By Helena Tunstall
It is well known that people living in neighbourhoods with poorer quality physical environments tend to have worse health than those living in better quality environments. For example, those in areas with higher levels of air pollution have greater risk of death from respiratory and cardiovascular disease. However, the vast majority of these studies do not consider the possibility that patterns of residential moves may concentrate people with poorer health in certain types of environments. This is important because it is feasible that the links between the environment and health may, at least partially, be explained by the migration of people with poorer health to poor quality environments.
The theory that migration may influence the association found between the environment and the health of populations that live in them has been supported by research that has assessed the health of movers between areas with more and less socio-economically deprived environments within the UK and other European countries. This research has suggested that, at younger ages, people moving towards more socio-economically deprived areas tend to have poor health, in particular, poor mental health. These studies have found that migration can strengthen the association between poor health and neighbourhood socio-economic deprivation among younger age groups. There is also evidence that migration may affect inequalities in exposure to environmental hazards found between more and less advantaged social groups. This is because more advantaged populations may move away from neighbourhoods where these hazards are located.
The health of migrants moving between physical environments with different degrees of disadvantage has however rarely been explored. In our study, recently published in ‘Social Science and Medicine’, we looked at this issue, assessing the general and mental health of people moving towards neighbourhoods with more and less disadvantaged physical environments. We also compared the health of these movers to people moving to neighbourhoods with more and less socio-economic deprivation.
This study used data from the British Household Panel Survey (BHPS), pooling cases from adult members over 10 years, 1996-2006, to create a dataset containing 122,570 observations. Moves between residential neighbourhoods were over a one year time period between adjacent waves of the survey. We defined neighbourhoods using Census Area Statistic wards (2001 population= ~6,000). Neighbourhood physical environment deprivation was indicated by the Multiple Environmental Deprivation Index (MEDIx). MEDIx gives neighbourhoods scores based upon five aspects of their neighbourhood physical environment: air pollution, cold temperature, proximity to industrial facilities, ultraviolet B radiation and green space. Neighbourhood socio-economic deprivation was measured using the Carstairs deprivation index, based upon indicators from the 2001 Census. We measured health using self-reported measures of general health and mental health problems from the BHPS respondents.
Key findings from this analysis were:
- Adults that had moved within UK in the last year had similar or worse general and mental health than people that had not moved in all age groups. Mental health problems were particularly elevated among movers compared to non-movers.
- Among people of all ages combined those moving to more socio-economically deprived neighbourhoods had notably worse mental health than those moving to less or similarly deprived areas. This pattern was more weakly echoed for general health.
- In contrast, when moves between different types of physical environments were considered among people of all ages combined we found, unexpectedly, that mental health was poorest people moving to better physical environments. There was little difference in risk of poor general health between movers to neighbourhoods with greater, lesser and similar levels of physical environment disadvantage.
- The association between mover’s health and the types of environments they moved between also varied significantly between age groups.
Some conclusions can be drawn from these findings:
First, the association between mover’s health status and the characteristics of the environments they move between may differ substantially between measures of the physical and socio-economic environment. The contrasting mental health results found in this study for physical and socio-economic environment disadvantage stress that we cannot presume that relationships found in research examining the relationship between mover health and neighbourhood socio-economic deprivation will be echoed in analysis of physical environment deprivation. Furthermore, this analysis suggests that the relationship between mover health and physical environments may also vary between health outcomes and by age group.
Second, residential mobility, in the short term, may not necessarily concentrate people with poor health in the worst physical environments. This is suggested by the finding that the risk of mental health problems was greater among people of all ages moving towards areas with less physical environment disadvantage compared to movers to more disadvantaged places. However, this study was focussed on the health of individual movers and did not directly assess the impact of their moves upon the rates of poor health found for populations in neighbourhoods. The question of how migration affects inequalities in area level health between neighbourhoods with different levels of physical environment deprivation will be assessed in a further paper building upon finding from this study.