Aurel T. Tankeu

Calcium supplementation and cardiovascular risk: A rising concern

Over the past decade, the number of individuals taking calcium supplementation worldwide has been on the rise, especially with the emergence of new pharmaceutical companies specialized in the marketing of dietary supplements; with calcium supplementation being their main business axis. This is mostly because of the established role of calcium in the prevention and treatment of osteoporosis and, to a lesser extent, its role in the prevention of fractures. Recently, a rising body of evidence on the adverse effect of calcium supplementation on nonskeletal, especially cardiovascular, health has been a cause for concern. In fact, a significant number of studies have reported an association between calcium supplementation and adverse cardiovascular events, even though high dietary calcium intake was shown to have a protective effect. The mechanism by which calcium supplementation could cause a cardiovascular event was still unclear until a recent study published in the Journal of the American Heart Association. Combining this recent finding with available data associating calcium supplementation with cardiovascular mortality and all‐cause mortality, we call on the need for an evidence‐based approach to calcium supplementation, while stressing on the safety of dietary calcium intake over the former on cardiovascular health.

Global prevalence of diabetes mellitus in patients with tuberculosis: a systematic review and meta-analysis protocol

Introduction Diabetes mellitus (DM) is an important risk factor for active tuberculosis (TB), which also adversely affect TB treatment outcomes. The escalating global DM epidemic is fuelling the burden of TB and should therefore be a major target in the strategy for ending TB. This review aims to estimate the global prevalence of DM in patients with TB. Methods and analysis This systematic review will include cross-sectional, case–control or cohort studies of populations including patients diagnosed with TB that have reported the prevalence of DM using one of the fourth standard recommendations for screening and diagnosis. This protocol is written in accordance with recommendations from the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols 2015 statement. Relevant abstracts published in English/French from inception to 31 December 2016 will be searched in PubMed, Excerpta Medica Database and online journals. Two investigators will independently screen, select studies, extract data and assess the risk of bias in each study. The study-specific estimates will be pooled through a random-effects meta-analysis model to obtain an overall summary estimate of the prevalence of diabetes across the studies. Heterogeneity will be assessed, and we will pool studies judged to be clinically homogenous. On the other hand, statistical heterogeneity will be evaluated by the χ² test on Cochrane’s Q statistic. Funnel-plots analysis and Egger’s test will be used to investigate publication bias. Results will be presented by continent or geographic regions. Ethics and dissemination This study is based on published data. An ethical approval is therefore not required. This systematic review and meta-analysis is expected to inform healthcare providers as well as general population on the co-occurrence of DM and TB. The final report will be published as an original article in a peer-reviewed journal, and will also be presented at conferences and submitted to relevant health authorities. We also plan to update the review every 5 years. Protocolregistration number PROSPERO International Prospective Register of Systematic Reviews (CRD42016049901).

Mechanism of worsening diabetic retinopathy with rapid lowering of blood glucose: the synergistic hypothesis

Insulin treatment has been associated with a paradoxical worsening of diabetes retinopathy since many years in European cohorts. Recently, this issue has been stressed by some studies conducted in other parts of the world. However, the mechanism underlying such evolution is not well understood. An osmotic theory has been evocated but failed to explain the clinical features of the disease. Considering recent findings from basic and clinical research, we discuss the possibility of a synergistic hypothesis based on the simultaneous action of insulin and vascular endothelial growth factor on eye blood vessels. We postulate that exogenous insulin could act synergistically with the vascular endothelial growth factor expressed by ischemic retina so as to trigger vascular proliferation and the worsening of diabetes retinopathy.

Fixed-dose combination therapy to reduce the growing burden of cardiovascular disease in low- and middle-income countries: feasibility and challenges

Cardiovascular disease (CVD) has become a major concern in low‐ and middle‐income countries, which bear about 80% of the cardiovascular mortality worldwide. Curbing the burden of CVD implies the management and control of many cardiovascular risk factors that act synergistically to increase cardiovascular mortality. Such actions may require expensive polymedications in a context of limited resources. Therefore, alternative solutions for CVD prevention in low‐ and middle‐income countries are urgently needed. In this context, the concept of a fixed‐dose combination therapy, a polypill composed of drugs known to effectively treat or prevent CVD, has been proposed as a scalable strategy to overcome nonadherence to polymedications and reduce costs. While this has recently been approved in more than 30 countries across America and Europe, there is a crucial need to analyze the potential benefits and challenges related to cardiovascular polypills implementation and vulgarization in low‐ and middle‐income countries, the epicenter of CVD.

Exercise-induced albuminuria and circadian blood pressure abnormalities in type 2 diabetes

AIM To investigate the relationship between circadian variations in blood pressure (BP) and albuminuria at rest, and during exercise in non-hypertensive type 2 diabetes (T2D) patients. METHODS We conducted a cross-sectional study in well controlled T2D patients, non-hypertensive, without clinical proteinuria and normal creatinine clearance. In each participant, we recorded the BP using ambulatory blood pressure monitoring (ABPM) for 24-h, and albuminuria at rest and after a standardized treadmill exercise. RESULTS We enrolled 27 type 2 patients with a median age of 52; and a mean duration of diabetes and HbA1c of 3.6 ± 0.8 years and 6.3% ± 0.5% respectively. Using a 24-h ABPM, we recorded a mean diurnal systolic blood pressure (SBP) of 128 ± 17 mmHg vs nocturnal of 123 ± 19 mmHg (P = 0.004), and mean diurnal diastolic blood pressure (DBP) of 83 ± 11 mmHg vs nocturnal 78 ± 14 mmHg (P = 0.002). There was a significant difference between albuminuria at rest [median = 23 mg, interquartile range (IQR) = 10-51] and after exercise (median = 35 mg, IQR = 23-80, P < 0.001). Patients with exercise induced albuminuria had an increase in nocturnal BP values on all three components (128 mmHg vs 110 mmHg, P = 0.03 for SBP; 83 mmHg vs 66 mmHg, P = 0.04; 106 vs 83, P = 0.02 for mean arterial pressure), as well as albuminuric patients at rest. Moreover, exercise induced albuminuria detect a less increase in nocturnal DBP (83 vs 86, P = 0.03) than resting albuminuria. CONCLUSION Exercise induced albuminuria is associated with an increase in nocturnal BP values in T2D patients.

Exercise-induced albuminuria vs circadian variations in blood pressure in type 1 diabetes

AIM To investigated the relationship between exercise-induced ambulatory blood pressure measurement (ABPM) abnormalities in type 1 diabetes mellitus (T1DM) adolescents. METHODS We conducted a case-control at the National Obesity Center of the Yaoundé Central Hospital, Cameroon. We compared 24 h ABPM and urinary albumin-to-creatinine ratio (ACR) at rest and after a standardized treadmill exercise between 20 Cameroonian T1DM patients and 20 matched controls. T1DM adolescents were aged 12-18 years, with diabetes for at least one year, without proteinuria, with normal office blood pressure (BP) and renal function according to the general reference population. Non-diabetic controls were adolescents of general population matched for sex, age and BMI. RESULTS Mean duration of diabetes was 4.2 ± 2.8 years. The mean 24 h systolic blood pressure (SBP) and diastolic blood pressure (DBP) were respectively 116 ± 9 mmHg in the diabetic group vs 111 ± 8 mmHg in the non-diabetic (P = 0.06), and 69 ± 7 mm Hg vs 66 ± 5 mm Hg (P = 0.19). There was no difference in the diurnal pattern of BP in diabetes patients and non-diabetic controls (SBP: 118 ± 10 mmHg vs 114 ± 10 mmHg, P = 0.11; DBP: 71 ± 7 mmHg vs 68 ± 6 mmHg, P = 0.22). Nighttime BP was higher in the diabetic group with respect to SBP (112 ± 11 mmHg vs 106 ± 7 mmHg, P = 0.06) and to the mean arterial pressure (MAP) (89 ± 9 mmHg vs 81 ± 6 mmHg, P = 0.06). ACR at rest was similar in both groups (5.5 mg/g vs 5.5 mg/g, P = 0.74), but significantly higher in diabetes patients after exercise (10.5 mg/g vs 5.5 mg/g, P = 0.03). SBP was higher in patients having exercise-induced albuminuria (116 ± 10 mmHg vs 108 ± 10 mmHg, P = 0.09). CONCLUSION Exercise-induced albuminuria could be useful for early diagnosis of kidney damage in adolescents with T1DM.

Prevalence and associated factors of active smoking among individuals living with hypertension and/or diabetes in Africa: a systematic review and meta-analysis protocol

Introduction Tobacco use significantly increases cardiovascular complications in people living with hypertension and/or diabetes. We aim to summarise data on the prevalence and factors associated with active smoking in these conditions in Africa. Method and analysis We will search PubMed, Embase, Google Scholar and African Journals Online for relevant abstracts of studies on active smoking in individuals living with diabetes and/or hypertension published from 1 January 2000 to 31 December 2016, with no language restriction. Additionally, relevant unpublished papers and conference proceedings will be checked, as well as references of included articles. Two investigators will independently screen, select studies, extract data and assess the risk of bias in each study. Data will be analysed using Stata software (Stata V.14, Texas, USA). The study-specific estimates will be pooled through a random-effects meta-analysis model to obtain an overall summary estimate of the prevalence of smoking across studies. Also, we will assess factors associated to smoking. Heterogeneity of studies will be evaluated by the χ2 test on Cochrane’s Q statistic. Funnel plots analysis and Egger’s test will be done to detect publication bias. Results will be presented by geographic region (central, eastern, northern, southern and western Africa). A p value less than 0.05 will be considered significant for factors associated to smoking. Ethics and dissemination This study is based on published data, and therefore ethical approval is not a requirement. This systematic review and meta-analysis is expected to serve as a basis for designing cost-effective interventions to reduce and prevent smoking in patients with diabetes and/or hypertension, and as a guide for future research based on the remaining gaps. The final report of this study in the form of a scientific paper will be published in peer-reviewed journals. Findings will further be presented at conferences and submitted to relevant health authorities.

Prevalence and incidence of hypertension in the global HIV-infected population: a systematic review and meta-analysis protocol

Introduction Hypertension, representing one of the most frequent cardiovascular risk factors, is thought to increase in individuals living with HIV as well as in general population, but summarised global data on the topic are scarce. We conduct this systematic review and meta-analysis to assess the prevalence/incidence of hypertension in the global HIV-infected population. Methods and analysis This review will include observational studies conducted among HIV-infected people, which reported prevalence/incidence of hypertension or enough data for its appraisal. We will consider published and unpublished studies from 1 January 2007 to 31 May 2017. Relevant records will be searched using PubMed/Medline, Global Index Medicus, Web of Science and EMBASE. Reference lists of eligible papers and relevant review articles will be screened. Two investigators will independently screen, select studies and extract data, with discrepancies resolved by consensus or by arbitration of a third investigator. Methodological quality of the included studies will be assessed using the scale developed by Hoy and colleagues. Funnel plots and Egger’s test will be used to determine publication bias. The study-specific estimates will be pooled through a random-effects meta-analysis model to obtain an overall summary estimate. To keep the effect of studies with extremely small or extremely large estimates on the overall estimate to a minimum, the variance of the study-specific prevalence/incidence will be stabilised with the Freeman-Tukey single arcsine transformation. The heterogeneity will be evaluated by the χ² test on Cochrane’s Q statistic. Results will be presented by geographic region, income and antiretroviral therapy status. Ethics and dissemination This study is based on published data; therefore, ethical approval is not a requirement. The final report of this study in the form of a scientific paper will be published in peer-reviewed journals. Trial registration number CRD42016051684.

Prevalence and patterns of congenital heart diseases in Africa: a systematic review and meta-analysis protocol

Introduction Congenital heart diseases (CHD) are common causes of cardiovascular morbidity and mortality among young children and adolescents living in Africa. Accurate epidemiological data are needed in order to evaluate and improve preventive strategies. This review aims to determine the prevalence of CHD and their main patterns in Africa. Methods and analysis This systematic review and meta-analysis will include cross-sectional, case–control and cohort studies of populations residing inside African countries, which have reported the prevalence of CHD, confirmed by an echocardiographic examination and/or describing different patterns of these abnormalities in Africa. Relevant abstracts published without language restriction from 1 January 1986 to 31 December 2016 will be searched in PubMed, Exerpta Medica Database and online African journals as well as references of included articles and relevant reviews. Two review authors will independently screen, select studies, extract data and assess the risk of bias in each study. The study-specific estimates will be pooled through a random-effects meta-analysis model to obtain an overall summary estimate of the prevalence of CHD across studies. Clinical and statistical heterogeneity will be assessed, and we will pool studies judged to be clinically homogeneous. On the other hand, statistical heterogeneity will be evaluated by the χ2 test on Cochranes Q statistic. Funnel-plots analysis and Eggers test will be used to detect publication bias. Results will be presented by geographic region (central, eastern, northern, southern and western Africa). Ethics and dissemination The current study will be based on published data, and thus ethical approval is not required. This systematic review and meta-analysis is expected to serve as a base which could help in estimating and evaluating the burden of these abnormalities on the African continent. The final report of this study will be published in a peer-reviewed journal. Trial registration number PROSPERO CRD42016052880.