- Chunyan Wang, 

- Qiaoyue Wei, 

- Wenwen Yin, 

- Shuibo Pan, 

- Chenyangzi Dai, 

- Linhua Zhou, 

- Xiaoyu Jiang, 

- Hong Cai & 

- Junduan Wu 

Abstract

Background

The unhealthy lifestyles not only affect physical development of adolescents but are also closely related to various psychological problems. This article will examine potential classes of middle school students' lifestyles and explore the associations between lifestyles and suicidal behaviors.

Methods

Data were collected from a cross-sectional survey of middle schools in five cities of Guangxi. A total of 5291 students completed the short questionnaire on suicidal behaviors and lifestyles. The latent class analysis was used to identify the unrecorded patterns of lifestyles. Multifactor logistic regression was used to explore the associations between health lifestyles and suicidal behaviors.

Results

The three classes lifestyles were identified: Class1(8.0%) – high risk lifestyle group, Class2(18.6%)—high lack of exercise group, and Class3(73.5%) – low risk lifestyle group, respectively.

Middle school students among Class 1 had higher odds than Class 3 (OR?=?2.061, 95%CI?=?1.474?~?2.882?OR?=?3.323, 95%CI?=?2.185?~?5.052 for self-injurious thoughts; OR?=?2.008, 95%CI?=?1.438?~?2.804?OR?=?3.217, 95%CI?=?2.125?~?4.868 for suicidal ideations; OR?=?1.488, 95%CI?=?1.063?~?2.081?OR?=?2.718, 95%CI?=?1.744?~?4.236 for self-injurious behaviors) for experiencing self-injurious thoughts, suicidal ideation, and self-injurious behaviors, whether occurring once, five times, or more, respectively. Class 2 were only more likely to engage in self-injurious behavior at once compared to Class 3(OR?=?1.414, 95%CI?=?1.110?~?1.800).

Conclusions

This finding highlighted the importance of improving unhealthy lifestyles for preventing and intervening in suicidal behavior among middle school students. More actions for intervention in the lifestyles of students should be needed to ensure their physical and mental health.

Peer Review reports

Introduction

Suicide is a major public health problem worldwide . So far, numerous studies, both national and international, have demonstrated the increasing prevalence of suicidal behaviors among adolescents, with serious physical and psychological consequences . Suicide is the second leading cause of death among adolescents between the ages of 10 and 19 in the US . However, in China, suicide is the leading cause of death in the young cohort aged 15–34 years, according to the 2023 National Health Commission (NHC) Report.

The unhealthy lifestyles

Unhealthy lifestyles, such as insufficient physical activity, poor dietary habits, and sleep deprivation, are the most common risk factors affecting the development and health of children and adolescents . Adolescence is a critical period for the establishment of lifestyle patterns . The formative years of adolescence with lifestyle habits are often solidified, making it a critical window for intervention to prevent the adoption of unhealthy behaviors that may persist into adulthood. Studies have shown that unhealthy lifestyles in children and adolescents associated with physical health such as hypertension , diabetes , and dental caries , and mental health problems such as anxiety, depression, suicide and schizophrenia .

Given the multifaceted nature of unhealthy lifestyles and their far-reaching consequences, it is essential to explore lifestyle interventions for improving health outcomes across the physical and mental health spectrum. However, the literature related to this topic is not conclusive regarding the existence of specific underlying categories of unhealthy lifestyles among middle school students. This gap is significant, as understanding these categories can inform the development of targeted and effective interventions tailored to this age group population. Therefore, the aims of this study is to enrich this content.

Suicidal behaviors

Suicide is a continuum of behaviors, non-fatal suicidal behaviors include Suicidal ideation, Suicide attempt and suicide plan . Suicidal ideation refers to the desire to die without taking actual action . Suicidal ideation reflects individual suicide risk, and self-injurious thoughts and behaviors are important correlates of suicidal ideation. The prevalence of suicidal ideation, self-injurious thoughts and self-injurious behaviors among adolescents varies internationally: the lifetime prevalence of self-injury ranges from 21 to 33% in South Asian countries , and prevalence of self-injurious behaviors and suicidal ideation is 18.8% and 15.8% respectively in the United Kingdom . In addition, cross-national studies have shown that the reported prevalence of suicidal ideation among adolescents was 21.1%, while self-injurious thoughts and behaviors were 9.55% and 2.83%, respectively .

Statistics shows that previous suicidal ideation, self-injurious thoughts and behaviors are the risk factor for suicide deaths . The results of suicide deaths highlight the importance of studying suicidal ideation, self-injurious thoughts and self-injurious behaviors. One of the aims of this article is to investigate the current prevalence of self-injurious thoughts, suicidal ideation and self-injurious behaviors among Chinese middle and high school students. Previous studies have explored the psychosocial, environmental, psychological and biological risk factors for adolescent suicide . Relatively few studies, however, have systematically explored patterns of lifestyles that precede or coincide with suicidal behaviors.

The lifestyles and suicidal behaviors

Low levels of physical activity, insufficient sleep, high consumption of sugary drink, and low intake of fruits and vegetables are common unhealthy lifestyle behaviors among adolescents, which may increase the risk of suicidal behaviors in this population. Specifically, previous research has demonstrated that increased physical activity is linked to reduced suicidal ideation and self-harm . Furthermore, the lack of sleep was a risk factor for self-harm . High levels of soft drink consumption have been associated with suicidal behaviors . Several studies have shown the correlation between mental health and the consumption of fruits and vegetables . Individuals with a history of attempted suicide have been found to consume significantly less fruits and vegetables . Additionally, some studies have investigated the collective influence of one or two specific types of health behaviors on suicide-related behaviors. For instance, a national sample of adolescents found that physical activity, sleep, and the school environment significantly predict suicidal ideation , adolescents with a lifestyle risk score of 5 or 6 are 3.36 times more likely to have suicidal ideation than those with a lifestyle risk score of 0 . Unhealthy lifestyle practices may contribute to increased inflammatory responses in the body which in turn can impact suicidal behaviors .

Research on the effects of lifestyles on suicide-related behaviors among Chinese middle students is limited, and previous research has primarily focused on individual health behaviors, overlooking the combined effects of multiple lifestyle factors on different suicidal behaviors. Our study will employ latent class analysis to identify student subgroups with similar lifestyle characteristics, thereby exploring the complex associations between lifestyle patterns and suicidal behaviors among Chinese middle school students. This approach contributes to a deeper understanding of the intricate relationships in this area.

The present study

The study focuses on three key domains of health behaviors related to daily activities that play a crucial role in suicidal behaviors: dietary behaviors (sugary drinks and fruit and vegetable intake), physical activity, and sleep. The purpose of this study is threefold, Firstly, to evaluate the prevalence of self-injurious thoughts, suicidal ideation and self-injurious behaviors among Chinese middle school students; secondly, to identify different lifestyle latent classes and to provide the socio-demographic and psychosexual-related characteristics of the latent classes; and finally, to explore the relationship between lifestyle latent classes and self-injurious thoughts, suicidal ideation and self-injurious behaviors among Chinese middle school students. It is worth mentioning that in our study, the relationship between lifestyle and suicidal behaviors is conceptualized through Latent Class Analysis (LCA). This method enables us to identify student groups with distinct lifestyle patterns and examine the association between these patterns and suicidal behaviors.

Methods

Participants

In 2022, a cross-sectional study was conducted using a multi-stage stratified random sampling method . Firstly, five cities (Nanning, Liuzhou, Beihai, Guigang, Hechi) were selected based on their level of economic development in Guangxi. Secondly, 1–2 urban areas or counties were randomly selected from each city. Thirdly, 1–2 middle schools were randomly selected from each urban/county. Finally, two classes from each grade of each school were selected for a questionnaire survey. Prior to the survey, both students and their legal guardians were fully informed of all relevant investigation content and procedures, and provided their written informed consent. Excluding students who refused to participate in this study and those who were absent that day, a total of 5331 participants aged 14 to 19 were initially included in the study. However, due to incomplete and logically flawed survey responses, 213 questionnaires were excluded from the analysis. The final sample size consisted of 5291 student questionnaires that met the study's inclusion criteria. The response rate was high at 99.25% (5291/5331). This study was approved by the Institutional Ethical Committee of Guangxi Medical University.

Measurements

Participants’ general information

The study collected basic demographic information from participants, including age, gender, race/ethnicity, place of residence, only child status, caregivers, gender identity, sexual orientation, parental affection, and parental absence of both father and mother. Furthermore, this study defines left-behind adolescents as individuals who have been left behind at their original residence while one or both parents work outside the family home for more than six months .

The lifestyles indicators

This study measured middle school students'diet, physical activity and sleep using four items. These three domains of health behaviors were actions and indicators covered in the Healthy China Action (2019–2030) (Healthy China Action (2019-2030), ). All the cutoff scores were based on recommendations from the Chinese Dietary Guidelines and significant thresholds used in previous studies on lifestyles and suicidal behaviors .

Frequency of exercise were assessed with a standard question'On average how frequently do you exercise each week?', and included options categorized as a five- point scale:"1? means"hardly ever exercise","2? means"1 time","3? means"2–3 times","4? means"4–5 times", and"5? means"more than 5 times". Participants were classified as in health status if their frequency of exercise scores were ??3 points; Frequency of consumptions of fruits and vegetables was assessed with a standard question'On average, how frequently do you consume fruits and vegetables each week?', and included options categorized as a five- point scale:"1? means"eating 0 time”,"2? means"1–2 times”,"3? means"3–4 times”,"4? means"5–6 times and"5? means"more than 7 times”. The participants were classified as healthy if their frequency of fruit and vegetables consumption scores equaled five points in our study; Frequency of consumptions of sugary drinks was assessed with a standard question'On average, how frequently do you consume sugary drinks per week? Such as Coke, Sprite, orange juice, milk tea, etc.', and included options categorized as a five- point scale:"1? means"never”,"2? means"1–2 times”,"3? means"3–4 times”,"4? means"5–6 times and"5? means"more than 7 times”. Participants were classified as healthy if their frequency of sugary drinks consumption scores ??2 points in our study; Frequency of sleep deprivation was assessed with a standard question:'Have you experienced sleep deprivation in the past month?', and included options categorized as a five- point scale:"1? means"never”,"2? means"1 time per week”,"3? means"1–2 times per week”,"4? means"3–5 times per week “and"5? means"5–7 times per week”. Participants were classified as Sleep deprivation if their scores ??3 points in our study. The four lifestyle-related survey questions we utilized have been extensively used in China .

Suicidal behaviors

Suicidal behaviors were assessed with the following three questions: (1) “Have you ever thought about deliberately injuring yourself when you don't want to die? Like slitting your wrists.” (Self-injurious thoughts), (2) “Have you ever considered suicide?” (suicidal ideation), and (3) “Have you ever injured yourself?” (Self-injury behaviors). The survey questions we utilized have been widely applied among Chinese middle school students . In order to reduce variability in suicidal behaviors frequency estimates, number of suicidal behaviors were categorized by the following frequencies: 0 time, 1 time, 2–4 times, and 5 or more times.

Covariates

Covariates included demographic and psychosexual related variables. Demographic information regarding age (continuous, 14 ~?19 years), sex (boy/girl), nationality (Han, Zhuang, other), place of residence (city?county?rural),only child status (yes/no), caregivers (parents/grandparents/other), parental affection(good/bad) and staying behind(yes/no) were collected during the self-report assessment. Previous studies have suggested that gender, age, ethnicity, place of residence, only child, caregiver, parental affection and leaving behind are important factors in adolescent suicide . Gender minority students and sexual minorities had significantly higher rates of suicide ideation and suicide attempts . Gender identity and sexual orientation variables were included to control for their effects. The survey asked students to indicate their gender identity and sexual orientation. The questions were phrased as follows:'Which gender do you identify with?'and'Which of the following options best describes your sexual orientation? (choose only one)". Response options were dichotomized into “male, female, none of the above”, and “heterosexual, homosexual, bisexual, and uncertain”.

Statistical analysis

Descriptive statistics

Statistical assumptions were checked for each variable prior to conducting the analyses. The level of significance was set at p?< 0.05, and all assumptions were met through chi-square tests, t-tests, and analysis of variance (ANOVA). Descriptive statistics for the demographic characteristics and psychosexual related variables of the study sample and comparisons across groups were analyzed using SPSS software version 23.0.

The latent class analysis (LCA)

The latent class analysis(LCA) was performed using Mplus version 8.3 to identify and describe the classes of students’ health lifestyles. In order to determine the exact number of latent classes, an exploratory approach was used . Starting from a two-class model, the analysis was carried out several times in a row, increasing this number of subgroups turn by turn. Then, statistical model adjustment indices, such as the Bayesian information criterion (BIC), the adjusted BIC, the Akaike information criterion (AIC), LoMendell-Rubin likelihood ratio test (LMR), and Bootstrapped likelihood ratio test (BLRT) were used, coupled to the entropy values to identify the final number of classes. Indeed, the selected classes had to have more than 5% observations to provide a representative profile of a population .

Bivariate analyses and multivariate logistic regression

After determining the appropriate number of latent classes, we conducted a series of cross-tabulations and bivariate analyses to explore the distribution of demographic and psychosexual-related characteristics across different latent classes. Additionally, we used univariate analysis to explore the influencing factors of suicide related behaviors. Finally, we adjusted for demographic and psychosexual characteristics based on the results of the univariate analysis. Multiple logistic regression analysis was used to investigate the influence of lifestyle latent classes on suicide-related behaviors. A statistically significant difference was defined as a two-sided p-value of less than 0.05.

Results

The prevalence of suicidal behaviors and general demographic data

A total of 5291 participants were included in this study, and their gender distribution was relatively average (47.3% Boys and 52.7% Girls). The respondents were predominantly Han Chinese students (54.8%), followed by Zhuang (29.1%), and other ethnic students (16.1%). The mean age of the students was 15.65 (Standard Deviation, SD =?1.353). The prevalence of self-injurious thoughts, suicidal ideation, and self-injurious behaviors among middle school students is 14.6%, 27.7%, and 17.0%, respectively. For sexual orientation, those who had self-injurious thoughts and suicidal ideation had the highest rate of homosexual students (42.6%; 60.3%)), however, those who had self-injurious behaviors had the highest rate of bisexual students (42.5%). Table 1 summarizes these results.Table 1 Demographic characteristics of suicidal behaviors

Full size table

Modeling of latent classes for adolescent healthy lifestyles

This study identified three-class model due to its entropy value (0.779) exceeding the standard for good class separation (i.e. entropy =?0.60; ) and having the smallest AIC, BIC, adjusted BIC and appropriate LMR and BLRT (P < 0.0001). Table 2 describes these indicators.Table 2 Summary of latent class model identification and fit statistics

Full size table

Figure 1 shows the three-class model and item probabilities for the 3 lifestyles indicators for each class. Class1, defined as the"high risk lifestyle"(8.0%), included adolescents reporting the medium lack of exercise; lower levels of fruit and vegetable intake, higher intake of sugary drinks and serious sleep deprivation. Class2, defined as the"high lack of exercise"(18.6%), included adolescents reporting the high lack of exercise, lower levels of fruit and vegetable intake, lower intake of sugary drinks, and medium sleep deprivation. Class3, defined as the"low risk lifestyle"(73.5%), included adolescents reporting the high levels of exercise, high levels intake of fruit and vegetable, lower intake of sugary drinks and low levels of sleep deprivation.

Fig. 1

Distribution of suicidal behaviors and covariates by lifestyle classes

Table 3 shows significant differences in the distribution of suicidal behaviors, demographic characteristics, and psychosexual-related characteristics among the 3-class model.Table 3 Self-injurious thoughts, Suicidal ideations, Self-injury behaviors and demographic characteristics by latent classes

Full size table

Regarding suicidal behaviors, class 1 (high-risk lifestyle) had higher percentages of self-injurious thoughts (11.9%, 5.5%, 9.0%), suicidal ideation (15.4%, 12.4%, 17.1%), and self-injurious behaviors (11.4%, 7.1%, 7.4%) compared to the other classes (P?< 0.001). In contrast, class 3 (low-risk lifestyle) had the lowest percentages (P?< 0.001). Significant differences were found among the three models in terms of age, gender, ethnicity, place of residence, only child status, parental affection, gender identity and sexual orientation (P?< 0.05). https://standingabovethecrowd.com/james-donaldson-on-mental-health-association-of-unhealthy-lifestyles-and-suicidal-behaviors-among-chinese-middle-school-students-a-latent-class-analysis/