Life course, environments & health
We know that factors throughout life influence our health and well-being in older age. Childhood poverty, early life education, difficult life events and many other factors have been shown to be strongly related to subsequent health outcomes. Yet almost all of this work has focused on our individual circumstances, and there have been few attempts to consider whether a wider set of factors – such as those at the community or neighbourhood level – affect our health over the life course. This is perhaps a surprise given the evidence that features of our local environment – such as air pollution, green space, and high numbers of retailers selling fast food, alcohol or cigarettes – are often associated with current health status. If these factors are causally related to health then there may be a number of policy opportunities (e.g. see our recent post on alcohol retail licensing).
So why have so few studies of health incorporated longitudinal environmental data? The probable reason is that it can be very challenging to do this sort of work! Detailed environmental information over time is often difficult (and sometimes impossible) to source. And when it is available the information often exists in awkward formats such as in the back of obscure paper reports or buried in an archive; a great deal of effort is required to collate these data.
Reconstructing past environments
The CRESH team have been trying to overcome these complications and collect a range of historical environmental data. As an earlier post detailed we have been finding out whether it is possible to use historical data sources to ‘reconstruct’ features of local environments that may relate to health. For example, we have used historical sources to map the availability of public green spaces across the Lothian region of Scotland over the past 100 years. We hope that this approach might not only tell us something about how local health-related environments have changed in recent years, but also provide us with much more convincing evidence as to how environments get ‘under our skin’ at different points in the life course to affect our health.
Food Environments in New Zealand
A new paper we have recently published in Public Health Nutrition (with colleagues at the GeoHealth Laboratory in New Zealand) is a new example of this approach. The aim of this New Zealand work was to examine changes in the urban food environments near schools over the past 50 years. This was an interesting historical example because there has been a great deal of contemporary work on the implications for nutrition, diet, overweight and obesity of local food environments, particularly around schools. We collected and geocoded the address data of food premises for five snapshots since 1966. For each year, the number of retailers (supermarkets, grocery stores, convenience stores, and fast-food outlets) in close proximity to schools was calculated. The results showed that over the study period, school food environments in Christchurch can be characterized by increased densities of fast-food outlets within walking distance of schools, especially around the most deprived schools. At the same time there was a reduction in supermarkets, grocery stores and convenience stores.
From a public health perspective, these findings are useful because they suggest that since the 1960s, there have been substantial changes to neighbourhood food environments. These alterations may increasingly facilitate away-from-home consumption for children, and provide easily accessible, cheap energy dense foods, a recognized contributor to the rise in prevalence of overweight and obesity among young people. But the results also emphasise the feasibility of collecting detailed historical data at various time points. Such approaches offer significant opportunities for understanding health-place relations over the life course.
Jamie Pearce, October 2014