- Email: [email protected]
The Incidence of Eye Injuries in Canada
The Incidence of Eye Injuries in Canada Keith David Gordon, PhD ABSTRACT ● RÉSUMÉ Objective: To provide information concerning the incidence of eye injuries in Canada. Design: Cross-sectional study. Participants: The study population consisted of all Canadians over the age of 18 years who agreed to participate in a telephone survey. Study participants were selected via random digit telephone dialing, with a roughly equal per capita geographic representation across Canada. Participating in the study were 4974 people, 51.8% of whom were female. Methods: People agreeing to participate in the survey were asked whether, during the past year, they had had an eye injury that required medical attention. Those who said they had were asked an additional set of questions to ascertain the nature, cause, and location of the injury. Results: Of the participants, 104 (2.09%) were found to have had an eye injury that required medical attention during the past year. The number of eye injuries occurring at home and at work was approximately the same (37.5% and 35.5%). Playing sports accounted for 8.6% of all injuries. Sharp objects were the primary cause of injury (23.1%), followed by dirt and debris (12.5%), and blunt objects (6.7%). The number of men reporting eye injuries was 3 times that of women. Approximately one quarter of all eye injuries (22.1%) had resulted in taking time off from work or school. Conclusions: This population-based study indicates that the incidence of eye injuries in Canada is extremely high and argues for a public prevention campaign that encourages the use of eye protection, both at home and in the workplace. Objet : Information concernant l’incidence des blessures oculaires au Canada. Nature : Étude transversale. Participants : La population à l’étude comprenait uniquement des Canadiens et Canadiennes de plus de 18 ans qui avaient acceptés de participer à un sondage téléphonique. Les participants ont été retenus en composant au hasard leurs numéros de téléphone, avec une représentation géographique per capita à peu près égale à travers le pays. En tout, 4 974 personnes, dont 51,8 % de femmes, ont ainsi participé. Méthodes : Les personnes qui ont accepté de participer se sont d’abord vues demander si elles avaient eu une blessure oculaire qui avait requis des soins médicaux au cours de la dernière année. Celles qui répondirent dans l’affirmative ont dû répondre à plusieurs questions pour confirmer la nature, la cause et l’emplacement de la blessure. Résultats : Il s’est avéré que 104 participants (2,09 %) avaient eu une blessure oculaire qui avait requis des soins médicaux au cours de l’année précédante. Les nombres de blessures survenues à la maison et au travail étaient approximativement semblables (37,5% et 35,5%). La pratique sportive a compté 8,6 % de toutes les blessures. Les objets tranchants étaient la cause principale de blessure (23,1 %), suivis de la saleté et des débris (12,5 %) et des objets contondants (6,7 %). Les hommes étaient 3 fois plus nombreux que les femmes à signaler une blessure oculaire. Environ le quart de toutes les blessures oculaires (22,1 %) ont entraîné des absences du travail ou de l’école. Conclusions : Cette étude basée sur la population indique qu’au Canada l’incidence des blessures oculaires est extrêmement élevée et soutient une campagne de prévention publique pour encourager l’utilisation de protecteurs oculaires, à la maison et au travail.
Eye injuries are a major cause of vision loss; an estimated 27% of people sustaining serious eye injuries become legally blind (visual acuity ⬍ 20/200) as a final result.1 In spite of the seriousness of the visual outcomes, very little research into the epidemiology and nature of eye injuries has been undertaken recently in Canada. The Canadian Ophthalmological Society has established an eye injury registry to encourage the reporting of eye injuries, but such registries are limited by the extent to which injuries are reported by ophthalmologists, optometrists, and the many other physicians that may be treating eye injuries.2 A recent study analyzed the nature of eye injuries reporting to a major Canadian pediatric hospital; however, to date no extensive population-based study of eye injuries has been conducted in Canada.3 Data from comprehensive population-based surveys in the United States estimated the annual incidence of eye injuries requiring treatment in an emergency department,
inpatient or outpatient facility, or private physician’s office at 6.98 per 1000 population, whereas another populationbased survey estimated the annual average incidence of eye injury to be 3.1 per 1000 population.4,5 Studies conducted in Baltimore, MD, and Melbourne, Australia, estimated the cumulative lifetime prevalence of eye injuries requiring medical attention to be 14.4% and 21.1%, respectively.6,7 A telephone-based population survey in New England reported the annual incidence of eye injuries requiring medical attention to be 9.75 per 1000 population.8 The wide variation in the incidence and prevalence of eye injuries reported in these studies results primarily from the differences in methodology used and the definitions of eye injury used in the various studies. These differences make it extremely difficult to compare data. The present study was conducted with the goal of obtaining comprehensive population-based data concerning the na-
Canadian National Institute for the Blind, Toronto, Ontario, Canada.
Can J Ophthalmol 2012;47:351–353
Originally received Jan. 11, 2012. Final revision Feb. 24, 2012. Accepted Mar. 6, 2012 Correspondence to Keith D Gordon, PhD, CNIB, 1929 Bayview Avenue, Toronto, Ontario M4G 3E8; [email protected]
0008-4182/11/$-see front matter © 2012 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved. dx.doi.org/10.1016/j.jcjo.2012.03.005
CAN J OPHTHALMOL—VOL. 47, NO. 4, AUGUST 2012
351
Eye injuries in Canada—Gordon Table 1—Number of eye injuries by province Number surveyed Newfoundland Nova Scotia New Brunswick & PEI Quebec Ontario Manitoba Saskatchewan Alberta British Columbia Total Canada
Number of injuries in past year
Table 3—Eye injuries by cause
Percentage of number surveyed
95% CI
88 154
3 3
3.41 1.95
1.17–9.55 0.67–5.57
144 1205 1894 186 159 498 646 4974
2 20 33 2 4 17 20 104
1.39 1.66 1.74 1.08 2.52 3.41 3.09 2.09
0.38–4.92 1.08–2.55 1.24–2.43 0.30–3.84 0.98–6.30 2.14–5.40 2.02–4.74 1.73–2.53
ture and extent of eye injuries in Canada so as to inform public health strategies for the prevention of eye injuries in Canada.
METHODS The study population consisted of all Canadians over the age of 18 years who agreed to participate in a telephone survey. Study participants were selected via random digit telephone dialing, with a roughly equal per capita geographic representation across Canada. The survey was conducted between June and August of 2011. People agreeing to participate in the telephone survey were asked whether they had had an eye injury that required medical attention during the past year. Those who said they had were then asked an additional set of questions to ascertain the nature, cause, and location of the injury. Many people cannot distinguish among ophthalmologists, optometrists and, in some cases, family practitioners, so this description of medical attention was deliberately kept broad and nonspecific so as to capture the complete spectrum of attention a patient may have received. A 2 analysis was used to assess the differences in incidence of injuries in male and female subjects.
Object description
Sharp object/metal/nail Dirt/dust/debris Blunt object Piece of wood/splinter/ tree Playing sports/sporting equipment Chemicals Fall Body part in the eye Don’t know/don’t remember All other
Number of eye injuries in past year
Percent of eye injuries in past year
95% CI
24 13 7
23.1 12.5 6.7
16.0–32.1 7.5–20.2 3.3–13.2
6
5.8
2.7–12.0
5 4 3 3
4.8 3.9 2.9 2.9
2.1–10.8 1.5–9.5 1.0–8.1 1.0–8.1
12 27
11.5 26.0
6.7–19.1 18.5–35.1
province, the percentage of people experiencing an eye injury during the past year ranged from 1.08% in Manitoba to 3.41% in Newfoundland and Alberta (Table 1). The number of eye injuries occurring at home and at work were approximately the same (Table 2), 37.5% and 35.5%, respectively. Playing sports accounted for 8.6% of all injuries. Sharp objects were the primary cause of injury (23.1%) followed by dirt and debris (12.5%) and blunt objects (6.7%) (Table 3). The number of men reporting eye injuries during the previous year was 3 times that of women. Men incurred 75% of all injuries (3.4% of all males surveyed), whereas women incurred 25% of all injuries (1.2% of all females surveyed) (p ⬍ 0.0001). Factory workers incurred 21.2% and office workers 19.2% of all injuries; retirees incurred 15.4% (Table 4). Approximately one quarter of all eye injuries had resulted in taking time off from work or school in the previous year (22.1%). This represents 0.46% (95% CI, 0.31% to 0.69%) of all the people surveyed.
DISCUSSION
RESULTS The study included 4974 people, 51.8% (2576) of whom were female. Of them, 104, or 2.09% (95% CI, 1.73% to 2.53%), were found to have had an eye injury that required medical attention during the past year. By
The incidence of 2.09% for eye injuries requiring medical attention during the previous year found in this study is significantly higher than that found by Glynn et al. in
Table 4 —Eye injuries by occupation Occupation
Table 2—Eye injuries by location Location
Home Work Playing sports On the farm Traffic accident At school On vacation/while traveling All other
352
Number of eye injuries in past year
Percentage of eye injuries in past year
95% CI
39 37 9 4 3 2
37.5 35.5 8.6 3.8 2.9 1.9
28.8–47.1 27.0–45.1 4.6–15.6 1.5–9.5 1.0–8.1 0.5–6.7
2 8
1.9 7.7
0.5–6.7 4.0–14.5
CAN J OPHTHALMOL—VOL. 47, NO. 4, AUGUST 2012
Factory worker Office worker Retired Construction/tradesperson Student Farm worker Homemaker Unemployed Health care worker Fireman All other
Number of eye injuries in past year
Percent of eye injuries in past year
95% CI
22 20 16 9 6 6 5 3 2 1 14
21.2 19.2 15.4 8.7 5.8 5.8 4.8 2.9 1.9 0.9 13.5
14.4–30.0 12.8–27.8 9.7–23.5 4.6–15.6 2.7–12.0 2.7–12.0 2.1–10.8 1.0–8.1 0.5–6.7 0.2–5.2 8.2–21.3
Eye injuries in Canada—Gordon New England in 1985, using a similar methodology.8 Possible reasons for this are, first, the fact that the current study included more men than did the Glynn et al. study. The current study sample consisted of 48% men, whereas the Glynn et al. study sample only had 42% men. Both studies showed that men were more likely to have experienced an eye injury. The greater number of men in the current study, therefore, might be expected to account for some of the difference. Second, because the survey question defined an eye injury as an injury requiring medical attention, one might expect a greater number of people in Canada to have gone for medical attention than in the United States because of the universal accessibility of health care in Canada. Further differences may be explained by differences in location and the fact that the Glynn et al. study was conducted in New England in 1985. Urbanization and machinery development for both home and industrial use have increased since then and may account for the greater number of injury-causing accidents. The results of this study are also higher than the annual incidence reported in the population-based study by McGwin et al. mentioned above (6.93 per 1000).4 This difference can be accounted for by the fact that optometric care is excluded from the previous study, whereas all forms of care are included in the current study. The finding that the annual incidence of eye injury in men was 3 times that for women was compared with similar ratios of injuries in total. The Canadian Community Health Survey for 2010 reported the 12-month incidence of all injuries in men in the age group of 20 years and older to be 1.35 times that for women in the same age group.9 More research is needed to determine the reason for this difference. This study has certain limitations. The ability of an individual to recall the exact nature of an eye injury when asked on the telephone may be limited, particularly if the injury was not a major one. Because of the limited time available in a telephone survey, it was not possible to ask more detailed questions about the cause of the injury and what type of eye protection had been used. Further study is necessary in this regard. The finding that 2.09% of people surveyed had had an eye injury during the previous year, when projected across the total Canadian population, would mean that 721 000 people had had an eye injury requiring medical attention during the past year. This study showed that 0.46% of all people surveyed had lost time from school or work in the
past year because of an eye injury. When this number is projected across the Canadian population between the ages of 20 and 64 years, it means that 99 700 people in Canada lost time from work last year due to an eye injury.10 These findings have significant implications for public health prevention in Canada. If only a small percentage of eye injury accidents could be prevented, a significant amount of suffering to individuals could be avoided. It would also result in financial savings to the health care system and the economy.
CONCLUSION This study shows that eye injuries represent a significant source of morbidity in Canada. The associated costs to society, both personal and financial, are extremely high. Prevention of eye injuries can provide significant financial savings to the health care system and the economy and can, at the same time, reduce the significant social and personal costs that may ensue as a result of vision loss.
Disclosure: The author has no proprietary or commercial interest in any materials discussed in this article. REFERENCES 1. Kuhn F, Morris R, Witherspoon CD, Mann L. Epidemiology of blinding trauma in the United States eye injury registry. Ophthalmol Epidemiol. 2006;13:209-16. 2. Canadian Ophthalmological Society 2007. Eye injury registry. Available at: www.eyesite.ca/english/press/eye-injury-registry.html. Accessed January 6, 2012. 3. Podbielski DW, Surkont M, Tehrani NN, Ratnapalan S. Pediatric eye injuries in a Canadian emergency department. Can J Ophthalmol. 2009; 44:519-22. 4. McGwin G, Xie A, Owsley C. Rate of eye injury in the United States. Arch Ophthalmol. 2005;123:970-6. 5. Wong TY, Klein BEK, Klein R. The prevalence and 5-year incidence of ocular trauma: The Beaver Dam Eye Study. Ophthalmology. 2000;107: 2196-202. 6. Katz J, Tielsch JM. Lifetime prevalence of ocular injuries from the Baltimore eye survey. Arch Ophthalmol. 1993;111:1564-8. 7. McCarty CA, Fu CLH, Taylor HR. Epidemiology of ocular trauma in Australia. Ophthalmology. 1999;106:1847-52. 8. Glynn RJ, Seddon JM, Berlin BM. The incidence of eye injuries in New England adults. Arch Ophthalmol. 1988;106:785-9. 9. Statistics Canada. Injuries in Canada: Insights from the Canadian Community Health Survey. Available at: www.statcan.gc.ca/pub/82-624-x/ 2011001/article/11506-eng.htm#a4. Accessed January 9, 2012. 10. Statistics Canada. Population by sex and age group. Available at: www.40.statcan.gc.ca/l01/cst01/demo10a-eng.htm. Accessed January 6, 2012.
CAN J OPHTHALMOL—VOL. 47, NO. 4, AUGUST 2012
353
Eye injuries are a major cause of vision loss; an estimated 27% of people sustaining serious eye injuries become legally blind (visual acuity ⬍ 20/200) as a final result.1 In spite of the seriousness of the visual outcomes, very little research into the epidemiology and nature of eye injuries has been undertaken recently in Canada. The Canadian Ophthalmological Society has established an eye injury registry to encourage the reporting of eye injuries, but such registries are limited by the extent to which injuries are reported by ophthalmologists, optometrists, and the many other physicians that may be treating eye injuries.2 A recent study analyzed the nature of eye injuries reporting to a major Canadian pediatric hospital; however, to date no extensive population-based study of eye injuries has been conducted in Canada.3 Data from comprehensive population-based surveys in the United States estimated the annual incidence of eye injuries requiring treatment in an emergency department,
inpatient or outpatient facility, or private physician’s office at 6.98 per 1000 population, whereas another populationbased survey estimated the annual average incidence of eye injury to be 3.1 per 1000 population.4,5 Studies conducted in Baltimore, MD, and Melbourne, Australia, estimated the cumulative lifetime prevalence of eye injuries requiring medical attention to be 14.4% and 21.1%, respectively.6,7 A telephone-based population survey in New England reported the annual incidence of eye injuries requiring medical attention to be 9.75 per 1000 population.8 The wide variation in the incidence and prevalence of eye injuries reported in these studies results primarily from the differences in methodology used and the definitions of eye injury used in the various studies. These differences make it extremely difficult to compare data. The present study was conducted with the goal of obtaining comprehensive population-based data concerning the na-
Canadian National Institute for the Blind, Toronto, Ontario, Canada.
Can J Ophthalmol 2012;47:351–353
Originally received Jan. 11, 2012. Final revision Feb. 24, 2012. Accepted Mar. 6, 2012 Correspondence to Keith D Gordon, PhD, CNIB, 1929 Bayview Avenue, Toronto, Ontario M4G 3E8; [email protected]
0008-4182/11/$-see front matter © 2012 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved. dx.doi.org/10.1016/j.jcjo.2012.03.005
CAN J OPHTHALMOL—VOL. 47, NO. 4, AUGUST 2012
351
Eye injuries in Canada—Gordon Table 1—Number of eye injuries by province Number surveyed Newfoundland Nova Scotia New Brunswick & PEI Quebec Ontario Manitoba Saskatchewan Alberta British Columbia Total Canada
Number of injuries in past year
Table 3—Eye injuries by cause
Percentage of number surveyed
95% CI
88 154
3 3
3.41 1.95
1.17–9.55 0.67–5.57
144 1205 1894 186 159 498 646 4974
2 20 33 2 4 17 20 104
1.39 1.66 1.74 1.08 2.52 3.41 3.09 2.09
0.38–4.92 1.08–2.55 1.24–2.43 0.30–3.84 0.98–6.30 2.14–5.40 2.02–4.74 1.73–2.53
ture and extent of eye injuries in Canada so as to inform public health strategies for the prevention of eye injuries in Canada.
METHODS The study population consisted of all Canadians over the age of 18 years who agreed to participate in a telephone survey. Study participants were selected via random digit telephone dialing, with a roughly equal per capita geographic representation across Canada. The survey was conducted between June and August of 2011. People agreeing to participate in the telephone survey were asked whether they had had an eye injury that required medical attention during the past year. Those who said they had were then asked an additional set of questions to ascertain the nature, cause, and location of the injury. Many people cannot distinguish among ophthalmologists, optometrists and, in some cases, family practitioners, so this description of medical attention was deliberately kept broad and nonspecific so as to capture the complete spectrum of attention a patient may have received. A 2 analysis was used to assess the differences in incidence of injuries in male and female subjects.
Object description
Sharp object/metal/nail Dirt/dust/debris Blunt object Piece of wood/splinter/ tree Playing sports/sporting equipment Chemicals Fall Body part in the eye Don’t know/don’t remember All other
Number of eye injuries in past year
Percent of eye injuries in past year
95% CI
24 13 7
23.1 12.5 6.7
16.0–32.1 7.5–20.2 3.3–13.2
6
5.8
2.7–12.0
5 4 3 3
4.8 3.9 2.9 2.9
2.1–10.8 1.5–9.5 1.0–8.1 1.0–8.1
12 27
11.5 26.0
6.7–19.1 18.5–35.1
province, the percentage of people experiencing an eye injury during the past year ranged from 1.08% in Manitoba to 3.41% in Newfoundland and Alberta (Table 1). The number of eye injuries occurring at home and at work were approximately the same (Table 2), 37.5% and 35.5%, respectively. Playing sports accounted for 8.6% of all injuries. Sharp objects were the primary cause of injury (23.1%) followed by dirt and debris (12.5%) and blunt objects (6.7%) (Table 3). The number of men reporting eye injuries during the previous year was 3 times that of women. Men incurred 75% of all injuries (3.4% of all males surveyed), whereas women incurred 25% of all injuries (1.2% of all females surveyed) (p ⬍ 0.0001). Factory workers incurred 21.2% and office workers 19.2% of all injuries; retirees incurred 15.4% (Table 4). Approximately one quarter of all eye injuries had resulted in taking time off from work or school in the previous year (22.1%). This represents 0.46% (95% CI, 0.31% to 0.69%) of all the people surveyed.
DISCUSSION
RESULTS The study included 4974 people, 51.8% (2576) of whom were female. Of them, 104, or 2.09% (95% CI, 1.73% to 2.53%), were found to have had an eye injury that required medical attention during the past year. By
The incidence of 2.09% for eye injuries requiring medical attention during the previous year found in this study is significantly higher than that found by Glynn et al. in
Table 4 —Eye injuries by occupation Occupation
Table 2—Eye injuries by location Location
Home Work Playing sports On the farm Traffic accident At school On vacation/while traveling All other
352
Number of eye injuries in past year
Percentage of eye injuries in past year
95% CI
39 37 9 4 3 2
37.5 35.5 8.6 3.8 2.9 1.9
28.8–47.1 27.0–45.1 4.6–15.6 1.5–9.5 1.0–8.1 0.5–6.7
2 8
1.9 7.7
0.5–6.7 4.0–14.5
CAN J OPHTHALMOL—VOL. 47, NO. 4, AUGUST 2012
Factory worker Office worker Retired Construction/tradesperson Student Farm worker Homemaker Unemployed Health care worker Fireman All other
Number of eye injuries in past year
Percent of eye injuries in past year
95% CI
22 20 16 9 6 6 5 3 2 1 14
21.2 19.2 15.4 8.7 5.8 5.8 4.8 2.9 1.9 0.9 13.5
14.4–30.0 12.8–27.8 9.7–23.5 4.6–15.6 2.7–12.0 2.7–12.0 2.1–10.8 1.0–8.1 0.5–6.7 0.2–5.2 8.2–21.3
Eye injuries in Canada—Gordon New England in 1985, using a similar methodology.8 Possible reasons for this are, first, the fact that the current study included more men than did the Glynn et al. study. The current study sample consisted of 48% men, whereas the Glynn et al. study sample only had 42% men. Both studies showed that men were more likely to have experienced an eye injury. The greater number of men in the current study, therefore, might be expected to account for some of the difference. Second, because the survey question defined an eye injury as an injury requiring medical attention, one might expect a greater number of people in Canada to have gone for medical attention than in the United States because of the universal accessibility of health care in Canada. Further differences may be explained by differences in location and the fact that the Glynn et al. study was conducted in New England in 1985. Urbanization and machinery development for both home and industrial use have increased since then and may account for the greater number of injury-causing accidents. The results of this study are also higher than the annual incidence reported in the population-based study by McGwin et al. mentioned above (6.93 per 1000).4 This difference can be accounted for by the fact that optometric care is excluded from the previous study, whereas all forms of care are included in the current study. The finding that the annual incidence of eye injury in men was 3 times that for women was compared with similar ratios of injuries in total. The Canadian Community Health Survey for 2010 reported the 12-month incidence of all injuries in men in the age group of 20 years and older to be 1.35 times that for women in the same age group.9 More research is needed to determine the reason for this difference. This study has certain limitations. The ability of an individual to recall the exact nature of an eye injury when asked on the telephone may be limited, particularly if the injury was not a major one. Because of the limited time available in a telephone survey, it was not possible to ask more detailed questions about the cause of the injury and what type of eye protection had been used. Further study is necessary in this regard. The finding that 2.09% of people surveyed had had an eye injury during the previous year, when projected across the total Canadian population, would mean that 721 000 people had had an eye injury requiring medical attention during the past year. This study showed that 0.46% of all people surveyed had lost time from school or work in the
past year because of an eye injury. When this number is projected across the Canadian population between the ages of 20 and 64 years, it means that 99 700 people in Canada lost time from work last year due to an eye injury.10 These findings have significant implications for public health prevention in Canada. If only a small percentage of eye injury accidents could be prevented, a significant amount of suffering to individuals could be avoided. It would also result in financial savings to the health care system and the economy.
CONCLUSION This study shows that eye injuries represent a significant source of morbidity in Canada. The associated costs to society, both personal and financial, are extremely high. Prevention of eye injuries can provide significant financial savings to the health care system and the economy and can, at the same time, reduce the significant social and personal costs that may ensue as a result of vision loss.
Disclosure: The author has no proprietary or commercial interest in any materials discussed in this article. REFERENCES 1. Kuhn F, Morris R, Witherspoon CD, Mann L. Epidemiology of blinding trauma in the United States eye injury registry. Ophthalmol Epidemiol. 2006;13:209-16. 2. Canadian Ophthalmological Society 2007. Eye injury registry. Available at: www.eyesite.ca/english/press/eye-injury-registry.html. Accessed January 6, 2012. 3. Podbielski DW, Surkont M, Tehrani NN, Ratnapalan S. Pediatric eye injuries in a Canadian emergency department. Can J Ophthalmol. 2009; 44:519-22. 4. McGwin G, Xie A, Owsley C. Rate of eye injury in the United States. Arch Ophthalmol. 2005;123:970-6. 5. Wong TY, Klein BEK, Klein R. The prevalence and 5-year incidence of ocular trauma: The Beaver Dam Eye Study. Ophthalmology. 2000;107: 2196-202. 6. Katz J, Tielsch JM. Lifetime prevalence of ocular injuries from the Baltimore eye survey. Arch Ophthalmol. 1993;111:1564-8. 7. McCarty CA, Fu CLH, Taylor HR. Epidemiology of ocular trauma in Australia. Ophthalmology. 1999;106:1847-52. 8. Glynn RJ, Seddon JM, Berlin BM. The incidence of eye injuries in New England adults. Arch Ophthalmol. 1988;106:785-9. 9. Statistics Canada. Injuries in Canada: Insights from the Canadian Community Health Survey. Available at: www.statcan.gc.ca/pub/82-624-x/ 2011001/article/11506-eng.htm#a4. Accessed January 9, 2012. 10. Statistics Canada. Population by sex and age group. Available at: www.40.statcan.gc.ca/l01/cst01/demo10a-eng.htm. Accessed January 6, 2012.
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