Mechanisms of brain injury related to mathematical modelling and epidemiological data

Measurements of the frequency response of head impact points on the exterior and the interior of a car were used to characterize the dynamic behavior of the object that was struck. These points were then arranged in a hierarchy of increasing stiffness. Thirty-two cases in which the distribution of injury to the brain had been recorded were grouped according to the stiffness of the object struck and by the location of the impact on the head. The distribution of the brain lesions were determined for each class of stiffness and location of impact. Three probable mechanisms of brain injury were distinguished: relative motion between the brain and the skull, local bone deformation, and intracerebral stresses. Each mechanism was related to a range of stiffness and natural frequency of the structure impacted. These theories of brain injury mechanisms are consistent with observed epidemiological data and with conclusions drawn from mathematical modelling.     

An emission-weighted proximity model for air pollution exposure assessment

Background

Among the most common spatial models for estimating personal exposure are Traditional Proximity Models (TPMs). Though TPMs are straightforward to configure and interpret, they are prone to extensive errors in exposure estimates and do not provide prospective estimates.

Method

To resolve these inherent problems with TPMs, we introduce here a novel Emission Weighted Proximity Model (EWPM) to improve the TPM, which takes into consideration the emissions from all sources potentially influencing the receptors. EWPM performance was evaluated by comparing the normalized exposure risk values of sulfur dioxide (SO₂) calculated by EWPM with those calculated by TPM and monitored observations over a one-year period in two large Texas counties. In order to investigate whether the limitations of TPM in potential exposure risk prediction without recorded incidence can be overcome, we also introduce a hybrid framework, a ‘Geo-statistical EWPM’. Geo-statistical EWPM is a synthesis of Ordinary Kriging Geo-statistical interpolation and EWPM. The prediction results are presented as two potential exposure risk prediction maps. The performance of these two exposure maps in predicting individual SO₂ exposure risk was validated with 10 virtual cases in prospective exposure scenarios.

Results

Risk values for EWPM were clearly more agreeable with the observed concentrations than those from TPM. Over the entire study area, the mean SO₂ exposure risk from EWPM was higher relative to TPM (1.00 vs. 0.91). The mean bias of the exposure risk values of 10 virtual cases between EWPM and ‘Geo-statistical EWPM’ are much smaller than those between TPM and ‘Geo-statistical TPM’ (5.12 vs. 24.63).

Conclusion

EWPM appears to more accurately portray individual exposure relative to TPM. The ‘Geo-statistical EWPM’ effectively augments the role of the standard proximity model and makes it possible to predict individual risk in future exposure scenarios resulting in adverse health effects from environmental pollution.     

The epidemiology and cost of falls requiring hospitalisation in children in Western Australia: a study using linked administrative data

OBJECTIVE: The aim of this study was to examine the epidemiology and health system cost of children's falls resulting in hospitalisation in 2003 in Western Australia. METHODS: The Injury Cost Database was used to identify children who were admitted to hospital with a falls related injury. Adjusted incidence rate ratios (IRR) of hospitalisation were modelled using Poisson regression. In-patient hospital costs were assigned using the published DRG costs for Western Australia. These costs were then extrapolated to health system costs based on previously published relative proportions. RESULTS: When adjusted for other covariates in the model males had a 53% higher incidence of falls requiring hospitalisation compared with females. Aboriginal children had a 36% higher incidence compared with their non-Aboriginal counterparts, and the incidence of falls reduced with increasing age. The total cost of in-patient hospitalisation associated with children's falls in Western Australia was A$4,554,000 with an average cost of A$1876 per case. In children aged 0-4 years and 10-14 years the highest cost resulted from falls on the flat (slips and trips). However, in children aged 5-9 years injuries resulting from falls from playground equipment resulted in both the highest cost group (A$539,000) and the highest cost per case (A$1917). The total cost to the health system of children's falls in Western Australia in 2003 were estimated to be A$21.5 million, with the total cost to the community estimated at A$108.5 million. CONCLUSION: Children's falls impose a considerable burden and cost to both the health care system and the community. This study has provided information on where the burden of risk and the majority of costs lie, namely males, Aboriginal children and for children aged 5-9 years, unlike their younger and older peers, playground equipment.     

Epidemiology of bicycle injuries in 13 health divisions, Islamic Republic of Iran 2003

Bicyclists are vulnerable road users for severe injury all over the world. The nature and extent of such injuries are less well known in Iran. Using data from a comprehensive survey conducted by the Ministry of Health and Medical Education in 13 health divisions of Iran, in 2003, we examined circumstances around bicyclist injury and death. Trained health workers completed the survey instruments by interviewing patients who stayed more than 24h in hospitals and/or relatives, hospital personnel and by reviewing patient charts. Data were cross-matched with medico-legal documents to prevent missing deaths. The information that was collected from 64 cities/towns' emergency departments (EDs), over the study period, showed that 440 injured cyclists were hospitalized and/or died due to traffic collisions. Most injuries occurred in males (94.8%) and in the young (median age: 14 years with 75% 相似文献   

Keratoconus: An updated review

Keratoconus is a bilateral and asymmetric disease which results in progressive thinning and steeping of the cornea leading to irregular astigmatism and decreased visual acuity. Traditionally, the condition has been described as a noninflammatory disease; however, more recently it has been associated with ocular inflammation. Keratoconus normally develops in the second and third decades of life and progresses until the fourth decade. The condition affects all ethnicities and both sexes. The prevalence and incidence rates of keratoconus have been estimated to be between 0.2 and 4,790 per 100,000 persons and 1.5 and 25 cases per 100,000 persons/year, respectively, with highest rates typically occurring in 20- to 30-year-olds and Middle Eastern and Asian ethnicities. Progressive stromal thinning, rupture of the anterior limiting membrane, and subsequent ectasia of the central/paracentral cornea are the most commonly observed histopathological findings. A family history of keratoconus, eye rubbing, eczema, asthma, and allergy are risk factors for developing keratoconus. Detecting keratoconus in its earliest stages remains a challenge. Corneal topography is the primary diagnostic tool for keratoconus detection. In incipient cases, however, the use of a single parameter to diagnose keratoconus is insufficient, and in addition to corneal topography, corneal pachymetry and higher order aberration data are now commonly used. Keratoconus severity and progression may be classified based on morphological features and disease evolution, ocular signs, and index-based systems. Keratoconus treatment varies depending on disease severity and progression. Mild cases are typically treated with spectacles, moderate cases with contact lenses, while severe cases that cannot be managed with scleral contact lenses may require corneal surgery. Mild to moderate cases of progressive keratoconus may also be treated surgically, most commonly with corneal cross-linking. This article provides an updated review on the definition, epidemiology, histopathology, aetiology and pathogenesis, clinical features, detection, classification, and management and treatment strategies for keratoconus.     

Reply to comments on "Derivation of numerical values for the World Health Organization guidelines for recreational waters"

The contribution addressed reveals an optimistic design philosophy likely to systematically underestimate risk in epidemiologic studies into the health effects of bathing water exposures. The authors seem to recommend that data on the 'exposure' measure (i.e. water quality) in such studies should be acquired in a similar manner to that used for regulatory sampling. This approach may compromise the quality of the epidemiologic investigations undertaken. It may result in imprecise estimates of exposure because it ignores the fact that regulatory timescales and spatial resolution (even if artificially compressed to a bathing day) can mask large spatial and temporal variability in water quality. If this variability is ignored by taking some mean value and attributing that to all of those exposed in a period at a study location, many bathers may be misclassified and the studies may be biased to a 'no-effect' conclusion. A more appropriate approach is to maximise the precision of the epidemiologic investigations by measurement of individual exposure (or water quality) at the place and time of the exposure, as has been done in randomised volunteer studies in the UK and Germany. The precise epidemiologic relationships linking 'exposure' with 'illness' can then be related to the probability of exposure to particular water quality by a 'normal bather' using the known probability distribution of the exposure variable (i.e. faecal indicator concentration) in the regulated bathing waters. We suggest that any research protocol where poor sampling design for water quality assessment is justified because regulatory monitoring is equally imprecise may be fundamentally flawed. The rationale for this assessment is that the epidemiology is the starting point and evidence-base for 'standards'. If precision is not maximised at this stage in the process it compromises the credibility of the standards design process. The negative effects of the approach advocated in this 'comment' are illustrated using published research findings used to derive the figures illustrated in Wymer et al. [2005. Comment on derivation of numerical values for the World Health Organization guidelines for recreational waters. Water Research 39, 2774-2777].     

驾驶员与儿童事故倾性研究

文章通过对全国部分城市驾驶员交通事故和儿童意外伤害事故的流行病学研究结果发现：（１）驾驶员交通事故和儿童意外伤害事故检出率不存在地区性差异；（２）驾驶员交通事故和儿童意外伤害事故的检出率无显著性的年龄差异；（３）不同年龄段驾驶员和儿童，男性事故检出率均高于女性事故检出率；（４）极少数的事故人群具有事故倾向性：在驾驶人群中有６％～８％的事故倾性驾驶员，其引起的交通事故数占总事故数的３０％～４０％，在１～１４岁儿童中有１％～２％的事故倾性儿童，其发生的意外伤害数占意外伤害总数的２５％～３５％；（５）事故倾性驾驶员和事故倾性儿童再发事故的比率均比对照组高。文章从流行病学角度证实了事故倾性人群的存在，并对事故倾性的本质作了初步探讨。     

Case Study of Factors contributing to a Crisis Building

Abstract Employees of a communications firm experienced an acute outbreak of nonspecific illness related to the workplace. Symptoms consisted primarily of coughing, throat irritation, shortness of breath and disorientation. Fifty-one individuals sought emergency medical care, and the building was evacuated. A multidisciplinary team was assembled to investigate and resolve the problem. Investigation activities focused on three major areas: epidemiology; environmental measurement; and mechanical engineering. Results indicated that the outbreak was due to multiple factors working in concert. The inside of the air handling system was contaminated with microbial growth and particulate matter; chemical products were used throughout the building with little control over use patterns; and the HVAC system was not delivering acceptable quantities of outdoor air to the employees’ breathing zones. Two unusual events may have triggered the employees’ response. An unusual odor/taste was reported, and the outside air damper abruptly opened and closed, possibly dislodging particulate matter from inside the air handling system. It appeared that psychosocial factors played an important role. Prevention of similar crises could be achieved by implementation of a policy/procedure that addresses specific responsibilities, communications, preventive maintenance, acceptable outdoor air ventilation rates, and guidelines for reporting and investigation.     

Epidemiology of accidental drowning in Denmark 1989–1993

Three hundred and forty-nine cases of accidental drowning or cooling in water occurring in Denmark from 1989 to 1993 have been studied. The incidence was highest in 0–4-year-old children, in middle-aged men, and in old people. A third of the children drowned in private pools. A quarter of all fatalities occurred during leisure boating. At least half of those that drowned in this way did not wear a life-jacket and could have been saved if they had been wearing one. Between a third and a half of the adult drownings were related to alcohol intake, and a large number of inebriated men fell into harbour basins and other water bodies. A few final remarks are made on the prospects for preventing accidental drowning in children, elderly people and adult males.     

Push/Pull Risk Factors at Workstations: A Case‐Control Study of Mexican Industrial Workers

The objective of this study was to quantify and assess whether push/pull tasks in the workplace are risk factors for lower back pain etiology. A case‐control study was conducted of 231 industrial workers 18–55 years old who were insured by the Mexican Social Security Institute (MSSI) in the Guadalajara Metropolitan Area of Jalisco, Mexico. Exposure was evaluated via a questionnaire. Multivariate analysis using conditional logistic regression showed risks for push/pull tasks (odds ratio = 5.7, 95% confidence interval, 1.4–23.1) adjusted for lifting, carrying, and driving work. The fraction attributable to push/pull tasks was 0.58, suggesting that the risk of developing lumbar spondyloarthrosis might be reduced by 58% with ergonomic redesign for pushing and pulling tasks at workstations. Additional research is needed to confirm this relationship and will ideally incorporate a greater number of subjects to assure detailed analyses of exposure categories and facilitate new comparisons with the results of the present study. © 2012Wiley Periodicals, Inc.