Two Koreas, war and health

Despite news in the morning of missile attack threats by North Korea and associated countermeasures by South Korea, like most South Koreans I spend a peaceful weekend playing with my kids at a playground. I hear from my father, who recently moved from the southernmost island to Seoul, that he was treated for lunch by his elderly neighbours seeking information about the island in case of evacuation. Although living on the Korean peninsula has been implied to be very dangerous in the international media, the South Korean people have been rather calm, as they have already spent their lifetime under such sustained tensions and war threats. While assuming that verbal provocations by North Korea may not have any significant health impacts, as an epidemiology and public health researcher I reflect on how the Korean War (1950–53) and subsequent political situation have affected the health of the two Koreas, what lessons there would be for international research communities from comparison studies of the two Koreas, and what should be the appropriate response of public health professionals to a potential war. War has direct, indirect, short-term and long-term impacts on public health.1,2 The Korean War, despite often being referred to as ‘The Forgotten War’ or ‘The Unknown War’, inflicted massive human losses. A total of 1 255 000 soldiers and civilians have been estimated to have been killed in combat during the war.3 This number is equivalent to 60% of Vietnam War (1955–75) battle deaths and thus the second largest number of battle deaths and the largest number of annual battle deaths in the world since World War II.3 Another source of data reported 5 220 000 casualties (including the numbers of the injured and missing) from the two Koreas.4 Many children became orphans and many families (estimated around 10 million)4 were separated. Humanitarian adoption for those orphans after the war was the beginning of the so-called ‘baby exporting nation’. Until now, only about 4000 split families in South Korea have held their first reunion with North Korean family members, but most of the members of split families are getting too old or are passing away without having any chance for such a reunion. The Korean War was not a conflict between the two Koreas but an international armed conflict involving China, the USA and the first United Nations (UN) force from 21 countries. About 1 080 000 casualties from the UN and Chinese forces have been reported.4 The long-term effects of war are also important. One recent Korean study showed that cohorts born in the most difficult stage of the Korean War (1951) experienced poor economic and health outcomes.5 Soldiers from many countries that survived the war suffered from long-term mental health problems.6,7 The Korean War left the two Koreas, now the only country divided for opposing political ideologies, in a state of war without a peace treaty. With a shared ethnic background, 5000-year history, culture and language, South and North Korea have built different social systems during the 60-year armistice. South Korea became a free market economy whereas North Korea adopted a socialist regime. As shown in Table 1, the South and North Korean people now experience profoundly different socioeconomic and health conditions. Differences in health status are quite large. The difference in life expectancy (LE) between the two Koreas is around 12 years for both men and women. These LE differences are two times greater than the LE difference between the highest and lowest income quartiles in South Korea8 and greater than the LE differences between college graduates and those with an elementary education or less.9 Both early-life mortality and non-communicable disease mortality in later life might have contributed to these LE differences (see Table 1). In addition, this LE difference is much greater than the difference between East and West Germany, where the LE differences were greatest around reunification (3.54 years for men and 2.95 years for women).10 Infant mortality also showed a huge difference between the two Koreas, much greater than the difference in Germany.11 Comparison of general characteristics between the two Koreas Data source: Statistics Korea. North Korea Statistics. Available at: http://kosis.kr/bukhan/. Data on age-standardized NCD mortality rates are from World Health Organization’s NCD country profiles in 2011. Comparison of general characteristics between the two Koreas Data source: Statistics Korea. North Korea Statistics. Available at: http://kosis.kr/bukhan/. Data on age-standardized NCD mortality rates are from World Health Organization’s NCD country profiles in 2011. Although information on the estimated LE and mortality in North Korea exists, data showing the specific health status of the North Korean people are very scarce. North Korea is known as the most reclusive nation in terms of statistical data, as North Korea has not released any statistical yearbooks since the 1960s.12 Two data sources have been used to describe the nutrition and health status of North Korea. One is from nutrition surveys done by UN agencies (WFP and UNICEP), and the other is from surveys on North Korean refugees in China and South Korea. Based on the nutrition surveys of North Korean children, South Korean children were reported to be 3–8 cm taller than their North Korean counterparts.12,13 Anthropometric differences have also been found in the studies on North Korean refugees.14 Many studies by South Korean researchers have shown severe mental distress among North Korean refugees.15 However, except for these data, community sample data of health and health risk factors, especially for the North Korean adult population, are quite limited. Recently, North Korea participated in the World Health Organization STEPwise approach to Surveillance (WHO STEPS) in 2005, 2007 and 2008, and survey reports are available.16 The 2008 survey included population samples aged 25–64 years from 12 urban and rural areas of North Korea. The report provides 10-year age-specific sample sizes; age-specific prevalences (95% confidence intervals) of smoking, alcohol consumption, overweight and hypertension; and age-specific mean values (95% confidence intervals) of obesity (body mass index and waist circumference) and blood pressure (systolic and diastolic) measures. South-North comparison is possible using the information from North Korea and the 2008 Korean National Health and Nutrition Examination Survey (KNHANES) by the Korea Centers for Disease Control and Prevention of South Korea, with the world standard population as a referent.17 Comparison of 2005 and 2007 WHO STEPS data with the 2005 and 2007 KNHANES showed similar results (data available upon request). As seen in Table 2, the prevalences of daily smoking among men from the two Koreas were similar. However, the absolute smoking amount of daily smokers was about 50% greater in South Korean men than North Korean men. South Korean daily smokers started smoking earlier than their North Korean counterparts. No female smoking was reported in the 2008 WHO STEPS report, and this was also true for the 2005 and 2007 reports. In the two Koreas, huge gender differences in cigarette smoking were found, but this will be partly due to underreporting associated with the social stigma of female smoking.18 Comparison of major non-communicable disease risk factors among those aged 25–64 years between the two Koreas (prevalences or mean values with 95% confidence intervals). The findings are from the 2008 World Health Organization STEPwise approach to Surveillance (WHO STEPS)16 for North Korea and the 2008 Korean National Health and Nutrition Examination Survey (KNHANES)17 for South Koreaa aAge-adjusted prevalences of smoking, alcohol drinking, obesity and hypertension were estimated with the WHO standard population as the referent. For the North Korean statistics, the information on the age-specific sample size and the age-specific prevalences and means (and associated 95% confidence intervals) in the 2008 WHO STEPS report were used for the estimate, whereas 2008 KNHANES raw data were analysed for the South Korean statistics. Using the 2005 KNHANES data containing information on current and daily smoking, I estimated the proportion of daily smokers among current smokers (94% for men and 77% for women) and associated statistics for daily smokers (smoking initiation age and smoking amount). Overweight means a body mass index of 25 or more. Hypertension refers systolic/diastolic blood pressure at or above 140/90 mmHg or current medication for raised blood pressure. Comparison of major non-communicable disease risk factors among those aged 25–64 years between the two Koreas (prevalences or mean values with 95% confidence intervals). The findings are from the 2008 World Health Organization STEPwise approach to Surveillance (WHO STEPS)16 for North Korea and the 2008 Korean National Health and Nutrition Examination Survey (KNHANES)17 for South Koreaa aAge-adjusted prevalences of smoking, alcohol drinking, obesity and hypertension were estimated with the WHO standard population as the referent. For the North Korean statistics, the information on the age-specific sample size and the age-specific prevalences and means (and associated 95% confidence intervals) in the 2008 WHO STEPS report were used for the estimate, whereas 2008 KNHANES raw data were analysed for the South Korean statistics. Using the 2005 KNHANES data containing information on current and daily smoking, I estimated the proportion of daily smokers among current smokers (94% for men and 77% for women) and associated statistics for daily smokers (smoking initiation age and smoking amount). Overweight means a body mass index of 25 or more. Hypertension refers systolic/diastolic blood pressure at or above 140/90 mmHg or current medication for raised blood pressure. Large differences in alcohol consumption were found between the two Koreas. Compared with North Korea, South Korea demonstrated a greater prevalence of current drinking and binge drinking and a greater amount of alcohol consumption among current drinkers. Based on South Korea’s country profile from the recent Global Burden of Disease Study 2010, alcohol consumption was the second most important contributor (after dietary factors) to disability-adjusted life-years in South Korea.19 The difference in obesity measures is even more dramatic. More than 10 times greater overweight prevalence was recorded in South Korean than North Korean men. About 3 kg/m2 differences in body mass index were found in both men and women. South Korea had greater mean waist circumferences (9.1 cm for men and 4.4 cm for women) than North Korea. Supplementary Figure 1 (available as Supplementary data at IJE online) illustrates that adult men and women from the two Koreas are living in different worlds in terms of distributions in obesity measures. Despite the predominance in obesity measures in South Korea, hypertension prevalences showed a rather similar level among men of the two Koreas. In women, South Korea recorded a lower hypertension prevalence than North Korea. Systolic and diastolic blood pressures were lower in South Korean men and women than in their North Korean counterparts, but the pattern was clearer in women (Supplementary Figure 2, available as Supplementary data at IJE online). These findings have several implications. High consumption of cigarette and alcohol products in South Korea could be due to capitalistic production and marketing and uncontrolled consumption of unhealthy commodities. However, gender differences in smoking and alcohol consumption were similar. Huge differences in obesity measures would be due to both food shortages in North Korea and urbanization and food overconsumption in South Korea. South Korea showed greater overweight prevalence but lower blood pressure: divergent patterns in obesity and blood pressure measures have been reported in South Korea.20 Hypertension treatment might have partly contributed to these patterns. South Korean men showed lower blood pressures but similar hypertension prevalence (including those medicated) to North Korean men. Consumption of salt would be one candidate for explaining the patterns, but physical activity would not be, considering the difference in urbanization level. In addition, early-life exposures would be another important factor to be considered in explaining the difference in blood pressures. Based on the additional analysis of those aged 25–34 years, where hypertension treatment and behavioural modification after hypertension diagnosis are not prevalent, similar levels of differences in blood pressure were found between the two Koreas. Research on health and health risk factors in the two Koreas would provide a unique opportunity for epidemiology and public health. The experience of a six-decade separation of those of the same ethnicity and cultural background could provide a ‘natural experiment’ research setting, despite all the painful costs associated with what was actually a man-made experiment. Comparison of health measures between the two Koreas may reveal important population-level determinants. For example, research on blood pressure and its determinants in the children of both Koreas could provide a meaningful early-ife determinant of blood pressure. Wide variations in risk factors (as seen in the Supplementary Figures) could provide an exceptional opportunity for examining causal relationships between risk factors and health outcomes.21 Time trend studies on health measures between the two Koreas may reveal roles of lifestyle or environmental determinants as seen in a study on differences in allergy trends between East and West Germany.22 However, important barriers hinder such comparative studies between the two Koreas. One is the paucity of health data from North Korea, as mentioned before. The other, often neglected, is the aim of such studies. The results of health research in the two Koreas could be used politically as an instrument for regime propaganda and competition. Political sensitivity has prevented Korean researchers from doing such studies. Politics matter for population health and no research is nonpolitical. However, the epidemiological research on the two Koreas should be independent from political interests, since such political interests divert the issue from the public health standpoint to regime propaganda. The research should not aim to prove the predominance of South Korea’s health status over that of North Korea. Epidemiological research by the international research community will be helpful in this sense. The aim of the epidemiological studies should be to benefit both the South and North Korean people. For example, the research should provide an opportunity for South Korean men to realize how large a quantity of cigarette and alcohol products they consume. South Korea should realize that the high consumption of these unhealthy commodities is a phenomenon of an ‘industrial epidemic’ due to a laissez-faire market economy.23 Epidemiological studies on anthropometric measurements may reveal the need for anti-obesity policy measures in South Korea, including urban planning and food policies, whereas in North Korea, the need for an adequate food supply may be clarified. With such aims, research may contribute to closing the gap between the two Koreas in terms of both health status and its social determinants. During the current tension on the Korean peninsula, several militant arguments have been made. One US professor argued: ‘Bomb North Korea before it’s too late’.24 A famous politician in South Korea advocates a policy of South Korea developing their own nuclear weapons.25 From the viewpoint of public health, these assertions and similar arguments that escalate tensions are not helpful. Seoul, capital city of South Korea, is only 50 km from the Korean Demilitarized Zone, the most heavily militarized border in the world, despite its name. Pyongyang, capital city of North Korea, is within an hour’s distance from major airbases in South Korea. About 25 million people are densely concentrated in Seoul and surrounding areas. One ‘war game’ simulation study in 2004 by the South Korea’s Joint Chiefs of Staff predicted that 2.4 million deaths and injuries would occur on the first day of full-scale war,26 which is equivalent to the 10 year total number of deaths in South Korea. Primordial and primary prevention of war is thus critical, especially on the Korean peninsula. Social efforts to prevent war can be one of the practices of public health.1 Epidemiological research and public health practice, if the aim is firmly established to value the life and health of people first, could contribute to the prevention of war, to improving the health of the divided Koreas and to international epidemiological research. I thank Dr Sung-Cheol Yun (Department of Clinical Epidemiology and Biostatistics, Asan Medical Center, University of Ulsan College of Medicine) for his statistical support.