In April 2014, the Sewol ferry disaster was a tragic event in Korea. The Sewol ferry sunk in the southern area of the West Sea in Korea with 476 passengers on board, including 325 students and 14 teachers from Danwon High School. Only 172 passengers survived, and 304 passengers died in the disaster. In total, 250 students and 11 teachers from Danwon High School died in this accident, and the sinking of the Sewol ferry harshly traumatized the Korean society.Reference Woo, Cho and Shim1 The mental health impacts of Ansan citizens and Danwon High School students were greater because many of the dead were students from Danwon High School located in Ansan (Figure 1).
FIGURE 1 Maps of the Affected Community (Ansan) and Danwon High School.
Disaster exposure affects the mental health of the victims and the community, often causing serious mental problems, such as posttraumatic stress disorder (PTSD) and acute stress disorder.Reference Rosen, Zhu and Shao2,Reference Bromet, Atwoli and Kawakami3 After a disaster, directly-affected victims and communities may also experience psychological problems, such as depression, anxiety, and suicide.Reference Han, Yun and Huh4,Reference Chae, Huh and Choi5 Even those community members who were not affected directly by the disaster experienced trauma-induced symptoms, including sleep disturbances or concentration problems.Reference Lee, Bhang and Lee6 These mental health problems can lead to notable social disruption and affect the health problems of the community.
In addition to mental health problems, physical health can be affected following a disaster.Reference Mukherjee, Clouston and Kotov7 After experiencing a disaster, the prevalence of chronic diseases, including cardiovascular disease, increases.Reference Hokimoto8 Additionally, people with chronic diseases receive worse management of the disease because there are changes in diets and physical activities that could affect physical health status and chronic disease management.Reference Fonseca, Smith and Kuhadiya9 Disasters also tend to impact the entire populationʼs physical and mental health, such as depression.Reference Fan, Prescott and Zhao10 Particularly, health care in a population can be neglected. However, to our knowledge, there has been no report about the impact of disaster on the health care of affected communities, specifically regarding medical screening examination and vaccination rates.
To address this research gap, our study examines the difference between health screening rates and vaccination rates between disaster-affected and unaffected cities. Our primary research aim was to examine the association of disaster exposure with national health screening program examination, cancer screening rate, and vaccination rate. Additionally, we explored the effect of depressive symptoms after a disaster on health and cancer screening rates and vaccination rates.
METHODS
Data
Data from the 2011–2016 Korea Community Health Survey (KCHS) were used for this study.Reference Kang, Ko and Kim11 The KCHS was conducted by the Korea Centers for Disease Control and Prevention and was performed by extracting an average of 900 population groups representing communities. Participants were adults ages 19 years and above, who were selected through a probability proportional to size systematic sampling. This survey was performed using a 1:1 direct interview conducted through computer-assisted personal interviewing. Among the study participants were 5524 persons who lived in Ansan city and participated in the survey in 2011–2013 (before the disaster), and 5502 participants who lived in Ansan and participated in the 2014–2016 survey (after the disaster). As a control group, all respondents living outside of Ansan city were included: 681 404 persons in 2011–2013 and 680 220 persons in 2014–2016.
Measurements
In this study, the questionnaire items related to the health screening examination (national health screening programs), cancer screening examination, influenza vaccination, age, sex, educational status, marital status, employment status, depressive mood, stress level, and health status were used in the analysis. The National Health Insurance Service in Korea conducts national health screening programs annually, consisting of the general health screening program and the transitional age health screening program.Reference Cheol Seong, Kim and Khang12 The stress level of daily life was measured through the following questions: “How much stress do you usually feel in your daily life?”Reference Lim, Williams and Hagen13 (Available answers were “very stressful,” “somewhat stressful,” “not very stressful,” and “not stressful at all”). Individuals with a depressed mood were defined as providing a “yes” answer to the question: “Have you ever felt sad or hopeless enough, which interfered with your daily life in the past year?”Reference Blozik, Scherer and Lacruz14 Self-reported health status was measured by a single-item self-reported indicator: “In general, how would you rate your health?”Reference Idler and Benyamini15 Responses to questions were “poor,” “fair,” “average,” “good,” and “excellent.” Receiving health screening and cancer screening examinations was defined as answers of “yes” to the question: “Have you ever had a health screening (or cancer screening) examination to check your health, even if you have no health problems in the last two years?” Receiving influenza vaccination was defined as an answer of “yes” to the question: “Have you been vaccinated for influenza in the last year?” The validity of the health screening questionnaire was confirmed.Reference Rim, Kim and Lee16
Statistical Analysis
In this study, the proportions of those who received and did not receive health checkups, cancer screenings, and vaccines were examined during the 2011–2013 and 2014–2016 periods before and after the Sewol ferry disaster occurred. The Sewol accident occurred in April 2014, and the 2014 Community Health Survey was conducted in October. Therefore, responses in 2014 were considered as post-disaster. We compared the rates of health checkups (national health screening programs), cancer screening examination, and vaccinations between respondents living in Ansan and non-residents. We performed a logistic regression analysis to investigate the difference. In logistic regression analysis, univariate and multivariate logistic analyses were performed. To determine the effect of post-accident depression on vaccination and screening rates, we divided the respondents in 2014–2016 by depression. We confirmed the difference in the health and cancer screening and vaccination rates between residents and non-residents in Ansan through ratio analysis and logistic regression analysis. We used Stata version 14.2 (StataCorp, College Station, TX) for all statistical analyses. A 2-sided P < 0.05 was considered statistically significant.Reference Hazra17
RESULTS
Depressive Mood, Stress, and Health Status of Participants in 2011–2013 and 2014–2016
In comparing before (2011–2013) and after (2014–2016) the Sewol accident, the depression of Ansan residents rose from 9.3% to 10.1%, whereas the depression rate of non-residents in Ansan increased from 5.4% to 6.6% (Table 1). In the case of stress level, the percentages of highly stressed Ansan residents rose from 4.7% to 5.1% and from 3.3% to 3.7% for non-residents in Ansan. In the case of self-reported health status, the respondents who reported that they had an excellent health status decreased from 5.8% to 5.1% for Ansan residents, and decreased from 6.1% to 5.7% for non-residents in Ansan. Group differences in the change of depressive mood, stress, and health status were not significant.
TABLE 1 Differences in Health Screening, Cancer Screening, and Vaccination Rates Between Ansan Residents and Non-Residents (Classified Before and After the Sewol Ferry Disaster)
a Adjusted for age, sex, educational status, marital status, employment status, depressive mood, stress level, and health status.
OR = odds ratio.
Differences in Health Screening, Cancer Screening, and Vaccination Rates Between Ansan Residents and Non-Residents
In the 2011–2013 period, there was no difference in the rate of medical screening examination between residents and non-residents in Ansan when adjusted for sociodemographic factors, depression, stress level, and health status (adjusted odds ratio [aOR] = 1.06; 95% CI = 0.96 to 1.17; P = 0.257; see Table 1). There was no significant difference in cancer screening (aOR = 0.96; 95% CI = 0.87 to 1.06; P = 0.425). However, in the case of influenza vaccination, residents in Ansan city showed a significantly lower vaccination rate even before the Sewol ferry accident (aOR = 1.09; 95% CI = 1.02 to 1.15; P = 0.009). In 2014–2016, those who did not live in Ansan city received more health screening (aOR = 1.13; 95% CI = 1.07 to 1.20; P < 0.001), more cancer screening (aOR = 1.41; 95% CI = 1.33 to 1.49; P < 0.001), and more vaccination than residents in Ansan (aOR = 1.10; 95% CI =1.04 to 1.17; P = 0.002). Vaccination rates showed a significant difference in both periods, but, in 2014–2016, there was a greater difference in proportions (ratio difference = 11.2% in 2014–2016, and 10.3% in 2011–2013).
Differences in Health Screening, Cancer Screening, and Vaccination Rates in 2014–2016 Between Ansan Residents and Non-Residents According to Having a Depressed Mood
When comparing Ansan residents and non-residents after the Sewol ferry incident, there was no difference in the medical screening examination (aOR = 1.05; 95% CI = 0.88 to 1.25; P = 0.611) and vaccination rates in the depressed mood group (aOR = 0.90; 95% CI = 0.75 to 1.09; P = 0.281; Table 2). However, in the depressed mood group, cancer screening rates were significantly higher among those not living in Ansan (aOR = 1.30; 95% CI = 1.09 to 1.56; P = 0.003). In the group without depressed mood, non-residents in Ansan received more health screening (aOR = 1.26; 95% CI = 1.08 to 1.48; P = 0.035), cancer screening (aOR = 1.41; 95% CI = 1.33 to 1.50; P < 0.001), and vaccination (aOR = 1.12; 95% CI =1.05 to 1.20; P < 0.001) than residents in Ansan. In the case of cancer screening rate, the difference in screening rate was significantly greater in the group without depression (difference in proportion = 13.6% in the group without depressed mood, and 8.4% in the group with depressed mood).
TABLE 2 Differences in Health Screening, Cancer Screening, and Vaccination Rates in 2014–2016 Between Ansan Residents and Non-Residents (Classified as Having Depressed Mood or Not)
a Adjusted for age, sex, educational status, marital status, employment status, stress level, and health status.
OR = odds ratio.
DISCUSSION
This study showed that the Sewol ferry disaster affected the community medical screening examination, including cancer screening and influenza vaccination rates. People living in the same area as disaster victims tended to receive fewer health checkups and vaccinations after the disaster, even if they did not directly experience the disaster. This difference was more evident in the group without a depressive mood, indicating that attention should be paid to health care even in groups that did not have mental health problems after the disaster.
Health concern for a society after a disaster is mainly focused on psychiatric aspects.Reference North and Pfefferbaum18 Especially in the case of disasters that result in many deaths, such as the Sewol disaster, many psychiatric problems, such as PTSD, can occur.Reference Yang, Kim and Lee19 However, in addition to psychiatric problems after a disaster, various health problems arise in the community. These health changes may be related to changes in socioeconomic status after a disasterReference Nagai, Ohira and Zhang20 or may be due to neglect of health care after a disaster. A previous study showed that residents in disaster areas were more likely to drink alcohol, which may affect their mental or physical health.Reference Ueda, Yabe and Maeda21 Moreover, disasters affect health behaviors, such as tobacco use and drug use.Reference Turner, Alderman and Huang22 In other words, the occurrence of a disaster could affect not only physical and mental health, but also health behavior.
However, the impact of disasters on preventive health care utilization, such as health screenings, is not yet known. Considering the long-term impacts of disasters on health,Reference Lawrence, Lin and Lipton23,Reference Tomata, Suzuki and Kawado24 identifying the impact of disasters on preventive health care utilization may be necessary to investigate the influences of disasters on community health. This study confirmed that disasters adversely affect the health concerns of residents. Neglect of health screenings and vaccinations in disaster areas could lead to long-term health burdens in the community. Specifically, disasters could increase the burden on physical health, as well as on mental health care in disaster areas. In view of the results of previous work that an increase in the incidence of diseases requires chronic management among disaster residents,Reference Wong and Li25 it is thought that this reduction in preventive health care utilization could have a marked impact on community health.
In order to consider the possibility of PTSD or post-disaster depression affecting health screening and vaccination, the participants were divided into 2 groups, namely, those who reported a depressive mood and those who did not. As a result, there was no significant difference in the screening rate and vaccination rate in the depressed mood group, but a significant difference was found in the non-depressed mood group. Accordingly, it could be confirmed that depression after the disaster did not affect health care. This finding means that even non-depressed populations are likely to have long-term health effects after a disaster. Based on our findings, we should also pay attention to screening and vaccination when managing population health in disaster areas.
Limitations
This study has several limitations. First, because of the cross-sectional nature of the data, we were unable to examine causal relationships between disaster and health screening or vaccination. Second, this study is based on self-response and may be underestimated. Finally, the results of the study may not be directly applied to other countries. Nevertheless, the study provides insights into the relationship between disasters, medical screening, and vaccination. Prospective studies may explore situations in other kinds of disasters and the causal relationship between disasters, medical screening examination, and vaccination.
CONCLUSIONS
People living in disaster areas tended to show lower rates of medical screening examination and receive fewer vaccinations after the disaster. Especially, the difference between screening rates and the vaccination rates was noticeable in the group that did not report a depressive mood. Decreased health screening and vaccination after a disaster could be associated with increased long-term health burdens. To reduce health impacts after a disaster, increased community health screenings and vaccinations may be needed.
Financial Support
This study was supported by the Seoul National University Hospital (SNUH) Research Fund [grant number 04-2019-0020]. None of the funding organizations had any role in the design of the study, analysis, or interpretation of the data, or in the preparation, review, and approval of the manuscript.
Conflict of Interest Statement
The author has no conflict of interest to declare.
Supplementary material
To view supplementary material for this article, please visit https://doi.org/10.1017/dmp.2020.29
