Most epidemiologic studies use traffic at residential address as a surrogate for total traffic exposure when investigating effects of traffic on respiratory health. This study used GIS (Geographical Information Systems) to estimate traffic exposure, not only on residential, but also on workplace address, in addition to survey questions on time spent in traffic during commuting or other daily activities.The aim was to investigate 1) if there is an association between traffic exposure and prevalence of adult asthma and asthma symptoms, and 2) if so, does this association become stronger using more complete traffic exposure information.
This study was conducted in two stages: A first cross-sectional survey in Southern Sweden 2004 (n = 24819, 18-80 years, response rate 59%) was followed by a case-control study in 2005 to obtain more detailed exposure and confounder information (n = 2856, asthmatics and controls (1:3), 86% response rate). In the first survey, only residential address was known. In the second survey, questions about workplace addresses and daily time spent in traffic were also included. Residential and workplace addresses were geocoded and linked with GIS to road data and dispersion modelled outdoor concentrations of NOx (annual mean, 250 × 250 m resolution).
Living within 50 m of a road (measured by GIS) with traffic intensity of >10 cars/minute (compared with no road within this distance) was associated with an increased prevalence of asthma, (OR = 1.8, 95% CI = (1.1-2.8), and with asthma symptoms last 12 months. No statistically significant effects were seen for traffic exposure at workplace address, daily time spent in traffic, or commuting time to work, after adjustment for confounders. A combined total exposure estimate did not give a stronger association with asthma prevalence or asthma symptoms.
Traffic exposure at close proximity to residential address showed association with asthma prevalence and asthma symptoms last 12 months, among adults in southern Sweden. The associations were not stronger when accounting for total traffic exposure. This could reflect exposure misclassfication at workplace address and for other daily time in traffic, but also that residential address remains the main determinant for traffic exposure among adults.
Cites: BMC Pulm Med. 2009;9:4219703291
Cites: Environ Sci Technol. 2009 Jul 1;43(13):4659-6419673248
Cites: Environ Health Perspect. 2010 Jul;118(7):1021-620371422
Cites: Environ Health Perspect. 2002 May;110(5):543-712003761
This investigation was designed to (a) develop an individualized mechanical model for measuring aerodynamic drag (F(d) ) while ski racing through multiple gates, (b) estimate energy dissipation (E(d) ) caused by F(d) and compare this to the total energy loss (E(t) ), and (c) investigate the relative contribution of E(d) /E(t) to performance during giant slalom skiing (GS). Nine elite skiers were monitored in different positions and with different wind velocities in a wind tunnel, as well as during GS and straight downhill skiing employing a Global Navigation Satellite System. On the basis of the wind tunnel measurements, a linear regression model of drag coefficient multiplied by cross-sectional area as a function of shoulder height was established for each skier (r > 0.94, all P
The authors investigated the use of Google Earth's Street View option to audit the presence of built environment features that support older adults' walking. Two raters conducted virtual (Street View) and in-the-field audits of 48 street segments surrounding urban and suburban assisted living sites in metropolitan Vancouver, BC, Canada. The authors determined agreement using absolute agreement. Their findings indicate that Street View may identify the presence of features that promote older adults' walking, including sidewalks, benches, public washrooms, and destinations. However, Street View may not be as reliable as in-the-field audits to identify details associated with certain items, such as counts of trees or street lights; presence, features, and height of curb cuts; and sidewalk continuity, condition, and slope. Thus, the appropriateness of virtual audits to identify microscale built environment features associated with older adults' walking largely depends on the purpose of the audits-specifically, whether the measurer seeks to capture highly detailed features of the built environment.
The propagation of communicable diseases through a population is an inherent spatial and temporal process of great importance for modern society. For this reason a spatially explicit epidemiologic model of infectious disease is proposed for a greater understanding of the disease's spatial diffusion through a network of human contacts.
The objective of this study is to develop an agent-based modelling approach the integrates geographic information systems (GIS) to simulate the spread of a communicable disease in an urban environment, as a result of individuals' interactions in a geospatial context.
The methodology for simulating spatiotemporal dynamics of communicable disease propagation is presented and the model is implemented using measles outbreak in an urban environment as a case study. Individuals in a closed population are explicitly represented by agents associated to places where they interact with other agents. They are endowed with mobility, through a transportation network allowing them to move between places within the urban environment, in order to represent the spatial heterogeneity and the complexity involved in infectious diseases diffusion. The model is implemented on georeferenced land use dataset from Metro Vancouver and makes use of census data sets from Statistics Canada for the municipality of Burnaby, BC, Canada study site.
The results provide insights into the application of the model to calculate ratios of susceptible/infected in specific time frames and urban environments, due to its ability to depict the disease progression based on individuals' interactions. It is demonstrated that the dynamic spatial interactions within the population lead to high numbers of exposed individuals who perform stationary activities in areas after they have finished commuting. As a result, the sick individuals are concentrated in geographical locations like schools and universities.
The GIS-agent based model designed for this study can be easily customized to study the disease spread dynamics of any other communicable disease by simply adjusting the modeled disease timeline and/or the infection model and modifying the transmission process. This type of simulations can help to improve comprehension of disease spread dynamics and to take better steps towards the prevention and control of an epidemic outbreak.
Cites: Int J Health Geogr. 2008;7:3518606008
Cites: Lancet. 2004 Nov 27-Dec 3;364(9449):1974-8315567014
Cites: Nature. 2003 Oct 16;425(6959):681-514562094
Cites: Phys Rev E Stat Nonlin Soft Matter Phys. 2003 Dec;68(6 Pt 2):06610214754264
The international trade in used tires, coupled with the ability to lay non-desiccating eggs, has enabled Aedes albopictus (Skuse) (Diptera: Culicidae) to travel and establish on new continents, including North, Central, and South America, the Caribbean, Australasia, Africa, and Europe. Concerns have been raised over its potential role in the transmission of arboviruses and Dirofilaria nematodes. Following importation into northerly latitudes, photoperiodically-induced egg diapause enables establishment of Ae. albopictus, and a number of abiotic factors determine the subsequent seasonal activity. The United Kingdom (U.K.) imports over 5 million used tires annually, and this seems the most likely route by which Ae. albopictus would be imported. The anthropophilic and container-breeding nature of Ae. albopictus could cause an urban human biting nuisance and the potential for involvement in (human and veterinary) disease transmission cycles needs to be assessed. This paper addresses the likelihood for importation of Ae. albopictus into the U.K. and assesses, using a Geographic Information Systems (GIS)-based model, the ability for Ae. albopictus to establish, and the likely seasonal activity. It also reviews its possible role as a potential disease vector in the U.K. The model predicts that abiotic risk factors would permit establishment of Ae. albopictus throughout large parts of lowland U.K., with at least four to five months of adult activity (May-September), being more prolonged in the urban centers around London and the southern coastal ports. Pre-emptive surveillance of possible imported Ae. albopictus, through a targeted approach, could prevent the establishment of this exotic mosquito and mitigate any subsequent human and animal health implications for the U.K., either now or in the future.
The EU EuroClim project developed a system to monitor and record climate change indicator data based on satellite observations of snow cover, sea ice and glaciers in Northern Europe and the Arctic. It also contained projection data for temperature, rainfall and average wind speed for Europe. These were all stored as data sets in a GIS database for users to download. The process of gathering requirements for a user population including scientists, researchers, policy makers, educationalists and the general public is described. Using an iterative design methodology, a user survey was administered to obtain initial feedback on the system concept followed by panel sessions where users were presented with the system concept and a demonstrator to interact with it. The requirements of both specialist and non-specialist users is summarised together with strategies for the effective communication of geographic climate change information.
Researchers and public health officials in Canada, the United States and Australia have for some time noted broader geographic accessibility to gambling establishments, above all in socioeconomically underprivileged communities. This increase in availability could lead to more and more gambling problems. This article focuses, in an ecological perspective, in particular on a spatial analysis of the geographic accessibility of sites possessing a VLT permit in the Montréal area, i.e. Montréal Island, the South Shore and Laval, from the standpoint of the development of an indicator of the vulnerability (socioeconomic components and demographic components) to gambling of populations at the level of certain neighbourhood units (dissemination areas). With the recent development of geographic information systems (GIS), it is now possible to ascertain accessibility to services much more accurately, for example by taking into account the configuration of the road network.
The findings of our analysis reveal widespread geographic accessibility to sites possessing a VLT permit in the downtown area and in pericentral districts. In some neighbourhood units, a site possessing a VLT permit may be within a three-minute walk. In the region studied overall, average walking time to a VLT site is nine minutes. Access to this type of service on foot is usually limited in the outskirts. However, a number of groups of sites possessing VLT permits are found along certain axial highways. According to local spatial self-correlation analyses, the findings suggest a significant link between walking accessibility to sites possessing VLT permits and the vulnerability of the communities. In a number of neighbourhood units with ready access to VLT's the populations display high vulnerability.
These findings reveal that accessibility to sites possessing a VLT permit is often linked to the vulnerability (socioeconomic and demographic components) of communities. Reliance in our analyses on neighbourhood units with fairly small areas enabled us to emphasize the rectilinear dimension of the spatial distribution of sites possessing VLT permits. This is a significant link that public health officials must consider when elaborating programs to combat pathological gambling.
Cites: J Epidemiol Community Health. 2001 Feb;55(2):111-2211154250
Access to a quiet side in one's dwelling is thought to compensate for higher noise levels at the most exposed façade. It has also been indicated that noise from combined traffic sources causes more noise annoyance than equal average levels from either road traffic or railway noise separately.
2612 persons in Malmö, Sweden, answered to a residential environment survey including questions on outdoor environment, noise sensitivity, noise annoyance, sleep quality and concentration problems. Road traffic and railway noise was modeled using Geographic Information System.
Access to a quiet side, i.e., at least one window facing yard, water or green space, was associated with reduced risk of annoyance OR (95%CI) 0.47 (0.38-0.59), and concentration problems 0.76 (0.61-0.95). Bedroom window facing the same environment was associated to reduced risk of reporting of poor sleep quality 0.78 (0.64-1.00). Railway noise was associated with reduced risk of annoyance below 55 dB(A) but not at higher levels of exposure.
Having a window facing a yard, water or green space was associated to a substantially reduced risk of noise annoyance and concentration problems. If this window was the bedroom window, sleeping problems were less likely.
Most studies assessing health effects of neighborhood characteristics either use self-reports or objective assessments of the environment, the latter often based on Geographical Information Systems (GIS). While objective measures require detailed landscape data, self-assessments may yield confounded results. In this study we demonstrate how self-assessments of green neighborhood environments aggregated to narrow area units may serve as an appealing compromise between objective measures and individual self-assessments.
The study uses cross-sectional data (N = 24,847) from a public health survey conducted in the county of Scania, southern Sweden, in 2008 and validates the Scania Green Score (SGS), a new index comprising five self-reported green neighborhood qualities (Culture, Lush, Serene, Spacious and Wild). The same qualities were also assessed objectively using landscape data and GIS. A multilevel (ecometric) model was used to aggregate individual self-reports to assessments of perceived green environmental attributes for areas of 1,000 square meters. We assessed convergent and concurrent validity for self-assessments of the five items separately and for the sum score, individually and area-aggregated.
Correlations between the index scores based on self-assessments and the corresponding objective assessments were clearly present, indicating convergent validity, but the agreement was low. The correlation was even more evident for the area-aggregated SGS. All three scores (individual SGS, area-aggregated SGS and GIS index score) were associated with neighborhood satisfaction, indicating concurrent validity. However, while individual SGS was associated with vitality, this association was not present for aggregated SGS and the GIS-index score, suggesting confounding (single-source bias) when individual SGS was used.
Perceived and objectively assessed qualities of the green neighborhood environment correlate but do not agree. An index score based on self-reports but aggregated to narrow area units can be a valid approach to assess perceived green neighborhood qualities in settings where objective assessments are not possible or feasible.
Cites: Occup Environ Med. 1997 Jan;54(1):44-89072033
Cites: Environ Health. 2004 Mar 31;3(1):315056391
Cites: Am J Prev Med. 2005 Feb;28(2 Suppl 2):126-3315694520
Cites: Scand J Work Environ Health. 2005 Jun;31(3):184-9015999570
Cites: J Epidemiol Community Health. 2006 Jul;60(7):587-9216790830
Cites: BMC Public Health. 2006;6:14916759375
Cites: Int J Epidemiol. 2006 Oct;35(5):1361-317008359
Cites: Am J Epidemiol. 2007 Apr 15;165(8):858-6717329713
Cites: Health Place. 2007 Dec;13(4):839-5017392016
Cites: Int Arch Occup Environ Health. 2007 Nov;81(2):179-9117541626
Cites: J Epidemiol Community Health. 2007 Dec;61(12):1042-918000125
Cites: Am J Epidemiol. 2000 Jul 1;152(1):75-8310901332
Cites: J Epidemiol Community Health. 2003 Aug;57(8):550-212883048
The stated and revealed travel behavior of a sample of 60 rural drivers aged 54-92 years provided a basis to explore the potential effectiveness of two common driver's license restrictions aimed at older drivers: time of day and road class. The potential utility and impact of these restrictions have not been explored with revealed data for jurisdictions with a large population of rural older drivers where automobile dependence is high. Data were drawn from a multiday Global Positioning System-based travel diary survey of rural older drivers in New Brunswick, Canada. Revealed travel data showed that over 50 percent of the rural drivers in the sample did not drive after dark, and 40 percent drove less than 1 percent of their total surveyed kilometers on major highways, higher rates than from participant-stated responses. The proportion of participants taking night trips and traveling on major highways decreased with age. The majority of trips taken after dark by all participants had a rural destination. The average daily kilometers driven on major highways by men and women aged 75 years and older was nearly identical (1.79 km/day). These exposure considerations suggest that restricting night travel and major highway travel for the oldest rural drivers (75 years and older) may have limited utility given that the majority of participants did not drive in these situations, and for those who did, most of their trips were in rural areas where enforcement could be expected to be limited. A better approach may be to encourage increased self-regulation through training, age-friendly upgrades to transportation infrastructure to help rural older drivers stay driving safely as long as possible, and the development of appropriate rural alternatives to help a driver transition to nondriver.