Age and Ageing 2015; 44: 511–514
doi: 10.1093/ageing/afu203
Published electronically 19 January 2015
© The Author 2015. Published by Oxford University Press on behalf of the British Geriatrics Society.
All rights reserved. For Permissions, please email: [email protected]
Visualising the distribution of individuals of
advanced age in Canada: linking census data
to maps
JULIA ROMANSKI1,2, WEI WU1, PETER J. ANDERSON1, PETER C. AUSTIN3,4, PAULA A. ROCHON1,3,5
1
Women’s College Research Institute, Women’s College Hospital, Toronto, Ontario, Canada
Brown University, Providence, RI, USA
3
Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada
4
Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada
5
Department of Medicine and Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto,
Ontario, Canada
2
Address correspondence to: P. A. Rochon. Tel: (+1) 4163513732; Fax: (+1) 4163513746. Email: [email protected]
Abstract
Objective: to link publically available aggregate census data to maps to visually convey information about the geographic distribution of those of advanced age in Canada.
Method: we obtained aggregate statistics derived from the most recent 2011 Canadian census data. We calculated the
Percentage of People 90 Years of Age or Older and the Longevity Index in each of the 292 census divisions. The data and the
Canadian census division map were merged to create thematic maps using Google Fusion Tables.
Results: overall, there were 217,930 women and men who were 90 years of age or older in Canada in 2011. The regions with
the highest proportion of elderly residents are in the south, rather than in the north of Canada. Southern Saskatchewan and
southern Manitoba emerged as high longevity areas based on both indices.
Conclusions: publically available data and free online tools can be used to create maps that visually display the geographic distribution of the oldest population across Canada. This approach provides an efficient way to observe patterns, identify adjacencies and perceive information that may not have been anticipated. This approach can be replicated in other jurisdictions using
publically available data.
Keywords: census, map, longevity, geographic distribution, older people
Introduction
According to a UN report, ‘the proportion of older persons
(60 years or older) is projected to reach 21 per cent in 2050’
[1]. This has made planning for the ageing population a
global priority [2]. The distribution of individuals of advanced
age is not homogeneous. Within countries, there are communities that have high concentrations of older people. This
phenomenon is partially caused by migration. Geographical
factors influencing longevity may also play a role. Identifying
geographic areas with a high concentration of older people is
important, because it can inform planning of required resources
and health services. Additionally, identifying geographic regions
with high population-based longevity, sometimes called ‘Blue
Zones’, is of interest to researchers as they explore factors associated with exceptional longevity [3].
Conveying messages using complex data can be challenging. Census data are a valuable resource that can be explored
using tables and figures. While they convey important information, these traditional methods of data presentation may
make it difficult to identify patterns, trends or adjacencies, limiting the potential value of the data. Overlaying existing census
data on maps facilitates the visualisation of geographic-specific
data and provides an opportunity to perceive information that
may not have been anticipated. Visualising data can assist with
decision making by communicating complex information in
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an accessible format [4]. While census data and maps are publically available, they are not routinely linked.
Our goal was to link publically available aggregate census
data to maps to visually convey information about the geographic distribution of those of advanced age in Canada.
Methods
Data sources
In Canada, publically available aggregate census data are
released every 5 years. These data are organised by geographically based census divisions. The 2011 Canadian census provides the most current data. There are 292 census divisions
in Canada. The number of people by age group (all ages, 65
years and older, 90 years and older) in each of the 292
Canadian census divisions was obtained from data tables
available on the Statistics Canada website [5].
Advanced age measures
We used two measures to identify regions with a large
number of people of advanced age.
The ‘Percentage 90 Years of Age or Older’ measures the
percentage of the population that is 90 years of age or older
in each census division.
The ‘Longevity Index’ was calculated as the percentage of
people over 65 who are over 90 years of age [6] in each
census division. The Longevity Index provides a measure of
longevity that is less influenced by migration and birth rates
[6]. Accordingly, this index allows researchers to explore the
link between longevity and geography.
Linking census data to maps
A four-step process was followed. First, the census-level division map was obtained from digital boundary files available
on the Statistics Canada website [7]. To create maps that can
accept data, the Canadian census division map was converted
into Keyhole Markup Language (.kml) format, which
expresses geospatial information.
Second, the Excel file containing census division data (for
the Percentage 90 Years of Age and Older and the Longevity
Index) and the .kml format of the related maps was uploaded
into Google Fusion Tables (https://support.google.com/
fusiontables/answer/2571232), a web-based application that
allows users to link data to maps. These two files were linked
using their shared census division identifier.
Third, the values obtained from each of the two advanced
age measures (the Percentage 90 Years and Older and the
Longevity Index) were divided into five equal intervals using
the Google Fusion Table application, where the range of the
metric was the same in each interval.
Fourth, each of the five equal interval groups was
assigned a colour. The five colours ranged from light blue
for the areas with the lowest values to dark blue representing
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the areas with the highest values. The same procedure was
used to assign colours for both thematic maps.
Analyses
Descriptive statistics were used. The ‘Percentage 90 Years of
Age or Older’ and the Longevity Index were both calculated
using an Excel formula.
Results
Overall, there were 217,930 women and men aged 90 or
older in Canada in 2011. In Figure 1, the northern regions of
the map were truncated, but no full census divisions were
removed.
The percentage of individuals aged 90 and older within
each census division ranged from 0 to 1.78% across the
country. In general, census divisions in the south had darker
colours compared with census divisions in the northern
areas of Canada. The darkest colour areas, indicating the
highest percentage of people aged 90 or older, were in southern Saskatchewan and southern Manitoba.
The Longevity Index within each census division ranged
from 0 to 8.6% across the country (Figure 2). In general,
southern areas had a higher Longevity Index than northern
areas. The darkest colour areas, indicating the highest
Longevity Index, were in southern Saskatchewan and southern Manitoba. Because both longevity measures were highest
in Manitoba and Saskatchewan, we illustrate the percentage of
people who are 90 years of age and older and the Longevity
Index for each of the census divisions within Manitoba and
Saskatchewan in Supplementary data, Appendix 1 available in
Age and Ageing online.
When the distribution of the percentage of adults aged 90
and older was compared with the distribution of the
Longevity Indices in Manitoba and Saskatchewan, there was
considerable agreement. The Spearman correlation coefficient was 0.842, P < 0.0001.
Discussion
We have linked publically available data from the most recent
Canadian census to corresponding maps, to visually illustrate
the distribution of adults of advanced age across the country
using free online tools. Accordingly, this approach could be
replicated.
Our data, using two measures of advanced age, demonstrate that the distribution of adults of advanced age in
Canada is not homogeneous. Our maps identify the southern areas of Saskatchewan and Manitoba as the areas of
Canada with the highest concentration of those of advanced
age. These findings are consistent with several studies that
internationally have found that the geographic distribution of
those living to advanced age is not homogeneous [8, 9].
Visualising the geographic distribution of the older population allows the ability to identify patterns that can be useful
Distribution of individuals of advanced age in Canada
Figure 1. Percentage 90 Years of Age or Older. Adapted from Statistics Canada, 98-311-X2011023, 25 June 2013. This does not constitute an endorsement by Statistics Canada of this product. This figure displays the Percentage 90 Years of Age or Older by census division across Canada. The areas with the darkest colour are those with the highest concentration of people aged 90 or older.
Figure 2. Longevity Index. Adapted from Statistics Canada, 98-311-X2011023, 25 June 2013. This does not constitute an endorsement by Statistics Canada of this product. This figure displays the Longevity Index by census division across Canada. The areas with
the darkest colour are those with the highest Longevity Index. The Longevity Index is the percentage of people over 65 who are over
90 years of age.
for a variety of purposes. For example, these maps can be
used at the local level to inform the need for community services to support the older population. These maps can also be
used at the provincial level to inform the provision of health
care services both in the community and the acute care sector.
Visualising data using maps may be an important step in
the process of identifying areas of the world with exceptional
longevity. The Longevity Index is a reasonable metric for this
purpose as it is designed to minimise the effect of migration.
This type of information may help to inform discussions
that link geography to longevity. Certain areas of the world
have been identified as areas where there is extreme longevity
[3, 6, 8–10], leading to hypotheses about why people live
longer. Some of these areas have been called Blue Zones [3].
At present, no Blue Zone has been identified in Canada.
Our maps provide consistent information about the geographic areas in Canada with the highest concentrations of
those of advanced age using two comprehensive measures.
Both maps identified southern Manitoba and southern
Saskatchewan as the areas with higher concentrations of
those of advanced age. This is consistent with data indicating
that Saskatchewan had the highest life expectancy of all
provinces and territories during the 20th century [11]. In
contrast to our study, which found high population-based
longevity in a flat area, research from Italy [9] and China [8]
found that the percentage of people of advanced age tended
to increase with altitude.
Limitations
We considered including the Centenarity Index in our study
as a measure of longevity ( percentage of people over 90 who
are over 100) [6]. This index could not be reliably calculated
as the random rounding by Statistics Canada rendered the
values for extremely old age groups unreliable for our purposes [12]. We focused on individuals aged 90 and older,
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which are a relatively larger number, and therefore, the
effects of rounding had little impact on the actual data from
Statistics Canada.
2.
3.
Conclusion
Publically available data and free online tools can be used to
create maps that visually display the geographic distribution
of the oldest population across Canada. This approach provides an efficient way to observe patterns, identify adjacencies and perceive information that may not have been
anticipated. This approach can be replicated in other jurisdictions using publically available data.
4.
5.
Key points
• We link publically available aggregate Canadian census data
to maps.
• We visually display the geographic distribution of the oldest
population in Canada.
• Southern Saskatchewan and southern Manitoba emerged
as high longevity areas.
6.
7.
8.
Conflicts of interest
None declared.
9.
Funding
10.
P.C.A. was supported in part by a Career Investigator Award
from the Heart and Stroke Foundation, Ontario Office.
11.
Supplementary data
Supplementary data mentioned in the text are available to
subscribers in Age and Ageing online.
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Received 27 May 2014; accepted in revised form 8 October
2014