This research summary says LITERALLY IN ITS CONCLUSION that it cannot make this link. I mean, it doesn't take long to read the whole thing.https://twitter.com/zeynep/status/1123240275869040640 …
You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
You're treating this disclaimer like some sort of boilerplate. It's really important that there are a whole host of other possible explanations.
*This* mechanism of decades of research behind it, though. If it were the first study of its kind, sure, I'd be more cautious. When a well-known and previously amply demonstrated mechanism occurs again, the intrinsic inability to perform true experiments is less of a disclaimer.
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.