Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BACKGROUND: Disorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021. METHODS: We estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined. FINDINGS: Globally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer. INTERPRETATION: As the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed

Efficacy of concrete constitutive models for bullet impact tests

Structures such as defenses/ammunition bunkers in the military and elsewhere are generally constructed at remote locations where concrete structures are more convenient to construct. Such protective structures in most cases are constructed from plain or reinforced concrete due to inherent ease of planning, transportation and construction. The design of these structures is based on field tests which ideally is required to be done for each caliber of weapon for which the protective structure is designed against. Such field tests are time consuming and uneconomical. A cost-effective alternative to field testing is the use of high fidelity physics based numerical modeling techniques. However, constitutive modeling of concrete when subjected to high velocity projectiles is very complex due to factors like material erosion and strain-rate effects. These factors lead to a highly non-linear response, hence, high accuracy of the concrete constitutive model is required to accurately simulate field test results. Commercial finite element software offer various concrete constitutive models. This paper reviews the concrete constitutive models available for modeling bullet impact. Experimental observations from bullet impact on plain concrete with a muzzle velocity (MV) of 900 m/s are presented and used to assess the concrete constitutive models in LS-DYNA. The importance of modeling parameters like strain-rate effects and erosion criteria have been reviewed. It was concluded that *MAT_CSCM (Mat_159) constitutive law was able to accurately simulate the field observations. The numerical results also suggest that an additional increase in the material strength to account for strain-rate effects is inappropriate

Understanding the response of reinforced concrete slabs due to contact explosion of TNT

Evaluating response of reinforced concrete (RC) structures to blast loads is now a matured field of research. The United Facilities Criteria (UFC) 3-340 design manual and similar other manuals lay out the design practice for blast resistant structures. However, most of the design methodologies are restricted to far-field (scaled distance > 1.18 m/kg 1/3 ) blast loading. The semi-empirical charts and equations presented in design manuals for far-field blast loading are not accurate in the near-field events and furthermore very little research is available on contact explosions. Contact explosions are more complex than the far-field explosion effects due to the spatially and temporally non-uniform overpressure. There are limited experimental studies available in the literature as many gauges do not survive the harsh near-field environment. Thus, most finite element models in the near-field events are validated based on post blast damage photos. This paper presents the results from field tests conducted on RC slabs with embedded piezo-electric based concrete vibration sensors (CVS). A correlation has been shown between the concrete strains and the voltage recorded by the sensors. These results have further been compared to the numerical results obtained from LS-DYNA. The contact explosion was modeled using the arbitrary-Lagrangian-Eulerian (ALE) element formulation. The study shows that contact explosion can be reliably modeled using the presented parameters. The readings obtained from CVS could capture the shock wave propagation and the strain time history in the slab at required locations

Safety of 6000 intravitreal dexamethasone implants

Purpose To evaluate the real-life safety profile of intravitreal dexamethasone implant injection for various retinal conditions. Methods Retrospective multicenter analysis of intravitreal dexamethasone implant injections (700 mu g) due to various retinal conditions including central retinal venous occlusion (1861 injections), diabetic macular oedema (3104 injections), post-surgical cystoid macular oedema (305 injections) and uveitis (381 injections). The eyes were evaluated mainly for the occurrence of adverse events such as glaucoma, cataract, retinal detachment and endophthalmitis along during the follow-up period. Results A total of 6015 injections in 2736 eyes of 1441 patients (mean age of 65.7 +/- 12.9 years) were in total analysed over an average period of 18 months (range 6 months to 102 months). A total of 576 eyes (32.5% of the phakic eyes) developed cataract requiring surgical intervention. However, visually insignificant cataract progression was observed in another 259 phakic eyes (14.6%) which did not require surgical removal. A total of 727 eyes (26.5%) experienced an intraocular pressure (IOP) rise of >25 mm Hg, with 155 eyes (5.67%) having a prior history of glaucoma and 572 eyes (20.9%) having new onset IOP rise. Overall, more than 90% of eyes with IOP rise were managed medically, and 0.5% eyes required filtering surgery. Endophthalmitis (0.07%), retinal detachment (0.03%) and vitreous haemorrhage (0.03%) were rare. There was no significant change in visual acuity (p=0.87) and central macular thickness (p=0.12) at the last follow-up. Conclusion This is the largest real-life study assessing the safety of intravitreal dexamethasone implant injections in various retinal conditions. Cataract progression and intraocular pressure rise are the most common side effects, but are often rather easily manageable

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

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