INTRODUCTION
In 2010, the American Heart Association (AHA) introduced Life’s Simple 7, outlining seven key factors and behaviors to improve cardiovascular health (CVH), which has played an important role in reducing the burden of cardiovascular and other chronic diseases while promoting both individual and population health [1,2]. In 2022, sleep was incorporated, resulting in the establishment of Life’s Essential 8 (LE8), which has since been widely utilized not only for assessing CVH but also for evaluating mental health status [2,3].
Recent large-scale studies in the United States and the United Kingdom have demonstrated that higher LE8 scores are associated with fewer depressive symptoms, whereas poorer CVH is linked to an increased risk of depression and anxiety among middle-aged and older adults [3,4]. However, previous research has primarily focused on symptomatology, with limited direct analysis of behavioral outcomes such as suicide attempts or the utilization of mental health services [5].
Furthermore, suicidal behavior remains a leading cause of mortality and disability worldwide, with South Korea exhibiting the highest suicide rate among OECD countries (24.1 per 100,000 population), highlighting a significant public health concern [6,7]. Moreover, numerous previous studies have demonstrated that early engagement with mental health services reduces the incidence of depression, whereas delays in mental health service utilization are linked to poorer prognoses [8,9]. Nevertheless, in South Korea, despite a lifetime prevalence of mental disorders of 27.8%, only 7.2% of individuals diagnosed within the past year accessed mental health services [10]. Therefore, investigating the impact of CVH on actual mental health behaviors and outcomes, and developing strategies to enhance mental health service utilization, are urgently needed. And analyzing the contributing factors in South Korea, where the suicide rate is particularly high but the mental service utilization is low, may provide valuable insights for global suicide prevention efforts.
Recently, a study among Korean adults demonstrated that lower CVH is associated with increased risks of depressive symptoms, suicidal planning, and suicide attempts [11]. However, the underlying mechanisms linking lower CVH to these mental health outcomes remain insufficiently explored. Although the authors adjusted for various demographic variables, including age, sex, education level, marital status, and employment status, the selection of these covariates often appeared to be guided by convention rather than empirical evidence. Furthermore, other relevant factors such as alcohol consumption [12,13], stress levels [14], and the use of mental health services [15] were not included, suggesting opportunities for additional research.
Given these gaps, using data from the 2021 Korea National Health and Nutrition Examination Survey (KNHANES), this study aims to examine the association between LE8 and key mental health outcomes, including psychological distress, suicidal behavior, and the utilization of mental health services. We hypothesize that higher LE8 scores will be associated with a lower risk of depressive symptoms, perceived stress, suicidal ideation, suicidal planning, and suicide attempts. Additionally, higher LE8 scores are expected to be linked to greater utilization of mental health services.
METHODS
Study population
This study analyzed data from the KNHANES, conducted by the Korea Disease Control and Prevention Agency. KNHANES is a cross-sectional national survey employing a stratified, multistage probability sampling design to assess the health and nutritional status of the Korean population. It aims to track trends in health risk factors and the prevalence of major chronic diseases [16].
The survey collects extensive data annually, encompassing demographic, social, health, and nutritional information through three primary components: a medical examination, a health interview, and a nutrition survey.
For this study, we utilized KNHANES data from 2021, focusing on adults aged 19 years and older. A total of 5,952 adults were initially included. However, participants meeting specific exclusion criteria were omitted, including pregnant or breastfeeding individuals (n=17), those with a fasting duration of less than 8 hours (n=585), and individuals with missing data for mental health (n=286) or LE8 metrics (n=958). After applying these exclusions, the final analytical sample consisted of 4,106 individuals.
The KNHANES dataset provided information on anthropometric measurements (height and weight), blood pressure (systolic and diastolic), and laboratory test results, including fasting plasma glucose, glycated hemoglobin (HbA1c), total cholesterol, and high-density lipoprotein (HDL) cholesterol. Additionally, questionnaire data were analyzed to assess lifestyle factors such as smoking and drinking habits, educational attainment, socioeconomic status, and marital status.
Measures
Definitions and quantification of the CVH metrics
The definitions and scoring criteria for the CVH metrics are detailed in Supplementary Table 1. Briefly, each CVH metric is scored on a scale from 0 to 100, with the overall CVH score calculated as the average of all eight metrics. Participants were categorized into three CVH status groups: high (80-100 points), moderate (50-79 points), and low (0-49 points) [2]. Further details regarding the assessment methods, classification criteria, and scoring system can be found in the Supplementary Material and Supplementary Table 1.
Psychological distress, suicidal behavior, and the utilization of mental health services
In this study, mental health values were defined based on survey items collected from KNHANES. These values included perceived stress, experience of depressive symptoms, suicidal ideation, suicide planning, suicide attempts, and mental health service utilization.
Perceived stress was assessed by asking participants how much stress they experience in their daily lives, with response options of “feeling very much,” “feeling a lot,” “feeling a little,” and “hardly feeling any.” For analysis, responses of “feeling very much” and “feeling a lot” were categorized as “high stress perception,” while “feeling a little” and “hardly feeling any” were categorized as “low stress perception.”
Experience of depressive mood was measured by asking whether participants had felt sad or hopeless for at least two consecutive weeks in the past year to the extent that it interfered with their daily lives, with responses recorded as “yes” or “no.”
Suicidal ideation in the past year was assessed by asking whether participants had seriously considered suicide within the past year, with response options of “yes” or “no.”
Suicide planning in the past year was evaluated by asking whether participants had made specific plans to commit suicide within the past year, with responses recorded as “yes” or “no.”
Suicide attempts in the past year were assessed by asking whether participants had actually attempted suicide within the past year, with responses recorded as “yes” or “no.”
Mental health service utilization in the past year was measured by asking whether participants had actually used counseling services for mental health issues through visits, phone calls, or the internet within the past year. Participants who reported having accessed any of these services at least once were categorized as “yes,” while those who had not used any such services were categorized as “no.”
Statistical analysis
Baseline characteristics were presented as percentages with confidence interval (CI) for categorical variables and as means±standard error for continuous variables. The prevalence of conditions was reported with 95% CI. Comparisons of continuous variables between two groups were conducted using independent t-tests, and comparisons among three or more groups were performed using analysis of variance. Categorical variables were analyzed using chi-square test. In cases of skewed distributions, logarithmic transformation was applied to achieve normality, and the results were expressed as geometric means with 95% CI. To compare mental health values across LE8 score groups, multiple logistic regression analysis was performed, adjusting for age, sex, education level, household income, living with a spouse, occupation, a diagnosis of depression and drinking habit as covariates. All p-values were two-tailed, with statistical significance set at 0.05. Data analysis was conducted using SAS software, version 9.4 (SAS Institute).
The study received approval from the KNHANES and the Institutional Review Board of the Catholic University of Korea (VC24ZISI0255). Consequently, the requirement for written informed consent was waived. All study procedures were conducted in accordance with applicable guidelines and regulations.
RESULTS
Baseline subject characteristics
The baseline characteristics of the study population, stratified by sex, are shown in Table 1. A total of 4,106 participants were included in the study. Among them, 667 participants were classified as the low group with an LE8 score below 50, 2,986 participants were classified as the moderate group with scores between 50 and 79, and 453 participants were classified as the high group with scores above 80. The mean age of the study population was 53.51 (±0.26) years. Variables that showed statistically significant differences among the LE8 score groups in the homogeneity comparison included age, sex, education level, living with a spouse, household income, body mass index (BMI), smoking habit, drinking habit, diabetes status, hypertension status and use of antihypertensive agents, hypercholesterolemia, use of lipid-lowering agents, height, weight, systolic blood pressure, diastolic blood pressure, fasting glucose, HbA1c, total cholesterol, HDL cholesterol, low-density lipoprotein cholesterol, and non-HDL cholesterol.
Outcome of psychological distress, suicidal behavior, and the utilization of mental health services
After adjusting for age, sex, education level, household income, living with a spouse, occupation, and drinking habits—factors that were statistically significant but not included in the LE8 assessment—lower perceived stress levels were observed in the CVH middle and high groups compared with the lower group, with the association reaching borderline statistical significance (p=0.041) (Table 2). The odds ratio (OR) for the middle group was 0.748 (95% CI: 0.587, 0.953), and for the high group, it was 0.685 (95% CI: 0.491, 0.956), suggesting a trend toward lower stress perception with higher LE8 scores.
Similarly, the incidence of suicidal ideation in the past year also showed significant differences between the low group and the moderate and high groups (p=0.001) (Table 2). The OR for the moderate group was 0.517 (95% CI: 0.329, 0.813), and for the high group, it was 0.199 (95% CI: 0.078, 0.507), suggesting that higher LE8 scores were associated with lower suicidal ideation rates in the past year.
In contrast, there were no statistically significant differences for experience of depressive mood, suicide planning, suicide attempts, or mental health service utilization with p-values of 0.137, 0.275, 0.337, and 0.428, respectively (Table 2).
Health behavior and health factors on psychological distress, suicidal behavior, and the utilization of mental health services
The eight LE8 components were divided into 4 health behaviors (diet, physical activity, smoking, sleep health) and 4 health factors (BMI, blood lipids, blood glucose, blood pressure) to compare their associations with psychological distress, suicidal behavior, and the utilization of mental health services (Table 3). The health factor score did not show statistically significant associations with any of them. However, the health behavior score was associated with stress perception (p<0.001), and suicidal ideation in the past year (p=0.008). As with the comparison between total LE8 scores and mental health values, higher health behavior scores were associated with lower stress perception. Compared to the low group, the OR for the middle group was 0.681 (95% CI: 0.575, 0.806), and for the high group, it was 0.553 (95% CI: 0.410, 0.746). Similarly, for suicidal ideation in the past year, the middle group had an OR of 0.607 (95% CI: 0.392, 0.940), and the high group had an OR of 0.287 (95% CI: 0.118, 0.696), showing that higher LE8 scores were associated with a lower frequency of suicidal ideation.
DISCUSSION
In this study, we aimed to investigate the association between the CVH and mental health to identify modifiable factors for mental health management. To the best of our knowledge, this is the first study to evaluate the relationship between suicidal behavior, mental health service utilization, and the LE8 score. Our findings revealed associations between the total LE8 score and perceived stress as well as suicidal ideation within the past year. Upon dividing the LE8 score into health behavior and health factor components, we observed that only the health behavior component showed significant associations with mental health outcomes, consistent with the pattern observed for the total LE8 score. Participants with higher health behavior scores exhibited a lower likelihood of perceiving stress or having suicidal ideation. In contrast, the health factor component score was not significantly associated with these mental health outcomes. These results suggest the beneficial role of favorable CVH behaviors in reducing mental health burdens.
First, higher LE8 scores were associated with a tendency toward lower perceived stress levels over the past year, whereas no significant association was observed with the experience of depressive mood. These findings suggest that LE8 may be more closely related to every stress management than to depressive mood itself, although its direct influence on depression appears limited. Stressful life events have been recognized as predictors of depression; however, several studies indicate that stress and depression are not entirely synonymous [17]. The relationship between stress and depression is not static over time, and clinical studies have shown that as depressive episodes progress, the role of stress in triggering episodes diminishes [18-20]. Therefore, rather than focusing solely on the prevention of depressive symptoms, prioritizing stress management may represent a more relevant target for mitigating the progression or exacerbation of depressive symptoms over time. In this context, maintaining a favorable LE8 score may contribute to lower stress levels and potentially reduce the likelihood that stress escalates in to depressive mood.
Second, our study also found that higher LE8 scores were associated with a lower likelihood of experiencing suicidal ideation over the past year. However, there was no significant association between LE8 scores and suicide planning or attempts. A meta-analysis has shown that while suicidal ideation is common, only about 29% of individuals progress to an actual attempt [21]. To better understand the transition from suicidal ideation to suicide attempts, Klonsky and May [22] proposed the “ideation-to-action” framework, which posits that suicidal ideation and suicidal behavior are independent processes with distinct mechanisms. Suicidal ideation is primarily influenced by psychological factors such as depression and stress [23]. This finding highlights the association between stress and suicidal ideation, aligning with our study’s results, which indicate that higher LE8 scores are associated with lower stress levels and a reduced likelihood of experiencing suicidal ideation over the past year. In contrast, suicide planning and attempts are shaped by a more complex interplay of psychological, environmental, and social factors, including behavioral components such as impulsivity, access to lethal means, and learned behavioral patterns [23]. Furthermore, the interpersonal psychological theory of suicide suggests that an acquired capability for suicide is a crucial factor in suicide attempts [24]. This acquired capability results from repeated exposure to painful and fear-inducing experiences, such as traumatic life events or occupations that require disregard for personal safety [21]. Therefore, while suicidal ideation is largely driven by psychological distress, suicide planning and attempts involve additional action-oriented and behavioral components, making them more complex processes. Our study did not consider these action-oriented and behavioral factors, which may explain the lack of observed association. In addition, the low prevalence of suicide planning and attempts in the present sample may have limited statistical power, which may have contributed to the lack of association between LE8 scores and suicide behaviors.
Third, this study found no significant association between LE8 scores and the utilization of mental health services. This may be because mental health service utilization is influenced by a variety of demographic and sociocultural factors, such as age, sex, education level, income, social support, and stigma [25,26]. In particular, in South Korea, cultural stigma surrounding mental illness can serve as a major barrier to service utilization [27]. Additionally, a limitation of this study is its cross-sectional design, which does not allow for the assessment of long-term service utilization following disease onset. Nevertheless, considering the significant association observed between LE8 and stress in this study, implementing early interventions based on LE8 in primary care settings may be potentially beneficial. Such proactive strategies could help prevent mental health problems from worsening to the point where mental health service utilization becomes necessary. Furthermore, for individuals who are reluctant to use mental health services due to concerns about social stigma, LE8 could serve as an accessible and culturally acceptable strategy to promote mental well-being and reduce the threshold for engaging with psychiatric services.
Finally, when LE8 was analyzed separately into health behavior and health factors, only the health behavior score showed a significant association with perceived stress and suicidal ideation in the past year. Additionally, in the analysis examining the association between mental health outcomes and LE8, with health behaviors and health factors analyzed separately, health factors showed no statistically significant associations with any mental health outcomes, including psychological distress, suicidal behavior, or the utilization of mental health services. These findings suggest that health behaviors may be more closely associated with mental health and underscore their importance in the prevention and intervention strategies, particularly in relation to depression. Previous studies also support our findings, indicating that health behaviors are more strongly associated with depression and anxiety than health factors [28]. Specifically, healthy diet and physical activity reduce the risk of depression and anxiety, while smoking increases it [29-31]. Meanwhile, the link between health factors and mental health outcomes, such as depression and hypertension, remains inconsistent, with both positive and inverse associations reported [32,33]. The health behavior component of LE8 reflects current lifestyle status and allows for immediate changes, whereas health factors such as blood pressure, blood glucose, and lipid levels require a longer period to show improvement [34]. Therefore, health behavior scores may serve as a more immediate indicator of mental health status. Furthermore, we should consider the potential bidirectional relationship between CVH and mental health. That is, while individuals who engage in health behaviors may have better mental health, it is also possible that those with better mental health are more likely to engage in health behaviors. Previous studies have reported that individuals with severe depressive symptoms or stress may find it difficult to maintain healthy behaviors due to psychiatric symptoms, and that those with poorer mental health are more likely to engage in unhealthy behaviors such as smoking, alcohol consumption, and low physical activity [35]. However, as this was a cross-sectional study, it was not possible to evaluate the longitudinal effects of LE8 health factors or to clarify the causal relationship between CVH and mental health. Therefore, a longitudinal study is required to investigate the long-term impact of changes in CVH factors on mental health and to clarify the causal relationship between them.
This study has several limitations. First, the LE8 health behavior components were using self-reported questionnaires, which may have introduced subjective bias. Second, mental health outcomes were assessed using a single-item self-reported measures rather than validated multi-item instruments such as the PHQ-9 (Patient Health Questionnaire-9). As a result, misclassification of depressive symptoms may have occurred, including the possibility of false-positive and false-negative responses. This approach may not fully capture the entire spectrum or severity of mental health problems; however, single-item assessments have demonstrated moderate sensitivity, high specificity, and high negative predictive value compared to validated scales, making them useful tools for initial screening and monitoring population-level trends in national health surveys [36].
Third, data on antidepressant use were not obtained, which may confound mental health outcomes. Fourth, suicidal planning and suicide attempts are relatively rare events in the general population; therefore, limited statistical power due to small event counts may have reduced the ability to detect significant associations between LE8 and these outcomes, potentially leading to underestimation of true association. Fifth, the cross-sectional design limits causal inference between LE8 and mental health. In addition, cultural and social factors—including social support, psychiatric history, and economic stress—could not be fully considered due to limitation of the available data. Future longitudinal studies that incorporate cultural and social factors are needed to clarify the long-term effects of changes in LE8 on mental health and to better understand causal relations. Nevertheless, this study is among the first to link LE8 with suicidal behavior and mental health service use in a large population, and highlights the importance of health behaviors for mental health improvement.
In this study, we examined the association between CVH, as assessed through LE8, and psychological distress, suicidal behavior, and the utilization of mental health services. Our findings indicate that LE8 is significantly associated with perceived stress and suicidal ideation, with health behaviors showing a stronger association with perceived stress and suicidal ideation over the past year. In contrast, health factors were not significantly associated with mental health outcomes. These results suggest that among the components of CVH, health behaviors play a crucial role in mental health. This study provides valuable insights for developing future mental health prevention strategies and highlights the need for longitudinal studies to assess the long-term impact of LE8 on mental health.
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