313 research outputs found
Dependence on temperature and salinity gradients and the injection rate of CO2 storage in saline aquifers with an angular unconformity
The importance of lithofacies control on fluid migration in heterogeneous aeolian formations for geological CO2 storage: Lessons from observational evidence and modelling of bleached palaeoreservoirs at Salt Wash Graben, Utah
Exhumed bleached palaeoreservoirs provide a means of understanding fluid flow processes in geological media because the former movement of fluids is preserved as visible geochemical changes (grey bleaching of continental red-beds). The bleached palaeoreservoirs of the Jurassic Entrada Sandstone occur in a region (Utah) where there are high fluxes of naturally-occurring CO2 and form outcrop analogues for processes related to geological storage of CO2. In this paper a bleached palaeoreservoir now exposed at outcrop is used to test the importance of geological heterogeneity on fluid flow. The bleached palaeoreservoir is developed in ‘wet aeolian’ lithofacies composed of alternating layers of sandstone and cemented muddy sandstone that range across three or more orders of magnitude in permeability. Despite these permeability contrasts the bleaching shows a remarkably uniform distribution within the palaeoreservoir that crosses lithofacies boundaries. Evidence from bleaching therefore suggests that geological heterogeneity within the range 1–103 millidarcies should not greatly impede the relatively uniform distribution of low-viscosity CO2 charged fluids throughout a reservoir: a conclusion that has been substantiated here by flow modelling. Residence time is an important factor and where flows are transient the distribution of bleaching and modelling shows that flows are confined to high-permeability lithofacies
The burden of injuries in Iranian children in 2005
<p>Abstract</p> <p>Background</p> <p>Child injury is recognized as a global health problem. Injuries caused the highest burden of disease among the total population of Iran in 2003. We aimed to estimate the morbidity, mortality, and disease burden caused by child injuries in the 0- to 14-year-old population of Iran in 2005.</p> <p>Methods</p> <p>We estimated average age- and sex-specific mortality rates for different types of child injuries from 2001 to 2006 using Iran's death registration data. Incidence rates for nonfatal outcomes of child injuries in 2005 were estimated through a time- and place-limited sample hospital registry study for injuries. We used the World Health Organization's methods for estimation of years of life lost due to premature mortality and years lived with disability in 2005.</p> <p>Results</p> <p>Injuries were the most important cause of death in children ages 1 to 14, with 35, 33.4, 24.9, and 22.9 deaths per 100,000 in the 0-14, 1-4, 5-9, and 10-14 age groups respectively. Road transport injuries were responsible for the highest death rate per 100,000 population among all types of injuries in children, with 15.5 for ages 0-14, 16.1 for ages 1-4, 16.3 for ages 5-9, and 13.1 for ages 10-14. Incidence rates of injuries leading to hospitalization were 459, 530, and 439 per 100,000 in the 0-14, 1-4, and 5-14 age groups respectively. Incidence rates of injuries leading to outpatient care were 1,812, 2,390, and 1,650 per 100,000 in the same age groups respectively. Among injury types, falls and burns had the highest hospitalization and outpatient care incidence rates.</p> <p>Conclusions</p> <p>Injuries, particularly road transport injuries, were the most important health problem of children in Iran in 2003 and 2005. Strong social policy is needed to ensure child survival.</p
Inequality in household catastrophic health care expenditure in a low-income society of Iran
Background We assessed change in household catastrophic health care expenditures (CHE) and inequality in facing such expenditures in south-west Tehran. Methods A cluster-sampled survey was conducted in 2003 using the World Health Survey questionnaire. We repeated the survey on the same sample in 2008 (635 and 603 households, respectively). We estimated the proportion of households facing CHE using the ‘household's capacity to pay'. We identified the determinants of the household CHE using regression analysis and used the concentration index to measure socio-economic inequality and decompose it into its determinants factors. Results Findings showed that the proportion of household facing CHE had no significant change in this period (12.6% in 2003 vs 11.8% in 2008). The key determinants of CHE for both years were health care utilization and health care insurance status. Socio-economic status was the main contributor to inequality in CHE, while unequal utilization of dentistry and outpatient services had reduced the inequality in CHE between socio-economic groups. Conclusions We observed no significant change in the CHE proportion despite policy interventions aimed at reducing such expenditures. Any solution to the problem of CHE should include interventions aimed at the determinants of CHE. It is essential to increase the depth of social insurance coverage by expanding the basic benefit package and reducing co-payment
Inequality in household catastrophic health care expenditure in a low-income society of Iran
Background We assessed change in household catastrophic health care expenditures (CHE) and inequality in facing such expenditures in south-west Tehran. Methods A cluster-sampled survey was conducted in 2003 using the World Health Survey questionnaire. We repeated the survey on the same sample in 2008 (635 and 603 households, respectively). We estimated the proportion of households facing CHE using the ‘household's capacity to pay'. We identified the determinants of the household CHE using regression analysis and used the concentration index to measure socio-economic inequality and decompose it into its determinants factors. Results Findings showed that the proportion of household facing CHE had no significant change in this period (12.6% in 2003 vs 11.8% in 2008). The key determinants of CHE for both years were health care utilization and health care insurance status. Socio-economic status was the main contributor to inequality in CHE, while unequal utilization of dentistry and outpatient services had reduced the inequality in CHE between socio-economic groups. Conclusions We observed no significant change in the CHE proportion despite policy interventions aimed at reducing such expenditures. Any solution to the problem of CHE should include interventions aimed at the determinants of CHE. It is essential to increase the depth of social insurance coverage by expanding the basic benefit package and reducing co-payment
Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015
SummaryBackground The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors—the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6–58·8) of global deaths and 41·2% (39·8–42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. Funding Bill & Melinda Gates Foundation
Algorithms for enhancing public health utility of national causes-of-death data
<p>Abstract</p> <p>Background</p> <p>Coverage and quality of cause-of-death (CoD) data varies across countries and time. Valid, reliable, and comparable assessments of trends in causes of death from even the best systems are limited by three problems: a) changes in the <it>International Statistical Classification of Diseases and Related Health Problems </it>(ICD) over time; b) the use of tabulation lists where substantial detail on causes of death is lost; and c) many deaths assigned to causes that cannot or should not be considered underlying causes of death, often called garbage codes (GCs). The Global Burden of Disease Study and the World Health Organization have developed various methods to enhance comparability of CoD data. In this study, we attempt to build on these approaches to enhance the utility of national cause-of-death data for public health analysis.</p> <p>Methods</p> <p>Based on careful consideration of 4,434 country-years of CoD data from 145 countries from 1901 to 2008, encompassing 743 million deaths in ICD versions 1 to 10 as well as country-specific cause lists, we have developed a public health-oriented cause-of-death list. These 56 causes are organized hierarchically and encompass all deaths. Each cause has been mapped from ICD-6 to ICD-10 and, where possible, they have also been mapped to the <it>International List of Causes of Death </it>1-5. We developed a typology of different classes of GCs. In each ICD revision, GCs have been identified. Target causes to which these GCs should be redistributed have been identified based on certification practice and/or pathophysiology. Proportionate redistribution, statistical models, and expert algorithms have been developed to redistribute GCs to target codes for each age-sex group.</p> <p>Results</p> <p>The fraction of all deaths assigned to GCs varies tremendously across countries and revisions of the ICD. In general, across all country-years of data available, GCs have declined from more than 43% in ICD-7 to 24% in ICD-10. In some regions, such as Australasia, GCs in 2005 are as low as 11%, while in some developing countries, such as Thailand, they are greater than 50%. Across different age groups, the composition of GCs varies tremendously - three classes of GCs steadily increase with age, but ambiguous codes within a particular disease chapter are also common for injuries at younger ages. The impact of redistribution is to change the number of deaths assigned to particular causes for a given age-sex group. These changes alter ranks across countries for any given year by a number of different causes, change time trends, and alter the rank order of causes within a country.</p> <p>Conclusions</p> <p>By mapping CoD through different ICD versions and redistributing GCs, we believe the public health utility of CoD data can be substantially enhanced, leading to an increased demand for higher quality CoD data from health sector decision-makers.</p
The burden of disease and injury in Iran 2003
<p>Abstract</p> <p>Background</p> <p>The objective of this study was to estimate the burden of disease and injury in Iran for the year 2003, using Disability-Adjusted Life Years (DALYs) at the national level and for six selected provinces.</p> <p>Methods</p> <p>Methods developed by the World Health Organization for National Burden of Disease (NBD) studies were applied to estimate disease and injury incidence for the calculation of Years of Life Lost due to premature mortality (YLL), Years Lived with Disability (YLD), and DALYs. The following adjustments of the NBD methodology were made in this study: a revised list with 213 disease and injury causes, development of new and more specific disease modeling templates for cancers and injuries, and adjustment for dependent comorbidity. We compared the results with World Health Organization (WHO) estimates for Eastern Mediterranean Region, sub-region B in 2002.</p> <p>Results</p> <p>We estimated that in the year 2003, there were 21,572 DALYs due to all diseases and injuries per 100,000 Iranian people of all ages and both sexes. From this total number of DALYs, 62% were due to disability premature deaths (YLD) and 38% were due to premature deaths (YLL); 58% were due to noncommunicable diseases, 28% – to injuries, and 14% – to communicable, maternal, perinatal, and nutritional conditions. Fifty-three percent of the total number of 14.349 million DALYs in Iran were in males, with 36.5% of the total due to intentional and unintentional injuries, 15% due to mental and behavioral disorders, and 10% due to circulatory system diseases; and 47% of DALYs were in females, with 18% of the total due to mental and behavioral disorders, 18% due to intentional and unintentional injuries, and 12% due to circulatory system diseases. The disease and injury causes leading to the highest number of DALYs in males were road traffic accidents (1.071 million), natural disasters (548 thousand), opioid use (510 thousand), and ischemic heart disease (434 thousand). The leading causes of DALYs in females were ischemic heart disease (438 thousand), major depressive disorder (420 thousand), natural disasters (419 thousand), and road traffic accidents (235 thousand). The burden of disease at the province level showed marked variability. DALY estimates by Iran's NBD study were higher than those for EMR-B by WHO.</p> <p>Conclusion</p> <p>The health and disease profile in Iran has made the transition from the dominance of communicable diseases to that of noncommunicable diseases and road traffic injuries. NBD results are to be used in health program planning, research, and resource allocation and generation policies and practices.</p
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