I love vague studies like this - it's like saying:
We observed several Ford Focus drivers yesterday and several Kia Rio drivers. Looks like many more of the Ford Focus drivers were overweight - so there may be a link between Ford and obesity!
Oh- but we didn't find out anything else about the drivers lifestyle, habits, history, genetics etc. So of course we can't say for sure.
What is the point?
I would happily file this away in the "not so significant" studies cabinet