Suicidal ideation and suicide attempts among asthma

Many chronic diseases are complicated by emotional and psychological disorders and yet the emotional dimensions of such chronic diseases are frequently overlooked when medical treatment is considered [1]. Several studies have found statistically significant correlates between asthma and suicide ideation and suicide attempts [2‐6].

Suicide is the fourth leading cause of death in Korea [7]. Suicide rate was 33.3 per 100,000 persons in Korea in 2011, which ranked first among the Organization for Economic Co-operation and Development (OECD) countries (https://​data.​oecd.​org/​healthstat/​suicide-rates.​htm). Since asthma and suicide are important public health burdens, epidemiological study investigating the mental health status in asthma patients and its relationship with suicidal ideations and attempts would be required to assess the potential risk for suicide, and ultimately prevent suicidal completion in patients with asthma. However, very few studies about the relationship between asthma and suicide have been done in Asia especially South Korea. There are a number of epidemiological differences among the studies that have evaluated suicidal behavior, and an investigation of the various comorbidities and risk factors that lead to suicide in different ethnic groups is therefore necessary. As far as I know, this is the first study suicidal prevalence among asthma patients in Korea.

We aimed to compare the status of mental health including suicidal ideations and attempts between patients with asthma and population without asthma using data from nationwide population-based health survey (The 2013 Korean Community Health Survey).

The baseline characteristics of the study population (n = 228,744) are presented in Table 1. As compared to population without asthma (n = 224,175), patients with asthma (n = 6372) were older and had higher proportions of female, smoker, being alone (divorced/separated/widowed), hypertension, stroke, arthritis, and had lower level of education, lower level of income, lower proportions of alcohol drinking, regular exercise, and less having a job (all p < 0.001).

Differences in mental health status between asthma patients and population without asthma were presented in Table 2. Asthma patients reported more moderate to severe stress (33.4%) and depressive mood (12.0%) as compared to population without asthma (25.4%, p < 0.001; 5.7%, p < 0.001). The rate of asthma patients who had suicidal ideations (21.4%) was higher than twice the rate in population without asthma (9.8%, p < 0.001). The rate of asthma patients who had suicidal attempts (1.0%) was higher than three times the rate in population without asthma (0.4%, p < 0.001).

The ORs of suicidal ideation and attempts among the asthma patients in comparison to population without asthma was presented in Table 3. A multivariate analysis adjusting for age and sex (model 1) revealed that the ORs for suicidal ideations and attempts were 2.01 (95% CI 1.89–2.14) and 2.42 (95% CI 1.87–3.12), respectively. When additional adjustments were performed for socioeconomic factors (i.e., family income, education, job, and marital status; model 2), the ORs for suicidal ideations and attempts were 1.84 (95% CI 1.72–1.96) and 2.12 (95% CI 1.63–2.75), respectively. After additional adjustments for factors related to physical health (i.e., smoking, alcohol, exercise, diabetes, hypertension, stroke, and arthritis; model 3), the ORs for suicidal ideations and attempts were 1.71 (95% CI 1.59–1.82) and 1.79 (95% CI 1.37–2.33), respectively. In a final model adjusted for all of factors including depressive mood (model 4), the ORs for suicidal ideations and attempts were 1.53 (95% CI 1.42–1.65) and 1.32 (95% CI 1.01–1.73), respectively.

Our study showed that asthma patients had more severe stress, depressive mood, suicidal ideations, and attempts than population without asthma. In addition, asthma was associated with an increase in the risk for suicidal ideations and attempts, even after adjusting for factors that are known to increase suicidality such as socioeconomic status, chronic medical diseases, and depressive symptoms.

Asthma is an important chronic condition that has previously been linked to a number of adverse outcomes including depression and risk-taking behavior. There is currently a body of research suggesting a link between suicidal behavior and asthma [2‐6]. Clarke and colleagues [5] examined data on 5692 adults aged 18 and older participating in a United States nationwide health study showed that 12% of the participants had a history of asthma, 8.7% had experienced suicidal ideation, and 4.2% had suicidal attempts. Despite adjustments for smoking, concurrent mental conditions and demographic factors, a statistically significant association observed between asthma and suicide ideation and attempt. Goodwin and Eaton [2] reported a relationship between asthma and increased likelihood of suicidal ideation (OR 2.3; 95% CI 1.03–5.3) and suicidal attempts (OR 3.5; 95% CI 1.4–9.0). The same result was found in Puerto Rico [6]. An analysis of 6584 adults whose data were drawn from the Third National Health and Nutrition Examination Survey (NHANES III) also reported an association between current asthma and suicide ideation (Odds Ratio 1.77) and suicide attempt (OR 3.26), after adjusting for confounding factors such as mood disorder, poverty, smoking, and demographics. Our study showed suicidal ideation (OR 1.53; 95% CI 1.42–1.65) and suicidal attempts (OR 1.32; 95% CI 1.01–1.73).

This present study cannot explain the mechanisms of the association between asthma and suicidal ideation and suicidal attempts. An association between asthma morbidity, risk-taking behavior, and depression has been presented in previous research, although the reasons and direction of this association are not clear [17]. Asthma may be associated with mood change, anxiety, and some difficulties in daily living which may themselves feel hopelessness and consequently increased suicide risk [18]. Another possible mechanism for this association concerns effects of hypoxia [19], and it has been suggested that an association between high altitude and suicide may be accounted for by metabolic stress associated with hypoxia in individuals who have mood disorders. Recent research reports that suicide rates are elevated in those living at higher altitudes [8, 20], smokers [21, 22] and asthma [6, 23]. A possible mechanism that was proposed is metabolic stress associated with hypoxia. Young SN propose that low brain serotonin synthesis due to hypoxia could be a factor in the high suicide rates seen in people living at altitude, smokers and patients with chronic obstructive pulmonary disease (COPD) and asthma [24]. As pulmonary function decreases, and as the disease progresses, the risk of alveolar hypoxia and consequent hypoxemia increases [25]. Another potential cause of depression in asthma sufferers is the use of particular medications, including corticosteroid or montelukast sodium, which, while reducing the symptoms of asthma, have also been linked to mood disturbances similar to the symptoms of major depression [26, 27].

Our study has some limitations that should be addressed. First, because this is a cross-sectional study, temporal relationship and causality between asthma and suicidality could not be determined. Second, all data in this survey are based on self-reported questionnaires; therefore, the recall bias leading to the possibility of over- or under-reporting cannot be excluded. In addition, our study sample might be biased toward mild asthma patients who could complete the questionnaires. Third, we could not obtain detailed information about severity of asthma.

In summary, we observed that asthma patients had more depressive mood and suicidal ideation and attempts than population without asthma using a large population-based survey. We also found that asthma increased the risk for suicidal ideation and attempts, independent of other factors that are known to be associated with suicidality, suggesting that asthma per se may be an independent risk factor for suicidality. Given that a previous suicidal attempt is among the strongest risk factors for future attempt [28], our findings may warrant the need for physicians to screen for suicidality and provide psychosocial support as well as interventions for preventing suicide in management of asthma patients. Hence any treatment modality for asthma, to minimize the possibility of suicide in patients with asthma, must incorporate. More research is required in the mental health field and asthma, but the indicators are clear that there is a significant association between asthma and suicide. Patients with asthma must be assessed not only for physical health but also for psychological morbidity.