Consider two Parisians, one living near Jardin du Luxembourg in the 6th arrondissement. The other in Stains, in the north of the city, not too far from the Stade de France. They are separated by about six stops on the metro (RER to be precise), but their life expectancy differs by eight years. How is that possible?

The 6th is, unsurprisingly, one of the wealthiest parts of Paris, while Stains, is among the poorest. The median disposable income in the 6th is more than 2.5 times that of Stains.

Paris is by no means an outlier. All over Europe certain neighbourhoods outlive others. In Vienna the gap is four years for women and eight years for men, and in Barcelona eight years for women and 16 for men, to name just a few.

Anyone who's looked for a place to stay knows location is always a key consideration in where to live. Distance to work, to parks, to the water. So, do we live longer because we have more money, because the location we choose is better for us, or is there another factor?

Let's look at the extreme example of Glasgow. Within the city, the life expectancy gap between neighbourhoods is even larger: up to 15 years for women and 20 years for men. And the gap has grown by 3 years since the early 2000s.

A 2021 report by the Glasgow Centre for Population Health links the widening gap, “at least in part, to UK Government austerity measures which have disproportionately affected our poorest communities.”

A country-wide analysis suggests, associatively, that this stems first from the direct reduction in income due to lower social security payments, and second from the removal or reduction of public services through cuts to local government funding.

But there are also ways to increase life expectancy. Across Paris, fine particles and NO2 have roughly halved over two decades, and premature deaths from air pollution fell by 40%, from 10,000 to 6,200 a year between 2010 and 2019.

This is mostly thanks to tighter emission rules that made cars cleaner and pushed out diesel. But Paris has gone further, closing streets to cars, planting trees and adding bike lanes. These measures have concentrated in the dense, wealthy core. So whether they narrow or widen the within-city life expectancy gap is still to be determined.

While policy can have a large impact on life expectancy, in the end, money allows us to make choices that extend our life. Income and life expectancy are closely intertwined. With less money, one might be exposed to more stress, food insecurity, pollution, noise or lack of green space, have less choice for healthy food options, go untreated longer, or work in more dangerous environments. And the list goes on and on, with many factors reducing life expectancy.

They all combine into one reality, in France the richest 5% of women outlive the poorest by eight years, the richest men, the poorest even by 13 years.

So while a higher life expectancy might be just a few metro stops away, reaching it will require more than just a metro card.