This study reveals a three times higher prevalence of anxiety and a five times higher prevalence of depression among Iraqi immigrants compared to native Swedes in the study population. Moreover, even after adjusting for potential confounders, Iraqis had three times higher odds of moderate to severe anxiety and/or depression compared to Swedes. A key finding of this study was that anxiety/depression was strongly associated with physical inactivity in Iraqi immigrants to Sweden, but not in native Swedes. Economic insecurity showed a strong association with anxiety/depression in both Iraqis and Swedes.
Although other studies have reported comparable figures for the prevalence and risk of anxiety and/or depression among non-European immigrants in Sweden, very few have focused solely on Iraqi immigrants. Studies on mental health and ethnicity conducted in Sweden have mainly focused on more severe mental illnesses such as psychosis, suicidal tendency and schizophrenia, as well as intake of psychotropic drugs and refugee immigrants [17, 18]. In one study, Tinghög et al., using the Hopkins Symptom Check List 25, demonstrated an anxiety/depression prevalence of 60.6% among Iraqi immigrants in Sweden compared to 11.7% in Finnish immigrants . In this study, female sex, poor social network and economic insecurity were found to be associated with low subjective well-being and anxiety/depression, in line with our findings; however, physical activity was not considered . In another study, Turkish immigrants were found to have two times increased risk for self- reported anxiety than Swedes after adjusting for age and socio-economic status which is comparable to our study as Turkish and Iraqi immigrants exhibit geographical and cultural similarities. The finding that Iraqis have higher odds of anxiety/depression even after adjusting for potential risk factors in the model is in agreement with previous studies in Sweden. These studies indicate that the risk of depression associated with immigrant status cannot be fully explained by socio-economic factors as well as report ethnicity as a risk factor for mental ill-health [5, 19, 20]. However this finding also indicates the need to further explore and identify variables that are associated with mental health among Iraqis.
The prevalence of anxiety/depression in Swedes was lower as compared to previous studies which reveal an anxiety and depression prevalence of 32% and 7-10% respectively [5, 21]. The prevalence estimates, therefore need to be interpreted with care, based on low response rate in Swedes which can result in underestimation. The association of marital status with anxiety/depression in Swedes seen in this study is in line with previous research [5, 21].
In many studies, physical activity has been shown to have a mental health-promoting effect in the general population. Clinical trials have revealed that its effects as a therapy for anxiety and depression are comparable to those of anti-depressant medication and psychotherapy ; however, the association between physical activity and mental health among immigrants is less frequently discussed compared to general populations and requires further research. In a randomized controlled trial conducted in the Netherlands, a physical activity intervention led to improved mental health among elderly Turkish immigrants . This indirectly supports the finding in the current study that Iraqi immigrants who performed less than 150 min/week of physical activity were more likely to be anxious and/or depressed than their counterparts born in Sweden, further supported by our finding that country of birth modified the effect of physical activity. Moreover, physical activity is supposed to increase norepinephrine neurotransmission in the central nervous system, serotonin synthesis and secretion of atrial natriuretic peptide, all of which are plausible biological explanations for its association with anxiety and depression .
In Iraqi immigrants as well as amongst native Swedes, economic insecurity was as strongly associated with anxiety/depression as physical inactivity was. Economic insecurity represents one aspect of poor socioeconomic status, a much discussed factor in the etiology of anxiety and depression . Most studies on the mental health of immigrants take into account employment status, income and education as indicators of socioeconomic status [17, 26], but few have also considered economic insecurity [5, 12]. The negative association between economic insecurity and the mental health of immigrants observed in these studies, as well as in our study, indicates the need for further research to strengthen existing evidence.
Mutual trust, a component of social capital, turned out to be associated with anxiety and depression in Iraqis. Over the past few years, the concept of social capital has evolved in health promotion research. Mutual trust and social participation, measured as membership of voluntary organizations, have been identified as two core aspects of social capital by many researchers . The association between cognitive components of social capital, i.e., mutual trust, and mental health has also been reported in other studies [28, 29]. A bi-directional association between social capital and mental health, according to which poor social capital could be the result or the cause of depressive symptoms, has been proposed. However such an association is more likely between social participation and common mental disorders than between mutual trust and common mental disorders .
Time since migration, Swedish reading skills and Swedish writing skills had no influence on anxiety and depression scores in Iraqi immigrants in the multivariate model. This indicates that among Iraqi immigrants in Sweden, who on average had lived in Sweden for 20 years, socioeconomic and lifestyle-related factors such as economic insecurity, feeling of trust in people and physical activity were more important determinants of mental health compared to lack of acculturation. That acculturation has a weak association with mental health in immigrants was also found in a large study of the mental health of aging immigrants in 11 European countries. In this study, Ladin et al. elaborated that acculturation-related variables such as time since migration and citizenship status, both of which are strongly correlated with language skills, were not predictive of depression risk among immigrants .
Strengths & limitations
The current study adds to the existing knowledge on mental health among immigrants in Sweden by providing a comparison of Swedes with Iraqis, the largest non-European immigrant group in Sweden. In addition, while most previous studies measured depression using one or another scale, anxiety was either ignored, replaced by measures of subjective well-being or self-reported. By contrast, the present study used a well validated instrument for detecting depression and anxiety in Iraqi immigrants in Malmö, a group that is at risk of the consequences of poor mental health in the form of chronic diseases and impaired quality of life.
It is also worth mentioning that immigrants tend to have somatic complaints like body pains and other physical symptoms as an expression of underlying psychological illness .
The HAD questionnaire used in this study aims to identify anxiety and depression in non-psychiatric clinical settings and tends to rule out somatic symptoms that might originate from physical illness rather than poor mental health. Although Swedish Council on Health Technology Assessment has criticized HADS for its indefinable sensitivity, in a literature review conducted by Bjelland et al., the HADS was found to have good sensitivity and specificity and performed well as an instrument for measuring depression and anxiety caseness [14, 31]. These findings were confirmed in a Swedish sample . Moreover in the current study, a large group was found to be anxious/depressed according to HADS which diminishes concerns regarding its sensitivity.
In the multivariate logistic analysis, depression and anxiety were considered together not only because anxiety is highly prevalent amongst patients with depression, but also because it can precede depression in many cases. In addition, shared pharmacotherapy and shared genetic risk indicate a common biological pathway underlying anxiety and depression, which in turn provides grounds for considering them together rather than as separate entities [33, 34].
The cross-sectional approach used in the study does not allow a causal association between physical inactivity and mental health among Iraqi immigrants to be established. Physical inactivity could be a consequence of depression rather than a cause as depressed individuals often lack motivation to engage in physical activities . However, considering our findings in relation to results from clinical trials on physical activity and mental health [23, 35], it can be inferred that physical activity interventions in clinical settings might prove to be beneficial for anxious and depressed Iraqi immigrants but intervention studies are warranted to prove this relationship.
The association between physical activity and anxiety/depression was near the level of significance for Swedes, but not significant, which we assume is a consequence of the smaller sample size.
The response rates in general were low though in Iraqis, it was comparable to other studies on Iraqi immigrants in Sweden . Nevertheless it should be acknowledged that low response rate can result in underestimation of prevalence rates especially when dealing with mental ill-health . It is alarming that prevalence of anxiety/depression could be even higher than what is reported in this study in both Swedes and Iraqis.