Hypertension in Sub-Saharan Africa: Cross-Sectional Surveys in Four Rural and Urban Communities

Background: Cardiovascular disease (CVD) is the leading cause of adult mortality in low-income countries but data on the prevalence of cardiovascular risk factors such as hypertension are scarce, especially in sub-Saharan Africa (SSA). This study aims to assess the prevalence of hypertension and determinants of blood pressure in four SSA populations in rural Nigeria and Kenya, and urban Namibia and Tanzania. Methods and Findings: We performed four cross-sectional household surveys in Kwara State, Nigeria; Nandi district, Kenya; Dar es Salaam, Tanzania and Greater Windhoek, Namibia, between 2009-2011. Representative population-based samples were drawn in Nigeria and Namibia. The Kenya and Tanzania study populations consisted of specific target groups. Within a final sample size of 5,500 households, 9,857 non-pregnant adults were eligible for analysis on hypertension. Of those, 7,568 respondents ≥18 years were included. The primary outcome measure was the prevalence of hypertension in each of the populations under study. The age-standardized prevalence of hypertension was 19.3% (95%CI:17.3-21.3) in rural Nigeria, 21.4% (19.8-23.0) in rural Kenya, 23.7% (21.3-26.2) in urban Tanzania, and 38.0% (35.9-40.1) in urban Namibia. In individuals with hypertension, the proportion of grade 2 (≥160/100 mmHg) or grade 3 hypertension (≥180/110 mmHg) ranged from 29.2% (Namibia) to 43.3% (Nigeria). Control of hypertension ranged from 2.6% in Kenya to 17.8% in Namibia. Obesity prevalence (BMI ≥30) ranged from 6.1% (Nigeria) to 17.4% (Tanzania) and together with age and gender, BMI independently predicted blood pressure level in all study populations. Diabetes prevalence ranged from 2.1% (Namibia) to 3.7% (Tanzania). Conclusion: Hypertension was the most frequently observed risk factor for CVD in both urban and rural communities in SSA and will contribute to the growing burden of CVD in SSA. Low levels of control of hypertension are alarming. Strengthening of health care systems in SSA to contain the emerging epidemic of CVD is urgently needed

Detection and localization of early- and late-stage cancers using platelet RNA

Cancer patients benefit from early tumor detection since treatment outcomes are more favorable for less advanced cancers. Platelets are involved in cancer progression and are considered a promising biosource for cancer detection, as they alter their RNA content upon local and systemic cues. We show that tumor-educated platelet (TEP) RNA-based blood tests enable the detection of 18 cancer types. With 99% specificity in asymptomatic controls, thromboSeq correctly detected the presence of cancer in two-thirds of 1,096 blood samples from stage I–IV cancer patients and in half of 352 stage I–III tumors. Symptomatic controls, including inflammatory and cardiovascular diseases, and benign tumors had increased false-positive test results with an average specificity of 78%. Moreover, thromboSeq determined the tumor site of origin in five different tumor types correctly in over 80% of the cancer patients. These results highlight the potential properties of TEP-derived RNA panels to supplement current approaches for blood-based cancer screening

Nonradioactive Techniques for Measurement of In Vitro T-Cell Proliferation: Alternatives to the [(3)H]Thymidine Incorporation Assay

T-cell proliferation is an important in vitro parameter of in vivo immune function and has been used as a prognostic marker of human immunodeficiency virus type 1 (HIV-1) disease progression. The proliferative capacity of T cells in response to various stimuli is commonly determined by a radioactive assay based on incorporation of [(3)H]thymidine ([(3)H]TdR) into newly generated DNA. In order to assess techniques for application in laboratories where radioactive facilities are not present, two alternative methods were tested and compared to the [(3)H]TdR assay as a “gold standard.” As an alternative, T-cell proliferation was measured by flow cytometric assessment of CD38 expression on T cells and by an enzyme-linked immunosorbent assay (ELISA) based on bromo-2′-deoxyuridine (BrdU) incorporation. Peripheral blood mononuclear cells (PBMCs), either in whole blood or Ficoll-Isopaque separated, from a total of 26 HIV-1-positive and 18 HIV-1-negative Dutch individuals were stimulated with CD3 monoclonal antibody (MAb) alone, a combination of CD3 and CD28 MAbs, or phytohemagglutinin. BrdU incorporation after 3 days of stimulation with a combination of CD3 and CD28 MAbs correlated excellently with the [(3)H]TdR incorporation in both study groups (HIV-1 positives, r = 0.96; HIV-1 negatives, r = 0.83). A significant correlation of absolute numbers of T cells expressing CD38 with [(3)H]TdR incorporation, both in HIV-1-positive (r = 0.96) and HIV-1-negative (r = 0.84) individuals, was also observed under these conditions. The results of this study indicate that determination of both the number of CD38-positive T cells and BrdU incorporation can be used as alternative techniques to measure the in vitro T-cell proliferative capacity. The measurement of CD38 expression on T cells provides the additional possibility to further characterize the proliferating T-cell subsets for expression of other surface markers

Prevalence of Hypertension and other CVD risk factors.

*<p>HT  =  hypertension;</p>†<p>In those with untreated or inadequately treated hypertension;</p>¶<p>WHO CVD risk charts start at age 40 years and older;</p>¶¶<p>Those with blood pressure ≥160/100 mmHg or 140/90 and 10 year CVD risk of ≥20%;</p>**<p>SBP  =  systolic blood pressure, DBP  =  diastolic blood pressure;</p>∥|<p>NP =  not performed;</p>††<p>BMI  =  Body Mass Index;</p>‡<p>WC  =  waist circumference, M  =  male, F  =  female;</p>&par<p>DM  = Diabetes Mellitus (non-fasting blood glucose of ≥11.1 mmol/L, or a fasting blood glucose of ≥7.0 mmol/L, or self reported use of drug treatment for DM);</p>§<p>High cholesterol ≥6.2 mmol/L;</p>§§<p>U = 1 standard unit of alcohol containing approximately 10 g of ethanol;</p>***<p>Reported parent with hypertension, diabetes or heart disease.</p

Awareness, treatment and blood pressure control in patients with hypertension.

<p>Definitions: Aware  =  respondents who self report to have hypertension, Treated  =  respondents who self report to have hypertension, and who indicate to take drug treatment for hypertension, Controlled  =  respondents who self report to have hypertension, and who have a blood pressure below 140/90 (patients who use drug treatment or for whom treatment status is unknown).</p

Hypertension prevalence and distribution of blood pressure.

<p>2A: Age-standardized and age stratified hypertension prevalence. 2B: Distribution of blood pressure in patients with hypertension (treated and untreated cases). Optimal  =  systolic blood pressure (SBP) <120 and diastolic blood pressure (DBP) <80; Normal  =  SBP 120–129 and/or DBP 80–84; Pre-HT (hypertension)  =  SBP 130–139 and/or DBP 85–89; Grade 1 =  SBP 140–159 and/or DBP 90–99; Grade 2 =  SBP 160–179 and/or DBP 100–109; Grade 3 =  SBP> = 180 and/or DBP> = 110.</p

Characteristics of the study populations.

†<p>NP  =  Not Performed;</p>*<p>Consumption per capita per year in USD corrected for purchasing power parity (PPP), 2009 conversion rate World bank (<a href="http://www.worldbank.org/" target="_blank">http://www.worldbank.org/</a>).</p

Participation in the 4 surveys (household and individual level).

<p>*HH  =  households, **Repeating sampling done because household were difficult to locate due to poor registries used for sampling, ^†BP =  blood pressure.</p