Income gradient in health-related quality of life — the role of social networking time

In recent decades, life expectancy has increased and the mortality rate has decreased, but socioeconomic disparities in health outcomes persist. Social gradients in health, whereby individuals from lower social class backgrounds have poorer health status, higher risk of illness and a shorter life expectancy, have been well documented in existing studies [1‐4]. Numerous efforts, such as increased investment in health and health services and the implementation of health promotion policies, have been made to reduce health inequalities; however, substantial evidence indicates that social class disparities in health are widening [5‐8]. Income, as a basic indicator of social class, plays a dominant role in the maintenance of people’s health [9]. Higher income is related to better health conditions and lower health risks, while lower income means more exposure to health risk factors. How is income related to health, and why is the income gradient in health continuing to widen?

Prior studies on the income-health relationship focus on two sets of issues: the effect of absolute income on health and the association between relative income and health. With regard to the effect of absolute income, money involves access to resources that benefit for health, such as medical services [10], better nutrition [11] and resources embedded in social networks [12]. The relative income aspect mainly concerns the psychosocial pathways of the income gradient in health, as the sense of relative deprivation that derives from income differences could have adverse psychosocial consequences [13]. People with lower relative income experience higher risks of mental health disorders, including depression and anxiety [14].

Among all the factors linking income and health, the effect of social networks attracts the most attention. However, the measurements of social networks vary across studies, and social networks are often conceptualized in terms of both functions and structures. The functional conceptualizations include supportive social contacts [15] and the availability of support [16]. As a main source of social support, social networks are considered protective factors of health. The structural aspects of social networks encompass the social ties in which people are embedded [17] and the pathways of network influence [18]. Smith and Christakis [19] reviewed the differences between social support and social networks and found that studies on social support focus on the number of contacts and the helpfulness of those contacts, while analyses of social networks concentrate on the nature and types of ties linking people together, including the closeness of the ties and the relationships of the people embedded in the ties, such as friends, relatives and neighbors. The influence of social networks on health appears uncertain when networks are conceptualized structurally. Different types of social ties are not always supportive of or beneficial for health, as a negative effect of neighborhood connections on mental health has been found [20].

Moreover, although income is positively related to the availability of social support, people of different income levels have distinctive preferences in relation to social network types. A study on the association between income and social network choices shows that people with higher income spend more time with their friends, while those with lower income spend more social networking time with neighbors [21]. Since income impacts people’s social networking time with their neighbors and neighborhood connections might be harmful for health, is it possible that neighborhood networks mediate the relationship between income and health and help explain the health inequalities between people with different income levels?

This study extends the current research on the income gradient in health by discussing the possible mediating effect of a typical type of social network: neighborhood ties. Income is considered a social contextual factor influencing people’s embeddedness in neighborhood ties. Furthermore, health-related quality of life (HRQoL) is adopted to evaluate people’s health outcomes [22‐24]. HRQoL is described as people’s perceived physical and mental health over time [25], reflecting individuals’ subjective feelings of the extent to which health problems influence their daily life. In the context of the epidemiological transition to an era in which non-communicable chronic diseases have become a major risk factor for people’s health, HRQoL, which implies a direct linkage to health conditions [26] and subjective assessment of health status, is more reflective of the modern biopsychosocial medical model than objective indicators such as life expectancy and mortality rate [24].

This study focuses on the income gradient in health and how it is reproduced through people’s social networking time in the United States. A positive association between income and HRQoL is captured, and the inequalities in HRQoL reproduced through neighborhood socializing mainly exist in relation to mental health.

The statistical results demonstrate that people with higher income generally have higher HRQoL, which has been well supported in existing studies [40]. The income gradient in HRQoL derives from various inequalities related to health, including differentiated access to healthcare services and unbalanced allocation of health-related resources, as well as distinctions in health-related lifestyles across social classes.

The study also confirms the negative association between income and social networking time with neighbors. This negative association could be explained by people’s structural embeddedness and their access to resources. Prior analyses show that people with abundant resources tend to be less dependent on others [41, 42]. Thus, people with lower income and limited access to resources may spend more time socializing to obtain social support. A psychological experiment studying patterns of nonverbal displays of disengagement and engagement among participants with varied socioeconomic statuses suggests that people of higher socioeconomic status display more disengagement cues in social contact than people from lower classes [43]. This is in line with the study of Bianchi & Vohs [21], which indicates that people from lower classes tend to spend more time socializing with neighbors than with relatives and friends, as neighbors may provide more immediate instrumental support based on geographic proximity than friends and relatives.

The reproduction of health disparities is examined through the mediating role of social networking time in the relationship between income and HRQoL. The reproduced inequalities are probably more related to mental HRQoL than other aspects, as neighborhood connections impact mental health more directly [44]. Social networks and ties are major sources of social support, which is beneficial for the maintenance of health, but the helpfulness of networks is uncertain. Several existing studies examining mental health inequalities across classes demonstrate that social connections may paradoxically increase the level of mental illness symptoms among less privileged groups [45‐47]. From the psychosocial perspective, the sense of relative deprivation arising from social networking with neighbors may harm people with lower income. Reciprocity and mutual instrumental support are the dominant basis of the establishment of neighborhood connections. However, those who are most in need of support are often the least likely to receive it and must bear a disproportionate cost of involvement [48]. People engaging in such relationships with limited resources may face greater difficulty in responding to others’ needs. Therefore, for people with lower income with limited access to resources, reciprocal neighborhood connections mean more psychological costs as a result of the sense of indebtedness. Finally, the contextual characteristics of social networks cannot be ignored in analyzing the reproduction of income gradients in HRQoL through neighborhood ties, as “interpersonal relationships occur within broader social contexts” [49]. People with lower income are more dependent on collective resources in the neighborhood, and neighborhood deprivation may have a negative effect on their mental health. The impact of social context on mental health is indicated by Durkheim in the illustration of the relationship between surrounding social climate and suicide rates [50]. Empirical studies on neighborhood deprivation and mental health indicate that neighborhood attachment is associated with higher reporting of common mental disorders [47]. The sense of relative deprivation, individual neighborhood socializing cost and a comparatively disadvantaged neighborhood environment may jointly or separately result in the reproduction of the income gradient in HRQoL.

This study offers two major contributions. Drawing insights from previous studies on differences in social networks and social support, this study shows that the supportiveness of social networks is uncertain and that social networks are not always helpful and beneficial for people’s health. It further suggests that the social networking time differences between people with different income levels could be considered one of the mechanisms of social class inequality in health.

The study should be viewed in light of several limitations. First, though the significant association between income and social networking time is confirmed, it is uncertain whether neighborhood networking affects people’s income. Although working status is controlled in the analytical models, it is still possible that people who are more engaged in neighborhood socializing are less concentrated on other money-making activities and thus earn less money. Nonetheless, this study maps out people’s social network preferences reconciled with their social positions as a product of their structural embeddedness and surrounding social world. Second, the results indicate that people’s HRQoL is influenced by their social networking time, and the reverse is also possible; that is, people of poorer health status have fewer opportunities to participate in activities other than neighborhood socializing. Finally, income is used as the indicator of people’s access to resources, but the neighborhood characteristics that affect the availability of resources are not included in this analysis. Therefore, multilevel models with more detailed neighborhood features are needed in future related studies.

This study analyzes the income-health relationship and how it is mediated through people’s social networking time based on a national-level representative sample from the GSS. The structure and nature of people’s social networks are associated with their structural embeddedness and contextual characteristics. The test of the mediation effect of social networking time on the relationship between income and health shows that neighborhood socializing may influence people’s mental health as a result of the sense of relative deprivation and the obligatory reciprocity entailed in neighborhood ties. This finding confirms the unequal distribution of HRQoL among people with different income levels and verifies its reproduction through neighborhood social ties.