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 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.

Prevalence and Risk Factors for Diabetes Mellitus in A State in South East Nigeria: Results of a Population Based House to House Survey.

BACKGROUND: Population based studies on diabetes mellitus (DM) are scarce in Nigeria. INTRODUCTION: This was a population-based house to house survey aimed at determining the prevalence of DM and assessing the risk factors associated with DM in a state in Southeast Nigeria. METHODS: This was a cross-sectional observational study in which 1680 adults were recruited using a multistage sampling method to randomly select not more than two suitable participants of both sex in each household from four enumeration areas (EAs) in each local government area (LGA) and the three senatorial zones in the state. A modified World Health Organization (WHO) Stepwise Approach to Surveillance questionnaire was used for data collection and random blood glucose (RBG) was measured after anthropometric assessment. Test statistics used were chi-square, t-test, and logistic regression. RESULTS: The overall prevalence of DM in this study was 3.3%. A positive family history of DM was significantly higher in patients with diabetes: 18.2% vs. 9.6% (p=0.036). The mean (SD) of weight, body mass index (BMI), hip circumference (HC) and waist circumference (WC) were significantly higher in patients with DM(p=0.001,<0.001,<0.001,<0.001, respectively).The odd ratio (95% CI) of a person>35years developing DM was 3.89(1.11-13.60). The OR (95% CI) for waist-hip ratio (WHR) was 3.04 (1.02-9.03) and family history of DM had an OR of 2.62(0.88-6.50). The odd of developing DM is positively associated with age>35years, increased WHR, WC, family history of DM, BMI>25Kg/m2, and HC. The odd of developing DM was negatively associated with smoking. CONCLUSION: The prevalence of DM in this study was 3.3%. A BMI>25 kg/m2, WHR >0.85, family history of DM, HC, and older age were associated with significantly higher prevalence.

Urban-Rural Differences in Health-Care-Seeking Pattern of Residents of Abia State, Nigeria, and the Implication in the Control of NCDs.

BACKGROUND: Understanding the differences in care-seeking pattern is key in designing interventions aimed at improving health-care service delivery, including prevention and control of noncommunicable diseases. The aim of this study was to identify the differences and determinants of care-seeking patterns of urban and rural residents in Abia State in southeast Nigeria. METHODS: This was a cross-sectional, community-based, study involving 2999 respondents aged 18 years and above. Data were collected using the modified World Health Organization's STEPS questionnaire, including data on care seeking following the onset of illness. Descriptive statistics and logistic regressions were used to analyze care-seeking behavior and to identify differences among those seeking care in urban and rural areas. RESULTS: In both urban and rural areas, patent medicine vendors (73.0%) were the most common sources of primary care following the onset of illness, while only 20.0% of the participants used formal care. Significant predictors of difference in care-seeking practices between residents in urban and rural communities were educational status, income, occupation, and body mass index. CONCLUSIONS: Efforts should be made to reduce barriers to formal health-care service utilization in the state by increasing health insurance coverage, strengthening the health-care system, and increasing the role of patent medicine vendors in the formal health-care delivery system.

Prevalence and determinants of hypertension in Abia State Nigeria: results from the Abia State Non-Communicable Diseases and Cardiovascular Risk Factors Survey.

OBJECTIVE: Hypertension is the most common non-communicable disease and risk factor for heart failure, stroke, chronic kidney disease and ischemic heart disease in sub-Saharan Africa. Few population-based studies have been conducted recently in Nigeria and, in Abia State, no previous study has been conducted on the prevalence and correlates of hypertension among the populace. The purpose of our study was, therefore, to determine the prevalence and determinants of high blood pressure in Abia State, southeastern Nigeria. We hypothesise that high blood pressure burden is high in Abia State. DESIGN: The study was a community based cross-sectional house-to-house survey aimed at ascertaining the burden/prevalence of hypertension in the state as well as identifying related risk factors associated with them. SETTING: The study was conducted in rural and urban communities in Abia State, Nigeria. PARTICIPANTS: Participants in the study were men and women aged > or =15 years and were recruited from the three senatorial zones in the state. MAIN OUTCOMES: A total of 2,999 respondents were selected for the survey and, 2,983 consented to be interviewed giving a response rate of 99.5%. The data for 2,928 participants were suitable for analysis. Of these, 1,399 (47.8%) were men. The mean age of the population was 41.7 +/- 18.5 years (range 18-96 years). About 54% of the population were < or =40 years. Ninety percent had at least primary education with about 47% having completed secondary education. Expectedly, 96% of the respondents were Ibos, the predominant tribe in the southeastern part of the country. Women had significantly higher BMI than the men. Similarly, waist circumference was also larger in women but waist-to-hip ratio was only significantly higher in women in the urban areas compared to those in rural areas. Thirty-one percent of all participants had systolic hypertension (33.5% in men and 30.5% in women). This sex difference was statistically different in the urban area. On the other hand, diastolic hypertension was 22.5% in all the population (23.4% in men and 25.4% in women). Age and indices of obesity were the strongest predictors of blood pressure. CONCLUSION: The prevalence of hypertension was high in our study both in rural and urban settings. The major determinants of blood pressure in our participants included age, sex, indices of obesity and pulse rate.

Blood pressure, prevalence of hypertension and hypertension related complications in Nigerian Africans: A review.

To review studies on hypertension in Nigeria over the past five decades in terms of prevalence, awareness and treatment and complications. Following our search on Pubmed, African Journals Online and the World Health Organization Global cardiovascular infobase, 1060 related references were identified out of which 43 were found to be relevant for this review. The overall prevalence of hypertension in Nigeria ranges from 8%-46.4% depending on the study target population, type of measurement and cut-off value used for defining hypertension. The prevalence is similar in men and women (7.9%-50.2% vs 3.5%-68.8%, respectively) and in the urban (8.1%-42.0%) and rural setting (13.5%-46.4%).The pooled prevalence increased from 8.6% from the only study during the period from 1970-1979 to 22.5% (2000-2011). Awareness, treatment and control of hypertension were generally low with attendant high burden of hypertension related complications. In order to improve outcomes of cardiovascular disease in Africans, public health education to improve awareness of hypertension is required. Further epidemiological studies on hypertension are required to adequately understand and characterize the impact of hypertension in society.