Georges Nguefack-Tsague

Association between WHO cut-offs for childhood overweight and obesity and cardiometabolic risk.

OBJECTIVE To examine the association between cardiovascular risk and childhood overweight and obesity using the BMI cut-offs recommended by the WHO. DESIGN Children were classified as normal weight, overweight and obese according to the WHO BMI-for-age reference. Blood pressure, lipids, glucose, insulin, homeostasis model assessment-insulin resistance (HOMA-IR) and uric acid levels were compared across BMI groups. ANOVA and tests of linearity were used to assess overall mean differences across groups. Crude and adjusted odds ratios were calculated for adverse plasma levels of biochemical variables. SETTING Paediatric care centres. SUBJECTS Children (n 149) aged 8-18 years. RESULTS About 37 %, 22 % and 41 % of children were classified respectively as normal weight, overweight and obese. There were significant linear mean differences between BMI groups in systolic blood pressure, HDL-cholesterol, TAG, insulin, HOMA-IR and uric acid. Obese children were 10·6 times more likely than normal-weight children to have hypertension; OR for other associations were 60·2 (high insulin), 39·5 (HOMA-IR), 27·9 (TAG), 16·0 (HDL-cholesterol), 4·3 (LDL-cholesterol) and 3·6 (uric acid). Overweight children were more likely than normal-weight children to have hypertension (OR = 3·5), high insulin (OR = 28·2), high HOMA-IR (OR = 23·3) and high TAG (OR = 16·1). Nearly 92 % and 57 % of the obese and overweight children, respectively, had one or more risk factor. CONCLUSIONS Obesity and overweight defined using the WHO BMI-for-age cut-offs identified children with higher metabolic and vascular risk. These results emphasize the importance of prevention of overweight and obesity in childhood to reduce cardiovascular risk.

On Weighting the Components of the Human Development Index: A Statistical Justification

Abstract The Human Development Index (HDI) published in the Human Development Report of the United Nations Development Program has been calculated as a simple average of the Life Expectancy Index, the Education Index and the Gross Domestic Product Index. This paper provides statistical support for the use of this seemingly arbitrary equal weighting of the three components by treating human development as a latent concept imperfectly captured by its three component indices. We show that a principal component analysis (PCA) based on the correlation matrix of the components leads to practically the same weights. Specifically we show that, for the period 1975–2005, the first principal component accounts for between 78% and 90% of the total variability in the data, and that its coefficients are positive and nearly equal. By normalizing the coefficients, the simple average weighting (1/3, 1/3, 1/3) scheme is obtained. The ranks of countries obtained using the PCA weightings are very similar to those based on the HDI. An advantage of the simple equal weighting is that one can define a simple index to measure the balance of a country’s development, given its HDI.

Using Bayesian Networks to Model Hierarchical Relationships in Epidemiological Studies

OBJECTIVES To propose an alternative procedure, based on a Bayesian network (BN), for estimation and prediction, and to discuss its usefulness for taking into account the hierarchical relationships among covariates. METHODS The procedure is illustrated by modeling the risk of diarrhea infection for 2,740 children aged 0 to 59 months in Cameroon. We compare the procedure with a standard logistic regression and with a model based on multi-level logistic regression. RESULTS The standard logistic regression approach is inadequate, or at least incomplete, in that it does not attempt to account for potentially causal relationships between risk factors. The multi-level logistic regression does model the hierarchical structure, but does so in a piecewise manner; the resulting estimates and interpretations differ from those of the BN approach proposed here. An advantage of the BN approach is that it enables one to determine the probability that a risk factor (and/or the outcome) is in any specific state, given the states of the others. The currently available approaches can only predict the outcome (disease), given the states of the covariates. CONCLUSION A major advantage of BNs is that they can deal with more complex interrelationships between variables whereas competing approaches deal at best only with hierarchical ones. We propose that BN be considered as well as a worthwhile method for summarizing the data in epidemiological studies whose aim is understanding the determinants of diseases and quantifying their effects.

Vaccines safety; effect of supervision or SMS on reporting rates of adverse events following immunization (AEFI) with meningitis vaccine (MenAfriVac™): a randomized controlled trial.

BACKGROUND To ensure vaccines safety, given the weaknesses of the national pharmacovigilance system in Cameroon, there is a need to identify effective interventions that can contribute to improving AEFI reporting. OBJECTIVE To assess the effect of: (i) sending weekly SMS, or (ii) weekly supervisory visits on AEFI reporting rate during a meningitis immunization campaign conducted in Cameroon in 2012 using the meningitis A conjugate vaccine (MenAfriVac™). METHODS Health facilities that met the inclusion criteria were randomly assigned to receive: (i) a weekly standardized SMS, (ii) a weekly standardized supervisory visits or (iii) no intervention. The primary outcome was the reported AEFI incidence rate from week 5 to 8 after the immunization campaign. Poisson regression model was used to estimate the effect of interventions after adjusting for health region, type of health facility, type and position of health workers as well as the cumulative number of AEFI reported from weeks 1 to 4. RESULTS A total of 348 (77.2%) of 451 health facility were included, and 116 assigned to each of three groups. The incidence rate of reported AEFI per 100 health facility per week was 20.0 (15.9-24.1) in the SMS group, 40.2 (34.4-46.0) in supervision group and 13.6 (10.1-16.9) in the control group. Supervision led to a significant increase of AEFI reporting rate compared to SMS [adjusted RR=2.1 (1.6-2.7); p<0.001] and control [RR=2.8(2.1-3.7); p<0.001)] groups. The effect of SMS led to some increase in AEFI reporting rate compared to the control group, but the difference was not statistically significant [RR=1.4(0.8-1.6); p=0.07)]. CONCLUSION Supervision was more effective than SMS or routine surveillance in improving AEFI reporting rate. It should be part of any AEFI surveillance system. SMS could be useful in improving AEFI reporting rates but strategies need to be found to improve its effectiveness, and thus maximize its benefits.

Indications for surgical removal of the eye in rural areas in cameroon.

Objective To determine the main clinical indications for surgical removal of the eye in rural areas in Cameroon. Design Retrospective non-comparative case series. Participants A total of 253 patients presenting to the Manna eye clinic Nkongsamba who underwent destructive eye surgery (DES) between January 2006 and December 2010 were reviewed. Main Outcome Measure Age, gender, occupation, prior medication, visual acuity, operation indications, and type of operation. Results There were 58.10% (n = 147) men and 41.90% (n = 106) women. Median age was 29 years (interquartile range: 14–69 years); age ranged from 10 to 88 years. A total of 67.19% (n = 170) of participants were farmers and lived in rural zones. In all, 79.05% (n = 200) confessed to have trying a medication before the presentation. Surgical indications included infective causes (perforated corneal ulcer 33.20% (n = 84) and endophthalmitis 18.20% (n = 46)), trauma 17.40% (n = 44), painful blind eyes 11.50% (n = 29), malignancy 10.70% (n = 27), and others 9.10% (n = 23). Conclusion The most common causes of DES in this series could be avoided. Therefore, preventive measures including extensive health education of the public and traditional healers on the risks linked to the use of traditional medicines in ophthalmology and the late presentation of eye disease, quality control of the campaigns that offer free cataract operations in the country.

Surgical outcome following treatment of obstetric vesicovaginal fistula among HIV-positive and HIV-negative patients in Cameroon.

a Department of Obstetrics and Gynecology, University Centre Hospital, Yaoundé, Cameroon b Ligue d’Initiative et de Recherche Active pour la Santé et l’Education de la Femme (LIRASEF), Yaoundé, Cameroon c Department of Obstetrics and Gynecology, Maroua Regional Hospital, Maroua, Cameroon d Department of Public Health, Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, Cameroon e Geneva Foundation for Medical Education and Research, Geneva, Switzerland

Risk factors for human immunodeficiency virus among blood donors in Cameroon: evidence for the design of an Africa-specific donor history questionnaire

In sub‐Saharan Africa improving the deferral of at‐risk blood donors would be a cost‐effective approach to reducing transfusion‐transmitted human immunodeficiency virus (HIV) infections. We performed a pilot case‐control study to identify the risk factors for HIV infection and to develop an adapted donor history questionnaire (DHQ) for sub‐Saharan Africa.

Ophthalmological findings in Cameroonian boxers

Background The purpose of this prospective, noncomparative consecutive study was to examine active and retired amateur boxers in order to evaluate the nature and incidence of ocular pathologic conditions related to the boxing practice. Results A total of 35 boxers were included in this study. The mean age of the boxers was 28.09±7.57 years (range 18–52 years). Sixteen (45.7%) boxers had >5 years of boxing experience. Fifteen (42.85%) of the boxers reported wearing protective equipment in the bouts and sparring rounds. The number of bouts ranged from 3 to 103, with a median of 20 (interquartile range [IQR] =7–44). The percentages of wins varied from 25% to 100%, with a median of 68.29% (IQR =50.00–79.54). Most of the eye injuries recorded were minor injuries (66.66%), with subconjunctival hemorrhage being the most common (24.24%). Lid scars were the second most common lesion, accounting for 18.18% of all lesions. Sight-threatening eye lesions accounted for 33.34% of injuries and included cataracts (12.12%), lens dislocation (3.03%), pseudoexfoliation syndrome (3.03%), unilateral glaucoma (3.03%), retinal detachment (3.03%), vitreous opacity (6.06%), and lattice degeneration (3.03%). Conclusion Boxing-related ocular traumas are common in Cameroon, and ocular surface lesions are the most common injury reported. Severe lesions are indications for premature retirement from boxing practice.

Fertility after ectopic pregnancy in a district hospital in Cameroon.

To assess spontaneous conception after an ectopic pregnancy (EP) in a rural area of a low‐resource country.

Prevalence and vaccination coverage of Hepatitis B among healthcare workers in Cameroon: A national seroprevalence survey

Hepatitis B virus (HBV) infection is hyperendemic in Cameroon, and healthcare workers (HCWs) are at high risk of infection. We aimed to assess prevalence, risk factors and vaccine coverage of HBV infection among HCWs in Cameroon. We conducted a cross‐sectional study in 16 hospitals across all regions of Cameroon. HCWs were tested for HBV using rapid diagnostic tests (RDT). We collected data on socio‐demographics and HBV vaccination status. We estimated prevalence of HBV and used Poisson regression models with robust standard errors to model the prevalence ratios of HBV positivity between covariates. We enrolled 1824 of 1836 eligible HCWs (97.5%). The mean age was 34 (SD: 10) years, 65.3% (n = 1787) were women, and 11.4% (n = 1747) had three or more doses of the HBV vaccine. Overall, we found a HBV prevalence of 8.7% (95% CI: 5.2%‐14.3%). Patient transporters had the highest crude prevalence (14.3%; 95%CI: 5.4%‐32.9%), whereas medical doctors had the lowest (3.2%; 95%CI: 0.8%‐12.1%). The Far North Region had the highest prevalence of HBV (24.0%; 95%CI: 18.3%‐30.8%). HBV prevalence decreased with increasing doses of the HBV vaccine (10.3% for no doses vs 3.5% for three or more doses; P < 0.001). In conclusion, approximately 1 in 12 HCWs in Cameroon have evidence of HBV infection, yet fewer than 1 in 6 have been fully vaccinated. Our results illustrate the urgent need to scale up systematic HBV screening and targeted vaccination of HCWs in the region.