Honorati Masanja

Ifakara Health Institute, Dār es Salām, Dar es Salaam, Tanzania

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Publications (49)244.23 Total impact

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    ABSTRACT: Background: Epilepsy is common in developing countries, and it is often associated with parasitic infections. We investigated the relationship between exposure to parasitic infections, particularly multiple infections and active convulsive epilepsy (ACE), in five sites across sub-Saharan Africa. Methods and Findings: A case-control design that matched on age and location was used. Blood samples were collected from 986 prevalent cases and 1,313 age-matched community controls and tested for presence of antibodies to Onchocerca volvulus, Toxocara canis, Toxoplasma gondii, Plasmodium falciparum, Taenia solium and HIV. Exposure (seropositivity) to Onchocerca volvulus (OR = 1.98; 95%CI: 1.52–2.58, p,0.001), Toxocara canis (OR = 1.52; 95%CI: 1.23–1.87, p,0.001), Toxoplasma gondii (OR = 1.28; 95%CI: 1.04–1.56, p = 0.018) and higher antibody levels (top tertile) to Toxocara canis (OR = 1.70; 95%CI: 1.30–2.24, p,0.001) were associated with an increased prevalence of ACE. Exposure to multiple infections was common (73.8% of cases and 65.5% of controls had been exposed to two or more infections), and for T. gondii and O. volvulus co-infection, their combined effect on the prevalence of ACE, as determined by the relative excess risk due to interaction (RERI), was more than additive (T. gondii and O. volvulus, RERI = 1.19). The prevalence of T. solium antibodies was low (2.8% of cases and 2.2% of controls) and was not associated with ACE in the study areas. Conclusion: This study investigates how the degree of exposure to parasites and multiple parasitic infections are associated with ACE and may explain conflicting results obtained when only seropositivity is considered. The findings from this study should be further validated.
    PLoS neglected tropical diseases. 05/2014; 8(5).
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    ABSTRACT: Under-five mortality has been declining rapidly in a number of sub-Saharan African settings. Malaria-related mortality is known to be a major component of childhood causes of death and malaria remains a major focus of health interventions. The paper explored the contribution of malaria relative to other specific causes of under-five deaths to these trends.
    Malaria Journal 05/2014; 13(1):180. · 3.49 Impact Factor
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    ABSTRACT: The precise nature of the relationship between malaria mortality and levels of transmission is unclear. Due to methodological limitations, earlier efforts to assess the linkage have lead to inconclusive results. The malaria transmission intensity and mortality burden across Africa (MTIMBA) project initiated by the INDEPTH Network collected longitudinally entomological data within a number of sites in sub-Saharan Africa to study this relationship. This work linked the MTIMBA entomology database with the routinely collected vital events within the Rufiji Demographic Surveillance System to analyse the transmission-mortality relation in the region. Bayesian Bernoulli spatio-temporal Cox proportional hazards models with village clustering, adjusted for age and insecticide-treated nets (ITNs), were fitted to assess the relation between mortality and malaria transmission measured by entomology inoculation rate (EIR). EIR was predicted at household locations using transmission models and it was incorporated in the model as a covariate with measure of uncertainty. Effects of covariates estimated by the model are reported as hazard ratios (HR) with 95% Bayesian confidence interval (BCI) and spatial and temporal parameters are presented. Separate analysis was carried out for neonates, infants and children 1-4 years of age. No significant relation between all-cause mortality and intensity of malaria transmission was indicated at any age in childhood. However, a strong age effect was shown. Comparing effects of ITN and EIR on mortality at different age categories, a decrease in protective efficacy of ITN was observed (i.e. neonates: HR = 0.65; 95% BCI: 0.39-1.05; infants: HR = 0.72; 95% BCI:0.48-1.07; children 1-4 years: HR = 0.88; 95% BCI: 0.62-1.23) and reduction on the effect of malaria transmission exposure was detected (i.e. neonates: HR = 1.15; 95% BCI:0.95-1.36; infants: HR = 1.13; 95% BCI:0.98-1.25; children 1-4 years: HR = 1.04; 95% BCI:0.89-1.18). A very strong spatial correlation was also observed. These results imply that assessing the malaria transmission-mortality relation involves more than the knowledge on the performance of interventions and control measures. This relation depends on the levels of malaria endemicity and transmission intensity, which varies significantly between different settings. Thus, sub-regions analyses are necessary to validate and assess reproducibility of findings.
    Malaria Journal 03/2014; 13(1):124. · 3.49 Impact Factor
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    ABSTRACT: Crude rates such as the crude death rate are functions of both the age-specific rates and the age composition of a population. However, differences in the age structure between two populations or two time periods can result in specious differences in the corresponding crude rates making direct comparisons between populations or across time inappropriate. Therefore, when comparing crude rates between populations, it is desirable to eliminate or minimize the influence of age composition. This task is accomplished by using a standard age structure yielding an age-standardized rate. This paper proposes an updated International Network for the Demographic Evaluation of Populations and Their Health (INDEPTH) standard for use in low- and middle-income countries (LMICs) based on newly available data from the health and demographic surveillance system site members of the INDEPTH network located throughout Africa and southern Asia. The updated INDEPTH standard should better reflect the age structure of LMICs and result in more accurate health indicators and demographic rates. We demonstrate use of the new INDEPTH standard along with several existing 'world' standards and show how resulting age-standardized crude deaths rates differ when using the various standard age compositions.
    Global Health Action 01/2014; 7:23286. · 2.06 Impact Factor
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    Francis Levira, Jim Todd, Honorati Masanja
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    ABSTRACT: Background : Prior to the scale-up of antiretroviral therapy (ART), demographic surveillance cohort studies showed higher mortality among migrants than residents in many rural areas. Objectives : This study quantifies the overall and AIDS-specific mortality between migrants and residents prior to ART, during ART scale-up, and after widespread availability of ART in Rufiji district in Tanzania. Design : In Health and Demographic Surveillance System (HDSS), the follow-up of individuals aged 15-59 years was categorized into three periods: before ART (1998-2003), during ART scale-up (2004-2007), and after widespread availability of ART (2008-2011). Residents were those who never migrated within and beyond HDSS, internal migrants were those who moved within the HDSS, and external migrants were those who moved into the HDSS from outside. Mortality rates were estimated from deaths and person-years of observations calculated in each time period. Hazard ratios were estimated to compare mortality between migrants and residents. AIDS deaths were identified from verbal autopsy, and the odds ratio of dying from AIDS between migrants and residents was estimated using the multivariate logistic regression model. Results : Internal and external migrants experienced higher overall mortality than residents before the introduction of ART. After widespread availability of ART overall mortality were similar for internal and external migrants. These overall mortality experiences observed were similar for males and females. In the multivariate logistic regression model, adjusting for age, sex, education, and social economic status, internal migrants had similar likelihood of dying from AIDS as residents (adjusted odds ratio [AOR]=1.14, 95% confidence interval [CI]: 0.70-1.87) while external migrants were 70% more likely to die from AIDS compared to residents prior to the introduction of ART (AOR=1.70, 95% CI: 1.06-2.73). After widespread availability of ART with the same adjustment factors, the odds of dying from AIDS were similar for internal migrants and residents (AOR=1.56, 95% CI: 0.80-3.04) and external migrants and residents (AOR=1.42, 95% CI: 0.76-2.66). Conclusions : Availability of ART has reduced the number of HIV-infected migrants who would otherwise return home to die. This has reduced the burden on rural communities who had cared for the return external migrants.
    Global Health Action 01/2014; 7:22956. · 2.06 Impact Factor
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    Francis Levira, Jim Todd, Honorati Masanja
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    ABSTRACT: Background : Prior to the scale-up of antiretroviral therapy (ART), demographic surveillance cohort studies showed higher mortality among migrants than residents in many rural areas. Objectives : This study quantifies the overall and AIDS-specific mortality between migrants and residents prior to ART, during ART scale-up, and after widespread availability of ART in Rufiji district in Tanzania. Design : In Health and Demographic Surveillance System (HDSS), the follow-up of individuals aged 15-59 years was categorized into three periods: before ART (1998-2003), during ART scale-up (2004-2007), and after widespread availability of ART (2008-2011). Residents were those who never migrated within and beyond HDSS, internal migrants were those who moved within the HDSS, and external migrants were those who moved into the HDSS from outside. Mortality rates were estimated from deaths and person-years of observations calculated in each time period. Hazard ratios were estimated to compare mortality between migrants and residents. AIDS deaths were identified from verbal autopsy, and the odds ratio of dying from AIDS between migrants and residents was estimated using the multivariate logistic regression model. Results : Internal and external migrants experienced higher overall mortality than residents before the introduction of ART. After widespread availability of ART overall mortality were similar for internal and external migrants. These overall mortality experiences observed were similar for males and females. In the multivariate logistic regression model, adjusting for age, sex, education, and social economic status, internal migrants had similar likelihood of dying from AIDS as residents (adjusted odds ratio [AOR]=1.14, 95% confidence interval [CI]: 0.70-1.87) while external migrants were 70% more likely to die from AIDS compared to residents prior to the introduction of ART (AOR=1.70, 95% CI: 1.06-2.73). After widespread availability of ART with the same adjustment factors, the odds of dying from AIDS were similar for internal migrants and residents (AOR=1.56, 95% CI: 0.80-3.04) and external migrants and residents (AOR=1.42, 95% CI: 0.76-2.66). Conclusions : Availability of ART has reduced the number of HIV-infected migrants who would otherwise return home to die. This has reduced the burden on rural communities who had cared for the return external migrants.
    Global Health Action 01/2014; 7:22956. · 2.06 Impact Factor
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    ABSTRACT: Mid-level cadres are being used to address human resource shortages in many African contexts, but insufficient and ineffective human resource management is compromising their performance. Supervision plays a key role in performance and motivation, but is frequently characterised by periodic inspection and control, rather than support and feedback to improve performance. This paper explores the perceptions of district health management teams in Tanzania and Malawi on their role as supervisors and on the challenges to effective supervision at the district level. This qualitative study took place as part of a broader project, "Health Systems Strengthening for Equity: The Power and Potential of Mid-Level Providers". Semi-structured interviews were conducted with 20 district health management team personnel in Malawi and 37 council health team members in Tanzania. The interviews covered a range of human resource management issues, including supervision and performance assessment, staff job descriptions and roles, motivation and working conditions. Participants displayed varying attitudes to the nature and purpose of the supervision process. Much of the discourse in Malawi centred on inspection and control, while interviewees in Tanzania were more likely to articulate a paradigm characterised by support and improvement. In both countries, facility level performance metrics dominated. The lack of competency-based indicators or clear standards to assess individual health worker performance were considered problematic. Shortages of staff, at both district and facility level, were described as a major impediment to carrying out regular supervisory visits. Other challenges included conflicting and multiple responsibilities of district health team staff and financial constraints. Supervision is a central component of effective human resource management. Policy level attention is crucial to ensure a systematic, structured process that is based on common understandings of the role and purpose of supervision. This is particularly important in a context where the majority of staff are mid-level cadres for whom regulation and guidelines may not be as formalised or well-developed as for traditional cadres, such as registered nurses and medical doctors. Supervision needs to be adequately resourced and supported in order to improve performance and retention at the district level.
    Human Resources for Health 09/2013; 11(1):43. · 1.83 Impact Factor
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    ABSTRACT: Complications of childbirth and pregnancy are leading causes of death among women of reproductive age. Developing countries account for 99% of maternal deaths. The aim of this study was to explore levels, causes and risk factors associated with maternal mortality in rural Tanzania. Longitudinal data (2002-2006) from Rufiji HDSS was used where a total of 26 427 women aged 15-49 years were included in the study; 64 died and there were 15 548 live births. Cox proportional hazards regression was used to assess the risk factors associated with maternal deaths. MMR was 412 per 100 000 live births. The main causes of death were haemorrhage (28%), eclampsia (19%) and puerperal sepsis (8%). An increased risk of 154% for maternal death was found for women aged 30-39 versus 15-19 years (HR=2.54, 95% CI=1.001-6.445). Married women had a protective effect of 62% over unmarried ones (HR=0.38, 95% CI=0.176-0.839).
    African Journal of Reproductive Health 09/2013; 17(3):119-30.
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    ABSTRACT: BACKGROUND: The prevalence of epilepsy in sub-Saharan Africa seems to be higher than in other parts of the world, but estimates vary substantially for unknown reasons. We assessed the prevalence and risk factors of active convulsive epilepsy across five centres in this region. METHODS: We did large population-based cross-sectional and case-control studies in five Health and Demographic Surveillance System centres: Kilifi, Kenya (Dec 3, 2007-July 31, 2008); Agincourt, South Africa (Aug 4, 2008-Feb 27, 2009); Iganga-Mayuge, Uganda (Feb 2, 2009-Oct 30, 2009); Ifakara, Tanzania (May 4, 2009-Dec 31, 2009); and Kintampo, Ghana (Aug 2, 2010-April 29, 2011). We used a three-stage screening process to identify people with active convulsive epilepsy. Prevalence was estimated as the ratio of confirmed cases to the population screened and was adjusted for sensitivity and attrition between stages. For each case, an age-matched control individual was randomly selected from the relevant centre's census database. Fieldworkers masked to the status of the person they were interviewing administered questionnaires to individuals with active convulsive epilepsy and control individuals to assess sociodemographic variables and historical risk factors (perinatal events, head injuries, and diet). Blood samples were taken from a randomly selected subgroup of 300 participants with epilepsy and 300 control individuals from each centre and were screened for antibodies to Toxocara canis, Toxoplasma gondii, Onchocerca volvulus, Plasmodium falciparum, Taenia solium, and HIV. We estimated odds ratios (ORs) with logistic regression, adjusted for age, sex, education, employment, and marital status. RESULTS: 586 607 residents in the study areas were screened in stage one, of whom 1711 were diagnosed as having active convulsive epilepsy. Prevalence adjusted for attrition and sensitivity varied between sites: 7·8 per 1000 people (95% CI 7·5-8·2) in Kilifi, 7·0 (6·2-7·4) in Agincourt, 10·3 (9·5-11·1) in Iganga-Mayuge, 14·8 (13·8-15·4) in Ifakara, and 10·1 (9·5-10·7) in Kintampo. The 1711 individuals with the disorder and 2032 control individuals were given questionnaires. In children (aged <18 years), the greatest relative increases in prevalence were associated with difficulties feeding, crying, or breathing after birth (OR 10·23, 95% CI 5·85-17·88; p<0·0001); abnormal antenatal periods (2·15, 1·53-3·02; p<0·0001); and head injury (1·97, 1·28-3·03; p=0·002). In adults (aged ≥18 years), the disorder was significantly associated with admission to hospital with malaria or fever (2·28, 1·06-4·92; p=0·036), exposure to T canis (1·74, 1·27-2·40; p=0·0006), exposure to T gondii (1·39, 1·05-1·84; p=0·021), and exposure to O volvulus (2·23, 1·56-3·19; p<0·0001). Hypertension (2·13, 1·08-4·20; p=0·029) and exposure to T solium (7·03, 2·06-24·00; p=0·002) were risk factors for adult-onset disease. INTERPRETATION: The prevalence of active convulsive epilepsy varies in sub-Saharan Africa and that the variation is probably a result of differences in risk factors. Programmes to control parasitic diseases and interventions to improve antenatal and perinatal care could substantially reduce the prevalence of epilepsy in this region. FUNDING: Wellcome Trust, University of the Witwatersrand, and South African Medical Research Council.
    The Lancet Neurology 01/2013; · 23.92 Impact Factor
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    ABSTRACT: Background: Disparities in health outcomes between the poor and the better off are increasingly attracting attention from researchers and policy makers. However, policies aimed at reducing inequity need to be based on evidence of their nature, magnitude, and determinants. Objectives: The study aims to investigate the relationship between household socio-economic status (SES) and under-five mortality, and to measure health inequality by comparing poorest/least poor quintile mortality rate ratio and the use of a mortality concentration index. It also aims to describe the risk factors associated with under-five mortality at Rufiji Demographic Surveillance Site (RDSS), Tanzania. Methods: This analytical cross sectional study included 11,189 children under-five residing in 7,298 households in RDSS in 2005. Principal component analysis was used to construct household SES. Kaplan-Meier survival incidence estimates were used for mortality rates. Health inequality was measured by calculating and comparing mortality rates between the poorest and least poor wealth quintile. We also computed a mortality concentration index. Risk factors of child mortality were assessed using Poisson regression taking into account potential confounders. Results: Under-five mortality was 26.9 per 1,000 person-years [95% confidence interval (CI) (23.7-30.4)]. The poorest were 2.4 times more likely to die compared to the least poor. Our mortality concentration index [-0.16; 95% CI (-0.24, -0.08)] indicated considerable health inequality. Least poor households had a 52% reduced mortality risk [incidence rate ratio (IRR) = 0.48; 95% CI 0.30-0.80]. Furthermore, children with mothers who had attained secondary education had a 70% reduced risk of dying compared to mothers with no education [IRR = 0.30; 95% CI (0.22-0.88)]. Conclusion: Household socio-economic inequality and maternal education were associated with under-five mortality in the RDSS. Targeted interventions to address these factors may contribute towards accelerating the reduction of child mortality in rural Tanzania.Appendices available online under Reading Tools.
    Global Health Action 01/2013; 6:1-8. · 2.06 Impact Factor
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    ABSTRACT: Millennium Development Goal (MDG) 5 commits us to reducing maternal mortality rates by three quarters and MDG 4 commits us to reducing child mortality by two-thirds between 1990 and 2015. In order to reach these goals, greater access to basic emergency obstetric care (EmOC) as well as comprehensive EmOC which includes safe Caesarean section, is needed.. The limited capacity of health systems to meet demand for obstetric services has led several countries to utilize mid-level cadres as a substitute to more extensively trained and more internationally mobile healthcare workers. Although this does provide greater capacity for service delivery, concern about the performance and motivation of these workers is emerging. We propose that poor leadership characterized by inadequate and unstructured supervision underlies much of the dissatisfaction and turnover that has been shown to exist amongst these mid-level healthcare workers and indeed health workers more generally. To investigate this, we conducted a large-scale survey of 1,561 mid-level cadre healthcare workers (health workers trained for shorter periods to perform specific tasks e.g. clinical officers) delivering obstetric care in Malawi, Tanzania, and Mozambique. Participants indicated the primary supervision method used in their facility and we assessed their job satisfaction and intentions to leave their current workplace. In all three countries we found robust evidence indicating that a formal supervision process predicted high levels of job satisfaction and low intentions to leave. We find no evidence that facility level factors modify the link between supervisory methods and key outcomes. We interpret this evidence as strongly supporting the need to strengthen leadership and implement a framework and mechanism for systematic supportive supervision. This will promote better job satisfaction and improve the retention and performance of obstetric care workers, something which has the potential to improve maternal and neonatal outcomes in the countdown to 2015.
    PLoS ONE 01/2013; 8(3):e58415. · 3.53 Impact Factor
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    ABSTRACT: Objective : Verbal autopsy (VA) is a systematic approach for determining causes of death (CoD) in populations without routine medical certification. It has mainly been used in research contexts and involved relatively lengthy interviews. Our objective here is to describe the process used to shorten, simplify, and standardise the VA process to make it feasible for application on a larger scale such as in routine civil registration and vital statistics (CRVS) systems. Methods : A literature review of existing VA instruments was undertaken. The World Health Organization (WHO) then facilitated an international consultation process to review experiences with existing VA instruments, including those from WHO, the Demographic Evaluation of Populations and their Health in Developing Countries (INDEPTH) Network, InterVA, and the Population Health Metrics Research Consortium (PHMRC). In an expert meeting, consideration was given to formulating a workable VA CoD list [with mapping to the International Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) CoD] and to the viability and utility of existing VA interview questions, with a view to undertaking systematic simplification. Findings : A revised VA CoD list was compiled enabling mapping of all ICD-10 CoD onto 62 VA cause categories, chosen on the grounds of public health significance as well as potential for ascertainment from VA. A set of 221 indicators for inclusion in the revised VA instrument was developed on the basis of accumulated experience, with appropriate skip patterns for various population sub-groups. The duration of a VA interview was reduced by about 40% with this new approach. Conclusions : The revised VA instrument resulting from this consultation process is presented here as a means of making it available for widespread use and evaluation. It is envisaged that this will be used in conjunction with automated models for assigning CoD from VA data, rather than involving physicians.
    Global Health Action 01/2013; 6:21518. · 2.06 Impact Factor
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    ABSTRACT: To analyse antiretroviral treatment (ART) knowledge and HIV- and ART-related stigma among the adult population in a rural Tanzanian community. Population-based cross-sectional survey of 694 adults (15-49 years of age). Latent class analysis (LCA) categorized respondents' levels of ART knowledge and of ART-related stigma. Multinomial logistic regression assessed the association between the levels of ART knowledge and HIV- and ART-related stigma, while controlling for the effects of age, gender, education, marital status and occupation. More than one-third of men and women in the study reported that they had never heard of ART. Among those who had heard of ART, 24% were east informed about ART, 8% moderately informed, and 68% highly informed. Regarding ART-related stigma, 28% were least stigmatizing, 41% moderately stigmatizing, and 31% highly stigmatizing toward persons taking ART. Respondents that had at least primary education were more likely to have high levels of knowledge about ART (OR 3.09, 95% CI 1.61-5.94). Participants highly informed about ART held less HIV- and ART-related stigma towards ART patients (OR 0.26, 95% CI 0.09-0.74). The lack of ART knowledge is broad, and there is a strong association between ART knowledge and individual education level. These are relevant findings for both HIV prevention and HIV treatment program interventions that address ART-related stigma across the entire spectrum of the community.
    PLoS ONE 01/2013; 8(1):e53993. · 3.53 Impact Factor
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    ABSTRACT: BACKGROUND: Poorly spaced pregnancies have been documented worldwide to result in adverse maternal and child health outcomes. The World Health Organization (WHO) recommends a minimum inter-birth interval of 33 months between two consecutive live births in order to reduce the risk of adverse maternal and child health outcomes. However, birth spacing practices in many developing countries, including Tanzania, remain scantly addressed. METHODS: Longitudinal data collected in the Rufiji Health and Demographic Surveillance System (HDSS) from January 1999 to December 2010 were analyzed to investigate birth spacing practices among women of childbearing age. The outcome variable, non-adherence to the minimum inter-birth interval, constituted all inter-birth intervals <33 months long. Inter-birth intervals >=33 months long were considered to be adherent to the recommendation. Chi-Square was used as a test of association between non-adherence and each of the explanatory variables. Factors affecting non-adherence were identified using a multilevel logistic model. Data analysis was conducted using STATA (11) statistical software. RESULTS: A total of 15,373 inter-birth intervals were recorded from 8,980 women aged 15--49 years in Rufiji district over the follow-up period of 11 years. The median inter-birth interval was 33.4 months. Of the 15,373 inter-birth intervals, 48.4% were below the WHO recommended minimum length of 33 months between two live births. Non-adherence was associated with younger maternal age, low maternal education, multiple births of the preceding pregnancy, non-health facility delivery of the preceding birth, being an in-migrant resident, multi-parity and being married. CONCLUSION: Generally, one in every two inter-birth intervals among 15--49 year-old women in Rufiji district is poorly spaced, with significant variations by socio-demographic and behavioral characteristics of mothers and newborns. Maternal, newborn and child health services should be improved with a special emphasis on community- and health facility-based optimum birth spacing education in order to enhance health outcomes of mothers and their babies, especially in rural settings.
    BMC Pregnancy and Childbirth 12/2012; 12(1):152. · 2.52 Impact Factor
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    ABSTRACT: Lack of birth and death registries in most of developing countries, particularly those in sub-Saharan Africa led to the establishment of Demographic Surveillance Systems (DSS) sites which monitor large population cohorts within defined geographical areas. DSS collects longitudinal data on migration, births, deaths and their causes via verbal autopsies. DSS data provide an opportunity to monitor many health indicators including mortality trends. Mortality rates in Sub-Sahara Africa show seasonal patterns due to high infant and child malaria-related mortality which is influenced by seasonal features present in environmental and climatic factors. However, it is unclear whether seasonal patterns differ by age in the first few months of life. This study provides an overview of approaches to assess, capture and detect seasonality peaks and patterns in mortality using the infant mortality data from the Rufiji DSS, Tanzania. Seasonality was best captured using Bayesian negative binomial models with time and cycle dependent seasonal parameters and autoregressive temporal error terms. Seasonal patterns are similar among different age groups during infancy and timing of their mortality peaks do not differ. Seasonality in mortality rates with two peaks per year is pronounced which corresponds to rainy seasons. Understanding of these trends is important for public health preparedness.
    Acta tropica 12/2012; · 2.79 Impact Factor
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    ABSTRACT: Vitamin A supplementation of 6-59 month old children is currently recommended by the World Health Organization based on evidence that it reduces mortality. There has been considerable interest in determining the benefits of neonatal vitamin A supplementation, but the results of existing trials are conflicting. A technical consultation convened by WHO pointed to the need for larger scale studies in Asia and Africa to inform global policy on the use of neonatal vitamin A supplementation. Three trials were therefore initiated in Ghana, India and Tanzania to determine if vitamin A supplementation (50,000 IU) given to neonates once orally on the day of birth or within the next two days will reduce mortality in the period from supplementation to 6 months of age compared to placebo. The trials are individually randomized, double masked, and placebo controlled. The required sample size is 40,200 in India and 32,000 each in Ghana and Tanzania. The study participants are neonates who fulfil age eligibility, whose families are likely to stay in the study area for the next 6 months, who are able to feed orally, and whose parent(s) provide informed written consent to participate in the study. Neonates randomized to the intervention group receive 50,000 IU vitamin A and the ones randomized to the control group receive placebo at the time of enrollment. Mortality and morbidity information are collected through periodic home visits by a study worker during infancy. The primary outcome of the study is mortality from supplementation to 6 months of age. The secondary outcome of the study is mortality from supplementation to 12 months of age. The three studies will be analysed independent of each other. Subgroup analysis will be carried out to determine the effect by birth weight, sex, and timing of DTP vaccine, socioeconomic groups and maternal large-dose vitamin A supplementation. The three ongoing studies are the largest studies evaluating the efficacy of vitamin A supplementation to neonates. Policy formulation will be based on the results of efficacy of the intervention from the ongoing randomized controlled trials combined with results of previous studies.
    Trials 02/2012; 13:22. · 2.21 Impact Factor
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    ABSTRACT: Injuries rank high among the leading causes of death and disability annually, injuring over 50 million and killing over 5 million people globally. Approximately 90% of these deaths occur in developing countries. To estimate and identify the risk factors for injury mortality in the Rufiji Health and Demographic Surveillance System (RHDSS) in Tanzania. Secondary data from the RHDSS covering the period 2002 and 2007 was examined. Verbal autopsy data was used to determine the causes of death based on the 10th revision of the International Classification of Diseases (ICD-10). Trend and Poisson regression tests were used to investigate the associations between risk factors and injury mortality. The overall crude injury death rate was 33.4/100 000 population. Injuries accounted for 4% of total deaths. Men were three times more likely to die from injuries compared with women (adjusted IRR (incidence risk ratios)=3.04, p=0.001, 95% CI (2.22 to 4.17)). The elderly (defined as 65+) were 2.8 times more likely to die from injuries compared with children under 15 years of age (adjusted IRR=2.83, p=0.048, 95% CI (1.01 to 7.93)). The highest frequency of deaths resulted from road traffic crashes. Injury is becoming an important cause of mortality in the Rufiji district. Injury mortality varied by age and gender in this area. Most injuries are preventable, policy makers need to institute measures to address the issue.
    BMJ Open 01/2012; 2(6). · 1.58 Impact Factor
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    ABSTRACT: Background: Major improvements are required in the coverage and quality of essential childhood interventions to achieve Millennium Development Goal Four (MDG 4). Long distance to health facilities is one of the known barriers to access. We investigated the effect of networked and Euclidean distances from home to formal health facilities on childhood mortality in rural Tanzania between 2005 and 2007. Methods: A secondary analysis of data from a cohort of 28,823 children younger than age 5 between 2005 and 2007 from Ifakara Health and Demographic Surveillance System was carried out. Both Euclidean and networked distances from the household to the nearest health facility were calculated using geographical information system methods. Cox proportional hazard regression models were used to investigate the effect of distance from home to the nearest health facility on child mortality. Results: Children who lived in homes with networked distance >5 km experienced approximately 17% increased mortality risk (HR=1.17; 95% CI 1.02-1.38) compared to those who lived <5 km networked distance to the nearest health facility. Death of a mother (HR=5.87; 95% CI 4.11-8.40), death of preceding sibling (HR=1.9; 95% CI 1.37-2.65), and twin birth (HR=2.9; 95% CI 2.27-3.74) were the strongest independent predictors of child mortality. Conclusions: Physical access to health facilities is a determinant of child mortality in rural Tanzania. Innovations to improve access to health facilities coupled with birth spacing and care at birth are needed to reduce child deaths in rural Tanzania.
    Global Health Action 01/2012; 5:1-9. · 2.06 Impact Factor
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    ABSTRACT: Background: Weather and climate changes are associated with a number of immediate and long-term impacts on human health that occur directly or indirectly, through mediating variables. Few studies to date have established the empirical relationship between monthly weather and mortality in sub-Saharan Africa. Objectives: The objectives of this study were to assess the association between monthly weather (temperature and rainfall) on all-cause mortality by age in Rufiji, Tanzania, and to determine the differential susceptibility by age groups. Methods: We used mortality data from Rufiji Health and Demographic Surveillance System (RHDSS) for the period 1999 to 2010. Time-series Poisson regression models were used to estimate the association between monthly weather and mortality adjusted for long-term trends. We used a distributed lag model to estimate the delayed association of monthly weather on mortality. We stratified the analyses per age group to assess susceptibility. Results: In general, rainfall was found to have a stronger association in the age group 0-4 years (RR=1.001, 95% CI=0.961-1.041) in both short and long lag times, with an overall increase of 1.4% in mortality risk for a 10 mm rise in rainfall. On the other hand, monthly average temperature had a stronger association with death in all ages while mortality increased with falling monthly temperature. The association per age group was estimated as: age group 0-4 (RR=0.934, 95% CI=0.894-0.974), age group 5-59 (RR=0.956, 95% CI=0.928-0.985) and age group over 60 (RR=0.946, 95% CI=0.912-0.979). The age group 5-59 experienced more delayed lag associations. This suggests that children and older adults are most sensitive to weather related mortality. Conclusion: These results suggest that an early alert system based on monthly weather information may be useful for disease control management, to reduce and prevent fatal effects related to weather and monthly weather.
    Global Health Action 01/2012; 5:1-11. · 2.06 Impact Factor
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    ABSTRACT: Background: Malaria transmission is measured using entomological inoculation rate (EIR), number of infective mosquito bites/person/unit time. Understanding heterogeneity of malaria transmission has been difficult due to a lack of appropriate data. A comprehensive entomological database compiled by the Malaria Transmission Intensity and Mortality Burden across Africa (MTIMBA) project (2001-2004) at several sites is the most suitable dataset for studying malaria transmission-mortality relations. The data are sparse and large, with small-scale spatial-temporal variation. Objective: This work demonstrates a rigorous approach for analysing large and highly variable entomological data for the study of malaria transmission heterogeneity, measured by EIR, within the Rufiji Demographic Surveillance System (DSS), MTIMBA project site in Tanzania. Design: Bayesian geostatistical binomial and negative binomial models with zero inflation were fitted for sporozoite rates (SRs) and mosquito density, respectively. The spatial process was approximated from a subset of locations. The models were adjusted for environmental effects, seasonality and temporal correlations and assessed based on their predictive ability. EIR was calculated using model-based predictions of SR and density. Results: Malaria transmission was mostly influenced by rain and temperature, which significantly reduces the probability of observing zero mosquitoes. High transmission was observed at the onset of heavy rains. Transmission intensity reduced significantly during Year 2 and 3, contrary to the Year 1, pronouncing high seasonality and spatial variability. The southern part of the DSS showed high transmission throughout the years. A spatial shift of transmission intensity was observed where an increase in households with very low transmission intensity and significant reduction of locations with high transmission were observed over time. Over 68 and 85% of the locations selected for validation for SR and density, respectively, were correctly predicted within 95% credible interval indicating good performance of the models. Conclusion: Methodology introduced here has the potential for efficient assessment of the contribution of malaria transmission in mortality and monitoring performance of control and intervention strategies.
    Spatial and Spatio-temporal Epidemiology 01/2012; submitted:-.

Publication Stats

1k Citations
244.23 Total Impact Points

Institutions

  • 2010–2014
    • Ifakara Health Institute
      Dār es Salām, Dar es Salaam, Tanzania
  • 2005
    • Swiss Tropical and Public Health Institute
      • Department of Epidemiology and Public Health
      Basel, BS, Switzerland
  • 1998–1999
    • National Institute for Medical Research (NIMR)
      Dār es Salām, Dar es Salaam, Tanzania
  • 1996–1998
    • Hospital Clínic de Barcelona
      Barcino, Catalonia, Spain