From maps to stats, and back again
Since I was a teenager in the 1970s, I have loved studying maps. Back then I was growing up in rural eastern Scotland, not far from St. Andrews, the home of golf (in the era when Jack Nicklaus and Tom Watson were the maestros of the links). My granny had
given me her collection of old maps of Scotland.
So, I broadened my horizons by setting off on my bike, map in my backpack. Each journey became more ambitious than the previous one. Not only did the maps help me make it back to youth club disco in the village hall, but they gave so much more than just
navigation. They provided tantalising hints to the social history of each place: the usage of the land, the reasons why communities had developed in their particular place. I guess I was a visual learner.
My love of maps took me onto study geography at university. And, it was there in Aberdeen that my second love of figures won over. A switch to studying statistics followed, which after a few years led onto actuarial science. I now appreciate that the maps,
the social history and the longevity outcomes are all part of the same story. Indeed, the maps are a way of exploring the connections between past sociology and longevity outcomes. This subtlety was not so obvious to a teenager in the height of Saturday Night
Fever.
Our social geography
Back in the 1970s, it was common to believe that our genes explained differences in lifespan. Whilst they certainly play a role, thanks to the breakthrough of sequencing the human genome, we now know that the size of that role is a modest one: only around
one-fifth of the variations are down to your ancestors.
"Everything is related to everything else. But near things are more related than distant things." - Tobler’s First Law of Geography
The other four-fifths is down to how you spend your time on the planet. Smoking, drinking and physical activity (e.g. walking rather than taking the car) are the most important factors and can lead to big differences in
expectation of life. As
Matt Forrest explained on Club Vita's recent Zooming in on ZIPcodes webinar, your personal behaviours are likely to be influenced by your family, your friends, your neighbours, your work colleagues,
your community. Your network creates a social geography of influences on your lifestyle.
The unexpected power of ZIP codes
My journey has now led to the mapping of longevity variations in the United States. The US postal service’s ZIP code system has given us a convenient way of aggregating residents of small areas across the nation who we expect to follow similar lifestyles.
We can then test our hypothesis by using survival records from pension plans to study the life expectancies in the aggregated data across the country. Club Vita's approach reveals a wider variation in lifespan between retirees of pension plans than were apparent
in the blunter instruments previously used.
Now you can see a more granular picture thanks to the talents of Club Vita's technologists in overlaying the statistical variation on Google maps. Whilst the headlines from past longevity research may have focussed on the differences at state or county level,
you’ll find small patches of similar longevity in pretty much all regions. There are bits of Mississippi that look like bits of Massachusetts, parts of New Hampshire can be paired with Nevada, Oregon with Ohio and so on. Lifestyle, and therefore longevity,
appears more associated with the habits of a community than with the physical geography of its surroundings.
Unleash your curiosity
You can go on your own virtual exploration across the United States. As a foreigner in a big country, I have only just scratched the surface on my travels, but I remain as curious as a teenager. I hope that first map
prompts some thoughts, some questions. Zoom in on those areas you know well, particularly those areas where you understand the social history. Of course, exploring the differences with your own eyes is even better. Bike remains best for me.
We’d love to hear what you think.
Lang may yer lums reek
Douglas