Association between social capital,health-related quality of life,and mental health: a structural-equation modeling approach

AimTo explore the association(s) between demographic factors, socioeconomic status (SES), social capital, health-related quality of life (HRQoL), and mental health among residents of Tehran, Iran.MethodsThe pooled data (n = 31 519) were extracted from a population-based survey Urban Health Equity Assessment and Response Tool-2 (Urban HEART-2) conducted in Tehran in 2011. Mental health, social capital, and HRQoL were assessed using the 28-item General Health Questionnaire (GHQ-28), social capital questionnaire, and Short-Form Health Survey (SF-12), respectively. The study used a multistage sampling method. Social capital, HRQoL, and SES were considered as latent variables. The association between these latent variables, demographic factors, and mental health was determined by structural-equation modeling (SEM).ResultsThe mean age and mental health score were 44.48 ± 15.87 years and 23.33 ± 11.10 (range, 0-84), respectively. The prevalence of mental disorders was 41.76% (95% confidence interval 41.21-42.30). The SEM model showed that age was directly associated with social capital (P = 0.016) and mental health (P = 0.001). Sex was indirectly related to mental health through social capital (P = 0.018). SES, HRQoL, and social capital were associated both directly and indirectly with mental health status.ConclusionThis study suggests that changes in social capital and SES can lead to positive changes in mental health status and that individual and contextual determinants influence HRQoL and mental health.Mental health is defined by World Health Organization (WHO) as “a state of well-being in which every individual realizes his/her own potential, can cope with the normal pressures of life, can work productively, and is able to make a contribution to his/her community” (1,2). Mental health and associated disorders have received increasing attention worldwide, largely due to their impact on socio-economic and overall health status of patients (3). Mental health problems remain a global concern, and account for a large fraction of diseases (4,5).The overall prevalence of mental disorders in Iran between 2000 and 2008 ranged from 12.5% to 38.9% and was similar in urban (20.9%) and rural areas (21.3%) (6). Anxiety and depression were more prevalent than somatization and social dysfunction (7). The provinces with the highest prevalence of mental problems were Chaharmahal with 38.3% and Golestan with 37.3% (8).Mental health is usually determined by a complex interaction of sociocultural, psychological, environmental, and demographic factors (9). The prevalence of mental health disorders is significantly associated with age, marital status, educational level, employment, and health-related to quality of life (HRQoL) (10). HRQoL incorporates physical and socio-emotional functioning and is used to measure individual''s perception of health status, welfare, and well-being in a society (11). A frequently used psychometrical tool for the assessment of HRQoL is Short-Form Health Survey (SF-12). Its two main components are physical component summary (PCS) and mental component summary (MCS), both of which are associated with mental health (12). Previous studies have confirmed a bidirectional association between physical health and depression (as one of the main dimensions of mental health) (13). However, it is not clear whether there is a causal relationship between them (13,14).The suggested mechanisms by which depression could lead to physical disability and decreased HRQoL are poor health behaviors, increased risk of physical disease, and characteristics of depression (eg, decreased pain threshold) (15). On the other hand, physical disability can lead to depression and deterioration of mental health due to restriction of social activities and loss of social capital (15). Ultimately, this bilateral association between depression and poor physical health can lead to increasing health risks (14).Mental disorders such as depression and anxiety are also influenced by socioeconomic status (SES) (16). SES is commonly conceptualized as an individual or group’s relative social standing or class (16,17). The main predictors of SES are education level, income, and occupation (15,17,18). The correlations between SES and mental health have been explained by various mechanisms. It has been found that negative impact of low SES on mental health (19) can be reduced by the mediating effect of social capital and physical health (4,18).Social capital has been defined as individual’s social networks and social interactions, shared norms, values, and understandings that facilitate collective action within or among groups. It can act as a protective factor, promoting mental health status by reducing socioeconomic inequalities (4,20) and play an important role in reducing the prevalence of mental disorders (4). Previous studies have found that social ties and support significantly improve mental health (9). Nonetheless, the association between social capital, mental health, quality of life, and SES is not consistently reported (21,22). This population-based study aims to explore the association between demographic factors, SES, social capital, HRQoL, and mental health among Tehran residents using structural-equation modeling (SEM).