1. Background

The cases of the novel coronavirus disease (henceforth COVID-19) were first reported in Wuhan, China in December, 2019, and as this infectious disease gradually spread across the world, the World Health Organization (WHO) declared the novel coronavirus disease (COVID-19) outbreak a global pandemic on March 11, 2020 [1]. As of the end of September, 2022, the total number of confirmed cases of COVID-19 globally has exceeded 612.23 million, and 6.51 million of them died from COVID-19 worldwide [2]. In Korea, as of the end of September, 2022, the total number of confirmed cases of COVID-19 has exceeded 24.63 million, the cumulative number of deaths from COVID-19 is 28,246, and older adults aged 60 or older account for 93.6% of the total deaths from COVID-19 [3].

As the spread of COVID-19 and social distancing as a major preventive measure have continued for three years, prolonged pandemic and social distancing have led to an increase in the number of people suffering from depression throughout the society. According to the COVID-19 National Mental Health Survey First Quarter 2021, the proportion of the group at risk for depression is 22.8%, and this figure represents the percentage increased by about 6 times, compared to 3.8% in 2018 before the COVID-19 pandemic [4]. Briggs et al. [5] also reported that the proportion of the group at risk for depression among older adults residing in Ireland has more than doubled after the outbreak of COVID-19 from 7.2% in 2016 and 2018 to 19.8% in 2020. In particular, among older adults living alone, the proportion of the group at risk for depression has increased to 26.1% in 2020, compared to 10.2% in 2016 and 11.2% in 2018 before the COVID-19 pandemic, showing a considerable increase in the prevalence rate of depression among older adults living alone during the COVID-19 pandemic [5]. Therefore, there is a need to take measures for the prevention and management of depression due to COVID-19 and provide support for the group at risk for depression.

In the COVID-19 pandemic situation, the spread of COVID-19 infections and social distancing measures can act as risk factors for depression in older adults. Older adults are a high-risk group for COVID-19 infections, and as older adults stay at home to avoid COVID-19 infections, it results in a reduction in their physical activity, which increases the level of depression in older adults [6]. In addition, the COVID-19 pandemic was reported to cause poor sleep quality and changes in sleep hours in some older adults [6]. Moreover, restrictions on going out to public places and participation in social activities due to social distancing measures may have a negative effect on the emotional health of older adults [6]. In addition, with the spread of COVID-19 infections, the levels of fear and the psychological impact due to COVID-19 were reported to be higher in older adults vulnerable to coronavirus infections than in other age groups [7], and they were reported to affect depression in older adults [8]. A higher level of the psychological impact due to COVID-19 has been shown to be associated with a higher level of the practice of COVID-19 infection prevention and control rules [7], and it has been reported that the practice of COVID-19 infection prevention and control rules may affect depression in older adults [9]. Therefore, to understand depression in older adults, it is necessary to examine risk factors for depression due to the COVID-19 pandemic.

In particular, the COVID-19 pandemic may have a significant impact on depression in older adults living alone. This study was conducted using data from the 2020 Korea Community Health Survey. This survey was carried out from August to October, 2020, when the social distancing level was elevated to level 2 nationwide in Korea, and level-2 social distancing was implemented for 7 weeks. The implementation of level-2 social distancing included measures such as prohibition of unnecessary going out, gatherings and rallies, closing social welfare facilities, and prohibition of face-to-face worship services at churches [10]. These COVID-19 social distancing measures may cause a greater sense of social isolation in older adults living alone who get social support or emotional support through the use of senior centers or senior welfare facilities or participation in social activities than in older adults living with their families, and disconnection of social networks and increased social isolation may result in the increased prevalence rate of depression in older adults living alone [11]. In addition, in previous studies conducted before the outbreak of the COVID-19 pandemic, the prevalence rate of depression was found to be higher in older adults living alone than in those living together with their families [12, 13]. Likewise, the prevalence rate of depression was found to be higher in older adults living alone than in older adults with cohabitants during the COVID-19 pandemic [5]. Therefore, since older adults living alone are a vulnerable group that cannot share their feelings and experience about COVID-19 or receive direct care from their families, the rate of depression is likely to be higher in older adults living along than in other population groups. For this reason, it is important not only for individuals but also for the society to identify the influencing factors for depression.

Depression in older adults living alone has been reported to be related to sociodemographic factors, such as age [14], sex, educational level [13, 14], status of the basic livelihood security recipient (henceforth, basic living recipient) [13], economic status [14], and health-related factors such as subjective health status [14], chronic disease [12, 13, 14], and stress [12]. Although a number of studies have been so far conducted on depression in older adults living alone, there has been a lack of studies to investigate risk factors for depression in older adults living alone through a comprehensive and integrated analysis of risk factors for depression arising during the COVID-19 pandemic, so there is a need to examine such risk factors using a large data representative of the national population. Therefore, this study attempted to investigate factors associated with depression in older adults living alone during the COVID-19 pandemic by using data from the 2020 Korea Community Health Survey with the aim of presenting basic data for interventions for the prevention and appropriate management of depression in older adults living alone in the future.

2. Purpose

This study aimed to examine factors associated with depression among older adults living alone during the COVID-19 pandemic, and the specific objectives of this study are as follows:

1. Study Design

This study is a secondary data analysis using data from the 2020 Korea Community Health Survey to investigate factors associated with depression in older adults living along during the COVID-19 pandemic.

2. Participants

This study was conducted using data from the 2020 Korea Community Health Survey provided by the Korea Disease Control and Prevention Agency. The participants of the survey are adults aged 19 or older who were the household members of the sample households at the time of the survey. They were selected by a complex sampling design that initially extracts sample points based on the number of households by housing type in the administrative divisions of tong/ban/li by probability proportional to size (PPS) systematic sampling, and secondarily extracts sample households by systematic sampling. The 2020 Korea Community Health Survey was conducted from August 16 to October 31, 2020, and trained interviewers personally visited the selected sample households and conducted a one-to-one interview survey by the computer assisted personal interviewing (CAPI) method using a laptop. The contents of the survey included the basic demographic information of participants, health status, the presence of diseases, the use of medical services, the sociophysical environment, educational level, economic activities, the experience of symptoms related to COVID-19, the practice of personal rules for infection prevention and control, the practice of social distancing, changes in daily life, and psychological concerns [15]. The participants of this study were older adults aged 65 or older living alone who participated in the 2020 Korea Community Health Survey. Among a total of 229,269 respondents of the 2020 Korea Community Health Survey, only 18,824 older adults aged 65 or older living alone were included in this study by sequentially excluding respondents aged under 65 years (n=156,457), those with one or more cohabitants (n=53,812), and those who did not respond to any of the 9 items of a Korean version of the Patient Health Questionnaire-9 (PHQ-9) (n=176) (Appendix 1).

3. Measures

4. Statistical Analysis

Data analysis was conducted using the SPSS/WIN version 26.0 program. Analysis of complex sample design data was performed by applying the individual weight (wt_p), stratification variable (kstrata), and colony variable (spot_no) presented in the data of the 2020 Korea Community Health Survey to estimate the population. In this study,'Nonresponse', 'Do not know', and 'Not applicable' were treated as missing values, and the rate of missing values of independent variables ranged from 0.01% (smoking) to 13.1% (physical activity). To maintain the sample size and reduce the non-response error, data analysis was conducted by treating missing values as valid values in the complex sample design analysis. The variance inflation factor (VIF) value ranged from 1.01 to 1.93, indicating that there was no multicollinearity among independent variables. The specific analysis methods were as follows.

5. Ethical Considerations

The 2020 Korea Community Health Survey was used in this study after obtaining approval from the Statistics Korea (KOSTAT) (Approval No. 117075). The Korea Community Health Survey is de-identified data and does not include personally identifiable information [15], and this study received an exempt determination from the IRB of the relevant institution (IRB No. 4-2021-1402).

1. The Characteristics and Depression of Older Adults Living Alone

Table 1 shows the results of the complex sample frequency analysis for the characteristics and depression of older adults living alone. Among older adults living alone, the depression group accounted for 6.3%. With respect to factors related to changes in daily life due to COVID-19, 57.8% reported that the level of their physical activity was increased or similar, and 90.4% reported that their sleep hours were increased or similar. The frequency of meeting with friends or neighbors was decreased in 83.5%. Regarding factors related to the practice of COVID-19 infection prevention and control rules, 97.9% performed regular ventilation, but 60.8% did not perform regular disinfection. Most participants reported that they wore a mask indoors or outdoors. 93.8% responded that they kept in touch with close people even though they did not meet together. As for factors related to the psychological impact due to COVID-19, for concerns about COVID-19 infection, the respondents who answered 'Yes' accounted for the largest proportion, and the group who answered 'No' took up the smallest proportion. In the case of concerns about death from COVID-19 infection, concerns about criticism from others due to COVID-19 infection, and concerns about economic damage due to COVID-19, the group who answered'Yes' took up the largest proportion of the responses, and the group who answered 'Average' accounted for the smallest percentage. Regarding the question about the number of people who can help the participant during quarantine treatment or self-quarantine, 74.6% responded that there was at least one person who could help them.

Table 1 Characteristics of the Participants (N=18,824) Click for larger image

With respect to sociodemographic factors, female accounted for 75.7%. As for age, the 65~74 age group made up the largest proportion (47.0%), followed by the 75~84 age group (42.7%) and the age group aged 85 and over (10.3%). As to educational level, people with the educational level of elementary school or lower accounted for 63.9% of the participants. In addition, 81.5% of the participants were not basic living recipients, 75.6% did not do any economic activities, and 67.3% resided in urban areas. In terms of health-related factors, for self-rated health status, 38.4% self-rated their health status as fair, 31.6% as poor, and 30.0% as good. 92.0% were non-smokers, and 72.0% were non-drinkers who did not consume alcohol at all. 88.2% reported that they ate breakfast every day during a week, and 85.4% reported that they did not feel stressed (Table 1).

2. Differences in Depression according to the Characteristics of Older Adults Living Alone

Table 2 shows the results of the complex sample Rao-Scott χ² test on differences in depression according to the characteristics of older adults living alone. Among older adults living alone, there were significant differences between the depression group and the non-depression group in all variables other than the following variables: wearing a mask outdoors, concerns about COVID-19 infection, concerns about death from COVID-19 infection, concerns about criticism from others due to COVID-19 infection, and sex. The proportions of people reporting decreased physical activity and those reporting decreased sleep hours were higher in the depression group than in the non-depression group. The proportion of people with an increased or similar frequency of meeting with friends or neighbors was also higher in the depression group (p<.001). The depression group showed a lower rate of wearing a mask indoors (p=.004). The rates of performing regular ventilation and regular disinfection were also lower in the depression group, and the rate of not meeting but keeping in touch with close people was also lower in the depression group (p<.001). The depression group showed less concerns about economic damage due to COVID-19, and the proportion of older adults without any persons who can help during quarantine treatment or self-quarantine was higher in the depression group (p<.001).

Table 2 Differences in Depression according to Variables Click for larger image

The age of the depression group was higher than that of the non-depression group, and the proportion of people with the educational level of elementary school or lower was higher in the depression group. Also, the proportion of basic living recipients, the proportion of people not doing economic activities, and the proportion of people living in urban areas were higher in the depression group (p<.001). Moreover, the proportion of smokers was higher in the depression group, while the proportion of drinkers was lower in the depression group (p=.003, p=.001). Further, the proportion of people not having breakfast every day during a week was higher in the depression group, and the proportion of people feeling stressed was also higher in the depression group (p<.001) (Table 2).

3. Factors associated with Depression in Older Adults Living Alone during the COVID-19 Pandemic

Table 3 shows the results of the complex sample multiple logistic regression analysis performed to identify factors associated with depression in older adults living alone. The result of calculating the odds ratios for depression in older adults living alone according to independent variables are as follows. First, with respect to the relationship between depression and factors related to changes in daily life due to COVID-19 among older adults living alone, the group of older adults living alone with a decreased amount of physical activity was found to be 1.42 times more likely to have depression than the group with an increased or similar amount of physical activity (95% Confidence Intervals [CI]=1.13~1.78), and the group reporting a decrease in sleep hours was shown to be 2.03 times more likely to have depression than the group with increased or similar sleep hours (95% CI=1.52~2.72). Also, the group with a decreased frequency of meeting with friends or neighbors was 0.69 times less likely to have depression than the group with an increased or similar frequency of meeting with friends or neighbors (95% CI=0.51~0.93). In terms of factors related to the practice of COVID-19 infection prevention and control rules, the group not practicing regular disinfection was 1.31 times more likely to have depression than the group performing regular disinfection (95% CI=1.03~1.67), and the group not wearing a mask indoors was 3.09 times more likely to suffer from depression than the group wearing a mask indoors (95% CI=1.35~7.08).

Table 3 The Results of Multiple Logistic Regression Click for larger image

With respect to the association between depression and sociodemographic factors, the ≥85 age group was found to be 1.68 times more likely to have depression than the 65-74 age group (95% CI=1.15~2.46). Also, basic living recipients were 1.57 times more likely to have depression than non-recipients (95% CI=1.22~2.02). Meanwhile, the odds ratio of depression for the group doing economic activities compared to the group not doing economic activities was 0.45 (95% CI=0.33~0.63). In terms of health-related factors, the group with fair self-rated health status and the group with poor self-rated health status were found to be 1.93 times and 6.88 times more likely to have depression, respectively, compared to the group with good self-rated health status (95% CI=1.23~3.03; 95% CI=4.44~10.66). Also, the group not having breakfast every day during a week was shown to be 2.06 times more likely to have depression than the group having breakfast every day (95% CI=1.54~2.75), and the group feeling stressed was found to be 5.42 times more likely to have depression than those not feeling stressed (95% CI=4.35~6.76) (Table 3).