Hazardous cosleeping environments and risk factors amenable to change: case-control study of SIDS in south west England

Objectives: To investigate the factors associated with sudden infant death syndrome (SIDS) from birth to age 2 years, whether recent advice has been followed, whether any new risk factors have emerged, and the specific circumstances in which SIDS occurs while cosleeping (infant sharing the same bed or sofa with an adult or child). Design: Four year population based case-control study. Parents were interviewed shortly after the death or after the reference sleep (within 24 hours) of the two control groups. Setting: South west region of England (population 4.9 million, 184 800 births). Participants: 80 SIDS infants and two control groups weighted for age and time of reference sleep: 87 randomly selected controls and 82 controls at high risk of SIDS (young, socially deprived, multiparous mothers who smoked). Results: The median age at death (66 days) was more than three weeks less than in a study in the same region a decade earlier. Of the SIDS infants, 54% died while cosleeping compared with 20% among both control groups. Much of this excess may be explained by a significant multivariable interaction between cosleeping and recent parental use of alcohol or drugs (31% v 3% random controls) and the increased proportion of SIDS infants who had coslept on a sofa (17% v 1%). One fifth of SIDS infants used a pillow for the last sleep (21% v 3%) and one quarter were swaddled (24% v 6%). More mothers of SIDS infants than random control infants smoked during pregnancy (60% v 14%), whereas one quarter of the SIDS infants were preterm (26% v 5%) or were in fair or poor health for the last sleep (28% v 6%). All of these differences were significant in the multivariable analysis regardless of which control group was used for comparison. The significance of covering the infant’s head, postnatal exposure to tobacco smoke, dummy use, and sleeping in the side position has diminished although a significant proportion of SIDS infants were still found prone (29% v 10%). Conclusions: Many of the SIDS infants had coslept in a hazardous environment. The major influences on risk, regardless of markers for socioeconomic deprivation, are amenable to change and specific advice needs to be given, particularly on use of alcohol or drugs before cosleeping and cosleeping on a sofa

Finite Element Modeling and Analysis Applications in Osteogenesis Imperfecta

Understanding the biomechanics of bones in persons with osteogenesis imperfecta (OI) is a key component to further understanding the disease, optimizing treatment and quality of life, as well as injury prevention. However, it is not feasible to study bone biomechanics in vivo. Thus, modeling may play a key role in understanding how OI bones respond to the loading experienced during various activities, especially ambulation. Biomechanical modeling can provide insight into bone fracture risks, such as type and location, from single applied loads or repetitive loading. One method for obtaining this information is via a finite element analysis (FEA). FEA is a general technique for mathematically approximating solutions to boundary-value problems.1 It is a powerful computational tool with numerous applications. These numerical methods are used to obtain an output from a system of differential equations in response to boundary condition inputs in many scenarios. FEA allows for the discretization of a structure into numerous subparts (elements) for analysis. Elements represent regular strait-side geometric 2-D or 3-D shapes that enclose a finite area or volume.2 Field output variables (stress, strain, etc.) are explicitly calculated at each vertex (node) of every element.3 These outputs provide information that corresponds to bone strength and, therefore, location and risk for potential fractures

Responding to unexpected infant deaths : experience in one English region

New national procedures for responding to the unexpected death of a child in England require a joint agency approach to investigate each death and support the bereaved family. As part of a wider population-based study of sudden unexpected deaths in infancy (SUDI) we evaluated the implementation of this approach. Methods: A process evaluation using a population-based study of all unexpected deaths from birth to 2 years in the South West of England between January 2003 and December 2006. Local police and health professionals followed a standardised approach to the investigation of each death, supported by the research team set up to facilitate this joint approach as well as collect data for a wider research project. Results: We were notified of 155/157 SUDI, with a median time to notification of 2 hours. Initial multi-agency discussions took place in 93.5% of cases. A joint home visit by police officers with health professionals was carried out in 117 cases, 75% within 24 hours of the death. Time to notification and interview reduced during the 4 years of the study. Autopsies were conducted on all cases, the median time to autopsy being 3 days. At the conclusion of the investigation, a local multi-agency case discussion was held in 88% of cases. The median time for the whole process (including family support) was 5 months. Conclusions: This study has demonstrated that with appropriate protocols and support, the joint agency approach to the investigation of unexpected infant deaths can be successfully implemented

Primary Care Validation of a Single-Question Alcohol Screening Test

BACKGROUND Unhealthy alcohol use is prevalent but under-diagnosed in primary care settings. OBJECTIVE To validate, in primary care, a single-item screening test for unhealthy alcohol use recommended by the National Institute on Alcohol Abuse and Alcoholism (NIAAA). DESIGN Cross-sectional study. PARTICIPANTS Adult English-speaking patients recruited from primary care waiting rooms. MEASUREMENTS Participants were asked the single screening question, "How many times in the past year have you had X or more drinks in a day?", where X is 5 for men and 4 for women, and a response of >1 is considered positive. Unhealthy alcohol use was defined as the presence of an alcohol use disorder, as determined by a standardized diagnostic interview, or risky consumption, as determined using a validated 30-day calendar method. MAIN RESULTS Of 394 eligible primary care patients, 286 (73%) completed the interview. The single-question screen was 81.8% sensitive (95% confidence interval (CI) 72.5% to 88.5%) and 79.3% specific (95% CI 73.1% to 84.4%) for the detection of unhealthy alcohol use. It was slightly more sensitive (87.9%, 95% CI 72.7% to 95.2%) but was less specific (66.8%, 95% CI 60.8% to 72.3%) for the detection of a current alcohol use disorder. Test characteristics were similar to that of a commonly used three-item screen, and were affected very little by subject demographic characteristics. CONCLUSIONS. The single screening question recommended by the NIAAA accurately identified unhealthy alcohol use in this sample of primary care patients. These findings support the use of this brief screen in primary care.National Institute on Alcohol Abuse and Alcoholism (R01-AA010870

Damage tolerant composite wing panels for transport aircraft

Commercial aircraft advanced composite wing surface panels were tested for durability and damage tolerance. The wing of a fuel-efficient, 200-passenger airplane for 1990 delivery was sized using grahite-epoxy materials. The damage tolerance program was structured to allow a systematic progression from material evaluations to the optimized large panel verification tests. The program included coupon testing to evaluate toughened material systems, static and fatigue tests of compression coupons with varying amounts of impact damage, element tests of three-stiffener panels to evaluate upper wing panel design concepts, and the wing structure damage environment was studied. A series of technology demonstration tests of large compression panels is performed. A repair investigation is included in the final large panel test

Simulating interventions in graphical chain models for longitudinal data

Simulating the outcome of an intervention is a central problem in many fields as this allows decision-makers to quantify the effect of any given strategy and, hence, to evaluate different schemes of actions. Simulation is particularly relevant in very large systems where the statistical model involves many variables that, possibly, interact with each other. In this case one usually has a large number of parameters whose interpretation becomes extremely difficult. Furthermore, in a real system, although one may have a unique target variable, there may be a number of variables which might, and often should, be logically considered predictors of the target outcome and, at the same time, responses of other variables of the system. An intervention taking place on a given variable, therefore, may affect the outcome either directly and indirectly though the way in which it affects other variables within the system. Graphical chain models are particularly helpful in depicting all of the paths through which an intervention may affect the final outcome. Furthermore, they identify all of the relevant conditional distributions and therefore they are particularly useful in driving the simulation process. Focussing on binary variables, we propose a method to simulate the effect of an intervention. Our approach, however, can be easily extended to continuous and mixed responses variables. We apply the proposed methodology to assess the effect that a policy intervention may have on poorer health in early adulthood using prospective data provided by the 1970 British Birth Cohort Study (BCS70).chain graph, conditional approach, Gibbs Sampling, Simulation of interventions, age at motherhood, mental health