Publications by authors named "Ibrahima Diouf"

31 Publications

Impact of different heat wave definitions on daily mortality in Bandafassi, Senegal.

PLoS One 2021 5;16(4):e0249199. Epub 2021 Apr 5.

NOAA Center for Weather and Climate Prediction Climate Prediction Center College Park, Maryland, United States of America.

Objective: The aim of this study is to find the most suitable heat wave definition among 15 different ones and to evaluate its impact on total, age-, and gender-specific mortality for Bandafassi, Senegal.

Methods: Daily weather station data were obtained from Kedougou situated at 17 km from Bandafassi from 1973 to 2012. Poisson generalized additive model (GAM) and distributed lag non-linear model (DLNM) are used to investigate the effect of heat wave on mortality and to evaluate the nonlinear association of heat wave definitions at different lag days, respectively.

Results: Heat wave definitions, based on three or more consecutive days with both daily minimum and maximum temperatures greater than the 90th percentile, provided the best model fit. A statistically significant increase in the relative risk (RRs 1.4 (95% Confidence Interval (CI): 1.2-1.6), 1.7 (95% CI: 1.5-1.9), 1.21 (95% CI: 1.08-1.3), 1.2 (95% CI: 1.04-1.5), 1.5 (95% CI: 1.3-1.8), 1.4 (95% CI: 1.2-1.5), 1.5 (95% CI: 1.07-1.6), and 1.5 (95% CI: 1.3-1.8)) of total mortality was observed for eight definitions. By using the definition based on the 90th percentile of minimum and maximum temperature with a 3-day duration, we also found that females and people aged ≥ 55 years old were at higher risks than males and other different age groups to heat wave related mortality.

Conclusion: The impact of heat waves was associated with total-, age-, gender-mortality. These results are expected to be useful for decision makers who conceive of public health policies in Senegal and elsewhere. Climate parameters, including temperatures and humidity, could be used to forecast heat wave risks as an early warning system in the area where we conduct this research. More broadly, our findings should be highly beneficial to climate services, researchers, clinicians, end-users and decision-makers.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0249199PLOS
April 2021

Regional brain iron associated with deterioration in Alzheimer's disease: A large cohort study and theoretical significance.

Alzheimers Dement 2021 Jan 25. Epub 2021 Jan 25.

Melbourne Dementia Research Centre, Florey Institute of Neuroscience and Mental Health, and The University of Melbourne, Parkville, Australia.

Objective: This paper is a proposal for an update of the iron hypothesis of Alzheimer's disease (AD), based on large-scale emerging evidence.

Background: Iron featured historically early in AD research efforts for its involvement in the amyloid and tau proteinopathies, APP processing, genetics, and one clinical trial, yet iron neurochemistry remains peripheral in mainstream AD research. Much of the effort investigating iron in AD has focused on the potential for iron to provoke the onset of disease, by promoting proteinopathy though increased protein expression, phosphorylation, and aggregation.

New/updated Hypothesis: We provide new evidence from a large post mortem cohort that brain iron levels within the normal range were associated with accelerated ante mortem disease progression in cases with underlying proteinopathic neuropathology. These results corroborate recent findings that argue for an additional downstream role for iron as an effector of neurodegeneration, acting independently of tau or amyloid pathologies. We hypothesize that the level of tissue iron is a trait that dictates the probability of neurodegeneration in AD by ferroptosis, a regulated cell death pathway that is initiated by signals such as glutathione depletion and lipid peroxidation.

Major Challenges For The Hypothesis: While clinical biomarkers of ferroptosis are still in discovery, the demonstration of additional ferroptotic correlates (genetic or biomarker derived) of disease progression is required to test this hypothesis. The genes implicated in familial AD are not known to influence ferroptosis, although recent reports on APP mutations and apolipoprotein E allele (APOE) have shown impact on cellular iron retention. Familial AD mutations will need to be tested for their impact on ferroptotic vulnerability. Ultimately, this hypothesis will be substantiated, or otherwise, by a clinical trial of an anti-ferroptotic/iron compound in AD patients.

Linkage To Other Major Theories: Iron has historically been linked to the amyloid and tau proteinopathies of AD. Tau, APP, and apoE have been implicated in physiological iron homeostasis in the brain. Iron is biochemically the origin of most chemical radicals generated in biochemistry and thus closely associated with the oxidative stress theory of AD. Iron accumulation is also a well-established consequence of aging and inflammation, which are major theories of disease pathogenesis.
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http://dx.doi.org/10.1002/alz.12282DOI Listing
January 2021

Effect of Disease-Modifying Therapy on Disability in Relapsing-Remitting Multiple Sclerosis Over 15 Years.

Neurology 2021 02 28;96(5):e783-e797. Epub 2020 Dec 28.

From CORe (T.K., I.D., S.S., C.M.), Department of Medicine, University of Melbourne; MS Centre (T.K., I.D., S.S., C.M.), Department of Neurology, Royal Melbourne Hospital, Australia; Karolinska Institute (T.S.), Stockholm, Sweden; Department of Neuroscience (T.S., V.J., A.v.d.W., O.S., H.B.), Central Clinical School, Monash University, Melbourne; Burnet Institute (T.S.), Melbourne, Australia; Department of Neurology and Center of Clinical Neuroscience (D.H., E.K.H.), General University Hospital and Charles University in Prague, Czech Republic; Department of Basic Medical Sciences, Neuroscience and Sense Organs (M. Trojano), University of Bari, Italy; Hospital Universitario Virgen Macarena (G.I.), Sevilla, Spain; Department of Neuroscience, Imaging and Clinical Sciences (A.L.), University "G. d'Annunzio," Chieti; Department of Biomedical and Neuromotor Sciences (A.L.), University of Bologna, IRCCS Istituto delle Scienze Neurologiche di Bologna, Italy; Hopital Notre Dame (A.P., M.G., P.D.), Montreal; CHUM and Universite de Montreal (A.P., M.G., P.D.); CISSS Chaudière-Appalache (P.G.), Levis, Canada; Department of Neurology (V.J., A.v.d.W., O.S., H.B.), Alfred Hospital, Melbourne, Australia; Neuro Rive-Sud (F. Grand'Maison), Quebec, Canada; Department of Neuroscience (P.S., D.F.), Azienda Ospedaliera Universitaria, Modena, Italy; Isfahan University of Medical Sciences (V.S.), Isfahan, Iran; Amiri Hospital (R. Alroughani), Kuwait City, Kuwait; Zuyderland Ziekenhuis (R.H.), Sittard, the Netherlands; Medical Faculty (M. Terzi), 19 Mayis University, Samsun; KTU Medical Faculty Farabi Hospital (C.B.), Karadeniz Technical University, Trabzon, Turkey; School of Medicine and Public Health (J.L.-S.), University Newcastle; Department of Neurology (J.L.-S.), John Hunter Hospital, Newcastle, Australia; UOC Neurologia (E.P.), Azienda Sanitaria Unica Regionale Marche-AV3, Macerata, Italy; Cliniques Universitaires Saint-Luc (V.V.P.), Brussels, Belgium; University of Parma (F. Granella); C. Mondino National Neurological Institute (R.B.), Pavia; Azienda Ospedaliera di Rilievo Nazionale San Giuseppe Moscati Avellino (D.S.), Italy; Flinders University (M. Slee), Adelaide; Westmead Hospital (S.V.), Sydney, Australia; Nemocnice Jihlava (R. Ampapa), Czech Republic; University of Queensland (P.M.), Brisbane; Royal Brisbane and Women's Hospital (P.M.), Brisbane, Australia; Hospital Germans Trias i Pujol (C.R.-T.), Badalona, Spain; CSSS Saint-Jérôme (J.P.), Canada; Hospital Universitario Donostia (J.O.), Paseo de Begiristain, San Sebastián, Spain; Hospital Italiano (E.C.), Buenos Aires, Argentina; Brain and Mind Centre (M.B.), University of Sydney, Australia; INEBA-Institute of Neuroscience Buenos Aires (M.L.S.), Argentina; Hospital de Galdakao-Usansolo (J.L.S.-M.), Galdakao, Spain; Liverpool Hospital (S. Hodgkinson), Sydney, Australia; Jahn Ferenc Teaching Hospital (C.R.), Budapest, Hungary; Craigavon Area Hospital (S. Hughes), UK; Jewish General Hospital (F.M.), Montreal, Canada; Deakin University (C.S.), Geelong; Monash Medical Centre (E.B.), Melbourne, Australia; South East Trust (O.G.), Belfast, UK; Perron Institute (A.K.), University of Western Australia, Nedlands; Institute of Immunology and Infectious Diseases (A.K.), Murdoch University; Sir Charles Gairdner Hospital (A.K.), Perth, Australia; Department of Neurology (T.C.), Faculty of Medicine, University of Debrecen, Hungary; Bombay Hospital Institute of Medical Sciences (B.S.), Mumbai, India; St Vincents Hospital (N.S.), Fitzroy, Melbourne, Australia; Veszprém Megyei Csolnoky Ferenc Kórház zrt (I.P.), Veszprem, Hungary; Royal Hobart Hospital (B.T.), Australia; Semmelweis University Budapest (M. Simo), Hungary; Central Military Emergency University Hospital (C.-A.S.), Bucharest; Titu Maiorescu University (C.-A.S.), Bucharest, Romania; BAZ County Hospital (A.S.), Miskolc, Hungary; and Box Hill Hospital (H.B.), Melbourne, Australia.

Objective: To test the hypothesis that immunotherapy prevents long-term disability in relapsing-remitting multiple sclerosis (MS), we modeled disability outcomes in 14,717 patients.

Methods: We studied patients from MSBase followed for ≥1 year, with ≥3 visits, ≥1 visit per year, and exposed to MS therapy, and a subset of patients with ≥15-year follow-up. Marginal structural models were used to compare the cumulative hazards of 12-month confirmed increase and decrease in disability, Expanded Disability Status Scale (EDSS) step 6, and the incidence of relapses between treated and untreated periods. Marginal structural models were continuously readjusted for patient age, sex, pregnancy, date, disease course, time from first symptom, prior relapse history, disability, and MRI activity.

Results: A total of 14,717 patients were studied. During the treated periods, patients were less likely to experience relapses (hazard ratio 0.60, 95% confidence interval [CI] 0.43-0.82, = 0.0016), worsening of disability (0.56, 0.38-0.82, = 0.0026), and progress to EDSS step 6 (0.33, 0.19-0.59, = 0.00019). Among 1,085 patients with ≥15-year follow-up, the treated patients were less likely to experience relapses (0.59, 0.50-0.70, = 10) and worsening of disability (0.81, 0.67-0.99, = 0.043).

Conclusion: Continued treatment with MS immunotherapies reduces disability accrual by 19%-44% (95% CI 1%-62%), the risk of need of a walking aid by 67% (95% CI 41%-81%), and the frequency of relapses by 40-41% (95% CI 18%-57%) over 15 years. This study provides evidence that disease-modifying therapies are effective in improving disability outcomes in relapsing-remitting MS over the long term.

Classification Of Evidence: This study provides Class IV evidence that, for patients with relapsing-remitting MS, long-term exposure to immunotherapy prevents neurologic disability.
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http://dx.doi.org/10.1212/WNL.0000000000011242DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7884998PMC
February 2021

Acute phase markers in CSF reveal inflammatory changes in Alzheimer's disease that intersect with pathology, APOE ε4, sex and age.

Prog Neurobiol 2021 Mar 31;198:101904. Epub 2020 Aug 31.

Clinical Memory Research Unit, Department of Clinical Sciences, Malmö, Lund University, Sweden; Memory Clinic, Skåne University Hospital, Malmö, Sweden. Electronic address:

It is unknown how neuroinflammation may feature in the etiology of Alzheimer's disease (AD). We profiled acute phase response (APR) proteins (α1-antitrypsin, α1-antichymotrypsin, ceruloplasmin, complement C3, ferritin, α-fibrinogen, β-fibrinogen, γ-fibrinogen, haptoglobin, hemopexin) in CSF of 1291 subjects along the clinical and biomarker spectrum of AD to investigate the association between inflammatory changes, disease outcomes, and demographic variables. Subjects were stratified by Aβ/t-tau as well as the following clinical diagnoses: cognitively normal (CN); subjective cognitive decline (SCD); mild cognitive impairment (MCI); and AD dementia. In separate multiple regressions (adjusting for diagnosis, age, sex, APOE-ε4) of each APR protein and a composite of all APR proteins, CSF Aβ/t-tau status was associated with elevated ferritin, but not any other APR protein in CN and SCD subjects. Rather, the APR was elevated along with symptomatic progression (CN < SCD < MCI < AD), and this was elevation was mediated by CSF p-tau181. APOE ε4 status did not affect levels of any APR proteins in CSF, while these were elevated in males and with increased age. The performance of the APR in predicting clinical diagnosis was influenced by APOE ε4 status, sex, and age. These data provide new insight into inflammatory changes in AD and how this intersects with pathology changes and patient demographics.
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http://dx.doi.org/10.1016/j.pneurobio.2020.101904DOI Listing
March 2021

Drivers of stunting reduction in Senegal: a country case study.

Am J Clin Nutr 2020 09;112(Suppl 2):860S-874S

Centre for Global Child Health, Hospital for Sick Children, Toronto, Canada.

Background: Senegal has been an exemplar country in the West African region, reducing child stunting prevalence by 17.9% from 1992 to 2017.

Objectives: In this study, we aimed to conduct a systematic in-depth assessment of factors at the national, community, household, and individual levels to determine the key enablers of Senegal's success in reducing stunting in children <5 y old between 1992/93 and 2017.

Methods: A mixed methods approach was implemented, comprising quantitative data analysis, a systematic literature review, creation of a timeline of nutrition-related programs, and qualitative interviews with national and regional stakeholders and mothers in communities. Demographic and Health Surveys and Multiple Indicator Cluster Surveys were used to explore stunting inequalities and factors related to the change in height-for-age z-score (HAZ) using difference-in-difference linear regression and the Oaxaca-Blinder decomposition method.

Results: Population-wide gains in average child HAZ and stunting prevalence have occurred from 1992/93 to 2017. Stunting prevalence reduction varied by geographical region and prevalence gaps were reduced slightly between wealth quintiles, maternal education groups, and urban compared with rural residence. Statistical determinants of change included improvements in maternal and newborn health (27.8%), economic improvement (19.5%), increases in parental education (14.9%), and better piped water access (8.1%). Key effective nutrition programs used a community-based approach, including the Community Nutrition Program and the Nutrition Enhancement Program. Stakeholders felt sustained political will and multisectoral collaboration along with improvements in poverty, women's education, hygiene practices, and accessibility to health services at the community level reduced the burden of stunting.

Conclusions: Senegal's success in the stunting decline is largely attributed to the country's political stability, the government's prioritization of nutrition and execution of nutrition efforts using a multisectoral approach, improvements in the availability of health services and maternal education, access to piped water and sanitation facilities, and poverty reduction. Further efforts in the health, water and sanitation, and agriculture sectors will support continued success.
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http://dx.doi.org/10.1093/ajcn/nqaa151DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7487429PMC
September 2020

Climate Variability and Malaria over West Africa.

Am J Trop Med Hyg 2020 05;102(5):1037-1047

General Direction of Public Health, Ministry of Health and Social Action, Dakar, Senegal.

Malaria is a major public health problem in West Africa. Previous studies have shown that climate variability significantly affects malaria transmission. The lack of continuous observed weather station data and the absence of surveillance data for malaria over long periods have led to the use of reanalysis data to drive malaria models. In this study, we use the Liverpool Malaria Model (LMM) to simulate spatiotemporal variability of malaria in West Africa using daily rainfall and temperature from the following: Twentieth Century Reanalysis (20th CR), National Center for Environmental Prediction (NCEP), European Centre for Medium-Range Weather Forecasts (ECMWF) Atmospheric Reanalysis of the Twentieth Century (ERA20C), and interim ECMWF Re-Analysis (ERA-Interim). Malaria case data from the national surveillance program in Senegal are used for model validation between 2001 and 2016. The warm temperatures found over the Sahelian fringe of West Africa can lead to high malaria transmission during wet years. The rainfall season peaks in July to September over West Africa and Senegal, and the malaria season lasts from September to November, about 1-2 months after the rainfall peak. The long-term trends exhibit interannual and decadal variabilities. The LMM shows acceptable performance in simulating the spatial distribution of malaria incidence. However, some discrepancies are found. These results are useful for decision-makers who plan public health and control measures in affected West African countries. The study would have substantial implications for directing malaria surveillance activities and health policy. In addition, this malaria modeling framework could lead to the development of an early warning system for malaria in West Africa.
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http://dx.doi.org/10.4269/ajtmh.19-0062DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7204584PMC
May 2020

Cerebrospinal fluid ceruloplasmin levels predict cognitive decline and brain atrophy in people with underlying β-amyloid pathology.

Neurobiol Dis 2020 06 19;139:104810. Epub 2020 Feb 19.

Melbourne Dementia Research Centre, The Florey Institute for Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia. Electronic address:

Objectives: The mechanisms leading to neurodegeneration in Alzheimer's disease (AD) may involve oxidative stress and neuroinflammation. Ceruloplasmin (Cp) is a circulating protein that intersects both these pathways, since its expression is increased during the acute phase response, and the protein acts to lower pro-oxidant iron in cells. Since the role of Cp in AD, and its potential for use as a biomarker is not established, we investigated CSF Cp and its association with longitudinal outcome measures related to AD.

Methods: This was an observational study of 268 people from the Alzheimer's Disease Neuroimaging (ADNI) cohort. Subjects were classified clinically as having AD, mild cognitive impairment (MCI) or were cognitively normal (CN), and were also classified as being positive for β-amyloid using established thresholds in the CSF t-tau/Aβ ratio. Subjects underwent cognitive tests and MRI studies every 6 months for 2 years, then yearly thereafter for up to 6 years.

Results: At baseline, CSF Cp was not associated with clinical or pathological diagnosis, but we found an unexpected association between CSF Cp and levels of CSF apolipoprotein E. In longitudinal analysis, high level of CSF Cp was associated with accelerated cognitive decline (as assessed by ADAS-Cog, CDR-SB, and MMSE) and ventricular volume enlargement in people classified as MCI and who had underlying β-amyloid pathology.

Conclusion: These results raise new questions into the role of Cp in neuroinflammation, oxidative stress, and APOE pathways involved in AD, and reveal the potential for this protein to be used as a biomarker in disease prognostication.
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http://dx.doi.org/10.1016/j.nbd.2020.104810DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7150625PMC
June 2020

For more than money: willingness of health professionals to stay in remote Senegal.

Hum Resour Health 2019 04 25;17(1):28. Epub 2019 Apr 25.

National Centre for Global Health and Medicine, Tokyo, Japan.

Background: Poor distribution of already inadequate numbers of health professionals seriously constrains equitable access to health services in low- and middle-income countries. The Senegalese Government is currently developing policy to encourage health professionals to remain in areas defined as 'difficult'. Understanding health professional's preferences is crucial for this policy development.

Methods: Working with the Senegalese Government, a choice experiment (CE) was developed to elicit the job preferences of physicians and non-physicians. Attributes were defined using a novel mixed-methods approach, combining interviews and best-worst scaling (Case 1). Six attributes were categorised as 'individual (extrinsic) incentive' attributes ('type of contract', 'provision of training opportunities', 'provision of an allowance' and 'provision of accommodation') or 'functioning health system' attributes ('availability of basic equipment in health facilities' and 'provision of supportive supervision by health administrators'). Using face-to-face interviews, the CE was administered to 55 physicians (3909 observations) and 246 non-physicians (17 961 observations) randomly selected from those working in eight 'difficult' regions in Senegal. Conditional logit was used to analyse responses. This is the first CE to both explore the impact of contract type on rural retention and to estimate value of attributes in terms of willingness to stay (WTS) in current rural post.

Results: For both physicians and non-physicians, a permanent contract is the most important determinant of rural job retention, followed by availability of equipment and provision of training opportunities. Retention probabilities suggest that policy reform affecting only a single attribute is unlikely to encourage health professionals to remain in 'difficult' regions. The relative importance of an allowance is low; however, the level of such financial incentives requires further investigation.

Conclusion: Contract type is a key factor impacting on retention. This has led the Senegalese Health Ministry to introduce a new rural assignment policy that recruits permanent staff from the pool of annually contracted healthcare professionals on the condition that they take up rural posts. While this is a useful policy development, further efforts to retain rural health workers, considering both personal incentives and the functioning of health systems, are necessary to ensure health worker numbers are adequate to meet the needs of rural communities.
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http://dx.doi.org/10.1186/s12960-019-0363-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6485088PMC
April 2019

Brain iron is associated with accelerated cognitive decline in people with Alzheimer pathology.

Mol Psychiatry 2020 11 18;25(11):2932-2941. Epub 2019 Feb 18.

Melbourne Dementia Research Centre, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Vic, Australia.

Cortical iron has been shown to be elevated in Alzheimer's disease (AD), but the impact of the directly measured iron on the clinical syndrome has not been assessed. We investigated the association between post-mortem iron levels with the clinical and pathological diagnosis of AD, its severity, and the rate of cognitive decline in the 12 years prior to death in subjects from the Memory and Aging Project (n = 209). Iron was elevated (β [SE] = 9.7 [2.6]; P = 3.0 × 10) in the inferior temporal cortex only in subjects who were diagnosed with clinical AD during life and had a diagnosis of AD confirmed post-mortem by standardized criteria. Although iron was weakly associated with the extent of proteinopathy in tissue with AD neuropathology, it was strongly associated with the rate of cognitive decline (e.g., global cognition: β [SE] = -0.040 [0.005], P = 1.6 × 10). Thus, cortical iron might act to propel cognitive deterioration upon the underlying proteinopathy of AD, possibly by inducing oxidative stress or ferroptotic cell death, or may be related to an inflammatory response.
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http://dx.doi.org/10.1038/s41380-019-0375-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6698435PMC
November 2020

Cerebrospinal fluid ferritin levels predict brain hypometabolism in people with underlying β-amyloid pathology.

Neurobiol Dis 2019 04 14;124:335-339. Epub 2018 Dec 14.

Melbourne Dementia Research Centre, The Florey Institute for Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia; Cooperative Research Center for Mental Health, Victoria, Australia. Electronic address:

β-Amyloid pathology is elevated in ~30% of cognitively normal people over 65, and is associated with accelerated neurodegeneration in the pre-clinical stages of Alzheimer's disease. Recent findings reveal that brain iron might also act to propel neurodegeneration in people with underlying amyloid pathology. Here, repeated PET scans of fluorodeoxyglucose (FDG) were used as a biomarker for brain hypometabolism and a downstream biomarker of neurodegeneration to investigate whether levels of ferritin in the cerebrospinal fluid (CSF; a reporter of brain iron load) are associated with prodromal disease progression of people with high β-amyloid pathology determined by established cut-off values in CSF t-tau/Aβ ratio. Nineteen cognitively normal participants with low t-tau/Aβ, and 71 participants with high t-tau/Aβ who were cognitively normal or had mild cognitive impairment were included as participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI) study. These subjects had repeated FDG-PET scans at 6-month intervals for 2 years, and yearly intervals for up to a further 3 years. In mixed-effects linear models of FDG signal, baseline CSF ferritin was associated with an accelerated decline in FDG PET in high t-tau/Aβ participants (β[SE] = -0.066 [0.017]; P = .0002), but not in people with low t-tau/Aβ (-0.029 [0.049]; P = .554). These data implicate iron as a contributing factor to neurodegeneration associated with β-amyloid pathology, and highlight CSF ferritin as a complementary prognostic biomarker to the t-tau/Aβ ratio that predicts near-term risk for disease progression.
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http://dx.doi.org/10.1016/j.nbd.2018.12.010DOI Listing
April 2019

Electro-generation of hydrogen peroxide using a graphite cathode from exhausted batteries: study of influential parameters on electro-Fenton process.

Environ Technol 2020 Apr 25;41(11):1434-1445. Epub 2018 Oct 25.

Laboratoire d'Electrochimie et des Procédés Membranaires, Ecole Supérieure Polytechnique, Université Cheikh Anta Diop, Dakar-Fann, Senegal.

In this work, the study of hydrogen peroxide (HO) electro-generation using graphite from exhausted batteries (Gr-Bat) was conducted. Linear sweep voltammetry and electrolysis experiments were carried out in a single compartment electrochemical cell. Study of the possibility to use this electrode revealed that it presents, as vitreous carbon (VC) electrode, a reduction of oxygen with two successive waves (bi-electronic reduction). The first wave corresponds to the reduction of O to HO, while the second one corresponds to the reduction of HO to HO. The cathodic potentials for electro-generation of HO appeared at -600 and -700 mV vs. Ag/AgCl for Gr-Bat and VC electrodes, respectively. Subsequently, electrolysis experiments were conducted by imposing the potentials required for HO formation. The effect of several operating parameters on HO production, such as the nature and concentration of the electrolyte, the pH, the presence of ferrous ions and O injection were studied using Gr-Bat and VC electrodes, respectively. For both electrodes, the acidic medium was more favorable for HO electro-generation. The oxygen injection in solution promoted an increase of HO concentration, but its effect was more pronounced in the case of VC electrode. Application for crystal violet degradation by electro-Fenton revealed that Gr-Bat had the best purification performance. A removal rate of 73.18% was obtained with Gr-Bat electrode against 62.27% with VC electrode for an electrolysis time of 120 min. This study has demonstrated the possibility of recycling Gr-Bat by using them as cathode materials in the electro-Fenton process.
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http://dx.doi.org/10.1080/09593330.2018.1537309DOI Listing
April 2020

Comparison of Malaria Simulations Driven by Meteorological Observations and Reanalysis Products in Senegal.

Int J Environ Res Public Health 2017 09 25;14(10). Epub 2017 Sep 25.

Laboratoire de Physique de l'Atmosphère et de l'Océan-Siméon Fongang, Ecole Supérieure Polytechnique de l'Université Cheikh Anta Diop (UCAD), BP 5085, Dakar-Fann, Dakar 10700, Senegal.

The analysis of the spatial and temporal variability of climate parameters is crucial to study the impact of climate-sensitive vector-borne diseases such as malaria. The use of malaria models is an alternative way of producing potential malaria historical data for Senegal due to the lack of reliable observations for malaria outbreaks over a long time period. Consequently, here we use the Liverpool Malaria Model (LMM), driven by different climatic datasets, in order to study and validate simulated malaria parameters over Senegal. The findings confirm that the risk of malaria transmission is mainly linked to climate variables such as rainfall and temperature as well as specific landscape characteristics. For the whole of Senegal, a lag of two months is generally observed between the peak of rainfall in August and the maximum number of reported malaria cases in October. The malaria transmission season usually takes place from September to November, corresponding to the second peak of temperature occurring in October. Observed malaria data from the (PNLP, National Malaria control Programme in Senegal) and outputs from the meteorological data used in this study were compared. The malaria model outputs present some consistencies with observed malaria dynamics over Senegal, and further allow the exploration of simulations performed with reanalysis data sets over a longer time period. The simulated malaria risk significantly decreased during the 1970s and 1980s over Senegal. This result is consistent with the observed decrease of malaria vectors and malaria cases reported by field entomologists and clinicians in the literature. The main differences between model outputs and observations regard amplitude, but can be related not only to reanalysis deficiencies but also to other environmental and socio-economic factors that are not included in this mechanistic malaria model framework. The present study can be considered as a validation of the reliability of reanalysis to be used as inputs for the calculation of malaria parameters in the Sahel using dynamical malaria models.
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http://dx.doi.org/10.3390/ijerph14101119DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5664620PMC
September 2017

Evidence that iron accelerates Alzheimer's pathology: a CSF biomarker study.

J Neurol Neurosurg Psychiatry 2018 05 22;89(5):456-460. Epub 2017 Sep 22.

The Florey Institute for Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.

Objective: To investigate whether cerebrospinal fluid (CSF) ferritin (reporting brain iron) is associated with longitudinal changes in CSF β-amyloid (Aβ) and tau.

Methods: Mixed-effects models of CSF Aβ and tau were constructed using data from 296 participants who had baseline measurement of CSF ferritin and annual measurement of CSF tau and Aβ for up to 5 years.

Results: In subjects with biomarker-confirmed Alzheimer's pathology, high CSF ferritin (>6.2 ng/mL) was associated with accelerated depreciation of CSF Aβ (reporting increased plaque formation; p=0.0001). CSF ferritin was neither associated with changes in CSF tau in the same subjects, nor longitudinal changes in CSF tau or Aβ in subjects with low baseline pathology. In simulation modelling of the natural history of Aβ deposition, which we estimated to occur over 31.4 years, we predicted that it would take 12.6 years to reach the pathology threshold value of CSF Aβ from healthy normal levels, and this interval is not affected by CSF ferritin. CSF ferritin influences the fall in CSF Aβ over the next phase, where high CSF ferritin accelerated the transition from threshold preclinical Aβ levels to the average level of Alzheimer's subjects from 18.8 to 10.8 years.

Conclusions: Iron might facilitate Aβ deposition in Alzheimer's and accelerate the disease process.
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http://dx.doi.org/10.1136/jnnp-2017-316551DOI Listing
May 2018

Retention of qualified healthcare workers in rural Senegal: lessons learned from a qualitative study.

Rural Remote Health 2017 Jul-Sep;17(3):4149. Epub 2017 Sep 12.

Department of Human Resources, Ministry of Health and Social Actions, Dakar, Senegal.

Introduction: Deployment and retention of a sufficient number of skilled and motivated human resources for health (HRH) at the right place and at the right time are critical to ensure people's right to access a universal quality of health care. Vision Tokyo 2010 Network, an international network of HRH managers at the ministry of health (MoH) level in nine Francophone African countries, identified maldistribution of a limited number of healthcare personnel and their retention in rural areas as overarching problems in the member countries. The network conducted this study in Senegal to identify the determining factors for the retention of qualified HRH in rural areas, and to explore an effective and feasible policy that the MoH could implement in the member countries.

Methods: Doctors, nurses, midwives and superior technicians in anesthesiology who were currently working (1) in a rural area and had been for more than 2 years, (2) in Dakar with experience of working in a rural area or (3) in Dakar without any prior experience working in a rural area were interviewed about their willingness and reasons for accepting work or continuing to work in a rural area and their suggested policies for deployment and retention of healthcare workers in rural areas. In-depth interviews were conducted with policy makers in MoH, asking for their perceptions on human resource management in health and about their suggested policies for deployment and retention.

Results: A total of 176 healthcare workers and eight policy makers were interviewed. The willingness to face challenges in a new place was one of the main reasons for accepting work in rural areas. The identified factors to motivate or demotivate healthcare workers in rural areas were related to pre-service and in-service education, regulatory systems, financial and non-financial incentive schemes and environmental support. Factors not included in WHO's global recommendation but highly valued in this study were (1) the fairness, transparency and predictability of human resource management by the MoH and (2) employment status, ie permanent government staff versus contract staff. Financial incentive schemes were less commonly suggested. Family bonding and religious-related non-financial incentive schemes were found to be specific factors in Senegal, but would also be applicable in countries where family and religion play important roles in the values of healthcare workers.

Conclusions: Improved HRH management, eg the transparency of human resource management by the MoH, was identified as a pre-condition of any policy implementation related to HRH. This factor can be considered in other countries struggling to retain healthcare workers in rural areas. The Vision Tokyo 2010 Network or HRH managers' network in Francophone Africa, Senegal MoH and the research team plan to conduct a quantitative survey to confirm the generalizability of the results of this qualitative survey, and to identify the most effective combination of policies to improve the retention of qualified healthcare workers and seek their implementation in other countries in the region as network activities.
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http://dx.doi.org/10.22605/RRH4149DOI Listing
February 2018

Cerebral quantitative susceptibility mapping predicts amyloid-β-related cognitive decline.

Brain 2017 Aug;140(8):2112-2119

Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia.

See Derry and Kent (doi:10.1093/awx167) for a scientific commentary on this article.The large variance in cognitive deterioration in subjects who test positive for amyloid-β by positron emission tomography indicates that convergent pathologies, such as iron accumulation, might combine with amyloid-β to accelerate Alzheimer's disease progression. Here, we applied quantitative susceptibility mapping, a relatively new magnetic resonance imaging method sensitive to tissue iron, to assess the relationship between iron, amyloid-β load, and cognitive decline in 117 subjects who underwent baseline magnetic resonance imaging and amyloid-β positron emission tomography from the Australian Imaging, Biomarkers and Lifestyle study (AIBL). Cognitive function data were collected every 18 months for up to 6 years from 100 volunteers who were either cognitively normal (n = 64) or diagnosed with mild cognitive impairment (n = 17) or Alzheimer's disease (n = 19). Among participants with amyloid pathology (n = 45), higher hippocampal quantitative susceptibility mapping levels predicted accelerated deterioration in composite cognition tests for episodic memory [β(standard error) = -0.169 (0.034), P = 9.2 × 10-7], executive function [β(standard error) = -0.139 (0.048), P = 0.004), and attention [β(standard error) = -0.074 (0.029), P = 0.012]. Deteriorating performance in a composite of language tests was predicted by higher quantitative susceptibility mapping levels in temporal lobe [β(standard error) = -0.104 (0.05), P = 0.036] and frontal lobe [β(standard error) = -0.154 (0.055), P = 0.006]. These findings indicate that brain iron might combine with amyloid-β to accelerate clinical progression and that quantitative susceptibility mapping could be used in combination with amyloid-β positron emission tomography to stratify individuals at risk of decline.
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http://dx.doi.org/10.1093/brain/awx137DOI Listing
August 2017

The Role of a Network of Human Resources for Health Managers in Supporting Leadership for Health Systems Strengthening in Francophone African Countries.

Health Syst Reform 2016 Jul;2(3):254-264

National Center for Global Health and Medicine , Tokyo , Japan.

This article presents the Vision Tokyo 2010 Network, a unique model of peer learning and information sharing among human resources for health (HRH) managers in Francophone African countries. It describes the network's origins, achievements, and factors underlying its success. The network's origins lie in an overseas training program in Tokyo between 2010 and 2014. Participants included directors and heads of HRH management departments at federal and provincial levels across nine Francophone African countries: Benin, Burkina Faso, Burundi, the Democratic Republic of Congo, Côte d'Ivoire, Niger, Mali, Senegal, and Togo. The network itself was established in 2012 based on the common strategic vision (Vision Tokyo 2010) developed during the training program, with an objective of tackling major problems to improve the performance of human resource development systems in the health systems of participants' countries. Some of the main outcomes of the network, demonstrated during the Ebola outbreak include: improved use of human resource information systems in Senegal established as a result of peer learning within the network and technical cooperation between the Democratic Republic of Congo and Côte d'Ivoire to develop standard operational procedures and to train health workers in the management of Ebola. Having a common strategic vision and contextualized framework-African house of solidarity-as a symbol for HRH system development, strong ownership by core members, participatory processes, a positive peer learning environment, and coaching-style support by partners were key elements of success in this initiative. The biggest challenge for this network thus far has been financial sustainability. However, steps are being taken to demonstrate the cost-effectiveness of networks such as these in order to garner further support from partners to invest in networked approaches rather than siloed, country-specific programs.
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http://dx.doi.org/10.1080/23288604.2016.1220778DOI Listing
July 2016

Prevalence, incidence, risk factors and treatment of atrial fibrillation in Australia: The Australian Diabetes, Obesity and Lifestyle (AusDiab) longitudinal, population cohort study.

Int J Cardiol 2016 Feb 15;205:127-132. Epub 2015 Dec 15.

Department of Clinical Diabetes and Epidemiology, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia.

Objective: We sought to describe the prevalence, incidence, risk factors and treatment (according to stroke risk) of atrial fibrillation (AF) in the national, population-based Australian Diabetes, Obesity and Lifestyle (AusDiab) study cohort.

Methods: ECG data were available from 8273/11,247 participants of AusDiab study in 1999/2000 and from 5422 participants in 2004/2005. Minnesota coding was used to identify prevalent and incident cases of AF.

Results: 90 prevalent cases of AF (14.1 per 1000) comprising 56 men (mean age 70.5 ± 1.9 years) and 34 women (aged 78.3 ± 1.2 years) were identified in 1999-2000. AF prevalence was associated with sedentary behaviour versus physically active (PR 2.0, 95% CI 1.2-3.6). 53 incident cases of AF (2.0, 95%, CI 1.5-2.6 per 1000 person-year) were subsequently identified in 2004-2005. Increased risk of incident AF was associated with male sex, obesity, history of angina, myocardial infarction and stroke. Both increased weight gain and increased weight loss appeared to be associated with increased risks of developing AF in women, while no obvious association was observed in men. Despite their high risk for stroke, anti-thrombotic therapy was observed in only 39.3% of participants with CHA2DS2-VASC scores ≥ 2.

Conclusions: This study contributes to a better understanding of the AF burden. With the ageing population, coordinated efforts will be needed to anticipate the future health care costs related to AF and its impacts on the health care system. This will include appropriate application of anti-thrombotic therapy according to risk of thrombo-embolic events.
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http://dx.doi.org/10.1016/j.ijcard.2015.12.013DOI Listing
February 2016

Trends in maternal and newborn health characteristics and obstetric interventions among Aboriginal and Torres Strait Islander mothers in Western Australia from 1986 to 2009.

Aust N Z J Obstet Gynaecol 2016 Jun 3;56(3):245-51. Epub 2015 Nov 3.

Aboriginal Health Department Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia.

Background: Detailed analyses of long-term trends in Aboriginal maternal and newborn health characteristics are lacking.

Aim: To examine trends in maternal and newborn health characteristics for all mothers who were recorded as Aboriginal in the Western Australian Midwives' Notification System from 1986 to 2009.

Materials And Methods: Births were categorised into four-year time intervals (1986-1989, 1990-1993, 1994-1997, 1998-2001, 2002-2005, 2006-2009). Trends in maternal demographic characteristics, pre-existing medical conditions, pregnancy complications and neonatal characteristics were examined.

Results: For 37 424 births recorded from 1986 to 2009, the proportion of births to mothers aged ≤19 years decreased (31-22%, P < 0.001) along with the prevalence of pre-eclampsia (6.8-4.0%, P < 0.001) and antepartum haemorrhage (4.8-3.2%, P < 0.001). There were increases in the prevalence of diabetes in pregnancy (3.8-6.6%, P < 0.001), induction of labour (17.8-21.4%, P < 0.001), elective caesarean (6.6-8.2%, P < 0.001) and emergency caesarean (9.5-14.9%, P < 0.001) deliveries. There were no changes in the overall prevalence of preterm births (15.4-15.9%, P = 0.32). However, increases were observed in the prevalence of medically indicated preterm births with and without prelabour rupture of membranes (1.0-1.7%; P < 0.001 and 3.3-4.3%; P = 0.005, respectively). There were no significant changes in the rates of smoking during pregnancy (51-52% from 1998 to 2009, P = 0.18), small-for-gestational age (16.9-17.2%, P = 0.07), suboptimal-birthweight (20.4-20.1%, P = 0.92), stillbirths (14.7 per 1000-12.1 per 1000, P = 0.22) and neonatal deaths (6.2 per 1000-5.5 per 1000, P = 0.68).

Conclusion: Encouraging trends include reduced rates of teenage pregnancy, pre-eclampsia and antepartum haemorrhage. The persistent high rates of smoking during pregnancy, preterm births, stillbirths, neonatal deaths and increasing rates of diabetes in pregnancy are of concern.
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http://dx.doi.org/10.1111/ajo.12416DOI Listing
June 2016

Sero-epidemiological evaluation of Plasmodium falciparum malaria in Senegal.

Malar J 2015 Jul 16;14:275. Epub 2015 Jul 16.

Service de Parasitologie-Mycologie, Faculté de Médecine, Pharmacie et Odontologie, Université Cheikh Anta Diop de Dakar, Dakar, Sénégal.

Background: In Senegal, a significant decrease of malaria transmission intensity has been noted the last years. Parasitaemia has become lower and, therefore, more difficult to detect by microscopy. In the context of submicroscopic parasitaemia, it has become relevant to rely on relevant malaria surveillance tools to better document malaria epidemiology in such settings. Serological markers have been proposed as an essential tool for malaria surveillance. This study aimed to evaluate the sero-epidemiological situation of Plasmodium falciparum malaria in two sentinel sites in Senegal.

Methods: Cross-sectional surveys were carried out in Velingara (south Senegal) and Keur Soce (central Senegal) between September and October 2010. Children under 10 years old, living in these areas, were enrolled using two-level, random sampling methods. P. falciparum infection was diagnosed using microscopy. P. falciparum antibodies against circumsporozoite protein (CSP), apical membrane protein (AMA1) and merozoite surface protein 1_42 (MSP1_42) were measured by ELISA method. A stepwise logistic regression analysis was done to assess factors associated with P. falciparum antibodies carriage.

Results: A total of 1,865 children under 10 years old were enrolled. The overall falciparum malaria prevalence was 4.99% with high prevalence in Velingara of 10.03% compared to Keur Soce of 0.3%. Symptomatic malaria cases (fever associated with parasitaemia) represented 17.37%. Seroprevalence of anti-AMA1, anti-MSP1_42 and anti-CSP antibody was 38.12, 41.55 and 40.38%, respectively. The seroprevalence was more important in Velingara and increased with age, active malaria infection and area of residence.

Conclusion: The use of serological markers can contribute to improved malaria surveillance in areas with declining malaria transmission. This study provided useful baseline information about the sero-epidemiological situation of malaria in Senegal and can contribute to the identification of malaria hot spots in order to concentrate intervention efforts.

Trial Registration Number: PACTR201305000551876 ( http://www.pactr.org ).
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http://dx.doi.org/10.1186/s12936-015-0789-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4502940PMC
July 2015

Prevalence of gestational diabetes mellitus among Indigenous women and comparison with non-Indigenous Australian women: 1990-2009.

Aust N Z J Obstet Gynaecol 2014 Oct 29;54(5):433-40. Epub 2014 Apr 29.

Global Health and Society Unit, Department of Epidemiology and Preventive Medicine, Faculty of Medicine, Nursing and Health Sciences, Monash University, Prahan, Victoria, Australia.

Background: Evidence on long-term trends in gestational diabetes mellitus (GDM) prevalence in Australia is lacking.

Aims: To assess and compare trends in GDM prevalence among Indigenous and non-Indigenous Australian women.

Materials And Methods: Analysis of crude and age-adjusted GDM prevalence over time by Indigenous status and age, using routinely collected midwives data from Australian states and territories on mothers giving birth from 1990 to 2009.

Results: Despite considerable data variation, particularly in 1990-1999, and likely underestimation of GDM prevalence, crude and age-adjusted GDM prevalences were higher in Indigenous than non-Indigenous women at all time-points (4.7% vs 3.1% in 1990-1999; 5.1% vs 4.5% in 2000-2009, P < 0.0001). Data variability precluded quantitative assessment of trends and changes in prevalence ratios before 2000. From 2000 to 2009, GDM prevalence increased significantly among Indigenous women by a mean 2.6% annually (Ptrend <0.0001), and non-Indigenous women by 3.2% annually (Ptrend <0.0001), with no significant trend in the age-adjusted Indigenous/non-Indigenous prevalence ratios (PR) (P = 0.34). GDM prevalence increased significantly with age (P < 0.0001), although the increase with age was significantly greater among Indigenous women (PR 5.34 (4.94-5.77), ≥35 vs <25 years) compared to non-Indigenous women (PR 3.72 (3.64-3.81), ≥35 vs <25 years), Pinteraction <0.0001.

Conclusions: Bearing data quality concerns in mind, GDM prevalence is increasing rapidly among Australian women, more than doubling in non-Indigenous women between 1990 and 2009. Prevalence is consistently higher in Indigenous versus non-Indigenous women, with statistically consistent differences between the groups in recent years. The marked increase in prevalence with age highlights an important period for prevention, particularly for Indigenous women.
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http://dx.doi.org/10.1111/ajo.12213DOI Listing
October 2014

Selection of antimalarial drug resistance after intermittent preventive treatment of infants and children (IPTi/c) in Senegal.

C R Biol 2013 May-Jun;336(5-6):295-300. Epub 2013 Jul 18.

Service de parasitologie-mycologie, faculté de médecine, université Cheikh-Anta-Diop, Dakar, Senegal.

Senegal has since 2003 used sulphadoxine-pyrimethamine (SP) for Intermittent Preventive Treatment (IPT) of malaria in risk groups. However, the large-scale IPT strategy may result in increasing drug resistance. Our study investigated the possible impact of SP-IPT given to infants and children on the prevalence of SP-resistant haplotypes in the Plasmodium falciparum genes Pfdhfr and Pfdhps, comparing sites with and without IPTi/c. P. falciparum positives samples (n=352) were collected from children under 5years of age during two cross-sectional surveys in 2010 and 2011 in three health districts (two on IPTi/c and one without IPTi/c intervention) located in the southern part of Senegal. The prevalence of SP-resistance-related haplotypes in Pfdhfr and Pfdhps was determined by nested PCR followed by sequence-specific oligonucleotide probe (SSOP)-ELISA. The prevalence of the Pfdhfr double mutant haplotypes (CNRN and CICN) was stable between years at<10% in the control group (P=0.69), while it rose significantly in the IPTi/c group from 2% in 2010 to 20% in 2011 (P=0.008). The prevalence of the Pfdhfr triple mutant haplotype (CIRN) increased in both groups, but only significantly in the IPTi/c group from 41% to 65% in 2011 (P=0.005). Conversely, the Pfdhps 437G mutation decreased in both groups from 44.6% to 28.6% (P=0.07) and from 66.7% to 47.5% (P=0.02) between 2010 and 2011 in the control and the IPTi/c groups, respectively. Combined with Pfdhfr, there was a weak trend for decreasing prevalence of quadruple mutants (triple Pfdhfr+Pfdhps 437G) in both groups (P=0.15 and P=0.34). During the two cross-sectional surveys, some significant changes were observed in the SP-resistance-related genes. However, since these changes were observed in the two groups, the IPTi/c strategy does only seem to have limited impact on resistance development and other factors as well. However, continuous monitoring will be needed, due to the up-scaling of the IPTi/c strategy in Senegal according to WHO recommendations.
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http://dx.doi.org/10.1016/j.crvi.2013.04.016DOI Listing
March 2014

Climate and health: observation and modeling of malaria in the Ferlo (Senegal).

C R Biol 2013 May-Jun;336(5-6):253-60. Epub 2013 Jun 14.

Laboratoire de physique de l'atmosphère et de l'océan Siméon-Fongang, École supérieure polytechnique de l'université Cheikh-Anta-Diop (UCAD), Dakar-Fann, Dakar, Senegal.

The aim of this work, undertaken in the framework of QWeCI (Quantifying Weather and Climate Impacts on health in the developing countries) project, is to study how climate variability could influence malaria seasonal incidence. It will also assess the evolution of vector-borne diseases such as malaria by simulation analysis of climate models according to various climate scenarios for the next years. Climate variability seems to be determinant for the risk of malaria development (Freeman and Bradley, 1996 [1], Lindsay and Birley, 1996 [2], Kuhn et al., 2005 [3]). Climate can impact on the epidemiology of malaria by several mechanisms, directly, via the development rates and survival of both pathogens and vectors, and indirectly, through changes in vegetation and land surface characteristics such as the variability of breeding sites like ponds.
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http://dx.doi.org/10.1016/j.crvi.2013.04.001DOI Listing
March 2014

Specific role of maternal weight change in the first trimester of pregnancy on birth size.

Matern Child Nutr 2014 Jul 12;10(3):315-26. Epub 2012 Jul 12.

INSERM, CESP Centre for Research in Epidemiology and Populations Health, U1018 Team 10 'Lifelong Epidemiology of Obesity, Diabetes and Chronic Renal Disease', Villejuif, France Univ Paris-Sud 11, UMRS 1018, Villejuif, France Regional Maternity, University of Nancy, Nancy, France INSERM, UMRS 953, Epidemiological Research on Perinatal Health and Women's and Children's Health, Villejuif, France UPMC Univ Paris 06, F-75005, Paris, France.

The specific role of weight change in the first weeks of gestation in fetal growth has not been fully explored in humans. Our aims were to investigate: (1) the specific association between weight change in the first trimester of pregnancy (WCT1) and size at birth in term pregnancies; and (2) the role of placental weight in this relationship. From 2002 women included in the French EDEN study, 1744 mother-child pairs reached term, had pre-pregnancy weight available and at least five measures of weight in pregnancy. We extrapolated women's weight at each week of gestation with a three-degree polynomial model and estimated weight change during each trimester of gestation. We used a multivariate linear model to investigate the associations between WCT1 and birth size after taking into account potential confounders (age, parity, BMI, tobacco use, educational level, length of gestation, newborn gender, weight change after the first trimester and centre of study). Then, we performed path analysis to investigate whether the relation between WCT1 and birth size could be mediated by placental weight. After taking into account weight gain in later gestation, WCT1 was positively associated with birthweight. Results of path analysis showed that there was no direct association between WCT1 and birth size, but that this association was mediated by placental weight. Weight change during the first weeks of pregnancy may impact on fetal growth independently of weight change later in pregnancy through its effects on placental growth and function.
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http://dx.doi.org/10.1111/j.1740-8709.2012.00423.xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6860237PMC
July 2014

Relationship between exposure to vector bites and antibody responses to mosquito salivary gland extracts.

PLoS One 2011 14;6(12):e29107. Epub 2011 Dec 14.

Unité de Parasitologie, Antenne Marseille de l'Institut de Recherche Biomédicale des Armées, Marseille, France.

Mosquito-borne diseases are major health problems worldwide. Serological responses to mosquito saliva proteins may be useful in estimating individual exposure to bites from mosquitoes transmitting these diseases. However, the relationships between the levels of these IgG responses and mosquito density as well as IgG response specificity at the genus and/or species level need to be clarified prior to develop new immunological markers to assess human/vector contact. To this end, a kinetic study of antibody levels against several mosquito salivary gland extracts from southeastern French individuals living in three areas with distinct ecological environments and, by implication, distinct Aedes caspius mosquito densities were compared using ELISA. A positive association was observed between the average levels of IgG responses against Ae. caspius salivary gland extracts and spatial Ae. caspius densities. Additionally, the average level of IgG responses increased significantly during the peak exposure to Ae. caspius at each site and returned to baseline four months later, suggesting short-lived IgG responses. The species-specificity of IgG antibody responses was determined by testing antibody responses to salivary gland extracts from Cx. pipiens, a mosquito that is present at these three sites at different density levels, and from two other Aedes species not present in the study area (Ae. aegypti and Ae. albopictus). The IgG responses observed against these mosquito salivary gland extracts contrasted with those observed against Ae. caspius salivary gland extracts, supporting the existence of species-specific serological responses. By considering different populations and densities of mosquitoes linked to environmental factors, this study shows, for the first time, that specific IgG antibody responses against Ae. caspius salivary gland extracts may be related to the seasonal and geographical variations in Ae. caspius density. Characterisation of such immunological-markers may allow the evaluation of the effectiveness of vector-control strategies or estimation of the risk of vector-borne disease transmission.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0029107PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3237593PMC
August 2012

Implication of haematophagous arthropod salivary proteins in host-vector interactions.

Parasit Vectors 2011 Sep 28;4:187. Epub 2011 Sep 28.

Unité de Parasitologie - UMR6236 - IFR48, Antenne Marseille de l'Institut de Recherche Biomédicale des Armées (IRBA), Le Pharo, BP 60109, 13 262 Marseille Cedex 07, France.

The saliva of haematophagous arthropods contains an array of anti-haemostatic, anti-inflammatory and immunomodulatory molecules that contribute to the success of the blood meal. The saliva of haematophagous arthropods is also involved in the transmission and the establishment of pathogens in the host and in allergic responses. This survey provides a comprehensive overview of the pharmacological activity and immunogenic properties of the main salivary proteins characterised in various haematophagous arthropod species. The potential biological and epidemiological applications of these immunogenic salivary molecules will be discussed with an emphasis on their use as biomarkers of exposure to haematophagous arthropod bites or vaccine candidates that are liable to improve host protection against vector-borne diseases.
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http://dx.doi.org/10.1186/1756-3305-4-187DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3197560PMC
September 2011

Maternal weight change before pregnancy in relation to birthweight and risks of adverse pregnancy outcomes.

Eur J Epidemiol 2011 Oct 28;26(10):789-96. Epub 2011 Jun 28.

INSERM, Unit 1018, Centre for Research in Epidemiology and Population Health (CESP), Team 10 Epidemiology of Obesity, Diabetes and Renal Disease Over the Life Course, 16 Avenue Paul Vaillant Couturier, 94807 Villejuif cedex, France.

Maternal weight change before pregnancy can be considered as an indicator of maternal energy balance and nutritional status before conception, and may be involved in early life programming. We aimed to investigate the association of maternal Weight Change Before Pregnancy (WCBP) with fetal growth and adverse pregnancy outcomes. Data are from the French EDEN mother-child cohort where 1,756 mother-child pairs had information on mother's weight at 20 years, weight just before pregnancy, fetal anthropometry at second and third trimesters, infant's birthweight and pregnancy complications. The average annual WCBP between 20 years and start of pregnancy (in kg/year) was categorized as: "Weight Loss" (n = 320), "Moderate weight gain" (n = 721) and "High weight gain" (n = 715). The associations of WCBP with fetal and newborn characteristics and with adverse pregnancy outcomes were analyzed, adjusting for maternal and pregnancy characteristics, including the mother's prepregnancy BMI. Interactions between WCBP and prepregnancy BMI were tested. Birthweight and estimated fetal weight in the third trimester increased significantly with increasing WCBP in mothers with BMI <25 kg/m(2). In these mothers, weight loss before pregnancy was associated with a higher risk of newborns small for gestational age (SGA). Whatever the prepregnancy BMI, WCBP was positively associated with a maternal risk of gestational diabetes and hypertension. The ponderal history of mothers before pregnancy can impact on fetal growth and on pregnancy outcomes such as gestational diabetes or hypertension. Our analysis is the first to report that in non-overweight women, those who lost weight before pregnancy are at higher risk of having SGA newborns.
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http://dx.doi.org/10.1007/s10654-011-9599-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3925097PMC
October 2011

Discordant time trends in maternal body size and offspring birthweight of term deliveries in France between 1972 and 2003: data from the French National Perinatal Surveys.

Paediatr Perinat Epidemiol 2011 May 7;25(3):210-7. Epub 2011 Mar 7.

INSERM, Unit 1018, Center for Epidemiology and Populations Health (CESP) Villejuif, France.

We investigated time trends in maternal weight before and during pregnancy and in infant birthweight in France, from 1972 to 2003, using data on singleton live term births from the representative National Perinatal Surveys of 1972, 1981, 1995, 1998 and 2003 (n=8,664, 4,494, 11,445, 12,006, 12,692, respectively). Mothers were interviewed a few days after delivery and data on delivery and the newborn were extracted from hospital records. Maternal prepregnancy weight, height, body mass index and pregnancy weight gain all increased from 1972 to 2003; however, birthweight did not show a parallel trend. After taking gestational age, maternal age, parity, country of origin, newborn gender and maternal smoking during pregnancy into account, mean birthweight increased between 1972 and 1995 but decreased thereafter and, consistently, there was an increase in small-for-gestational age (SGA) and a decrease in large-for-gestational age newborns. Further adjustment for induced delivery, an indicator of obstetric practice, did not change the results. A similar variation has been observed very recently in the US and in Germany. Further research is needed to identify the factors responsible for these discordant changes and especially the factors responsible for the recent increase in SGA since this has been shown to be associated with poorer health in later life.
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http://dx.doi.org/10.1111/j.1365-3016.2010.01188.xDOI Listing
May 2011

Evolution of obesity prevalence in France: an age-period-cohort analysis.

Epidemiology 2010 May;21(3):360-5

INSERM, Unit 780 Research in Epidemiology and Biostatistics, IFR69, Villejuif, France.

Background: A rapid increase in the prevalence of obesity has been reported in France since 1990. We investigated the impact of birth cohort on the changes in obesity prevalence after taking into account age and survey period.

Methods: We analyzed data from 4 national surveys in 1997, 2000, 2003, and 2006. For each survey, self-reported data on weight and height were recorded on mailed questionnaires sent to a sample of 20,000 households, representative of the French population. Obesity was defined according to World Health Organization criteria as body mass index >or=30 kg/m. We modeled the prevalence of obesity using logistic regression with age, cohort, and period as explanatory variables. As these variables are linearly dependent, only nonlinear effects can be estimated uniquely and interpreted, after including specific chosen constraints in the models.

Results: There was a progressive increase in the prevalence of obesity between 1997 and 2006, attributable either to a period effect or to a cohort effect. There was a substantial departure from a linear trend for the cohort effect only, which seemed to be stronger in women: there was an acceleration in the prevalence of obesity with birth cohort for individuals born after the mid-1960s, in both sexes.

Conclusions: Our results are consistent with previous studies in other countries. Compared with older generations, men and women born in the late 1960s may have been subject to early exposures that increased their lifelong susceptibility to obesity.
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http://dx.doi.org/10.1097/EDE.0b013e3181d5bff5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3315475PMC
May 2010

IL-12 producing monocytes and IFN-gamma and TNF-alpha producing T-lymphocytes are increased in placentas infected by Plasmodium falciparum.

J Reprod Immunol 2007 Jun 27;74(1-2):152-62. Epub 2006 Dec 27.

UR 010, Mother and Child Health in the Tropics, Institut de Recherche pour le Développement (IRD), BP 1386, Dakar, Senegal.

Placental Plasmodium falciparum sequestration is associated with dysregulated immune function. Placental inflammatory responses via IFN-gamma and TNF-alpha are implicated in functional damage. However, they are needed during placental infection to control asexual stage parasites. To test the hypothesis that placental immunomodulation associated with malaria disturbs cytokine secretion differently in monocytes and lymphocytes, we have determined the proportion of monocytes and/or lymphocytes secreting IFN-gamma, TNF-alpha, IL-10 and IL-12. Intervillous and peripheral blood monocyte (CD14+) and lymphocyte (CD3/CD4+; CD3/CD8+) cytokine production was compared between 17 P. falciparum-infected and 12 non-infected Senegalese women. After culture with phorbolmyristate acetate/ionomycin (PMA/iono), lipopolysaccharide (LPS) or P. falciparum-infected erythrocytes (IE), the intracellular expression of cytokines in lymphocytes (IFN-gamma, TNF-alpha) and monocytes (IL-10, IL-12, TNF-alpha), was detected. In response to IE, CD4+ and CD8+ T-cells produced IFN-gamma and TNF-alpha at similar rates in both compartments. In response to PMA/iono, the frequencies of CD4+ and CD8+ T-cells producing IFN-gamma and TNF-alpha were similar in both compartments, but increased in P. falciparum-infected placentas. In response to LPS or IE, IL-12 secreting monocytes were increased in infected women, while the frequency of TNF-alpha secreting monocytes was decreased compared to that in non-infected placenta. The monocyte IL-12 response is not impaired in infected women. IL-12 is an important factor for inducing IFN-gamma in T-cells. Thus, IL-12 and IFN-alpha responses may synergistically allow a protective immune response in placental malaria. TNF-alpha production by CD4+ and CD8+ T-cells is up-regulated in P. falciparum-infected placentas, suggesting that T-cells actively participate to inflammatory responses.
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http://dx.doi.org/10.1016/j.jri.2006.10.001DOI Listing
June 2007

Acquisition of antibodies to variant antigens on the surface of Plasmodium falciparum-infected erythrocytes during pregnancy.

Infect Genet Evol 2006 Nov 18;6(6):459-63. Epub 2006 Apr 18.

Institut de Recherche pour le Développement, UR 010, Mother and Child Health in the Tropics, BP1386 CP 18524 Dakar, Senegal.

Pregnancy-associated malaria is characterized by Plasmodium falciparum adherence to chondroitin sulfate A (CSA) in placenta, through a particular variant surface antigen (VSA). VSA(CSA)-specific IgG are involved in protection against placental malaria. In order to assess the relationship between VSA(CSA)-specific antibody responses and parity as well as protection against placental malaria, the occurrence of P. falciparum infection was assessed in 306 pregnant women from a low malaria transmission area of Senegal. Anti-VSA(CSA) antibodies against three placental parasite isolates were measured by flow cytometry, at enrollment and delivery. Placental infection prevalence rates were highest in primigravidae, but no clear decreasing trend was observed from the second pregnancy onwards. Anti-VSA(CSA) antibody prevalence rates increased with parity. Both anti-VSA(CSA) antibody prevalence rates and levels increased during pregnancy only in women infected with P. falciparum. Although a single or a very limited number of P. falciparum infections were able to induce an anti-VSA(CSA) antibody response, the level or the quality of this response did not appear to confer protection against placental malaria infection.
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http://dx.doi.org/10.1016/j.meegid.2006.02.006DOI Listing
November 2006