Methods
To determine the physical access to services, a network analysis database was created based on surface travel time, in minutes, from the central point of a dissemination area (DA) to the nearest health facility. Due to the vast inhabited regions of the North Shore, some central points of DAs were moved to an area where people actually live – defined here as urban areas - and relocated within 300m of a road. Two network analysis routes were created: 1) Shortest route (in travel minutes) to a chronic disease service in the North Shore (three chronic disease services and Lions Gate Hospital which provides chronic disease services: North Shore Primary Care and Chronic Care Services) and 2) the shortest route (in travel minutes) to Lions Gate Hospital. Central points of the DAs (termed Incidents) were linked to the road network based on a 300m buffer and the health services (termed facilities) were given a 150m buffer from the road network (Road Network). The road network database was created using CanMap Route Logistics 2007; and travel time was created using TRVLTIM_E. Elevation was not included in the analysis and travel times were based on road length and speed limits. For reference, several travel times were compared to Google Map travel times and were found to be very similar.
Locations of the general practitioners (GPs) and Chronic Disease Services were obtained from Vancouver Coastal Health and entered into a geodatabase (see North Shore Primary Care and Chronic Care Services). GP locations were mapped using the first four characters of their postal code; all GP offices sharing the first four characters were clustered and a central point was determined using ArcMap. The FSA (first three characters of the postal code) were not used because they did not provide enough granularity, hence a 4th character was used for finer detail. Most GP locations were found in Lonsdale and Ambleside (GP Zoom), total GPs = 222.
The North Shore’s 296 DA locations and demographics (DA Population Density) were obtained from the GVRD and Health Statistics Canada, based on 2006 census data. To determine the social access to health services, each DA was attributed a Socioeconomic Status (SES) score; 1-100%. The SES scores were derived from BC’s Local Health Authority Socio-Economic Indices (BC Stats). SES were calculated based on the following weighting structure: Mean Family Income given 40%, Employment Rate given 20%, Education Rate given 20%, Minority proportion given 10% and age 10%, for a total score ranked 1 to 100. Each demographic was scored 1-100, and then multiplied by their respective weight and added together to give a SES score. Average Family income scores were determined based on the maximum average family income in the North Shore (maximum avg. = $323, 414) – thus each DA was a proportion of that that maximum value. Employment rate was determined by % of DA, aged >25yrs employed; Education rate was determined by % of DA, aged >25yrs having received a high school certificate; Minority proportion was determined by % of DA defined as a visible minority; and Age over 65 was determined the proportion of the DA >65yrs of age. Minority and age demographics were inversed to give a lower SES score, based on the fact that the greater the age and proportion of minorities of a DA, the more vulnerable the population is. Thus, the lower SES scores highlight more vulnerable populations.
A regression analysis was used to determine a correlation between travel time to Lions Gate Hospital and SES scores, however it was not believed any relationship should exist between the two. Though a more appropriate regression would examine the correlation between travel time and SES to health outcomes, but unfortunately this project did not have access to health data.