Assessment of a national voucher scheme to deliver insecticide-treated mosquito nets to pregnant women

Background

The benefits of a health-related intervention may be compromised by the challenges of delivering the intervention on a large scale. We analyzed the process involved in the Tanzania National Voucher Scheme, a system for delivering insecticide-treated mosquito nets to pregnant women. We aimed to identify potential ways to equitably improve overall coverage of the intervention.

Methods

We defined five steps in the process. We collected data from a multistage cluster survey of nationally representative households conducted in 2007 across 21 districts in Tanzania. Using these data, we multiplied the rate of success of each step cumulatively to estimate the overall success of the system.

Results

The rate of coverage for use of insecticide-treated nets among pregnant women was 23% (95% confidence interval [CI] 19%–27%). We observed large differences in coverage by socio-economic status, from 7% (95% CI 4%–13%) among participants in the poorest households to 48% (95% CI 38%–59%) among those in the richest households. The rate of success of each step in the process was high (60%–98%). However, the cumulative rate of success for the process as a whole was low (30%). The largest and most inequitable reduction in coverage occurred in the step involving treatment of nets with insecticide.

Interpretation

The cumulative effect of modest attrition at several steps in the process substantially diminished the overall rate of coverage for all women, but most markedly among the poorest participants. Analysis of the process suggests that delivery of nets treated with long-lasting insecticide rather than untreated nets packaged with an insecticide-treatment kit could result in an improvement in coverage of 22 percentage points, from 30% to 52%.Systems designed to deliver health-related interventions on a large scale re quire a number of operational steps to reach targeted groups. Some people will not be reached at each step because of attrition, which creates a staircase effect of diminishing effectiveness at the population level.^1,2 This cumulative effect may be further pronounced among people in poor households, because they may be more likely than those in wealthier households to drop out at each step.³We investigated the impact of reductions in coverage on the effectiveness of a national multistep system in Tanzania to deliver insecticide-treated mosquito nets to pregnant women. The use of such nets has been shown to reduce childhood mortality by 17% across different African settings.⁴ When used by pregnant women, these nets have been associated with a reduction of 38% in the incidence of maternal malaria parasitemia, of 47% in the incidence of severe malarial anemia and of 28% in the prevalence of infants with low birth weights.⁵All socio-economic groups are susceptible to malaria.⁶ However, there can be large socio-economic inequities in knowledge of the risks associated with infection, in access to prevention and treatment, and in ability to pay for prevention and treatment.⁷ Over the last 10 years, political commitment to achieve high and equitable coverage for the delivery of insecticide-treated nets has grown. Many countries in sub-Saharan Africa have committed to the target set at a meeting in Abuja, Nigeria, in 2000 to increase coverage among children and pregnant women to at least 60%, a target recently increased to 80% by 2010.⁸ However, progress has been slow: coverage among children under five years of age in malaria-endemic regions of Africa was estimated to be less than 20% in 2007.⁹Since 2006, Tanzania has implemented a discount voucher system on a national level to deliver insecticide-treated nets to pregnant women. Although relatively simple, the process involves a sequence of five steps that include the woman attending an antenatal clinic, obtaining a voucher there, using the voucher to buy a mosquito net packaged with insecticide, treating the net with the insecticide and, finally, using the net. Each step depends on the success of the previous one. At each point, a pregnant woman may drop out of the process and end up unprotected. If we assume hypothetically that 90% of women are reached at each step, the coverage would be only 59% (100 × 0.9 × 0.9 × 0.9 × 0.9 × 0.9 = 59). Furthermore, there are likely to be socio- economic differences that give rise to an “equity gap” at each step.We conducted this study to analyze the processes involved in the Tanzanian discount voucher system. Using survey data collected as part of the program for monitoring and evaluating the system, we calculated the cumulative success of the system for different socio-economic groups. We also explored opportunities to improve the system.     

Safety of insecticide-treated mosquito nets for infants and their mothers: randomized controlled community trial in Burkina Faso

The Asia Pacific Malaria Elimination Network (APMEN) is a collaboration of 18 country partners committed to eliminating malaria from within their borders. Over the past 5 years, APMEN has helped to build the knowledge, tools and in-country technical expertise required to attain this goal. At its inaugural meeting in Brisbane in 2009, Plasmodium vivax infections were identified across the region as a common threat to this ambitious programme; the APMEN Vivax Working Group was established to tackle specifically this issue. The Working Group developed a four-stage strategy to identify knowledge gaps, build regional consensus on shared priorities, generate evidence and change practice to optimize malaria elimination activities. This case study describes the issues faced and the solutions found in developing this robust strategic partnership between national programmes and research partners within the Working Group. The success of the approach adopted by the group may facilitate similar applications in other regions seeking to deploy evidence-based policy and practice.     

Mutual benefits of associations between breeding and non-breeding White-fronted Geese Anser albifrons

The relationships between yearlings and adult pairs of White-fronted Geese Anser albifrons were studied during pre-nesting, laying and early incubation in the central Canadian Arctic. Prior to nesting, females of lone pairs spent 75–81% of their time feeding, while males spent only 42–47% of time feeding and 46–50% alert. In pairs with one or more associated yearlings, both females and males fed significantly more and spent less time vigilant. Yearlings spent significantly less time (59%) feeding when alone compared with 71–76% when with pairs. Associations between yearlings and paired adults were most frequent before adult females began prospecting for nest sites. No prospecting pairs were associated with yearlings. After the egg-laying period, groups of geese, predominantly yearlings, made distraction flights over humans and terrestrial predators approaching nests, in contrast to the more cryptic behaviour of nesting pairs. The presence of groups of geese associated with some nest sites suggests that continuing parent-offspring relationships may involve assistance with nest defence.     

Internal standard-based analysis of microarray data2--analysis of functional associations between HVE-genes

In this work we apply the Internal Standard-based analytical approach that we described in an earlier communication and here we demonstrate experimental results on functional associations among the hypervariably-expressed genes (HVE-genes). Our working assumption was that those genetic components, which initiate the disease, involve HVE-genes for which the level of expression is undistinguishable among healthy individuals and individuals with pathology. We show that analysis of the functional associations of the HVE-genes is indeed suitable to revealing disease-specific differences. We show also that another possible exploit of HVE-genes for characterization of pathological alterations is by using multivariate classification methods. This in turn offers important clues on naturally occurring dynamic processes in the organism and is further used for dynamic discrimination of groups of compared samples. We conclude that our approach can uncover principally new collective differences that cannot be discerned by individual gene analysis.     

Provision of preventive health care in systemic lupus erythematosus: data from a large observational cohort study

Introduction  

Cancer and infections are leading causes of mortality in systemic lupus erythematosus (SLE) after diseases of the circulatory system, and therefore preventing these complications is important. In this study, we examined two categories of preventive services in SLE: cancer surveillance (cervical, breast, and colon) and immunizations (influenza and pneumococcal). We compared the receipt of these services in SLE to the general population, and identified subgroups of patients who were less likely to receive these services.     

Increasing coverage of insecticide-treated nets in rural Nigeria: implications of consumer knowledge, preferences and expenditures for malaria prevention

Background

The coverage of insecticide-treated nets (ITNs) remains low despite existing distribution strategies, hence, it was important to assess consumers' preferences for distribution of ITNs, as well as their perceptions and expenditures for malaria prevention and to examine the implications for scaling-up ITNs in rural Nigeria.

Methods

Nine focus group discussions (FGDs) and questionnaires to 798 respondents from three malaria hyper-endemic villages from Enugu state, south-east Nigeria were the study tools.

Results

There was a broad spectrum of malaria preventive tools being used by people. The average monthly expenditure on malaria prevention per household was 55.55 Naira ($0.4). More than 80% of the respondent had never purchased any form of untreated mosquito net. People mostly preferred centralized community-based sales of the ITNS, with instalment payments.

Conclusion

People were knowledgeable about malaria and the beneficial effects of using nets to protect themselves from the disease. The mostly preferred community-based distribution of ITNs implies that the strategy is a potential untapped additional channel for scaling-up ITNs in Nigeria and possibly other parts of sub-Saharan Africa.     

The Anopheles gambiae cE5 salivary protein: a sensitive biomarker to evaluate the efficacy of insecticide-treated nets in malaria vector control

Evaluation of vector control is crucial for improving malaria containment and, according to World Health Organization, new complementary indicators would be very valuable. In this study the IgG response to the Anopheles-specific cE5 salivary protein was tested as a tool to evaluate the efficacy of insecticide-treated nets in reducing human exposure to malaria vectors. Sera collected during a longitudinal study carried out in Angola, and including entomological and parasitological data, were used to assess the IgG response to the Anopheles gambiae cE5 in both children and adults, before and after the application of insecticide-treated nets. Seasonal fluctuation of specific IgG antibody levels according to exposure was only found in children (up to ≈14 years old) whose anti-cE5 IgG response dropped after bed nets installation. These results were fully consistent with previous findings obtained with the same set of sera and indicating a substantial reduction of human-vector contact shortly after nets implementation. Overall, children IgG response to the cE5 protein appeared a very sensitive biomarker, which allowed for the detection of even weak exposure to Anopheles bites, indicating it may represent a reliable additional tool to evaluate the efficacy of vector control interventions.     

Effects of stratification in the analysis of affected-sib-pair data: benefits and costs

The benefits and costs of stratification of affected-sib-pair (ASP) data were examined in three situations: (1) when there is no difference in identity-by-descent (IBD) allele sharing between stratified and unstratified ASP data sets; (2) when there is an increase in IBD allele sharing in one of the stratified groups; and (3) when the data are stratified on the basis of IBD allele-sharing status at one locus, and the stratified ASPs are then analyzed for linkage at a second locus. When there is no difference in IBD sharing between strata, a penalty is always paid for stratifying the data. The loss of power to detect linkage in the stratified ASP data sets is the result of multiple testing and the smaller sample size within individual strata. In the case in which etiologic heterogeneity (i.e., severity of phenotype, age at onset) represents genetic heterogeneity, the power to detect linkage can be increased by stratifying the ASP data. This benefit is obtained when there is sufficient IBD allele sharing and sample sizes. Once linkage has been established for a given locus, data can be stratified on the basis of IBD status at this locus and can be tested for linkage at a second locus. When the relative risk is in the vicinity of 1, the power to detect linkage at the second locus is always greater for the unstratified ASP data set. Even for values of the relative risk that diverge sufficiently from 1, with adequate sample sizes and IBD allele sharing, the benefits of stratifying ASP data are minimal.     

Phylogenetic analysis of RAD‐seq data: examining the influence of gene genealogy conflict on analysis of concatenated data

One of the major issues in phylogenetic analysis is that gene genealogies from different gene regions may not reflect the true species tree or history of speciation. This has led to considerable debate about whether concatenation of loci is the best approach for phylogenetic analysis. The application of Next‐generation sequencing techniques such as RAD‐seq generates thousands of relatively short sequence reads from across the genomes of the sampled taxa. These data sets are typically concatenated for phylogenetic analysis leading to data sets that contain millions of base pairs per taxon. The influence of gene region conflict among so many loci in determining the phylogenetic relationships among taxa is unclear. We simulated RAD‐seq data by sampling 100 and 500 base pairs from alignments of over 6000 coding regions that each produce one of three highly supported alternative phylogenies of seven species of Drosophila. We conducted phylogenetic analyses on different sets of these regions to vary the sampling of loci with alternative gene trees to examine the effect on detecting the species tree. Irrespective of sequence length sampled per region and which subset of regions was used, phylogenetic analyses of the concatenated data always recovered the species tree. The results suggest that concatenated alignments of Next‐generation data that consist of many short sequences are robust to gene tree/species tree conflict when the goal is to determine the phylogenetic relationships among taxa.     

Honey and obesity-related dysfunctions: a summary on health benefits

Honey is a natural product, containing flavonoids and phenolic acids, appreciated for its therapeutic abilities since ancient times. Although the bioactive potential is linked to the composition, that is variable depending on mainly the botanical origin, honey has antioxidant and anti-inflammatory properties. Therefore, honey, administered alone or in combination with conventional therapy, might result useful in the management of chronic diseases that are commonly associated with oxidative stress and inflammation state. Obesity is a metabolic disorder characterized by visceral adiposity. The adipose tissue becomes hypertrophic and undergoes hyperplasia, resulting in a hypoxic environment, oxidative stress and production of pro-inflammatory mediators that can be responsible for other disorders, such as metabolic syndrome and neurodegeneration. Experimental evidence from animals have shown that honey improves glycemic control and lipid profile with consequent protection from endothelial dysfunction and neurodegeneration. The purpose of the present review is to summarize the current literature concerning the beneficial effects of honey in the management of the obesity-related dysfunctions, including neurodegeneration. Based on the key constituents of honey, the paper also highlights polyphenols to be potentially responsible for the health benefits of honey. Further well-designed and controlled studies are necessary to validate these benefits in humans.     

One-year health status outcomes of unstable angina versus myocardial infarction: a prospective, observational cohort study of ACS survivors

Background

Unstable angina (UA) patients have lower mortality and reinfarction risks than ST-elevation (STEMI) or non-ST elevation myocardial infarction (NSTEMI) patients and, accordingly, receive less aggressive treatment. Little is known, however, about the health status outcomes (angina, physical function, and quality of life) of UA versus MI patients among survivors of an ACS hospitalization.

Methods

In a cohort of 1,192 consecutively enrolled ACS survivors from two Kansas City hospitals, we evaluated the associations between ACS presentation (UA, NSTEMI, and STEMI) and one-year health status (angina, physical functioning and quality of life), one-year cardiac rehospitalization rates, and two-year mortality outcomes, using multivariable regression modeling.

Results

After multivariable adjustment for demographic, hospital, co-morbidity, baseline health status, and treatment characteristics, UA patients had a greater prevalence of angina at 1 year than STEMI patients (adjusted relative risk [RR] = 1.42; 95% CI [1.06, 1.90]) and similar rates as NSTEMI patients (adjusted RR = 1.1; 95% CI [0.85, 1.42]). In addition, UA patients fared no better than MI patients in Short Form-12 physical component scores (UA vs. STEMI score difference -0.05 points; 95% CI [-2.41, 2.3]; UA vs. NSTEMI score difference -1.91 points; 95% CI [-4.01, 0.18]) or Seattle Angina Questionnaire quality of life scores (UA vs. STEMI score difference -1.39 points; 95% CI [-5.63, 2.85]; UA vs. NSTEMI score difference -0.24 points 95% CI [-4.01, 3.54]). Finally, UA patients had similar rehospitalization rates as MI patients (UA vs. STEMI adjusted hazard ratio [HR] = 1.31; 95% CI [0.86, 1.99]; UA vs. NSTEMI adjusted HR = 1.03; 95% CI [0.73, 1.47]), despite better 2-year survival (UA vs. STEMI adjusted HR = 0.51; 95% confidence interval (CI) [0.28, 0.95]; UA vs. NSTEMI adjusted HR = 0.40; 95% CI [0.24, 0.65]).

Conclusion

Although UA patients have better survival rates, they have similar or worse one-year health status outcomes and cardiac rehospitalization rates as compared with MI patients. Clinicians should be aware of the adverse health status outcome risks for UA patients and consider close monitoring for the opportunity to improve their health status and minimize the need for subsequent rehospitalization.     

Bayesian data analysis in population ecology: motivations,methods, and benefits

During the 20th century ecologists largely relied on the frequentist system of inference for the analysis of their data. However, in the past few decades ecologists have become increasingly interested in the use of Bayesian methods of data analysis. In this article I provide guidance to ecologists who would like to decide whether Bayesian methods can be used to improve their conclusions and predictions. I begin by providing a concise summary of Bayesian methods of analysis, including a comparison of differences between Bayesian and frequentist approaches to inference when using hierarchical models. Next I provide a list of problems where Bayesian methods of analysis may arguably be preferred over frequentist methods. These problems are usually encountered in analyses based on hierarchical models of data. I describe the essentials required for applying modern methods of Bayesian computation, and I use real-world examples to illustrate these methods. I conclude by summarizing what I perceive to be the main strengths and weaknesses of using Bayesian methods to solve ecological inference problems.     

Temporal associations between weather and headache: analysis by empirical mode decomposition

Background

Patients frequently report that weather changes trigger headache or worsen existing headache symptoms. Recently, the method of empirical mode decomposition (EMD) has been used to delineate temporal relationships in certain diseases, and we applied this technique to identify intrinsic weather components associated with headache incidence data derived from a large-scale epidemiological survey of headache in the Greater Taipei area.

Methodology/Principal Findings

The study sample consisted of 52 randomly selected headache patients. The weather time-series parameters were detrended by the EMD method into a set of embedded oscillatory components, i.e. intrinsic mode functions (IMFs). Multiple linear regression models with forward stepwise methods were used to analyze the temporal associations between weather and headaches. We found no associations between the raw time series of weather variables and headache incidence. For decomposed intrinsic weather IMFs, temperature, sunshine duration, humidity, pressure, and maximal wind speed were associated with headache incidence during the cold period, whereas only maximal wind speed was associated during the warm period. In analyses examining all significant weather variables, IMFs derived from temperature and sunshine duration data accounted for up to 33.3% of the variance in headache incidence during the cold period. The association of headache incidence and weather IMFs in the cold period coincided with the cold fronts.

Conclusions/Significance

Using EMD analysis, we found a significant association between headache and intrinsic weather components, which was not detected by direct comparisons of raw weather data. Contributing weather parameters may vary in different geographic regions and different seasons.     

Comparison of breast-conserving surgery and mastectomy in early breast cancer using observational data revisited: a propensity score-matched analysis

Recent observational studies showed that breast-conserving surgery (BCS) resulted in superior survival compared to mastectomy in breast cancer patients. This study compared the clinical outcomes of BCS and mastectomy using propensity score (PS) matching analysis, which had advantages over conventional methods in reducing bias. Nonmetastatic breast cancer patients who underwent BCS and mastectomy were matched 1:1 based on their PS. We used the Kaplan-Meier method and Cox-regression model to estimate the treatment effects. A total of 2,866 patients with a median follow-up time of 67 months were included in the original study population. Although the mastectomy cohort (N=1,219) had more advanced disease compared to the BCS cohort (N=1,647), LRFS was similar between the two groups (93.8% vs. 92.4%, P>0.05). BCS (vs. mastectomy) was associated with improved DFS (73.8% vs. 58.7%, P<0.01) and CSS (91% vs. 78.2%, P<0.01) in the original population. In the PS-matched population (N=1,668), clinicopathological features were equally distributed between the two cohorts. BCS (vs. mastectomy) was not associated with improved DFS (70.7% vs. 66.9%, P>0.05) or CSS (87.5% vs. 84.9%, P>0.05). We found that PS methods reduce bias when estimating treatment effects using observational data. BCS and mastectomy show equivalent outcomes in nonmetastatic breast cancer patients.     

Naps and exercise: reinforcing a range of benefits for elderly health

According to the United Nations, in 2017, people aged 60 or over in the world, comprised 13 per cent of the global population. It is a fact that elderly people are keeping a health lifestyle, such as practicing physical exercises and avoiding excessive dosages of medications. However, this population is also more prone to have injuries while practicing exercises. Sleep architecture is physiologically different among elderly, and naps can be very beneficial to improve their mental and physical health. Thus, in this article, we encourage health professionals to recommend regular naps to this population, which could lead to an improve in their well-being and quality of life.     

Costs of reproduction in a lizard species: a comparison of observational and experimental data

Life history theory predicts that increasing investments into reproduction compromises survival and future reproduction. However, demonstrating such costs is confounded by positive correlations between life history traits. For example, individuals in good condition may be good at both surviving and reproducing. We studied such processes in a viviparous snow skink lizard ( Niveoscincus microlepidotus ) from high elevation sites in Tasmania, Australia. Our results show a stark difference in costs of reproduction between unmanipulated females from the natural population versus experimentally manipulated females (using follicle stimulating hormones). In the unmanipulated females, females with relatively larger reproductive investments survived better than females with smaller reproductive investments. In the experimental group, however, females forced to 'over-invest' into a larger clutch survived less well than controls. Thus, our study confirms the potential dangers of non-experimental estimation of costs of reproduction.     

Prevalence and incidence of young onset dementia and associations with comorbidities: A study of data from the French national health data system

BackgroundDementia onset in those aged <65 years (young onset dementia, YOD) has dramatic individual and societal consequences. In the context of population aging, data on YOD are of major importance to anticipate needs for planning and allocation of health and social resources. Few studies have provided precise frequency estimates of YOD. The aim of this study is to provide YOD prevalence and incidence estimates in France and to study the contribution of comorbidities to YOD incidence.Methods and findingsUsing data from the French national health data system (Système National des Données de Santé, SNDS) for 76% of the French population aged 40 to 64 years in 2016 (n = 16,665,795), we identified all persons with dementia based on at least 1 of 3 criteria: anti-Alzheimer drugs claims, hospitalization with the International Classification of Diseases-10th Revision (ICD-10) dementia codes (F00 to F03, G30, G31.0, G31.1, or F05.1), or registration for free healthcare for dementia. We estimated prevalence rate (PR) and incidence rate (IR) and estimated the association of comorbidities with incident YOD. Sex differences were investigated. We identified 18,466 (PR_standardized = 109.7/100,000) and 4,074 incident (IR_standardized = 24.4/100,000 person-years) persons with prevalent and incident YOD, respectively. PR and IR sharply increased with age. Age-adjusted PR and IR were 33% (95% confidence interval (CI) = 29 to 37) and 39% (95% CI = 31 to 48) higher in men than women (p < 0.001 both for PR and IR). Cardio- and cerebrovascular, neurological, psychiatric diseases, and traumatic brain injury prevalence were associated with incident YOD (age- and sex-adjusted p-values <0.001 for all comorbidities examined, except p = 0.109 for antihypertensive drug therapy). Adjustment for all comorbidities explained more than 55% of the sex difference in YOD incidence. The lack of information regarding dementia subtypes is the main limitation of this study.ConclusionsWe estimated that there were approximately 24,000 and approximately 5,300 persons with prevalent and incident YOD, respectively, in France in 2016. The higher YOD frequency in men may be partly explained by higher prevalence of cardiovascular and neurovascular diseases, substance abuse disorders, and traumatic brain injury and warrants further investigation.

In an observational study, Laure Carcaillon-Bentata and colleagues investigate the prevalence and incidence of dementia onset among adults younger than 65 years of age using data from the French national health data system from 2016.