The pattern of stressful life events prior to suicide among the elderly in rural China: a national case-control psychological autopsy study

Background: There is a lack of evidence concerning the stressful life events experienced prior to suicide which may be associated with an increased suicide risk for Chinese rural elderly. The aim of this study was to identify the pattern of stressful life events prior to suicide among the elderly in China. Methods: A total of 12 counties were randomly selected using two-stage strati�ed cluster sampling method. Suicide cases aged 60 years and older (n =242) were collected from those counties from June 2014 to September 2015. Matched living controls were selected 1:1 with suicide cases by age, gender, and location. Data in the study were collected through face-to-face interviews by a psychological autopsy method. The Life Event Scale for the Elderly was used to measure the stressful life events prior to suicide/interviews. Results: Approximately 99.6% of suicide cases and 88.4% of controls experienced at least one stressful life event. The suicide group experienced more long-term stressful life events than recent stressful life events. The top three most frequent stressful life events for the suicide group were being diagnosed with chronic disease, hospitalization, and being diagnosed with terminal illness. More female suicide cases experienced the death of a spouse, while more males experienced hospitalization, diagnosis with terminal illness and family poverty. Experiencing at least one stressful life event, having unstable marital status, physical diseases and mental disorders were the factors that increased the risk of suicide. Conclusions: Stressful life events were common for the rural elderly, especially long-term stressful life events. The experience of at least one stressful life event can increase suicide risk for this population. More attention should be given to the rural elderly who experienced more long-term stressful life events and experienced health related life events.


Background
Suicide is a major public health and mental challenge for people all over the world.The global agestandardized suicide rate was 10.6 per 100,000 in 2016.The suicide rate is the highest in people aged 70 years and older for both men and women in almost every region in the world [1].In China, the agestandardized suicide rate (per 100, 000) was 8.0 in 2016 [1].In the age groups 60-69, 70-79, 80+, the suicide rates were 23.4,44.0, and 61.3 [2], respectively, which were approximately 3 to 8 times higher than the rate in the general population.Furthermore, the suicide rates in rural areas are higher than those in urban areas in China [3].Considering the pressure of the aging population, suicide prevention among the older adults in rural China is of great signi cant.
Family problems, work stress and physical diseases are the major stressful life events that most people experience [4].These major stressful life events were reported to be high-risk factors for suicide through psychological strain [5][6][7].A population-based study reported that those stressful life events are positively associated to suicide [8].Stressful life events may increase the probability of people killing themselves.
Stressful life events have been identi ed as factor increasing suicide risk by a number of empirical studies [9].Life events have been linked to suicide among younger and older individuals, including Western, as well as Chinese youth [7].The relationship between stressful life events and suicide suggests that stressful life events may be associated with suicide among Chinese rural elderly which has not been tested yet [10].
The frequency of stressful life events is an important aspect related to the risk of suicide.One previous study reported that suicide risk increased with the frequency of life events [11].People who experience more stressful life events are more likely to kill themselves.Routine risk assessments of vulnerable groups and an assessment of the variety of events which may indicate which individuals may be at immediate risk are necessary [12].
The relationship between stressful life events and suicidal behaviors among vulnerable people has been well studied, excluding Chinese rural elderly.To the best of our knowledge, no study has ever focused on the stressful life events happening prior to suicide among Chinese rural elderly.The purpose of this study was to summarize the pattern of stressful life events prior to suicide among elderly living in rural areas with psychological data.

Participants and procedures
A two-stage strati ed cluster sampling method was used to select research sites.Three provinces were randomly selected from the GDP ranking of the top 10, 11-20, 21-31 provinces in mainland China which are Shandong, Hunan, and Guangxi.Counties were divided into three stratums based on average income within each province.Counties were randomly selected from each stratum, and total of 12 counties were selected as research sites.A case-control psychological autopsy study was devised and implemented from June 2014 to September 2015 [13,14].
In each of the selected counties, suicide cases aged 60 years and older were collected consecutively from the death certi cation system.The controls were community members matched with suicide case by age (± 3 years), gender, and location.For every participant, two informants were selected to obtain the data related to them.Generally, the rst informant was a family member, and the second informant was a friend, a neighbor, or other important people.For each pair of suicide and control, 4 interviews were conducted, a total of 968 interviews were completed for 242 pair.The survey was conducted through face-to-face interview with an average interview time of 90 minutes.
The investigators consisted of teachers and graduate students from Shandong University, Central South University and Guangxi Medical University.All investigators were trained intensively for 10 days in a standardized way on the instruments and the skills of the interview.
The study was approved by the Institutional Review Board of the Shandong University, Central South University, and Guangxi Medical University.The aim and procedure of the research were explained to all participants.Written informed consent was obtained before interviews were conducted.

Measurements Demographic characteristics
Demographic variables included age (in years), gender (male/female), marital status (stable/unstable), family income (yuan), if having a physical disease (yes/no), if having a mental disorder (yes/no), if living alone (yes/no) and left behind by children (yes/no).In the study, people who were married and living with a spouse, or cohabitation with a partner were classi ed as "stable marital status", while people with other marital status were classi ed as "unstable".
Stressful life event for the elderly Stressful life events were measured by the Life Events Scale for the Elderly (LESE), which was developed speci cally for older Chinese adults [15].LESE is a valid and reliable scale among the elderly generally, and elderly people who died by suicide in particular [15,16].A total of 46 life events were categorized into three separate categories: (1) Health/Hospital (16 items); (2) Family/Home (18 items); (3) Friends/Relationships (12 items).Each life event was assessed by ve questions: (1) The date it happened (never occur, one month, one year, and more than one year); (2) Whether it was positive or negative for the participant; (3) The effect on participants' mental health, measured by a ve-point Likert scale from 1 = no impact, to 5 = very severe impact; (4) The duration of the event (three months, six months, one year, and more than one year); and (5) The number of times it happened.
Both positive and negative life events can cause a psychological stress response to the participants.Stressful life events included positive life events as well as negative.In this study, stressful life events happened within one month were converted to recent stressful life event.Stressful life events happened within one year (excluding one month) or more than one year were converted to long-term stressful life events.

Statistical analysis
The information provided by two informants was combined as proxy data for the suicides and controls.The demographic characteristics based on the information provided by the rst informant was relied on.Answers which were associated with an increased risk of suicide were used when two informants reported differently for each item of LESE.The rationale for this practice is that a targeting behavior may exist as long as one of the two informants has observed it.
All participants were divided into two groups using the median number of stressful life events.The t-test and chi-square test were used to compare the difference of demographic characteristics between the elderly who experienced fewer life events and more life events both among suicides and living controls.Chi-square test was used to analyze the incidence of 46 stressful life events between suicides and controls.Chi-square test was also used to compare the frequency of the top 10 stressful life events between males and females among suicide cases.Logistic regression analysis was used to explore the relationship between stressful life events and suicide.
All analyses were performed using SPSS 24.0 for Windows (SPSS Inc, Chicago, IL).In the study, statistical signi cance was determined if P less than 0.05.

Demographic characteristics between suicides and controls by number of stressful life events
A total of 242 suicide cases and 242 living controls were included in this study.The number of stressful life events prior to suicide/interview ranged from 0 to 16 with a median value of 4 (Interquartile Range=5) among all participants.As shown in Table 1, suicide cases and controls were divided into two groups according to the median number of stressful life events they experienced.There were no signi cant differences between most demographic characteristics between suicide cases experiencing more stressful life events and those experiencing fewer.Individuals who died by suicide were diagnosed with mental disorders or left behind by children experienced more stressful life events than those without a mental disorder or not left behind by children.Living controls with unstable marital status, who lived alone, had physical diseases or were left behind by children experienced more stressful life events than controls with a stable marital status, who lived with others, did not have physical diseases, or had not been left behind by children.

Stressful life events by time among the suicide and living control cases
The incidence of recent stressful life events and long-term stressful life events for suicide cases were 32.6% and 98.3%, while the incidences for controls were 17.8% and 86.4%.As presented in Table 2, the incidence of recent stressful life events and long-term stressful life events for suicide cases were both signi cantly higher than those for controls (P<0.05).

Comparison of all items of stressful life events between the suicide and living control cases
The LESE contained a total of 46 items for life events.As presented in Table 3, the incidences of most stressful life events among suicide cases was higher than those among controls.The incidences of two categories of stressful life events, which were Health/Hospital and Family/Home were signi cantly higher among the suicide group than among controls.Health/Hospital was the most reported for both suicide cases and living controls (97.5% and 83.9%).

Comparison of top 10 stressful life events by gender among suicide cases
As shown in Table 4, the top three most reported stressful life events in individuals in the suicide group were being diagnosed with a chronic disease, hospitalization, and being diagnosed with a terminal illness.The same three most reported stressful life events were also observed in males.While, the top three stressful life events for female suicide cases were being diagnosed with a chronic disease, hospitalization, and the death of a spouse.More females experienced the death of a spouse than males.The frequency of hospitalization, being diagnosed with a terminal illness, and family poverty in males were signi cantly higher than in females.
In uence factors for suicide among the Chinese rural elderly A total of 484 elderly were enrolled in the logistic regression model.After adjusting the variables of living alone and left behind by children, the model identi ed four factors which were all signi cant increasing the risk of suicide among Chinese rural elderly, as shown in Table 5. Elderly people with an unstable marital status, physical diseases, mental disorders or who have experienced at least one stressful life event were more likely to kill themselves.

Discussion
The major ndings in the current study were: (1) Chinese rural elderly left behind by children experienced more stressful life events; (2) the incidence of long-term stressful life events were higher than that of recent stressful life events for the rural elderly; (3) the most common stressful life events for suicide cases were being diagnosed with a chronic disease, hospitalization, and being diagnosed with a terminal illness; (4) experiencing at least one stressful life event, had unstable marital status, had physical diseases and diagnosed with mental disorders were the factors that increasing the probability of suicide for rural elderly in China.
Elderly who experienced at least one stressful life event were at higher risk to kill themselves.This nding has been reported by previous studies [17].Furthermore, for rural elderly, a great number of empirical studies supporting stressful life events were associated with increased psychosocial distress and poor pain management [18,19].The experiences of new stressful situations can lead to suicidal behaviors [20].The elderly lived in worse conditions and this seemed to increase the risk of suicide.People prior to suicide are not sensitive to a particular event that triggers suicide, but they are sensitive to a whole set of living conditions, many of which contribute to the behavior of suicide [21].This study emphasizes the important role of stressful life events for suicide among Chinese rural elderly.
Long-term stressful life events were more common than recent stressful life events for both suicide cases and controls.Stress from life events accumulated and increased the risk of suicide.Accompanied with increasing age for the elderly, some stressful life events maybe always be present, including physical illness, death of a spouse, and poverty.The incidence of at least one long-term stressful life event for older suicide cases was higher than that for younger suicide cases in rural China.The impact of long-term stressful life events on their suicide decision may be more profound.In our study, approximate 98.3% of suicide cases experienced long-term stressful life event, and 32.6% of suicide cases experienced recent stressful life events.However, 82.4% of younger suicide cases experienced long-term stressful life events and 41.8% experienced recent stressful life events in an early psychological autopsy study in Chinese rural areas [22].The difference between the incidences of long-term and recent stressful life events among rural younger and older individuals may indicate the impulsive personalities of young and old suicide cases.More attention needs to be paid to long-term stressful life events for rural elderly and reduce their stress.
The results suggested that elderly left behind by children experience more stressful life events.Similar results were reported by a previous study.Being left behind by children parallels long-term separation and lack of social support, company, and care from family members, which may be profound in itself [18].Nowadays, most of the young people in rural area leave their parents and hometown for a better life.Those elderly are more vulnerable to many stressful life events, such as self-care di culties, family poverty, and children leaving home.Besides, the elderly living in rural area are more likely to experience various stressful life events due to a worse quality of life and smaller social circle, as well as a poorer self-perceived health status [23,24].
The most common stressful life events for elderly suicide in rural China were health related.The top three frequently stressful life events among suicide cases were being diagnosed with a chronic disease, hospitalization, and being diagnosed with terminal illness.When people become old, physical diseases cannot be avoided due to the natural aging of organs for the elderly.Similar to ndings in previous literatures, the current study supported having psychical illness as a factor which increased suicide risk [25].Older adults with chronic diseases had more severe depressive symptoms, experienced stressful life events, had lower social support and a less positive coping method [26].Taking care of the elderly with physical illnesses may be one method to reduce the risk of suicide associated with stressful life events.There are differences between male and female when it comes to stressful life events.Females were more likely to experience the death of a spouse due to their higher life expectancy, while males experienced more hospitalization, were diagnosed with terminal illness and had family poverty.Family poverty, work problems and family discord were more commonly reported among male suicide cases within Western society [7].
Unstable marital status was a risk factor of suicide.A spouse is always the most important and available caregiver during old age for the elderly.A stable marital status has a positive impact on the physical and mental health of elderly people, both in terms of life care and emotional well-being [27].The elderly without a spouse tend to lose spiritual comfort and gain less support than they would from a spouse [28].
There were some limitations in our psychological autopsy study.Firstly, the recalling bias is an inevitable limitation in such a retrospective investigation when interviewees reported previous life events.Secondly, the proxy data were used to assess the stressful life events which happened prior to the suicide/interview.The accuracy of information should be further improved.Thirdly, the long-term impact of stressful life events has not been assessed.Further studies should focus on the long-term effect of stressful life events on the elderly suicide.

Conclusions
The present study demonstrates the characteristics of stressful life events among suicides and the relationship between stressful life events and suicide.Stressful life events are one of the factors which increase the risk of suicide.Long-term stressful life events were common for rural elderly.More attention should be given to the rural elderly who experienced more long-term stressful life events and experienced health-related stressful life events to reduce the risk of suicide.

Table 3
Comparison of all items of stressful life events between the suicide and living control cases

Table 3
Comparison of all items of stressful life events between the suicide and living control cases (Continued)

Table 4
Comparison of top 10 stressful life events between females and males among the suicide cases

Table 5
The analysis of in uence factors for suicide among Chinese rural elderly cOR: crude odds ratio -Single factor analysis; aOR: adjusted odds ratio -Multiple factors analysis