Postcode Lottery: Is your home neighbourhood affecting how you age?

by kirstinleslie · July 26, 2019

Image Credit: Kamyq via Pixabay

Flat hunting is, without a doubt, the most tedious chore. To begin with, you need to find something you can afford; somewhere close enough or at least accessible via public transport to your work or uni; a property that is actually habitable (half-decent insulation, preferably no damp/mice/weird neighbours); an acceptable trade-off between council tax bands and the safety of the area; a landlord or estate agent that isn’t *awful*; and that’s to name a few. And now, to add to that list, it turns out that the neighbourhood you live in may actually affect the way you age.

Recent research from the University of Glasgow has found that living in a “stressful neighbourhood” may accelerate your biological age¹. This may not sound too surprising, especially as lower standards of health have been associated with social deprivation in numerous previous studies. If you’ve heard of the unpleasantly named ‘Glasgow effect’ – whereby the life expectancy of Glaswegians is lower than that of people living in similar post-industrial cities in the UK – you may already have a sense that the location you live in can literally shorten your life.

The finding that our home neighbourhood can affect ageing adds to our understanding of the ‘Glasgow effect’ phenomenon, as it demonstrates a biological component. By looking closely at the cellular structures of residents in these “stressful” neighbourhoods, it was found that they were, in fact, ageing more quickly. The structures that the researchers used to measure this accelerated ageing are called telomeres.

Telomeres are the protective ‘caps’ on DNA, which can be found at both ends of a chromosome². Each time a cell divides, the DNA within it must also divide in order to pass genetic information on to the two new daughter cells. While DNA replication is a highly controlled process, it is still imperfect; each time a chromosome replicates, it gets a little bit shorter. Luckily, it loses its length from telomere caps – areas of DNA that do not hold any important information for the cell – and which the chromosome can therefore afford to lose without suffering any loss of function. This means that we can tell the age of a cell by the length of a telomere – if the telomeres are shorter, it means the DNA in that cell has been replicated many times, indicating that it is ‘older’.

Process of telomere shortening across sequential cellular divisions. Credit: Kirstin Leslie

In this study, researchers took a blood sample from people who had previously been asked about their perceptions of their neighbourhood multiple times over a 12 year period. From this sample, their DNA was extracted in order to check the length of their telomeres. This information was then compared across study participants and their different neighbourhood experiences. As telomere length was only measured at one time point, it is not possible to completely rule out reverse causality – for example, people with poorer health may not be able to work full-time and may be priced out of more affluent neighbourhoods. These people may have shorter telomeres for other valid biological reasons. To minimise this bias as much as possible, additional factors known to influence telomere length were considered by the researchers, such as fitness, diet, smoking, and a diagnosis of depression. Even after this, it was still found that people who reported higher rates of burglaries, vandalism, littering, disturbances, assaults, and muggings tended to have shorter telomeres in the follow-up.

This doesn’t mean to say we should make a mass exodus from Glasgow – in fact, Glasgow recently ranked within the top 10 cities in the world³ and it has been voted as the most millennial-friendly UK city ⁴. For one thing, the study focused on people’s local areas, so we don’t need to rule out entire cities. It also, as with all research, has its limitations. The study measured neighbourhood stressors by how people perceived their local areas to be, not by recorded levels of crime. It’s possible that people who are reporting more disturbances in their area are just more perceptive to these stressful happenings than others. It could be that this, in turn, leads to higher levels of stress and has a knock-on effect on their telomere length.

Scientists are always interested in ‘modifiable risk factors’ – any characteristics that may increase your chance of disease or ill health that can be changed or improved, especially by policy changes. The researchers behind this study are hopeful that their research will be influential, as “neighbourhood environments are potentially modifiable, […] future efforts directed towards improving disadvantaged local environments may be useful to lessen the effects [on] how fast people age”. If the government or local councils use this evidence as a basis to invest in deprived neighbourhoods and reduce inequality, then this sort of research could promote real change. Unfortunately, we are currently living in times of austerity, and that is unlikely to change anytime soon, especially given the continuous expense of Brexit negotiations. But research like this is important – it gives us an informed foothold from which we can ask for change. If politicians are aware of the biological impact their decisions can have, they may endeavour to make decisions that are healthier for all of us. But that’s a big ‘may’.

This artcile was specialist edited by Niamh Armstrong and copy-edited by Sonya Frazier.