In my last article I looked at the extent of residential segregation between people from Catholic and Protestant backgrounds in Belfast. We saw that there are a large number of areas where more than 80 percent of the population come from one or other religious background and a comparatively small number of areas where the population is evenly balanced between the two religious denominations. In this article we'll look at whether there is a relationship between the proportion of the population in an area from either religious background and the health outcomes of the area's residents. My interest in this question comes from previous work I have done on what is termed social capital. Before looking at any data I'll therefore outline what this is and why it might play a role in shaping health. I'll then have a look at some data.
The concept of capital is used in the social sciences to refer to resources which have the character of an investment and carry the anticipation of future returns. For example, financial capital might refer to investment in the stock market and the expectation of future dividends, while human capital is often used to refer to individual decisions about investment in education and how that is related to expectations of future earnings. In a similar vein, social capital is used to capture the idea that social relationships might have economic benefits and refers to resources such as trust and the habits of co-operation which individuals develop through group memberships.
Social capital is principally an ecological construct reflecting the shared level of trust and co-operation within a group rather than the extent of any individuals social contacts. Numerous research studies have examined the association between the level of social capital in a community and indicators of residents' wellbeing. These studies have often shown that living in an area of high social capital has a positive relationship with residents' health outcomes. The general type of explanation for this association is that in areas of high social capital the environment acts as a source of support and positive interactions while in areas of low social capital the environment is perceived to be a threat and a source of stress.
Although living in an area of high social capital has usually been described as a resource, researchers have noted that there may be a downside to social capital. Communities characterised by high levels of trust can have high levels of anti-social behaviour and cohesive ties between group members may exclude individuals who are not group members. The typical example given of this 'dark-side' to social capital is the mafia. In response to such criticisms the concept of social capital has been extended and bonding and bridging forms of social capital are now commonly distinguished by researchers. Bonding social capital refers to cohesive community relationships usually between people of similar background, while bridging social capital refers to relationships outside your own group. Bonding social capital, corresponding to trust between people who know and interact with each other, may have a 'dark-side' but patterns of trust between strangers, or bridging social capital, is felt to be almost always a beneficial resource.
I have been thinking about whether these ideas might provide a useful way of looking at relationships between residential segregation and health. The general idea I have in mind for a study is that bonding social capital is likely to be present in both strongly Catholic and Protestant areas of Belfast but may not be associated with positive health outcomes given the context of segregation across the city. Bonding social capital might be useful in mobilising local community resources, however, strongly Catholic or Protestant communities might also lack bridging social capital and this might limit the extent to which communities can access resources outside the local area.
To look at this I'll need some data on social capital and might be able to use data on voluntary organisations or household survey data. But to see whether this idea is worth pursuing I have been doing some simple exploratory analysis using data from the 2001 census and the Northern Ireland Index of Multiple Deprivation. The results are interesting. The figure below plots the percentage of the working-age population who have a long-term illness and the level of employment deprivation for census output areas in Belfast. The figure distinguishes areas where more than 80 percent of the population is from a Catholic background (green dots), more than 80 percent are from a Protestant background (blue dots) and mixed areas where neither group makes up more than 80 percent of the population (red dots). The figure shows that there is a strong positive association between the incidence of long-term illness and employment deprivation in an area. The areas where neither religious group makes up more than 80 percent of the population (red dots) tend, however, to have both lower levels of illness and lower levels of employment deprivation. What role social resources have in shaping this relationship is unclear but I hope to be able to make some headway in understanding soon.