A weather-driven model of malaria transmission

BACKGROUND: Climate is a major driving force behind malaria transmission and climate data are often used to account for the spatial, seasonal and interannual variation in malaria transmission. METHODS: This paper describes a mathematical-biological model of the parasite dynamics, comprising both the weather-dependent within-vector stages and the weather-independent within-host stages. RESULTS: Numerical evaluations of the model in both time and space show that it qualitatively reconstructs the prevalence of infection. CONCLUSION: A process-based modelling structure has been developed that may be suitable for the simulation of malaria forecasts based on seasonal weather forecasts

Simulating disease transmission dynamics at a multi-scale level

We present a model of the global spread of a generic human infectious disease using a Monte Carlo micro-simulation with large-scale parallel-processing. This prototype has been constructed and tested on a model of the entire population of the British Isles. Typical results are presented. A microsimulation of this order of magnitude of population simulation has not been previously attained. Further, an efficiency assessment of processor usage indicates that extension to the global scale is feasible. We conclude that the flexible approach outlined provides the framework for a virtual laboratory capable of supporting public health policy making at a variety of spatial scales.high-performance computing; global modelling; disease transmission

Utilization of insecticide-treated nets by under-five children in Nigeria: Assessing progress towards the Abuja targets

<p>Abstract</p> <p>Background</p> <p>The Abuja target of increasing the proportion of people sleeping under insecticide-treated nets (ITNs) to 60% by the year 2005, as one of the measures for malaria control in Africa, has generated an influx of resources for malaria control in several countries in the region. A national household survey conducted in 2005 by the Malaria Control Programme in Nigeria assessed the progress made with respect to ITN ownership and use among pregnant women and children under five years of age since 2000. The survey was the first nationally representative study of ITN use assessing progress towards the Abuja target amongst vulnerable groups.</p> <p>Population and Method</p> <p>A cross-sectional survey of a sample of 7,200 households, selected by a multistage stratified sampling technique from 12 randomly selected states from the six geopolitical zones of the country. Data collection was done during the malarious rainy season (October 2005) using a modified WHO Malaria Indicator Survey structured questionnaire about household ownership and utilization of mosquito nets (treated or untreated) from household heads.</p> <p>Results</p> <p>Household ownership of any net was 23.9% (95% CI, 22.8%–25.1%) and 10.1% for ITNs (95% CI, 9.2%–10.9%). Education, wealth index, presence of an under-five child in the household, family size, residence, and region by residence were predictive of ownership of any net. The presence of an under-five child in the household, family size, education, presence of health facility in the community, gender of household head, region by residence and wealth index by education predicted ITN ownership.</p> <p>Utilization of any net by children under-five was 11.5% (95% CI, 10.4%–12.6%) and 1.7% (95% CI, 1.3%–2.2%) for ITN. Predictors of use of any net among under-five children were fever in the previous two weeks, presence of health facility in the community, caregiver's education, residence, and wealth index by caregiver's education; while religion, presence of health facility and wealth index by caregiver's education predicted the use of ITN among this group.</p> <p>Conclusion</p> <p>This study demonstrated that the substantial increase in ITN utilization among children under five years of age in Nigeria is still far from the Abuja targets.</p

Vitamin D and risk of cause specific death: systematic review and meta-analysis of observational cohort and randomised intervention studies.

OBJECTIVE: To evaluate the extent to which circulating biomarker and supplements of vitamin D are associated with mortality from cardiovascular, cancer, or other conditions, under various circumstances. DESIGN: Systematic review and meta-analysis of observational studies and randomised controlled trials. DATA SOURCES: Medline, Embase, Cochrane Library, and reference lists of relevant studies to August 2013; correspondance with investigators. STUDY SELECTION: Observational cohort studies and randomised controlled trials in adults, which reported associations between vitamin D (measured as circulating 25-hydroxyvitamin D concentration or vitamin D supplement given singly) and cause specific mortality outcomes. DATA EXTRACTION: Data were extracted by two independent investigators, and a consensus was reached with involvement of a third. Study specific relative risks from 73 cohort studies (849,412 participants) and 22 randomised controlled trials (vitamin D given alone versus placebo or no treatment; 30,716 participants) were meta-analysed using random effects models and were grouped by study and population characteristics. RESULTS: In the primary prevention observational studies, comparing bottom versus top thirds of baseline circulating 25-hydroxyvitamin D distribution, pooled relative risks were 1.35 (95% confidence interval 1.13 to 1.61) for death from cardiovascular disease, 1.14 (1.01 to 1.29) for death from cancer, 1.30 (1.07 to 1.59) for non-vascular, non-cancer death, and 1.35 (1.22 to 1.49) for all cause mortality. Subgroup analyses in the observational studies indicated that risk of mortality was significantly higher in studies with lower baseline use of vitamin D supplements. In randomised controlled trials, relative risks for all cause mortality were 0.89 (0.80 to 0.99) for vitamin D3 supplementation and 1.04 (0.97 to 1.11) for vitamin D2 supplementation. The effects observed for vitamin D3 supplementation remained unchanged when grouped by various characteristics. However, for vitamin D2 supplementation, increased risks of mortality were observed in studies with lower intervention doses and shorter average intervention periods. CONCLUSIONS: Evidence from observational studies indicates inverse associations of circulating 25-hydroxyvitamin D with risks of death due to cardiovascular disease, cancer, and other causes. Supplementation with vitamin D3 significantly reduces overall mortality among older adults; however, before any widespread supplementation, further investigations will be required to establish the optimal dose and duration and whether vitamin D3 and D2 have different effects on mortality risk

Defining the role of medication adherence in poor glycemic control among a general adult population with diabetes.

AIMS: This study assesses the attributable impact of adherence to oral glucose medications as a risk factor for poor glycemic control in population subgroups of a large general population, using an objective medication adherence measure. METHODS: Using electronic health records data, adherence to diabetes medications over a two-year period was calculated by prescription-based Medication Possession Ratios for adults with diabetes diagnosed before January 1, 2010. Glycemic control was determined by the HbA1c test closest to the last drug prescription during 2010-2012. Poor control was defined as HbA1c>75 mmol/mol (9.0%). Medication adherence was categorized as "good" (>80%), "moderate" (50-80%), or "poor" (<50%). Logistic regression models assessed the role medication adherence plays in the association between disease duration, age, and poor glycemic control. We calculated the change in the attributable fraction of glucose control if the non-adherent diabetic medication population would become adherent by age-groups. RESULTS: Among 228,846 diabetes patients treated by oral antiglycemic medication, 46.4% had good, 28.8% had moderate, and 24.8% had poor adherence. Good adherence rates increased with increasing disease duration, while glycemic control became worse. There was a strong inverse association between adherence level and poor control (OR = 2.50; CI = 2.43-2.58), and adherence was a significant mediator between age and poor control. CONCLUSIONS: A large portion of the diabetes population is reported to have poor adherence to oral diabetes medications, which is strongly associated with poor glycemic control in all disease durations. While poor adherence does not mediate the poorer glycemic control seen in patients with longer-standing disease, it is a significant mediator of poor glycemic control among younger diabetes patients. A greater fraction of poorly controlled younger patients, compared to older patients, could be prevented if at least 80% adherence to their medications was achieved. Therefore, our results suggest that interventions to improve adherence should focus on this younger sub-group

MicroRNAs as a potential prognostic factor in gastric cancer

AIM: To compare the microRNA (miR) profiles in the primary tumor of patients with recurrent and non-recurrent gastric cancer

Patient exclusions flow chart.

<p>The figure shows the process for arriving at the final sample size. After all exclusion criteria were applied, a final study population of 228,846 patients with diabetes who had a prescription for oral anti-glycemic medications and an HbA1c test performed was yielded.</p

Demographic and clinical characteristics according to glucose control.

<p>*mo  =  months.</p><p>Demographic and clinical characteristics according to glucose control.</p

Multivariable Regression Analysis for Poor Glycemic Control (HbA1c>75 mmol/mol [9.0%]).

<p>*SES  =  socio-economic status.</p><p>**mo  =  months.</p><p>Multivariable Regression Analysis for Poor Glycemic Control (HbA1c>75 mmol/mol [9.0%]).</p