Quite stark, but there's obviously some genetic confounding. How much is really causal? Data like these cannot answer the question.https://twitter.com/WilcoxNMP/status/576223336109309952 …
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
Protip: the precautionary principle sucks. Risk aversion causes huge mostly unseen losses in innovation etc.
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.