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.

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.

Research participants' perception of ethical issues in stroke genomics and neurobiobanking research in Africa

Background

There is a growing interest in stroke genomics and neurobiobanking research in Africa. These raise several ethical issues, such as consent, re-use, data sharing, storage, and incidental result of biological samples. Despite the availability of ethical guidelines developed for research in Africa, there is paucity of information on how the research participants' perspectives could guide the research community on ethical issues in stroke genomics and neurobiobanking research. To explore African research participants' perspectives on these issues, a study was conducted at existing Stroke Investigation Research and Education Network (SIREN) sites in Nigeria and Ghana.

Method

Using an exploratory design, twenty-eight Focus Group Discussions (FGDs) sessions were conducted with stroke survivors (n=7), caregivers(n=7), stroke - free controls(n=7), and Community Advisory Board members(n=7). Data were collected using an interview guide. Interviews were conducted in English and indigenous languages of the community, audio recorded, and transcribed verbatim. Data were analyzed using NVivo (March, 2020) Software.

Result

Results revealed that stroke genomics and neurobiobanking research in Africa require researchers' direct attention to ethical issues. Concerns were raised about understanding, disclosure and absence of coercion as components of true autonomous decision making in research participation. Participants argued that the risk and benefits attached to participation should be disclosed at the time of recruitment. Fears around data sharing were voiced as adherence to the principle of privacy and confidentiality were of paramount importance to participants. The preference was to receive the results of incidental findings with no stigma attached from society.

Conclusion

Research participants' perspectives are a vital aspect of community engagement in stroke genomics and neurobiobanking research. Findings from this study suggest that research participants are interested in these fields of research in Africa if their concerns about ethical issues are appropriately addressed within the research framework.

Knowledge and perspectives of community members on risk assessment for stroke prevention using mobile health approaches in Nigeria

OBJECTIVES

To assess the knowledge of community dwelling adults on stroke risk and their willingness to use mobile health (mHealth) technology in assessing their stroke risk.

MATERIALS AND METHODS

A cross-sectional study was conducted among adults (≥18 years old) using survey questionnaires designed by neurologists and health promotion experts and administered by trained study staff. Logistic regression models were used to assess factors associated with receptivity toward knowing individual stroke risk score and willingness to use a mobile application (App) to assess stroke risk.

RESULTS

The survey was administered to 486 participants in Nigeria, with a mean age of 47.4 ± 15.5 years, comprising 53.5% females. Up to 84% of participants wanted to know their risk for developing stroke but only 29.6% of respondents had ever previously had their stroke risk assessed. Factors associated with willingness to know stroke risk were age [aOR (95% CI): 0.97 (0.95 - 0.99)], and Hausa tribe [16.68 (2.16 - 128.92)]. Up to 66% of participants wanted to know their immediate risk of stroke, compared with 6.6% and 2.1% who wanted to know their 5-year or 10-year future stroke risks respectively. Regarding locations, participants preferred stroke risk assessment to be performed at a health facility, at home by health professional, on their own using mHealth (stroke risk calculator application), or at communal gatherings (decreasing order). About 70% specifically wished to learn about their stroke risk via an mHealth application.

CONCLUSIONS

Community dwelling Nigerians wanted to know their immediate risk of stroke using digital platforms, such as a mobile phone stroke risk calculator application. Clinical trials are needed to assess the effectiveness of such a strategy for primary prevention of stroke in sub-Saharan African communities.

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.

Sociodemographic and behavioural risk factors for obesity among community-dwelling older adults in Ghana and Nigeria: A secondary analysis of data from the SIREN study

OBJECTIVES

To explore the prevalence and risk factors of obesity among older adults from low- and middle-income countries (LMICs).

METHODS

This is a secondary analysis of data obtained from the SIREN study through in-person interviews and measurements from healthy stroke-free older adults (≥60 years). Overweight/obesity was defined as body mass index ≥25 kg/m². Abdominal obesity was defined as waist-to-hip ratio (WHR) of >0.90 for males and >0.85/females or waist circumference (WC) of >102 cm for males/>88 cm for females. Adjusted odds ratio (aORs) with 95% confidence interval (CIs) of the relationship between obesity and sociodemographic factors were assessed at P < 0.05.

RESULTS

Overall, 47.5% of participants were overweight/obese, 76.6% had a larger than recommended WHR, and 54.4% had a larger than recommended WC. Abdominal obesity (WC; aOR: 9.43, CI: 6.99-12.50), being a Nigerian (aOR: 0.55; CI: 0.42-0.72), living in an urban setting (aOR: 1.92; CI: 1.49-2.46), earning >$100/month (aOR: 1.53; CI: 1.19-1.96), and having formal education (aOR: 1.42; CI: 1.08-1.87) were associated with overweight/obesity.

CONCLUSION

Living in urban settings, earning a higher income, and having a formal education were associated with a higher odds of obesity among older adults from LMICs.

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.

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.

Differential associations between pre-diabetes, diabetes and stroke occurrence among West Africans

BACKGROUND

There are limited data from Africa on the burden and associations between pre-diabetes (pre-DM), diabetes mellitus (DM) and stroke occurrence in a region experiencing a profound rise in stroke burden.

PURPOSE

To characterize the associations between stroke and dysglycemic status 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 clinical and radiological evidence of an acute stroke. Controls were age-and-gender matched stroke-free adults. Detailed evaluations for vascular factors were performed. Pre-diabetes was defined as HBA1c of 5.7%-6.4% or Fasting blood glucose (FBG) 5.6-7.0 mmol/L and DM as HBA1c >6.5% or FBG>7.0 mmol/L. We used conditional logistic regression to estimate adjusted odds ratios (aOR) with 95% Confidence Interval.

RESULTS

Among 2,935 stroke cases the mean age was 60.0 ± 14.2 years with 55.2% being males. By glycemic status, 931 (31.7%) were euglycemic, 633 (21.6%) had Pre-diabetes and 1371 (46.7%) had DM. Of the age- and sex-matched stroke-free controls 69.2% were euglycemic, 13.3% had pre-DM and 17.5% had DM. Pre-DM [aOR (95% CI): 3.68(2.61-5.21)] and DM [4.29 (3.19-5.74)] were independently associated with stroke. The aOR of Pre-DM for ischemic stroke 3.06 (2.01-4.64)] was lower than 4.82 (3.37-6.89) for DM. However, the aOR of Pre-DM for hemorrhagic stroke 6.81 (95% CI: 3.29 - 14.08)] was higher than 3.36 (1.94-5.86) for DM. Furthermore, the aOR of pre-DM for ischemic stroke subtypes were 9.64 (1.30-71.57) for cardio-embolic stroke, 3.64 (1.80-7.34) for small-vessel occlusive disease and 4.63 (0.80-26.65) for large-vessel disease.

CONCLUSION

Pre-DM is strongly and independently associated with stroke in Africans. Improving glycemic control through screening, healthy lifestyle and pharmacotherapy at a population level may be strategic in reducing the rising burden of stroke in Africa.

Abstract P023: Risk Scoring Model For Predicting Hypertension Among Indigenous Africans: Findings From The SIREN Study

Background: Hypertension is one of the leading risk factors for cerebrovascular and cardiovascular diseases. Early identification of populations at risk of hypertension might be critical in managing hypertension, particularly in Sub-Saharan Africa, where the burden of hypertension is very high. This study aimed to develop a risk-scoring model for predicting hypertension among indigenous Africans.

Methods: We used 4390 population-based (80% and 20% for training and validating the model, respectively) stroke-free controls from the SIREN study to develop and validate a risk-scoring model for hypertension among Africans. Fifteen risk factors were attempted to predict hypertension using multivariable logistic regression, and the beta coefficient of significant variables were weighted using a constant and standardized weighting procedure. A standardized score was generated between 0-and 100%, and the risk-score cut-off point was estimated using the receiver operating characteristics (ROC) curve, sensitivity, specificity, positive predicted value (PPV), negative predicted value (NPV), and the Cohen’s kappa value at P<0.05.

Results: Standardized and constant weight was applied to eight statistically significant risk factors, and the risk-score cut-off was 56% at a maximum Cohen’s kappa value of ≥0.71. The model performance had a ROC of 93.0% (95%CI: 92.0, 94.0), sensitivity of 84.8%, specificity of 87.9%, PPV of 90.6%, and NPV of 80.8% in the training data set. The validation data set had an ROC of 91.0% (95%CI: 89.0, 93.0), sensitivity of 80.0%, specificity of 92.8%, PPV of 91.1%, and NPV of 83.5%.

Conclusion: The risk-scoring model for hypertension in this population was robust, sturdy with high predictive accuracy, and might be promising in the timely identification of populations at risk of hypertension for early prevention and management among indigenous Africans.

Abstract P069: Vegetable Consumption And Hypertension Among 16,445 Africans

Background: The association of vegetable consumption with hypertension remains poorly described in sub-Saharan Africa. This study assessed the relationship between vegetable consumption and hypertension among indigenous Africans.

Methods: We harmonized data on the frequency of vegetable consumption (servings/week) and hypertension (defined as systolic blood pressure ≥ 140mmHg or diastolic blood pressure ≥ 90mmHg or previous diagnosis or use of antihypertensive medications) from 16,445 participants across five African countries (Ghana, Burkina Faso, Kenya, Nigeria and South Africa) from the SIREN and AWI-Gen studies. Using the recommendation of at least five servings/day (35 servings/week) adapted from the World Health Organization recommendations, and vegetable consumption was classified as 'inadequate' (<35 servings/week) or 'adequate' (≥35 servings/week). The odds ratio (OR) and 95% confidence interval (CI) for hypertension risk was estimated for adequate vegetable consumption using multivariable-adjusted logistic regressions at a two-sided P <0.05.

Results: The mean age of participants was 53.0±10.7years, 45.9% (7,552 of 16,445) were males, and 42.9% (7,070 of 16,445) were hypertensives. Adequate vegetable consumption was associated with lower odds of hypertension; OR: 0.86 (95%CI: 0.76, 0.97). The sex-stratified odds was; OR: 0.87 (95%CI: 0.73, 1.02) for females and 0.84 (95%CI: 0.71, 1.00) for males.

Conclusion: These findings provide new evidence for promoting regular vegetable consumption in the guidelines for the primary prevention of hypertension among Africans.

Abstract P017: Association Of Secondhand Smoke Exposure With Hypertension Among Non-smoking Stroke-free Africans

Background: Secondhand smoking (SHS) is the exposure to smoke arising from a burning cigarette or exhaled by a smoker. It is a significant public health problem worldwide and whether it is associated with hypertension, particularly among Africans, is yet to be clearly understood. This study evaluated the relationship between SHS and hypertension among stroke-free adults who are non-smokers in the Stroke Investigation Research and Educational Network (SIREN) study.

Methods: We identified 3905 adults (≥18years who had never smoked) in the SIREN study conducted in Ghana and Nigeria. Participants reported a history of SHS exposure in an indoor environment. Hypertension was defined as one of the following conditions; mean SBP≥140mmHg, DBP≥90mmHg or use of antihypertensive medications. Logistic regression was used to estimate the multivariable-adjusted odds ratio (OR) and 95% confidence interval (CI) for hypertension by SHS exposure at a two-sided P <0.05.

Results: Overall, mean age was 55.8±14.9years, 18.2% (712 of 3905) had SHS exposure, with a higher proportion among males 20.0% (360 of 1803) than females 16.7% (352 of 2102). SHS was associated with higher odds of having hypertension in the overall population; OR: 1.2 (95%CI: 1.0, 1.5) among females; OR: 1.6 (95%CI: 1.2, 2.1), but not among males; OR: 0.9 (95%CI: 0.7, 1.2).

Conclusion: SHS was associated with higher odds of hypertension, particularly among females in this sample. The viability of public interventions in mitigating the potential effect of SHS cannot be underestimated in managing the hypertension burden among Africans, pending longitudinal studies to establish causal associations between SHS and hypertension.

Abstract WP211: Dietary Patterns And Blood Pressure Profiles Among Stroke-free Africans: Evidence From The Stroke Investigative Research And Educational Network Study In Sub-Saharan Africa

Introduction: High blood pressure is a prominent risk factor for stroke in Sub-Saharan Africa (SSA) where dietary factors associated with blood pressure are often under-reported.

Hypothesis: Dietary patterns (DP) are not associated with systolic blood pressure (SBP) and diastolic blood pressure (DBP) among stroke-free Africans from Ghana and Nigeria.

Methods: Information on diet history (including servings and frequency of consumption) was collected from 4,413 stroke-free persons (recruited from Nigeria and Ghana) and transformed using principal component analysis to estimate seven distinct factor scores that represented seven DP. SBP and DBP measurements were taken using standard operating procedures and linear regression models (adjusting for age, sex, smoking and alcohol use) were applied to estimate beta (β) coefficients and 95% confidence interval (CI) for the association of the DP (using the factor scores) with SBP and DBP at P <0.05.

Results: Mean age was 56.18±14.90years, 48.6% were females, 6.1% reported ever smoked cigarette and 24,8% reported alcohol use. Mean SBP and DBP were 135.53±24.21mmHg and 82.62±14.27mmHg respectively. Seven dietary patterns ('Vegetables', 'Sweetened food&Carbonated drinks', 'Organ & Red meat', 'Processed foods', 'Dairy, Legumes&Whole grains', 'Potatoes, Refined grains&Fish' and 'Fried&Salty foods') were identified in this sample. Overall, factors scores of DP were not significantly associated with SBP, but DBP was significantly reduced by factors of 'Vegetables' patterns (β = -0.60; 95% CI: -1.02, -0.18, P =0.005), 'Dairy, Legume&Whole grain' patterns (β = -0.50; 95% CI: -0.92, -0.06, P =0.019) and Potatoes, Refined grains & Fish patterns (β = -0.54 (-0.99, 95% CI: -0.10, P =0.016).

Conclusion(s): Adherence to plant-based diets was associated with reduced blood pressure particularly diastolic blood pressure. The association between DP and blood pressure may be complex but dietary advisory encouraging the consumption of plant-based diets may be helpful in the primary prevention of high blood pressure in this population.

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.

Frequency and factors associated with post-stroke seizures in a large multicenter study in West Africa

BACKGROUND

Post-stroke seizures (PSS) are associated with significant morbidity and mortality across the globe. There is a paucity of data on PSS in Africa.

PURPOSE

To assess the frequency and factors associated with PSS by stroke types across 15 hospitals in Nigeria and Ghana.

METHODS

We analyzed data on all stroke cases recruited into the Stroke Investigative Research and Educational Network (SIREN). We included adults aged ≥18 years with radiologically confirmed ischemic stroke (IS) or intracerebral hemorrhage (ICH). PSS were defined as acute symptomatic seizures occurring at stroke onset and/or during acute hospitalization up until discharge. We used logistic regression to estimate adjusted odds ratios (aOR) with 95% Confidence Interval.

RESULTS

Among 3344 stroke patients, 499 (14.9%) had PSS (95% CI: 13.7-16.2%). The mean duration of admission in days for those with PSS vs no PSS was 17.4 ± 28.6 vs 15.9 ± 24.7, p = 0.72. There were 294(14.1%) PSS among 2091 ischemic strokes and 159(17.7%) among 897 with ICH, p = 0.01. The factors associated with PSS occurrence were age < 50 years, aOR of 1.59 (1.08-2.33), National Institute of Health Stroke Score (NIHSS), 1.29 (1.16-1.42) for each 5 units rise and white cell count 1.07 (1.01-1.13) for each 10^3 mm3 rise. Factors associated with PSS in ischemic were NIHSS score, aOR of 1.17 (1.04-1.31) and infarct volume of 10-30 cm3 aOR of 2.17(1.37-3.45). Among ICH, associated factors were alcohol use 5.91 (2.11-16.55) and lobar bleeds 2.22 (1.03-4.82).

CONCLUSION

The burden of PSS among this sample of west Africans is substantial and may contribute to poor outcomes of stroke in this region. Further longitudinal studies are required to understand the impact on morbidity and mortality arising from PSS in Africa.

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.

Effect of short-term exposure to indoor particulate matter on noctunal blood pressure dipping among hypertensive adults in ibadan: a pilot study

Introduction

While blunted nocturnal blood pressure is a major risk factor for cardiovascular events, limited information exist on the association between indoor particulate and circadian blood pressure variation. We report the association of short-time exposure to PM2.5 and PM10 with blunted nocturnal blood pressure among hypertensive adults in Ibadan.

Purpose

This study was to determine the association between short time exposure to air particulates and blunted nocturnal blood pressure among people of African descent.

Methods

We conducted a cross-sectional study among fifty hypertensive cases attending our University College Hospital. A 24-hours blood pressure (BP) monitoring was carried out at the same time as indoor particulate matter monitoring in their homes. Exposure to indoor fine particles (PM2.5) and thoracic particles (PM10) was estimated using a real-time particle counter and compared to the World Health Organization (WHO) 24-hours threshold of 25 μg/m3 and 50 μg/m3 for PM2.5 and PM10 respectively. All monitoring was carried out over a 24-hours period during the wet season. Linear regression model was fitted to determine predictors of non-dipping hypertension.

Results

Of the 50 hypertensive patients studied, 5 (10.0%), 39 (78.0%), 6 (12.0%) were reverse dippers, non-dippers and dippers respectively. The mean indoor PM2.5 (44.17±19.18 μg/m3) and PM10 (60.10±27.13 μg/m3) among the non-dippers were significantly higher than values obtained among dippers (PM2.5 = 22.97±10.19 μg/m3; PM10 = 29.51±12.74 μg/m3); p&lt;0.0001, and the WHO threshold limit. More non-dippers than dippers (54.5% vs 37.8%) used unimproved fuel such as firewood for cooking. PM10 was an independent predictors of non-dipping status in our regression analysis.

Conclusion

Short-term exposure to indoor PM air pollution was associated with blunted nocturnal blood pressure. Therefore air pollution reduction strategies through improved cooking pattern is advocated in order to prevent future cardiovascular events.

Funding Acknowledgement

Type of funding source: None

Interrelationship of inflammatory biomarkers with ambulatory heart rate phenotypes in a cohort of Nigerian chronic kidney disease patients compared with controls; findings from symbolic study

Background

Inflammatory biomarkers have been identified as strong independent risk factor for cardiovascular events outcome in chronic kidney disease. The positive effect of the autonomic nervous system on inflammatory biomarkers is also being explored. Using the Heart rate as a representative tool for autonomic activity, the exact heart rate metrics in 24 hours associated with increased level of inflammatory activity in chronic kidney disease needs to be assessed among people of African descent.

Purpose

This study assessed the associations between inflammatory biomarkers and the Heart Rates phenotypes in a population of chronic kidney disease patients compared with controls.

Methods

All the participants had a 24-hour ambulatory blood pressure monitoring done using SpaceLabs ABPM (Spacelab's Healthcare, Issaquah, WA) which was placed on the non-dominant hand and Cuff sizes were selected after measuring participants' non-dominant arm circumference. Blood samples were analyzed for fasting plasma glucose, lipid profile, electrolytes, urea and creatinine, C - reactive protein (CRP), White cell counts (WBC) and differentials. CRP group was classified as mild, moderate and severe. Heart rate dipping was estimate using formula (1- night time heart rate/daytime heart rate) x100. Normal dipping of heart rate was defined as &gt;10%. Estimated GFR was calculated using CKD-EPI Creatinine Equation and CKD was defined as eGFR&lt;60ml/min/1.73m2. The association between markers of inflammation, heart rate phenotypes and mortality was determined using univariate analysis. Logistic regression model was fitted to determine predictors of all – cause mortality.

Results

Four hundred and sixty consented participants comprising 231 (50.2%) women, 195 (42.4%) hypertensive without CKD, 98 (21.3%) normotensive and 167 (36.3%) CKD patients with mean age 49.42±13.54 years were analyzed. Compared with controls, greater proportion of CKD patients were non dippers with highest mean White blood cell count, neutrophil counts, and CRP; p&lt;0.05. The mean 24 Hr, daytime and night time heart rate were significantly highest among CKD patients &lt;0.0001. Non-dipping was associated with higher mean WBC, Neutrophils counts, and CRP. Most non-dippers were associated with moderate and severe CRP risk (72.8% vs 27.2%; P&lt;0.0001. Compared with inflammatory markers (CRP), non-dipping status was an independent determinant of all-cause mortality (OR 16.03, CI 2.57–100.1, p=0.003).

Conclusion

This study highlights a higher prevalence of heart rate non- dipping and inflammatory activities among people with CKD compared with controls. Non dipping status was associated with higher inflammatory activity and higher risk of death. These observations lend some insight into the roles of autonomic nervous system in the pathophysiological mechanisms that implicate inflammatory biomarkers in cardiovascular risk and event outcomes in chronic kidney disease patients.

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): International society of hypertension

Unraveling the Ethical, Legal, and Social Implications of Neurobiobanking and Stroke Genomic Research in Africa: A Study Protocol of the African Neurobiobank for Precision Stroke Medicine ELSI Project

The ethical, legal, and social implications (ELSI) of emerging neurobiobanks and data resources are unclear in an African scientific landscape with unique cultural, linguistic, and belief systems. The overarching goal of the African Neurobiobank for Precision Stroke Medicine-ELSI Project is to identify, examine, and develop novel approaches to address ELSI issues of biobanking and stroke genomic research in sub-Saharan Africa (SSA). To accomplish the goal we will (1) explore knowledge, attitude, perceptions, barriers, and facilitators influencing ELSI issues related to biobanking and stroke genomic research; (2) use information obtained to craft a community intervention program focused on ELSI issues; and (3) build capacity and careers related to genomics and biobanking for effective client/community engagement while enhancing regulatory, governance, and implementation competences in biobanking science in SSA. A community-based participatory research and mixed-methodological approach, focused on various levels of the social ecological model, will be used to identify and examine relevant ELSI issues. Contextual intervention tools, platforms, and practices will be developed to enhance community understanding and participation in stroke biobanking and genomics research activities while facilitating enduring trust, and equitable and fair utilization of biobanking resources for genetic and trans-omics research. A concurrent capacity building program related to genetic counseling and biobanking will be implemented for early career researchers. The huge potential for neurobiobanking and genomics research in Africa to advance precision medicine applicable to stroke and other neurological disorders requires addressing ELSI challenges while building sustainable research, career, and regulatory capacities in trans-omics and biobanking science.

Randomized Trial of an Intervention to Improve Blood Pressure Control in Stroke Survivors

BACKGROUND

We conducted the first-of-its kind randomized stroke trial in Africa to test whether a THRIVES (Tailored Hospital-based Risk reduction to Impede Vascular Events after Stroke) intervention improved blood pressure (BP) control among patients with stroke.

METHODS AND RESULTS

Intervention comprised a patient global risk factor control report card, personalized phone text-messaging, and educational video. Four hundred patients recruited from 4 distinct medical facilities in Nigeria, aged ≥18 years with stroke-onset within one-year, were randomized to THRIVES intervention and control group. The control group also received text messages, and both groups received modest financial incentives. The primary outcome was mean change in systolic BP (SBP) at 12 months. There were 36.5% females, 72.3% with ischemic stroke; mean age was 57.2±11.7 years; 93.5% had hypertension and mean SBP was 138.33 (23.64) mm Hg. At 12 months, there was no significant difference in SBP reduction from baseline in the THRIVES versus control group (2.32 versus 2.01 mm Hg, P=0.82). In an exploratory analysis of subjects with baseline BP >140/90 mm Hg (n=168), THRIVES showed a significant mean SBP (diastolic BP) decrease of 11.7 (7.0) mm Hg while control group showed a significant mean SBP (diastolic BP) decrease of 11.2 (7.9) mm Hg at 12 months.

CONCLUSIONS

THRIVES intervention did not significantly reduce SBP compared with controls. However, there was similar significant decrease in mean BP in both treatment arms in the subgroup with baseline hypertension. As text-messaging and a modest financial incentive were the common elements between both treatment arms, further research is required to establish whether these measures alone can improve BP control among stroke survivors.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01900756.

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.

The role of traditional birth attendants in Atakumosa, Nigeria

All 26 traditional birth attendants (TBAs) and their 109 clients in 15 settlements in Atakumosa West Local Government Area (LGA) in Nigeria were interviewed to assess TBA training, practices and utilisation. The study showed that more than 80% of TBAs were older women with more than four children, practiced single-handedly and held other occupations. About 54% of those studied had no designated room for deliveries; twenty-one (80.8%) did not consider any pregnant woman to be at high risk; three (11.5%) perform intravaginal examinations during labour and only a few recognise complications; twelve (46.2%) never refer patients. Despite these deficiencies, TBAs continue to practise in appreciable numbers and their services continue to be on demand in the communities under study. Nearly all of the clients interviewed had started to use TBAs by the age of 25 and 50% had used TBAs for all of their deliveries. Most TBAs provide antenatal care and 77% had a case load of less than five clients per month. Ninety-six per cent of the clients had not been referred by the TBA before. Although 61% of clients felt TBAs in a future pregnancy and 49% would recommend TBA care to other women. Low socio-economic status, illiteracy, poor awareness of modern maternal health (MCH) facilities, personalized care, strong family influence and easy access to TBA services were strong factors promoting traditional midwifery in the LGA. If adequately trained, equipped, supported and supervised, TBAs can contribute towards safe motherhood in Nigeria and in other developing countries.