoking, alcohol use, physical inactivity, body mass index, diabetes mellitus and dyslipidaemia using logistic regressions at P < 0.05. The mean age of participants was 53.0 ( ± 10.7) years, and 7552 (45.9%) were males, whereas 7070 (42.9%) had hypertension. In addition, 6672(40.6%) participants had 'low' vegetable consumption, and 1758(10.7%) had 'high' vegetable consumption. Multivariable-adjusted OR for hypertension by distribution of vegetable consumption (using 'low' consumption as reference) were 1.03 (95% CI: 0.95, 1.12) for 'moderate' consumption; 0.80 (0.73, 0.88) for 'sufficient', and 0.81 (0.72, 0.92) for 'high' consumption, P-for-trend <0.0001. CONCLUSION: Indigenous Africans who consumed at least 12 servings of vegetables per week were less likely to be found hypertensive, particularly among males and young adults.

Determinants of metabolic syndrome and its prognostic implications among stroke patients in Africa: Findings from the Stroke Investigative Research and Educational Network (SIREN) study.

BACKGROUND: The prognostic implications of metabolic syndrome (METS) among African stroke patients are poorly understood. This study aimed to investigate the determinants of METS and its prognostic implications among Africans with newly diagnosed stroke in the SIREN study. METHODS: We included stroke cases (adults aged >18 years with CT/MRI confirmed stroke). The validated tools comprehensively evaluated vascular, lifestyle, and psychosocial factors. We used logistic regression to estimate adjusted odds ratios (OR) with 95% CIs for the association between METS and risk factors. We also computed the prediction power of the domain of covariates in a sequential manner using the area under the receiver operating curve (ROC) curve. RESULTS: Among 3998 stroke subjects enrolled in the study, 76.8% had METS by at least one of the clinical definitions. Factors associated with METS were age > 50 years (OR- 1.46, CI-1.19-1.80), male gender (OR 4.06, CI- 3.28-5.03), income >100USD (OR1.42, CI-1.17-1.71), stress (OR1.46, CI-1.14-1.87), family history of diabetes mellitus (OR1.38, CI-1.06-1.78), and cardiac disease (OR1.42, CI-1.18-1.65). Stroke severity was higher among those with METS (SLS = 5.8 ± 4.3) compared with those without METS (6.2 ± 4.5) at p = 0.037. METS was associated with higher odds (aOR 1.31, CI-1.08-1.58) of one-month fatality after adjusting for stroke severity, age > 50 years, and average monthly income >100USD. CONCLUSION: METS is very common among African stroke patients and is associated with stroke severity and worse one-month fatality. Lifestyle interventions may prevent METS and attenuate its impact on stroke occurrence and outcomes.

Risk Factor Characterization of Ischemic Stroke Subtypes Among West Africans.

BACKGROUND AND PURPOSE: To identify the qualitative and quantitative contributions of conventional risk factors for occurrence of ischemic stroke and its key pathophysiologic subtypes among West Africans. METHODS: The SIREN (Stroke Investigative Research and Educational Network) is a multicenter, case-control study involving 15 sites in Ghana and Nigeria. Cases include adults aged ≥18 years with ischemic stroke who were etiologically subtyped using the A-S-C-O-D classification into atherosclerosis, small-vessel occlusion, cardiac pathology, other causes, and dissection. Controls were age- and gender-matched stroke-free adults. Detailed evaluations for vascular, lifestyle, and psychosocial factors were performed. We used conditional logistic regression to estimate adjusted odds ratios with 95% CI. RESULTS: There were 2431 ischemic stroke case and stroke-free control pairs with respective mean ages of 62.2±14.0 versus 60.9±13.7 years. There were 1024 (42.1%) small vessel occlusions, 427 (17.6%) large-artery atherosclerosis, 258 (10.6%) cardio-embolic, 3 (0.1%) carotid dissections, and 719 (29.6%) undetermined/other causes. The adjusted odds ratio (95% CI) for the 8 dominant risk factors for ischemic stroke were hypertension, 10.34 (6.91-15.45); dyslipidemia, 5.16 (3.78-7.03); diabetes, 3.44 (2.60-4.56); low green vegetable consumption, 1.89 (1.45-2.46); red meat consumption, 1.89 (1.45-2.46); cardiac disease, 1.88 (1.22-2.90); monthly income $100 or more, 1.72 (1.24-2.39); and psychosocial stress, 1.62 (1.18-2.21). Hypertension, dyslipidemia, diabetes were confluent factors shared by small-vessel, large-vessel and cardio-embolic subtypes. Stroke cases and stroke-free controls had a mean of 5.3±1.5 versus 3.2±1.0 adverse cardio-metabolic risk factors respectively (P<0.0001). CONCLUSIONS: Traditional vascular risk factors demonstrate important differential effect sizes with pathophysiologic, clinical and preventative implications on the occurrence of ischemic stroke among indigenous West Africans.

Influence of age on links between major modifiable risk factors and stroke occurrence in West Africa.

Background The burden of stroke in Africa is high. Understanding how age associates with major modifiable stroke risk factors could inform tailored demographic stroke prevention strategies. Purpose To quantify the magnitude and direction of the effect sizes of key modifiable stroke risk factors according to three age groups: <50 years (young), 50-65 years (middle age) and > 65 years (elderly) in West Africa. Methods This was a case-control study involving 15 sites in Ghana and Nigeria. Cases included adults aged ≥18 years with CT/MRI scan-typed stroke. Controls were age-and gender-matched stroke-free adults. Detailed evaluations for vascular, lifestyle and psychosocial factors were performed. We estimated adjusted odds ratios (aOR) using conditional logistic regression and population attributable risk (PAR) with 95% Confidence Interval of vascular risk factors by age groups. Results Among 3553 stroke cases, 813 (22.9%) were young, 1441 (40.6%) were middle-aged and 1299 (36.6%) were elderly. Among the 5 co-shared risk factors, dyslipidemia with PAR and aOR (95%CI) of 62.20% (52.82-71.58) and 4.13 (2.64-6.46) was highest among the young age group; hypertension with PAR of 94.31% (91.82-96.80) and aOR of 28.93 (15.10-55.44) was highest among the middle-age group. Diabetes with PAR of 32.29%(27.52-37.05) and aOR of 3.49 (2.56-4.75); meat consumption with PAR of 42.34%(32.33-52.35) and aOR of 2.40 (1.76, 3.26); and non-consumption of green vegetables, PAR of 16.81%(12.02-21.60) and aOR of 2.23 (1.60-3.12) were highest among the elderly age group. However confidence intervals of risk estimates overlapped across age groups. Additionally, among the young age group cigarette smoking, psychosocial stress and cardiac disease were independently associated with stroke. Furthermore, education, stress, physical inactivity and salt intake were associated with stroke in the middle-age group while cardiac disease was associated with stroke in the elderly age group. Conclusion There is a differential influence of age on the associations of major risk factors with stroke in this West African cohort. Targeting modifiable factors predominant within an age group may be more effective as a stroke prevention strategy.

A Novel Afrocentric Stroke Risk Assessment Score: Models from the Siren Study.

BACKGROUND: Stroke risk can be quantified using risk factors whose effect sizes vary by geography and race. No stroke risk assessment tool exists to estimate aggregate stroke risk for indigenous African. OBJECTIVES: To develop Afrocentric risk-scoring models for stroke occurrence. MATERIALS AND METHODS: We evaluated 3533 radiologically confirmed West African stroke cases paired 1:1 with age-, and sex-matched stroke-free controls in the SIREN study. The 7,066 subjects were randomly split into a training and testing set at the ratio of 85:15. Conditional logistic regression models were constructed by including 17 putative factors linked to stroke occurrence using the training set. Significant risk factors were assigned constant and standardized statistical weights based on regression coefficients (ß) to develop an additive risk scoring system on a scale of 0-100%. Using the testing set, Receiver Operating Characteristics (ROC) curves were constructed to obtain a total score to serve as cut-off to discriminate between cases and controls. We calculated sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) at this cut-off. RESULTS: For stroke occurrence, we identified 15 traditional vascular factors. Cohen's kappa for validity was maximal at a total risk score of 56% using both statistical weighting approaches to risk quantification and in both datasets. The risk score had a predictive accuracy of 76% (95%CI: 74-79%), sensitivity of 80.3%, specificity of 63.0%, PPV of 68.5% and NPV of 76.2% in the test dataset. For ischemic strokes, 12 risk factors had predictive accuracy of 78% (95%CI: 74-81%). For hemorrhagic strokes, 7 factors had a predictive accuracy of 79% (95%CI: 73-84%). CONCLUSIONS: The SIREN models quantify aggregate stroke risk in indigenous West Africans with good accuracy. Prospective studies are needed to validate this instrument for stroke prevention.

Factors associated with hypertension among stroke-free indigenous Africans: Findings from the SIREN study.

Hypertension is one of the most important risk factors for stroke and cardiovascular diseases (CVD) globally. Understanding risk factors for hypertension among individuals with matching characteristics with stroke patients may inform primordial/primary prevention of hypertension and stroke among them. This study identified the risk factors for hypertension among community-dwelling stroke-free population in Ghana and Nigeria. Data for 4267 community-dwelling stroke-free controls subjects in the Stroke Investigative Research and Education Network (SIREN) study in Nigeria and Ghana were used. Participants were comprehensively assessed for sociodemographic, lifestyle and metabolic factors using standard methods. Hypertension was defined as a previous diagnosis by a health professional or use of an anti-hypertensive drug or mean systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg. Logistic regression analysis was used to estimate adjusted odds ratios (aOR) of hypertension and their 95% confidence intervals (CI) at p < .05. Overall, 56.7% of the participants were hypertensive with a higher proportion among respondents aged ≥60 years (53.0%). Factors including physical inactivity (aOR: 9.09; 95% CI: 4.03 to 20.53, p < .0001), diabetes (aOR: 2.70; CI: 1.91 to 3.82, p < .0001), being ≥60 years (aOR: 2.22; 95% CI: 1.78 to 2.77, p < .0001), and family history of CVD (aOR 2.02; CI: 1.59 to 2.56, p < .0001) were associated with increased aOR of hypertension. Lifestyle factors were associated with hypertension in the current population of community-dwelling stroke-free controls in west Africa. Community-oriented interventions to address sedentary lifestyles may benefit this population and reduce/prevent hypertension and stroke among them.

Antecedent febrile illness and occurrence of stroke in West Africa: The SIREN study.

BACKGROUND: Acute infections have been posited as potential precipitants or triggers of the occurrence of stroke among adults with traditional vascular risk factors. We evaluated associations between stroke occurrence and reported febrile illness within 4 weeks (potential antecedent infections) among West Africans. METHODS: The Stroke Investigative Research and Educational Network (SIREN) is a multicenter, case-control study involving 15 sites in Ghana and Nigeria. Cases include adults aged ≥18 years with radiologically confirmed strokes. Controls were stroke-free adults matched with cased by age, gender and ethnicity. Detailed evaluations for vascular, lifestyle and psychosocial factors were performed. Participants were asked for evidence of any febrile illness within the past 4 weeks. We used conditional logistic regression to estimate adjusted odds ratios (aOR) with 95% Confidence Interval. RESULTS: Among 3588 stroke cases recruited in Ghana and Nigeria between August 2014 and July 2018, 363 cases (10.1%) reported having a febrile illness within the 4 weeks prior to stroke occurrence. Having an antecedent infection was associated with stroke occurrence with an unadjusted OR of 1.19 (1.00-1.51) but aOR of 0.83 (0.59-1.17) upon adjusting for traditional vascular risk factors. Stress, aOR of 4.69 (2.59-8.50) and consumption of green vegetables 2.27 (1.35-2.85) were associated with antecedent febrile illness. CONCLUSION: 1 in 10 stroke cases reported antecedent history of febrile illness prior to occurrence of stroke but no independent association was observed in this study. Infectious exposures may be important triggers of cardiovascular events requiring further exploratory studies to better understand the role of this emerging risk factor.