459 research outputs found
Can a deterministic spatial microsimulation model provide reliable small-area estimates of health behaviours? An example of smoking prevalence in New Zealand
No full textModels created to estimate neighbourhood level health outcomes and behaviours can be difficult to validate as prevalence is often unknown at the local level. This paper tests the reliability of a spatial microsimulation model, using a deterministic reweighting method, to predict smoking prevalence in small areas across New Zealand. The difference in the prevalence of smoking between those estimated by the model and those calculated from census data is less than 20% in 1745 out of 1760 areas. The accuracy of these results provides users with greater confidence to utilize similar approaches in countries where local-level smoking prevalence is unknow
The neighbourhood effects of geographical access to tobacco retailers on individual smoking behaviour
Get PDFObjective: To investigate whether neighbourhood measures of geographical accessibility to outlets selling tobacco (supermarkets, convenience stores and petrol stations) are associated with individual smoking behaviour in New Zealand.Methods: Using Geographical Information Systems, travel times from the population-weighted centroid of each neighbourhood to the closest outlet selling tobacco were calculated for all 38,350 neighbourhoods across New Zealand. These measures were appended to the 2002/03 New Zealand Health Survey; a national survey of 12,529 adults. Two-level logistic regression models were fitted to examine the effects of neighbourhood locational access upon individual smoking behaviour after controlling for potential individual- and neighbourhood-level confounding factors, including deprivation and urban/rural status.Results: After controlling for individual-level demographic and socioeconomic variables, individuals living in the quartiles of neighbourhoods with the best access to supermarkets (OR1.23, 95% CI 1.06-1.42) and convenience stores (OR 1.19, 95% CI 1.03-1.38) had a higher odds of smoking compared to individuals in the worst access quartiles. However, theassociation between neighbourhood accessibility to supermarkets and convenience stores was not apparent once other neighbourhood-level variables (deprivation and rurality) were included.Conclusions: At the national level, there is little evidence to suggest that after adjustment for neighbourhood deprivation better locational access to tobacco retail provision in New Zealand is associated with individual-level smoking behaviour
Which urban land covers/uses are associated with residents’ mortality? A cross-sectional, ecological, pan-European study of 233 cities
Get PDFObjectives: The study aim was to determine whether the range and distribution of all, and proportions of specific, land covers/uses within European cities are associated with city-specific mortality rates.
Setting: 233 European cities within 24 countries.
Participants: Aggregated city-level all-cause and age-group standardised mortality ratio for males and females separately and Western or Eastern European Region.
Results: The proportion of specific land covers/uses within a city was related to mortality, displaying differences by macroregion and sex. The land covers/uses associated with lower standardised mortality ratio (SMR) for both Western and Eastern European cities were those characterised by ‘natural’ green space, such as forests and semi-natural areas (Western Female coefficient: −18.3, 95% CI −29.8 to −6.9). Dense housing was related to a higher SMR, most prominently in Western European cities (Western Female coefficient: 17.4, 95% CI 9.6 to 25.2).
Conclusions: There is pressure to build on urban natural spaces, both for economic gain and because compact cities are regarded as more sustainable, yet here we offer evidence that doing so may detract from residents’ health. Our study suggests that urban planners and developers need to regard retaining more wild and unstructured green space as important for healthy city systems
The tobacco endgame: the neglected role of place and environment
No full textAn increasing number of countries across the world are planning for the eradication of the tobacco epidemic. The actions necessary to realise this ambition have been termed the tobacco endgame. The focus of this paper is on the intersection between the tobacco endgame with place, a neglected theme in recent academic and policy debates. We begin with an overview of the key themes in the literature on endgame strategies before detailing the international landcape of engame initatives, paying particular attention to the opportunities and challenges of endgame strategies in low and middle income countries. Finally, we critically assess the current endgame debates and suggest a novel agenda for integrating geographical perspectives into research on the endgame that provides enhanced understanding of the challenges associated with this important global health vision
Retrieval and principle variable analysis of 127 M2a-38mm™ metal on metal hip replacements
No full textINTRODUCTION: The need to revise metal on metal (MoM) implants early due to adverse reaction to debris and corrosion products is a major concern within the orthopaedic community. However the in-vivo performance of these joints depends on a range of variables related to the patient, the joint design and the surgical positioning. These variables can impact on the performance of the bearing but also the taper interface in modular components, with both capable of metal debris and corrosion products capable of causing the adverse reactions and pain which results in the need for joint retrieval. The objective of this study was to investigate the design, alignment and patient specific factors which affected the level of material loss for the bearing surfaces and taper of a cohort of M2a-38mm™ MoM hip replacements.METHODS: The cohort consisted of 127 M2a-38mm™retrieved femoral head and acetabular components which had been paired with Bi-metric™ uncemented titanium stems. Each joint had patient specific data for the weight, height, BMI, age at Primary surgery, functional time. They also had positional data including neck angle, horizontal and vertical offset, neck length, cup inclination and version angles, the bearing clearance, the taper angle and taper clearance angle based on the perfect trunnion angle of the Bi-metric™ stem.Material loss analysis was undertaken on the femoral and acetabular bearing surfaces and the taper interface of the head using an OrthoLux (RedLux, Southampton, UK). In addition wear scar location on the bearings was analysed to differentiate the joints into one of three groups, either edge worn (EW), normally wearing (NW) or edge interaction (EI). The patient, implant and positional variables were compared to the material loss values using both Spearman and Pearson’s correlations so as to determine the variables having significant effects but also to account for linear and non-linear relationships.RESULTS SECTION: Based on the wear scar location classification the 28 joints were wearing normally, 12 had edge interaction and 87 showed signs of having been edge wearing. Table 1 shows the mean volumetric loss rates and ranges of the loss for the joints in the different classifications. The comparisons between the loss values and the independent variables showed a number of significant correlations but varied between the wear scar location groups. For the NW joints, only the bearing clearance was significantly linked to the femoral head volumetric loss rate (r = 0.419). The EW joints had a larger number of significant correlations. The femoral head volume loss was linked to both the bearing clearance (r = 0.379) and the version angle (r = 0.23) of the cup. The Acetabular cup loss was significantly correlated to the inclination and version angles of its placement (r = 0.35 and 0.44). For the EI group The Cup loss was linked to the vertical offset (r = -0.701) and the Neck length (r = -0.596).The taper loss wasn’t linked to any variables in the NW group, but was linked to the bearing clearance (r = 0.316), but also to the height (r = 0.331), weight (r = 0.29) and taper angle(r = 0.314) in the EW group and Weight (r = -0.756) in the EI group. While not showing any significance in correlation there was a visible effect of taper clearance angle on the taper failure with positive taper angles providing a higher level of loss than negative ones.DISCUSSION: This is one of the few studies to have reported the assessment of the loss from well aligned MoM bearings and demonstrates that when aligned well these M2a-38mm™ joints were wearing at the rate expected and below that of other joints1. There was only one significant correlation for the NW joints which was a positive one with the bearing clearance. This shows that the lower clearance joints had a lower level of loss than their higher clearance compatriots. This can be attributed to both the higher running in wear experienced by high clearance joints but also the potential for enhanced lubrication of the bearings at lower clearances. The highest levels of loss shown in the EW group are expected given the nature of the bearing contact. The positive correlation with clearance was maintained in this group as well. The loss values were predominantly linked to the acetabular cup positioning, however the correlations were less than r = 0.45 suggesting other factors not assessed in this study were having an effect. It was also notable that a number of joints classified as edge wearing fell within the ‘safe zone’ (Figure 1.).The levels of material loss from the tapers are lower than other comparable MoM joint designs2,3. The negativecorrelationto bearing clearancein both the EW and the cohort as a whole offsets the benefits seen to the bearing wear and suggests a transfer of load or torque to the interface as a result of the lower clearance.Taper loss was the onlyvariable which was linked to patient variable, with a weak but positive correlation to weight in the EW and whole cohort analysis.The positive taper angle effect is likely due to the production of a crevice environment and the more ready ability for the exchange of fluid and ions compared to the negative clearances. In conclusion, the NW joints showed levels of material loss which would be expected of these joints in-vivo and levels of taper loss which is below that reported from other similar joint designs. The major issue was the number of joints which exhibited edge wear or interaction which exacerbated the loss from the bearings. However, the variable analysis suggests that positioning explains only a portion of the loss values, with well aligned joints exhibiting edge wear.SIGNIFICANCE/CLINICAL RELEVANCE: This study is the largest single cohort analysis of this joint design.The control of the joint to a single design, size and stem design provided an opportunity to minimise the different variables between joints provided a unique ability to focus on those which are affecting their performance.REFERENCES:1. Morlock MM, J Bone Joint. Surg Am, Vol. 90, 2008:89-95.2.Langton DJ, Bone Joint Res 2012;1-4:56-63. 3.Matthies AK J Orthop Res 2013;31-11:1677-85..
Rethinking the relationship between greenspace and mental health in China: from over-head perspective to eye-level perspective, from quantity to quality
No full textGlobally, there has been a rapid increase in mental health problems over the past 10 years, with
global prevalence rising 13% from 2010 to 2017, and further exacerbated by the Coronavirus
disease 2019 (COVID-19) pandemic. In China, from 2013 to 2025, the burden of mental disorders
prevalence in China is estimated to increase by 10% (a total increase of 3.6 million
disability-adjusted life-year), which highlights the urgency of addressing this emerging public
health crisis. Mental health can be influenced by both individual- and environment-level factors at
various spatial scales. One potential opportunity for addressing the growing burden of mental
health, is the availability of local greenspace which is increasingly being recognized as vital for
supporting people's mental health. The mechanisms linking greenspace to mental health can be
summarized as three domains including reducing harmful exposures, promoting health behaviors, and assisting in recovery from attention fatigue and stress. However, most existing studies mainly
measure people' exposure to greenspace from an over-head and quantity perspective, which
neglects eye-level and quality perspective of greenspace. This is important because different
measures of greenspace may have different influence on health. Remote sensing and land use data
measure greenspace from an over-head (vertical) perspective, while new source of data such as
street view data can measure greenspace from an eye-level (horizontal) perspective. Also, greenspace quantity reflects the objective presence of greenspace, while greenspace quality
reflects how people's subjective evaluation and attitude towards greenspace. Previous studies
indicate that the association between greenspace and mental health various across different
measures of greenspace, but evidence is scant regarding how and why the measure of greenspace
matters especially in developing countries. Therefore, the central research question of this thesis
aims to address is: do different measurements (eye-level and over-head view) and aspects
(quantity and quality) of greenspace have different influence on mental health? Adopting a
socio-ecological framework for the relationship between greenspace and mental health, this thesis
not only contributes methodologically by developing a new approach for estimating greenspace
exposure, but also makes theoretical contribution to existing literature through examining how
different aspects of greenspaces influence mental health in the Chinese context.
Using a cross-sectional survey data in Guangzhou, street view data and machine learning approach, multilevel regression models and structural equation models were used to examine different
exposure contexts, mechanisms, 'equigenesis' and demographic difference in greenspace-mental
health association. This research is the first to develop a new method for assessing visible
greenspace quality at scale and to systematically explore mechanisms linking exposure to
greenspace quantity and quality to mental health among people living in Chinese cities. Results
from empirical chapters show that the proposed method is efficient and valid to achieve high
accuracy for assessing greenspace quality. Also, the findings also reveal that socioeconomic
disparities are more prominent in greenspace quality than quantity. Empirical results also show
that greenspace quantity and quality have influence on mental health in different exposure
contexts and through different pathways. After examining “equigenesis” theory for both
greenspace quantity and quality, the results indicate that greenspace quantity and quality have
different effects on promoting equitable mental health. Last, differences by gender and age are
also observed in the effect of greenspace quantity and quality on mental health. Overall, the findings from this research demonstrated that different measurements (eye-level and
over-head view) and aspects (quantity and quality) of greenspace differentially influence mental
health. To achieve the goal of promoting mental health through urban planning and design in
Chinese urban settings, policymakers and planners are advised to provide greater focus to visible
greenspace quality at the neighbourhood scale
Fusion of Perceptual Cues using Covariance Estimation
No full textThe paradigm of perceptual integration provides robust solutions to computer vision problems. By combining the outputs of multiple vision modules, the assumptions and constraints of each module are factored out to result in a more robust system overall. The integration of dierent modules can be regarded as a form of data fusion. To this end, we propose a framework for fusing dierent information sources through estimation of covariance from observations. The framework is demonstrated in a pose tracking method that fuses similarity-to-prototypes measures and skin colour to track head pose and face position. The use of data fusion through covariance introduces constraints that allow the tracker to robustly estimate head pose and track face position. Contact Author Jamie R. Sherrah Contact Address Department of Computer Science Queen Mary and Westeld College Mile End, E1 4NS London UK Contact email [email protected] Contact Tel. (+44) (0)171 975 5230 Contact Fax (+44) (0)181 980 Bri..
Do general medical practice characteristics influence the effectiveness of smoking cessation programs? A multilevel analysis
No full textIntroduction: general practice is a recommended setting for the delivery of smoking cessation programs. Little is known about the types of practice that achieve higher cessation rates. To address this gap in knowledge, we assessed the impact of general practice characteristics on the outcomes of a large scale smoking cessation intervention delivered in general practice settings. Method: a cross-sectional study was undertaken of 7,778 participants enrolled on a structured cessation program comprising repeated brief interventions in one-to-one sessions and nicotine replacement therapy in Christchurch New Zealand, 2001–2007. We employed a logistic multilevel analysis of respondents nested in general practices with cessation at 6 months as the outcome measure. Results: after taking into account relevant individual-level predictors (age, sex, smoking intensity) and area-level surrogates for individual predictors (socioeconomic status and access to tobacco retail outlets), there remained significant variation in quit rates between practices. This variation reduced when practice characteristics were included. Practices with a majority of male doctors and practices with fewer male patients were associated with better quit rates. Practices with large numbers of doctors were less effective in achieving cessation with heavy smokers. Conclusions: the effectiveness of smoking cessation programs can be influenced significantly by practice characteristics. To increase quit rates, more attention should be paid to the institutional setting of smoking cessation programs. Assessments of the effectiveness of cessation programs should give appropriate recognition to the fact that some practices may find higher quit rates more difficult to achieve<br/
Developing summary measures of health-related multiple physical environmental deprivation for epidemiological research
Get PDFSocioeconomic deprivation accounts for much of the spatial inequality in health in the UK, but a significant proportion remains unexplained. It is highly likely that the physical environment is a key factor in this unexplained variation. The role of the socioeconomic environment in health inequalities has been studied using small-area measures of multiple socioeconomic deprivation that capture the burden of socioeconomic adversity. Although similar composite measures of the physical environment would greatly assist investigations of environmental determinants of health no such measures are available. In this study we developed two small-area measures of health-related multiple physical environmental deprivation for the UK. A thorough review and evidence appraisal process was used to identify health-relevant dimensions of physical environmental deprivation. As a result we selected both health-detrimental (air pollution, cold climate, industrial facilities) and health-beneficial (ultraviolet radiation and green space) dimensions. Datasets describing each of the selected dimensions were acquired, and rendered to UK Census Area Statistics wards (n = 10 654, average population = 5518). We developed two summary measures: the multiple environmental deprivation index (MEDIx) and classification (MEDClass). MEDIx, on an ordinal scale, can be used to distinguish areas exposed to greater or lesser environmental deprivation. MEDClass groups areas with similar environmental characteristics and will be useful for exploring health effects of specific types of environment. Mapping these measures demonstrated a wide variation in physical environmental deprivation across the UK. MEDIx revealed greater environmental deprivation in urban and industrial areas, and at more northerly latitudes. Although created using a different methodology MEDClass also differentiated these environmental types. We concluded that it is possible to capture and characterise multiple attributes of health-related physical environmental deprivation in the UK, at a small area level. The measures we developed offer opportunities to researchers and policy makers for developing our understanding of the role of exposure to multiple dimensions of physical environmental deprivation on health outcomes. <br/
Evidence-based selection of environmental factors and datasets for measuring multiple environmental deprivation in epidemiological research
Get PDFThis Environment and Human Health project aims to develop a health-based summary measure of multiple physical environmental deprivation for the UK, akin to the measures of multiple socioeconomic deprivation that are widely used in epidemiology. Here we describe the first stage of the project, in which we aimed to identify health-relevant dimensions of physical environmental deprivation and acquire suitable environmental datasets to represent population exposure to these dimensions at the small-area level. We present the results of this process: an evidence-based list of environmental dimensions with population health relevance for the UK, and the spatial datasets we obtained and processed to represent these dimensions. This stage laid the foundations for the rest of the project, which will be reported elsewhere
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