Neighbourhood disadvantage, network capital and restless sleep: Is the association moderated by gender in urban-dwelling adults?

Highlights

• Women residing in disadvantaged neighbourhoods have higher odds of restless sleep.

• Social environmental factors are differentially associated with restless sleep in men and women.

• High trust decreases the odds of restless sleep in women.

• Network capital increases the odds of restless sleep in men.

• Gender should be considered in studying social influences on restless sleep.

Abstract

Despite evidence suggesting that social and neighbourhood contexts may relate to sleep in adults, the underlying social and demographic mechanisms involved remain relatively unexplored. This study proposes a conceptual framework for examining the link between social environments and restless sleep, and assesses whether associations among restless sleep, social capital, and neighbourhood environments differ by gender. Data come from the 2008 Montreal Neighborhood Networks and Healthy Aging Study (n = 2707). Participants self-reported restless sleep. Network and cognitive dimensions of social capital were examined. Neighbourhood disadvantage and population density were measured using 2006 Canada Census data. Multilevel logistic analyses adjusting for socio-economic and -demographic variables were used to estimate associations among study variables. The final sample size for this study was 2643 adults (n_men = 930; n_women = 1713). Women were more likely to experience restless sleep than men (OR: 1.29; 95% CIs: 1.07, 1.55). Network capital increased the likelihood of restless sleep in men (OR = 1.25; 95% CI: 1.04–1.50) but not women. High generalized trust decreased the odds of restless sleep in women (OR = 0.75; 95% CI: 0.59–0.94); neighbourhood disadvantage increased the odds of restless sleep in women but not men (OR = 1.18; 95% CI: 1.01–1.38). The association among restless sleep, social capital, and neighbourhood environmental factors differed in male and female Montreal adults. This study contributes to a greater understanding of possible differential associations between social environments and health in men and women. Greater knowledge of the social and environmental factors that contribute to poor sleep in men and women can aid in the design of interventions to improve sleep patterns in the general population. Social and health promotion interventions might aim to improve general neighbourhood environmental conditions to improve the sleep health of women.

Introduction

Poor sleep quality is associated with adverse physical and mental health outcomes, including chronic disease, respiratory problems, depressive symptoms, anxiety, and poor general and self-reported health (Strine and Chapman, 2005, Foley et al., 1995, Devins et al., 1993). Restless sleep, characterized by trouble falling asleep and maintaining sleep throughout the night, is a complaint that is prevalent in about 30% of the Canadian population (Hurst, 2008). Self-reported restless sleep has been linked with chronic illness, poorer perceived health, depressive symptoms, illness comorbidities, and increased illness intrusiveness (Devins et al., 1993, Kutner et al., 2001). Although men have been shown to sleep shorter durations than women (Hurst, 2008), studies on self-reported sleep and gender have reported that women tend to have more sleep problems than men (Arber et al., 2009, Foley et al., 1995, Hurst, 2008, Nordin et al., 2005). Approximately 35% of women from a nationally representative survey had trouble falling asleep or trouble staying asleep, whereas 25% of men reported the same difficulties (Hurst, 2008).

Research on sleep has conventionally focused on the physiological, behavioural, and psychological factors associated with poor sleep (Freedman and Sattler, 1982). More recently, however, social epidemiological research has begun to examine the importance of social environmental characteristics, including social relationships and neighbourhood environments, in people's experience of poor sleep (Hill et al., 2009, Nieminen et al., 2013, Nordin et al., 2005, Riedel et al., 2012). The present study addresses theoretical, methodological, and substantive gaps in our knowledge of social environments and sleep. Little is known about the specific mechanisms underlying associations between neighbourhood and social environmental characteristics and restless sleep, and whether these associations differ in men and women (Arber et al., 2009). Previous research has suggested that women's sleep may be more vulnerable to features of social and neighbourhood environments, whereas men's sleep may be more vulnerable to economic and employment conditions. For example, studies have shown that low social support, low social network integration, and environmental noise are associated with poor sleep in women, whereas unemployment and work-related causes are associated with poor sleep in men (Li et al., 2002, Nordin et al., 2005, Urponen et al., 1988). From an epidemiological and public health perspective, social and environmental factors are potentially modifiable and amenable to population health interventions, policies, and programs. Greater knowledge of the social and environmental factors that contribute to poor sleep in men and women can aid in the design of interventions to improve sleep patterns in the general population. Given the importance of sleep for a range of physical and mental health outcomes (Strine and Chapman, 2005, Foley et al., 1995, Devins et al., 1993), such interventions could have additional benefits for broader population health.

Fig. 1 presents the conceptual model underlying our analysis of gender, neighbourhood and social environments, and restless sleep. Daniel et al.'s (2008) conceptual model on the biosocial pathways and multilevel influences underlying the association between place and cardiometabolic disease guided our study. We have extracted several theoretical elements in Daniel et al.'s model and added a gender dimension so as to conceptualize more specifically the role of gender as a potential effect modifier in the associations among social, neighbourhood environments, and restless sleep. Daniel et al.'s (2008) model provided three theoretical elements: (1) recognition of the role of macrosocial, multilevel environmental influences on health; (2) the situating of environmental structures and neighbourhood contexts as risk conditions that affect the expression of individual outcomes; and (3) the positing of direct-contextual and indirect-cognitive pathways to explain place–person–health relationships. First, recognition of the role of macrosocial and multilevel influences on health has been an essential aspect of neighbourhood health effects research. Nevertheless, researchers have suggested that there remains a lack of attention to these multilevel social influences in research on sleep (Arber et al., 2009). Second, risk conditions represent the objective and subjective properties of social and built environments that increase the underlying vulnerability of people to places. Risk conditions consist of structural (i.e., asymmetries in the production and allocation of social resources) and contextual factors (i.e., the local attributes of places). Third, Daniel et al. (2008) posit that risk conditions impact health via direct-contextual and indirect-cognitive paths. The direct-contextual path represents the non-conscious stress responses by which neighbourhood contexts directly affect important biological mediators (e.g., allostatic load) of person-health relationships. The indirect-cognitive path is predicated on the conscious perception of environmental influences along with a person's psychosocial and behavioural responses to those influences (Daniel et al., 2008). Based on these theoretical elements, our model posits that gender acts as a potential effect modifier in the association between socio-environmental characteristics and restless sleep, whereby the way in which neighbourhood contexts and social relationships are associated with restless sleep differ in men and women.

First, our model suggests that sleep behaviour and patterns differ in men and women. This is based on a large body of evidence finding gender differences in adult sleep (Arber et al., 2009, Burgard et al., 2010, Foley et al., 1995, Hurst, 2008, Nordin et al., 2005, Reyner et al., 1995). It is widely accepted in the sleep literature that women have higher prevalence rates of insomnia, and are more likely to report poor sleep than men (Li et al., 2002, Reyner et al., 1995, van den Berg et al., 2009). Conversely, men may be vulnerable to other indicators of sleep disturbance. For example, men are more likely to go to bed later than women, and to sleep for shorter durations (Ohayon et al., 2004, Reyner et al., 1995). Longer sleep duration in women does not however always translate into better overall sleep quality. Burgard et al. (2010) showed that despite sleeping for longer, women reported more interrupted sleep than men. These gender differences were largely explained by women's social roles, particularly mothers with young children, since it was this element of caregiving that contributed to interrupted sleep in women (Burgard et al., 2010). Studies that have used objective measures of sleep have also found differences in sleep among men and women (Ohayon et al., 2004, Lauderdale et al., 2006, Redline et al., 2004). These studies have confirmed that women typically have longer total sleep time than men, but that they also take longer to fall asleep (Ohayon et al., 2004, Lauderdale et al., 2006). Based on this body of research, hypothesis one states:

Hypothesis 1

Women are more likely to experience restless sleep than men.

Previous research on neighbourhood environments and sleep have tended to examine sleep as either mediating or moderating the relationship between neighbourhood exposures, mainly neighbourhood disorder, and physical health or psychological distress. For example, Hale et al. (2010) reported that neighbourhood disorder was associated with poor sleep quality, and that poor sleep quality also partially mediated the relationship between neighbourhood disorder and poor physical health. In another study, Hill et al. (2009) showed that sleep quality moderated the association between neighbourhood disorder and psychological distress, with disorder more strongly associated with distress among those persons who reported poor sleep quality (Hill et al., 2009).

Neighbourhood disadvantage is characterized by residential areas with high proportions of mother-only households, renters, immigrants, and unemployment (Haines et al., 2011; Kim, 2010, Ross and Mirowsky, 2001, Schneiders et al., 2003, Silver et al., 2002). While disadvantage captures socioeconomic aspects of neighbourhood environments, it also includes added dimensions of social marginalization. Previous research has shown high neighbourhood disadvantage associated with serious sleep problems in children (Singh and Kenney, 2013).

Despite research on the direct association between neighbourhood conditions and sleep, little research has examined whether gender moderates the association between neighbourhood disadvantage and sleep. Nevertheless, recent studies have suggested that social and environmental characteristics might contribute differently to sleep in women compared to men (Arber et al., 2009, Burgard et al., 2010, Nordin et al., 2005, Riedel et al., 2012, Yao et al., 2008). Researchers have hypothesized that women may be more vulnerable to poor sleep due to differences in social roles, experiences, and levels of social embeddedness in their places of residence (Arber et al., 2009, Burgard et al., 2010, Sekine et al., 2006). Arber et al. (2009), for example, found that half of the self-reported sleep problems of women could be attributed to their higher likelihood of being socio-economically disadvantaged. This research leads to our second hypothesis:

Hypothesis 2

Neighbourhood disadvantage is more strongly associated with restless sleep in women than men such that women residing in disadvantaged neighbourhoods are more likely to experience restless sleep.

Third, our model posits gender differences in the association between social capital and restless sleep. Social capital refers to the resources to which individuals and groups have access through their social networks (Moore et al., 2009a). Recent research on social capital and health has tended to measure social capital along different dimensions, including generalized trust, social participation, and network capital (Fujiwara and Kawachi, 2008, Haines et al., 2011). Generalized trust captures cognitive aspects of social capital, whereas measures of participation and network capital capture structural and resource-related aspects of the concept. Although social capital has been shown associated with a range of health outcomes (Kawachi et al., 2008), few studies have examined whether social capital is associated with poor sleep. In a sample of Finnish adults, Nieminen et al. (2013) examined the association between sleep duration and social capital, showing that social participation, higher social support, and higher generalized trust were positively associated with adequate duration of sleep. Adequate sleep duration was defined as reporting between 7 and 8 h of sleep per 24 h. Nasermoaddeli et al. (2005) examined sleep in a sample of British and Japanese civil servants and showed that social engagement in clubs and organizations was associated with better self-reported sleep quality (Nasermoaddeli et al., 2005). To our knowledge, associations of sleep with resource-related components of network social capital have not been studied.

Given the general lack of research on social capital and sleep, it may be useful to consider studies that have examined the importance of social support for sleep. Social support and social capital each emerge from social networks, although social support tends to come from a person's strong ties (Nordin et al., 2005). Research on social support and sleep has shown that sleep quality was higher in those persons who reported closer relationships with family and friends (Yao et al., 2008). In another study, Nordin et al. (2005) found lower levels of social support and integration associated with poor sleep ratings in women but not men. Nordin et al.'s (2005) findings suggests that gender differences may also exist in the association between social capital and sleep. This research leads to our third hypothesis:

Hypothesis 3

Social capital is more strongly associated with sleep in women such that women with higher social capital are less likely to experience restless sleep.

The current study tests three hypotheses on the association among gender, neighbourhood contexts, social capital, and restless sleep. These hypotheses allow us to investigate more generally the importance of direct-contextual and indirect-cognitive paths in the link between macrosocial environmental factors and health. In so doing, our study aims to increase current knowledge on the underlying mechanisms potentially linking social and environmental factors with restless sleep.