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Regarding “Changes in Mortality after the Recent Economic crisis in South Korea”
LETTER Regarding ‘‘Changes in Mortality after the Recent Economic crisis in South Korea’’
Dear Editors: Kim et al. (1) report increased all-cause, cardiovascular, and stroke mortality that they attribute to increased unemployment, income inequality, and social isolation caused by the South Korean economic crisis. We have previously showed decreasing age-adjusted all-cause mortality during the 1990s (2, 3) and also recently examined the impact of the South Korean economic crisis on cause-specific mortality between 1996 and 2002 (4). Here we question two points about Kim et al.’s investigation. First, we question whether Kim et al.’s time series analyses are an accurate representation of real trends in all-cause and cause-specific mortality. Using time series analyses, Kim et al. estimated that 8426 deaths in 1999 were attributable to the economic crisis. They also determined that 9118 excess deaths from cardiovascular disease and 2691 excess deaths from ischemic heart disease (IHD) were likely due to the economic crisis. According to our calculation through the National Statistical Office’s (NSO) Korean Statistical Information System (5), the average numbers of deaths per year during the 1995 to 1997 period (the baseline period used in Kim et al.’s analysis) were 58,914 from cardiovascular disease and 6065 from IHD. Thus, the authors’ estimates (9118 cardiovascular deaths and 2691 IHD deaths) mean a 15.5% rise in cardiovascular mortality and 44.4% increase in IHD mortality in 1999. A 44.4% increase in IHD is similar to that observed during the Russian mortality crisis, where IHD mortality increased by 51% from 1991 to 1994 (6). Reading Kim et al. we wondered, if their estimates were accurate, why there was no report after 1999 on these alarming statistics from NSO of South Korea, which is responsible for monitoring trends in all-cause and causespecific mortality. In addition, we thought that 8426 excess deaths, which account for 3.5% of all deaths (about 240,000 deaths per year) in South Korea, might have dampened increasing trends in life expectancy. However, NSO of South Korea reported a graded increase in life expectancy at birth (73.53 in 1995, 74.39 in 1997, 75.55 in 1999, 76.53 in 2001) (7). The gain in life expectancy between 1997 and 1999 (75.55 ÿ 74.39 Z 1.16) was greater than the gain between 1995 and 1997 (74.39 ÿ 73.53 Z 0.86). Ó 2005 Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010
In addition, it should be noted that a previous South Korean study showed that age-adjusted mortality from cardiovascular disease and stroke decreased between 1995 and 1999 (8). As shown in Fig. 1, we computed age-standardized mortality rates for selected causes of death between 1990 and 2002 using mid-year population estimates of 5-year age groups (denominators) and death certificate raw data (numerators) from NSO of South Korea (5). The 2000 world standard population was the reference (9). We did not show age 0 and age 80C because infant mortality data is incomplete (10) and the proportion of ill-defined cause of death (e.g., senility) was high at age 80C, although inclusion of age 0 or age 80C produced similar results. The figures show that mortality rates from all-cause, cardiovascular disease, stroke, and transport accidents continued to decrease in both sexes during South Korea’s economic crisis. Although mortality from IHD and suicide did increase, these causes accounted for a relatively small proportion of total mortality. Given that there are some variations in cause-specific mortality trends during the precrisis years in Fig. 1, use of baseline data of longer periods (e.g., 1990–1997 data) rather than relatively short-term periods (1995–1997) in the authors’ analyses may present different results. Second, we question Kim et al.’s explanation about the role of the economic crisis in influencing cause-specific mortality. Binge consumption of alcohol played a major role in the abrupt increase in mortality from cardiovascular disease, external causes, and some infectious diseases during the Russian mortality crisis (6). However, National Tax Administration data on alcoholic beverages showed that delivered quantity of alcoholic beverages per person aged over 19 years decreased during the economic crisis: 87.4% in 1998 and 90.3% in 2000 compared with the 1996 level (11). In addition, Social Statistics Survey of NSO in 1999 presented similar levels of drinkers and lower levels of daily drinkers as compared with those in 1995 (11). Although Kim et al. suggested deteriorating psychosocial environments such as increased unemployment rates, income inequality, and a lack of social support, it is unclear whether those psychosocial factors can immediately affect cardiovascular mortality without other indirect behavioral pathways such as increased alcohol 1047-2797/05/$–see front matter doi:10.1016/j.annepidem.2004.09.015
Khang and Lynch LETTER
AEP Vol. 15, No. 7 August 2005: 535–537
Males aged 1-79
No. of death/ 100,000
Females aged 1-79
800
400
600
300
400
200 All-cause mortality
All-cause mortality
0 96 19
19
20
96 19
19
100
90
0 02
100
90
200
02
Cardiovascular disease
Cardiovascular disease
20
536
80
80
60 60
40 Cerebrovascular accident Transport accidents
40 Cerebrovascular accident Transport accidents
20
0
30
19
02 20
96
90
02 20
19
19
96
90
0 19
20
20 Ischemic heart disease
Ischemic heart disease
Suicide
Suicide
20 10 10
Year
02 20
96 19
90 19
02 20
96
0 19
19
90
0
Year
FIGURE 1. Trends in age-standardized mortality rate for selected causes of death at age 1–79 in South Korea, 1990–2002 (standardized to world standard population).
consumption. The increase in suicide death would be the most important phenomenon potentially linked with the economic crisis and has been reported elsewhere (12, 13). However, the increasing trends in IHD mortality between
1990 and 2002 are likely due to westernization of life style (e.g., increase in animal fat intake) (14) that has occurred in South Korea during the past decades, as the previous study suggested (8).
AEP Vol. 15, No. 7 August 2005: 535–537
Young-Ho Khang, MD, PHD Department of Preventive Medicine University of Ulsan College of Medicine Seoul, Korea John W. Lynch, PHD Department of Epidemiology University of Michigan School of Public Health Ann Arbor, MI
REFERENCES 1. Kim H, Song YJ, Yi JJ, Chung WJ, Nam CM. Changes in mortality after the recent economic crisis in South Korea. Ann Epidemiol. 2004;14: 442–446.
Khang and Lynch LETTER
537
5. National Statistical Office of Korea. Vital statistics. Available at: http:// kosis.nso.go.kr/. Accessed August 10, 2004. 6. Shkolnikov V, McKee M, Leon DA. Changes in life expectancy in Russia in the mid-1990s. Lancet. 2001;357:917–921. 7. National Statistical Office of Korea. Life tables. Available at: http://kosis. nso.go.kr/. Accessed August 10, 2004. 8. Suh I. Cardiovascular mortality in Korea: A country experiencing epidemiologic transition. Acta Cardiol. 2001;56:75–81. 9. United Nations Population Division. World Population Prospects: The 2002 Revision Population Database. Available at: http://esa.un.org/unpp/. Accessed December 18, 2003. 10. Han YJ, Lee SW, Jang YS, Kim DJ, Lee SW. Infant and Perinatal Mortality Rates of Korea in 1999 and 2000. Seoul: Korea Institute for Health and Social Welfare; 2002. 11. NSO (National Statistical Office of Korea) (2004). Social Indicators in Korea. Available at: http://kosis.nso.go.kr/. Accessed March 11, 2004.
2. Lynch J, Harper S, Davey Smith G. Commentary: Plugging leaks and repelling boardersdwhere to next for the SS Income Inequality? Int J Epidemiol. 2003;32:1029–1036.
12. Watts J. Suicide rate rises as South Korea’s economy falters. Lancet. 1998; 352:1365.
3. Khang YH, Lynch JW, Yoon SC, Lee SI. Trends in socioeconomic health inequalities in Korea: Use of mortality and morbidity measures. J Epidemiol Community Health. 2004;58:308–314.
13. Park JS, Lee JY, Kim SD. A study for effects of economic growth rate and unemployment rate to suicide rate in Korea. The Korean Journal of Preventive Medicine. 2003;36:85–91.
4. Khang YH, Lynch JW, Kaplan GA. Impact of economic crisis on causespecific mortality in South Korea. Int J Epidemiol. (under review)
14. Kim S, Moon S, Popkin BM. The nutrition transition in South Korea. Am J Clin Nutr. 2000;71:44–53.
Dear Editors: Kim et al. (1) report increased all-cause, cardiovascular, and stroke mortality that they attribute to increased unemployment, income inequality, and social isolation caused by the South Korean economic crisis. We have previously showed decreasing age-adjusted all-cause mortality during the 1990s (2, 3) and also recently examined the impact of the South Korean economic crisis on cause-specific mortality between 1996 and 2002 (4). Here we question two points about Kim et al.’s investigation. First, we question whether Kim et al.’s time series analyses are an accurate representation of real trends in all-cause and cause-specific mortality. Using time series analyses, Kim et al. estimated that 8426 deaths in 1999 were attributable to the economic crisis. They also determined that 9118 excess deaths from cardiovascular disease and 2691 excess deaths from ischemic heart disease (IHD) were likely due to the economic crisis. According to our calculation through the National Statistical Office’s (NSO) Korean Statistical Information System (5), the average numbers of deaths per year during the 1995 to 1997 period (the baseline period used in Kim et al.’s analysis) were 58,914 from cardiovascular disease and 6065 from IHD. Thus, the authors’ estimates (9118 cardiovascular deaths and 2691 IHD deaths) mean a 15.5% rise in cardiovascular mortality and 44.4% increase in IHD mortality in 1999. A 44.4% increase in IHD is similar to that observed during the Russian mortality crisis, where IHD mortality increased by 51% from 1991 to 1994 (6). Reading Kim et al. we wondered, if their estimates were accurate, why there was no report after 1999 on these alarming statistics from NSO of South Korea, which is responsible for monitoring trends in all-cause and causespecific mortality. In addition, we thought that 8426 excess deaths, which account for 3.5% of all deaths (about 240,000 deaths per year) in South Korea, might have dampened increasing trends in life expectancy. However, NSO of South Korea reported a graded increase in life expectancy at birth (73.53 in 1995, 74.39 in 1997, 75.55 in 1999, 76.53 in 2001) (7). The gain in life expectancy between 1997 and 1999 (75.55 ÿ 74.39 Z 1.16) was greater than the gain between 1995 and 1997 (74.39 ÿ 73.53 Z 0.86). Ó 2005 Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010
In addition, it should be noted that a previous South Korean study showed that age-adjusted mortality from cardiovascular disease and stroke decreased between 1995 and 1999 (8). As shown in Fig. 1, we computed age-standardized mortality rates for selected causes of death between 1990 and 2002 using mid-year population estimates of 5-year age groups (denominators) and death certificate raw data (numerators) from NSO of South Korea (5). The 2000 world standard population was the reference (9). We did not show age 0 and age 80C because infant mortality data is incomplete (10) and the proportion of ill-defined cause of death (e.g., senility) was high at age 80C, although inclusion of age 0 or age 80C produced similar results. The figures show that mortality rates from all-cause, cardiovascular disease, stroke, and transport accidents continued to decrease in both sexes during South Korea’s economic crisis. Although mortality from IHD and suicide did increase, these causes accounted for a relatively small proportion of total mortality. Given that there are some variations in cause-specific mortality trends during the precrisis years in Fig. 1, use of baseline data of longer periods (e.g., 1990–1997 data) rather than relatively short-term periods (1995–1997) in the authors’ analyses may present different results. Second, we question Kim et al.’s explanation about the role of the economic crisis in influencing cause-specific mortality. Binge consumption of alcohol played a major role in the abrupt increase in mortality from cardiovascular disease, external causes, and some infectious diseases during the Russian mortality crisis (6). However, National Tax Administration data on alcoholic beverages showed that delivered quantity of alcoholic beverages per person aged over 19 years decreased during the economic crisis: 87.4% in 1998 and 90.3% in 2000 compared with the 1996 level (11). In addition, Social Statistics Survey of NSO in 1999 presented similar levels of drinkers and lower levels of daily drinkers as compared with those in 1995 (11). Although Kim et al. suggested deteriorating psychosocial environments such as increased unemployment rates, income inequality, and a lack of social support, it is unclear whether those psychosocial factors can immediately affect cardiovascular mortality without other indirect behavioral pathways such as increased alcohol 1047-2797/05/$–see front matter doi:10.1016/j.annepidem.2004.09.015
Khang and Lynch LETTER
AEP Vol. 15, No. 7 August 2005: 535–537
Males aged 1-79
No. of death/ 100,000
Females aged 1-79
800
400
600
300
400
200 All-cause mortality
All-cause mortality
0 96 19
19
20
96 19
19
100
90
0 02
100
90
200
02
Cardiovascular disease
Cardiovascular disease
20
536
80
80
60 60
40 Cerebrovascular accident Transport accidents
40 Cerebrovascular accident Transport accidents
20
0
30
19
02 20
96
90
02 20
19
19
96
90
0 19
20
20 Ischemic heart disease
Ischemic heart disease
Suicide
Suicide
20 10 10
Year
02 20
96 19
90 19
02 20
96
0 19
19
90
0
Year
FIGURE 1. Trends in age-standardized mortality rate for selected causes of death at age 1–79 in South Korea, 1990–2002 (standardized to world standard population).
consumption. The increase in suicide death would be the most important phenomenon potentially linked with the economic crisis and has been reported elsewhere (12, 13). However, the increasing trends in IHD mortality between
1990 and 2002 are likely due to westernization of life style (e.g., increase in animal fat intake) (14) that has occurred in South Korea during the past decades, as the previous study suggested (8).
AEP Vol. 15, No. 7 August 2005: 535–537
Young-Ho Khang, MD, PHD Department of Preventive Medicine University of Ulsan College of Medicine Seoul, Korea John W. Lynch, PHD Department of Epidemiology University of Michigan School of Public Health Ann Arbor, MI
REFERENCES 1. Kim H, Song YJ, Yi JJ, Chung WJ, Nam CM. Changes in mortality after the recent economic crisis in South Korea. Ann Epidemiol. 2004;14: 442–446.
Khang and Lynch LETTER
537
5. National Statistical Office of Korea. Vital statistics. Available at: http:// kosis.nso.go.kr/. Accessed August 10, 2004. 6. Shkolnikov V, McKee M, Leon DA. Changes in life expectancy in Russia in the mid-1990s. Lancet. 2001;357:917–921. 7. National Statistical Office of Korea. Life tables. Available at: http://kosis. nso.go.kr/. Accessed August 10, 2004. 8. Suh I. Cardiovascular mortality in Korea: A country experiencing epidemiologic transition. Acta Cardiol. 2001;56:75–81. 9. United Nations Population Division. World Population Prospects: The 2002 Revision Population Database. Available at: http://esa.un.org/unpp/. Accessed December 18, 2003. 10. Han YJ, Lee SW, Jang YS, Kim DJ, Lee SW. Infant and Perinatal Mortality Rates of Korea in 1999 and 2000. Seoul: Korea Institute for Health and Social Welfare; 2002. 11. NSO (National Statistical Office of Korea) (2004). Social Indicators in Korea. Available at: http://kosis.nso.go.kr/. Accessed March 11, 2004.
2. Lynch J, Harper S, Davey Smith G. Commentary: Plugging leaks and repelling boardersdwhere to next for the SS Income Inequality? Int J Epidemiol. 2003;32:1029–1036.
12. Watts J. Suicide rate rises as South Korea’s economy falters. Lancet. 1998; 352:1365.
3. Khang YH, Lynch JW, Yoon SC, Lee SI. Trends in socioeconomic health inequalities in Korea: Use of mortality and morbidity measures. J Epidemiol Community Health. 2004;58:308–314.
13. Park JS, Lee JY, Kim SD. A study for effects of economic growth rate and unemployment rate to suicide rate in Korea. The Korean Journal of Preventive Medicine. 2003;36:85–91.
4. Khang YH, Lynch JW, Kaplan GA. Impact of economic crisis on causespecific mortality in South Korea. Int J Epidemiol. (under review)
14. Kim S, Moon S, Popkin BM. The nutrition transition in South Korea. Am J Clin Nutr. 2000;71:44–53.